High barrier multilayer packaging by the coextrusion method: The effect of nanocomposites and biodegradable polymers on flexible film properties

NASA Astrophysics Data System (ADS)

Thellen, Christopher T.

The objective of this research was to investigate the use of nanocomposite and multilayer co-extrusion technologies for the development of high gas barrier packaging that is more environmentally friendly than many current packaging system. Co-extruded bio-based and biodegradable polymers that could be composted in a municipal landfill were one direction that this research was aimed. Down-gauging of high performance barrier films using nanocomposite technology and co-extrusion was also investigated in order to reduce the amount of solid waste being generated by the packaging. Although the research is focused on military ration packaging, the technologies could easily be introduced into the commercial flexible packaging market. Multilayer packaging consisting of poly(m-xylylene adipamide) nanocomposite layers along with adhesive and tie layers was co-extruded using both laboratory and pilot-scale film extrusion equipment. Co-extrusion of biodegradable polyhydroxyalkanoates (PHA) along with polyvinyl alcohol (PVOH) and tie layers was also accomplished using similar co-extrusion technology. All multilayer films were characterized for gas barrier, mechanical, and thermal properties. The biodegradability of the PVOH and PHA materials in a marine environment was also investigated. The research has shown that co-extrusion of these materials is possible at a research and pilot level. The use of nanocomposite poly(m-xylylene adipamide) was effective in down-gauging the un-filled barrier film to thinner structures. Bio-based PHA/PVOH films required the use of a malefic anhydride grafted PHA tie layer to improve layer to layer adhesion in the structure to avoid delamination. The PHA polymer demonstrated a high rate of biodegradability/mineralization in the marine environment while the rate of biodegradation of the PVOH polymer was slower.

Impact of solids retention time on dissolved organic nitrogen and its biodegradability in treated wastewater.

PubMed

Simsek, Halis; Kasi, Murthy; Ohm, Jae-Bom; Murthy, Sudhir; Khan, Eakalak

2016-04-01

Dissolved organic nitrogen (DON) and its biodegradability in treated wastewater have recently gained attention due to increased regulatory requirements on effluent quality to protect receiving waters. Laboratory scale chemostat experiments were conducted at 9 different solids retention times (SRTs) (0.3, 0.7, 2, 3, 4, 5, 7, 8, and 13 days) to examine whether SRT could be used to control DON, biodegradable DON (BDON), and DON biodegradability (BDON/DON) levels in treated wastewater. Results indicated no trend between effluent DON and SRTs. Effluent BDON was comparable for SRTs of 0.3-4 days and had a decreasing trend with SRT after that. Effluent DON biodegradability (effluent BDON/effluent DON) ranging from 23% to 59% tended to decrease with SRT. Chemostat during longer SRTs, however, was contributing to non-biodegradable DON (NBDON) and this fraction of DON increased with SRT above 4 days. Model calibration results indicated that ammonification rate, and growth rates for ordinary heterotrophs, ammonia oxidizing bacteria and nitrite oxidizing bacteria were not constants but have a decreasing trend with increasing SRT. This study indicates the benefit of high SRTs in term of producing effluent with less DON biodegradability leading to relatively less oxygen consumption and nutrient support in receiving waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Geochemistry of Dissolved Organic Matter in a Spatially Highly Resolved Groundwater Petroleum Hydrocarbon Plume Cross-Section.

PubMed

Dvorski, Sabine E-M; Gonsior, Michael; Hertkorn, Norbert; Uhl, Jenny; Müller, Hubert; Griebler, Christian; Schmitt-Kopplin, Philippe

2016-06-07

At numerous groundwater sites worldwide, natural dissolved organic matter (DOM) is quantitatively complemented with petroleum hydrocarbons. To date, research has been focused almost exclusively on the contaminants, but detailed insights of the interaction of contaminant biodegradation, dominant redox processes, and interactions with natural DOM are missing. This study linked on-site high resolution spatial sampling of groundwater with high resolution molecular characterization of DOM and its relation to groundwater geochemistry across a petroleum hydrocarbon plume cross-section. Electrospray- and atmospheric pressure photoionization (ESI, APPI) ultrahigh resolution mass spectrometry (FT-ICR-MS) revealed a strong interaction between DOM and reactive sulfur species linked to microbial sulfate reduction, i.e., the key redox process involved in contaminant biodegradation. Excitation emission matrix (EEM) fluorescence spectroscopy in combination with Parallel Factor Analysis (PARAFAC) modeling attributed DOM samples to specific contamination traits. Nuclear magnetic resonance (NMR) spectroscopy evaluated the aromatic compounds and their degradation products in samples influenced by the petroleum contamination and its biodegradation. Our orthogonal high resolution analytical approach enabled a comprehensive molecular level understanding of the DOM with respect to in situ petroleum hydrocarbon biodegradation and microbial sulfate reduction. The role of natural DOM as potential cosubstrate and detoxification reactant may improve future bioremediation strategies.

Anaerobic biodegradability of fish remains: experimental investigation and parameter estimation.

PubMed

Donoso-Bravo, Andres; Bindels, Francoise; Gerin, Patrick A; Vande Wouwer, Alain

2015-01-01

The generation of organic waste associated with aquaculture fish processing has increased significantly in recent decades. The objective of this study is to evaluate the anaerobic biodegradability of several fish processing fractions, as well as water treatment sludge, for tilapia and sturgeon species cultured in recirculated aquaculture systems. After substrate characterization, the ultimate biodegradability and the hydrolytic rate were estimated by fitting a first-order kinetic model with the biogas production profiles. In general, the first-order model was able to reproduce the biogas profiles properly with a high correlation coefficient. In the case of tilapia, the skin/fin, viscera, head and flesh presented a high level of biodegradability, above 310 mLCH₄gCOD⁻¹, whereas the head and bones showed a low hydrolytic rate. For sturgeon, the results for all fractions were quite similar in terms of both parameters, although viscera presented the lowest values. Both the substrate characterization and the kinetic analysis of the anaerobic degradation may be used as design criteria for implementing anaerobic digestion in a recirculating aquaculture system.

Kinetics of Substrate Biodegradation under the Cumulative Effects of Bioavailability and Self-Inhibition.

PubMed

Gharasoo, Mehdi; Centler, Florian; Van Cappellen, Philippe; Wick, Lukas Y; Thullner, Martin

2015-05-05

Microbial degradation is an important process in many environments controlling for instance the cycling of nutrients or the biodegradation of contaminants. At high substrate concentrations toxic effects may inhibit the degradation process. Bioavailability limitations of a degradable substrate can therefore either improve the overall dynamics of degradation by softening the contaminant toxicity effects to microorganisms, or slow down the biodegradation by reducing the microbial access to the substrate. Many studies on biodegradation kinetics of a self-inhibitive substrate have mainly focused on physiological responses of the bacteria to substrate concentration levels without considering the substrate bioavailability limitations rising from different geophysical and geochemical dynamics at pore-scale. In this regard, the role of bioavailability effects on the kinetics of self-inhibiting substrates is poorly understood. In this study, we theoretically analyze this role and assess the interactions between self-inhibition and mass transfer-limitations using analytical/numerical solutions, and show the findings practical relevance for a simple model scenario. Although individually self-inhibition and mass-transfer limitations negatively impact biodegradation, their combined effect may enhance biodegradation rates above a concentration threshold. To our knowledge, this is the first theoretical study describing the cumulative effects of the two mechanisms together.

The abundance and distribution of diamondoids in biodegraded oils from the San Joaquin Valley: Implications for biodegradation of diamondoids in petroleum reservoirs

USGS Publications Warehouse

Wei, Z.; Moldowan, J.M.; Peters, K.E.; Wang, Y.; Xiang, W.

2007-01-01

The biodegradability of diamondoids was investigated using a collection of crude oil samples from the San Joaquin Valley, California, that had been biodegraded to varying extent in the reservoir. Our results show that diamondoids are subjected to biodegradation, which is selective as well as stepwise. Adamantanes are generally more susceptible to biodegradation than other diamondoids, such as diamantanes and triamantanes. We report a possible pathway for the microbial degradation of adamantane. This cage hydrocarbon possibly breaks down to a metabolic intermediate through the action of microbes at higher levels of biodegradation in petroleum reservoirs. Microbial alteration has only a minor effect on diamondoid abundance in oil at low levels of biodegradation. Our results suggest that most diamondoids (with the exception of adamantane) are resistant to biodegradation, like the polycyclic terpanes (e.g. C19-C24 tricyclic terpanes, hopanes, gammacerane, oleananes, Ts, Tm, C29 Ts), steranes and diasteranes. Microbial alteration of diamondoids has a negligible impact on the quantification of oil cracking achieved using the diamondoid-biomarker method. ?? 2007 Elsevier Ltd. All rights reserved.

Polymeric micelles with ionic cores containing biodegradable cross-links for delivery of chemotherapeutic agents.

PubMed

Kim, Jong Oh; Sahay, Gaurav; Kabanov, Alexander V; Bronich, Tatiana K

2010-04-12

Novel functional polymeric nanocarriers with ionic cores containing biodegradable cross-links were developed for delivery of chemotherapeutic agents. Block ionomer complexes (BIC) of poly(ethylene oxide)-b-poly(methacylic acid) (PEO-b-PMA) and divalent metal cations (Ca(2+)) were utilized as templates. Disulfide bonds were introduced into the ionic cores by using cystamine as a biodegradable cross-linker. The resulting cross-linked micelles with disulfide bonds represented soft, hydrogel-like nanospheres and demonstrated a time-dependent degradation in the conditions mimicking the intracellular reducing environment. The ionic character of the cores allowed to achieve a very high level of doxorubicin (DOX) loading (50% w/w) into the cross-linked micelles. DOX-loaded degradable cross-linked micelles exhibited more potent cytotoxicity against human A2780 ovarian carcinoma cells as compared to micellar formulations without disulfide linkages. These novel biodegradable cross-linked micelles are expected to be attractive candidates for delivery of anticancer drugs.

Biodegradable DNA Nanoparticles that Provide Widespread Gene Delivery in the Brain

PubMed Central

Mastorakos, Panagiotis; Song, Eric; Zhang, Clark; Berry, Sneha; Park, Hee Won; Kim, Young Eun; Park, Jong Sung; Lee, Seulki; Suk, Jung Soo; Hanes, Justin

2016-01-01

Successful gene therapy of neurological disorders is predicated on achieving widespread and uniform transgene expression throughout the affected disease area in the brain. However, conventional gene vectors preferentially travel through low-resistance perivascular spaces and/or are confined to the administration site even with the aid of a pressure-driven flow provided by convection-enhanced delivery. Biodegradable DNA nanoparticles offer a safe gene delivery platform devoid of adverse effects associated with virus-based or synthetic non-biodegradable systems. Using a state-of-the-art biodegradable polymer, poly(β-amino ester), we engineered colloidally stable sub-100 nm DNA nanoparticles coated with a non-adhesive polyethylene glycol corona that are able to avoid the adhesive and steric hindrances imposed by the extracellular matrix. Following convection enhanced delivery, these brain-penetrating nanoparticles were able to homogeneously distribute throughout the rodent striatum and mediate widespread and high-level transgene expression. These nanoparticles provide a biodegradable DNA nanoparticle platform enabling uniform transgene expression patterns in vivo and hold promise for the treatment of neurological diseases. PMID:26680637

Response of microbial growth to orthophosphate and organic carbon influx in copper and plastic based plumbing water systems.

PubMed

Park, Se-Keun; Kim, Yeong-Kwan; Choi, Sung-Chan

2008-07-01

Consequences of orthophosphate addition for corrosion control in water distribution pipes with respect to microbial growth were investigated using batch and dynamic tests. Batch tests showed that the release of copper in either low or high organic carbon content water was decreased by 69% and 56% with addition 206 microg PO(4)-P, respectively. Dosing of orthophosphate against corrosion did not increase microbial growth potential in the water and in the biofilm in both corroded and uncorroded systems receiving tap water with a low content of organic carbon and of biodegradable organic fraction. However, in tap water having a high concentration of organic carbon from acetate addition, orthophosphate addition promoted the growth of bacteria, allowed more bacteria to assemble on corroded and uncorroded surfaces, and increased the consumption of organic carbon. Orthophosphate consumption did not exceed 1% of the amount of easily biodegradable organic carbon required for microbial growth, and the orthophosphate demand for corrosion control greatly exceeded the nutritional requirement of microbial growth. The results of the dynamic tests demonstrated that there was a significant effect of interaction between biodegradable organic carbon and orthophosphate on biofilm growth, whereby the effect of orthophosphate flux on microbial growth was dependent on the levels of biodegradable organic carbon. Controlling an easily biodegradable organic carbon would be therefore necessary to minimize the microbial growth potential induced by orthophosphate-based anticorrosion treatment.

Potential for natural and enhanced attenuation of sulphanilamide in a contaminated chalk aquifer.

PubMed

Bennett, Karen A; Kelly, Simon D; Tang, Xiangyu; Reid, Brian J

2017-12-01

Understanding antibiotic biodegradation is important to the appreciation of their fate and removal from the environment. In this research an Isotope Ratio Mass Spectrometry (IRMS) method was developed to evaluate the extent of biodegradation of the antibiotic, sulphanilamide, in contaminated groundwater. Results indicted an enrichment in δ 13 C of 8.44‰ from -26.56 (at the contaminant source) to -18.12‰ (300m downfield of the source). These results confirm reductions in sulphanilamide concentrations (from 650 to 10mg/L) across the contaminant plume to be attributable to biodegradation (56%) vs. other natural attenuation processes, such as dilution or dispersion (42%). To understand the controls on sulphanilamide degradation ex-situ microcosms assessed the influence of sulphanilamide concentration, redox conditions and an alternative carbon source. Results indicated, high levels of anaerobic capacity (~50% mineralisation) to degrade sulphanilamide under high (263mg/L), moderate (10mg/L) and low (0.02mg/L) substrate concentrations. The addition of electron acceptors; nitrate and sulphate, did not significantly enhance the capacity of the groundwater to anaerobically biodegrade sulphanilamide. Interestingly, where alternative carbon sources were present, the addition of nitrate and sulphate inhibited sulphanilamide biodegradation. These results suggest, under in-situ conditions, when a preferential carbon source was available for biodegradation, sulphanilamide could be acting as a nitrogen and/or sulphur source. These findings are important as they highlight sulphanilamide being used as a carbon and a putative nitrogen and sulphur source, under prevailing iron reducing conditions. Copyright © 2017. Published by Elsevier B.V.

Acquisition of the Concept "Biodegradable" Through Written Instruction: Pretest and Age Effects.

ERIC Educational Resources Information Center

Arganian, Mourad P.; And Others

The primary purpose of this study/experiment was to determine whether children in the middle elementary grades would be able to learn the concepts "biodegradable agent,""biodegradable material," and "biodegradable process" from a short written lesson. Secondary purposes were to examine the degree to which a pretest, grade level, and sex of the…

Evaluation of Toxicity and Biodegradability of Cholinium Amino Acids Ionic Liquids

PubMed Central

Hou, Xue-Dan; Liu, Qiu-Ping; Smith, Thomas J.; Li, Ning; Zong, Min-Hua

2013-01-01

Cholinium amino acid ionic liquids ([Ch][AA] ILs), which are wholly composed of renewable biomaterials, have recently been demonstrated to have very promising properties for applications in organic synthesis and biomass pretreatment. In this work, the toxicity of these ILs toward enzymes and bacteria was assessed, and the effect of the anion on these properties is discussed. The inhibitory potentials of this type of ILs to acetylcholinesterase were weaker approximately an order of magnitude than the traditional IL 1-butyl-3-methylimidazolium tetrafluoroborate. Additionally, the [Ch][AA] ILs displayed low toxicity toward the bacteria tested. Furthermore, the biodegradability of the [Ch][AA] ILs was evaluated via the closed bottle and CO2 headspace tests using wastewater microorganisms. All the ILs were classified as ‘readily biodegradable’ based on their high levels of mineralization (62-87%). The presence of extra carboxyl or amide groups on the amino acid side chain rendered the ILs significantly more susceptible to microbial breakdown. In addition, for most of the [Ch][AA] ILs, low toxicity correlated with good biodegradability. The low toxicity and high biodegradability of these novel [Ch][AA] make them promising candidates for use as environmentally friendly solvents in large-scale applications. PMID:23554985

Biodegradation of Ochratoxin A by Aspergillus tubingensis Isolated from Meju.

PubMed

Cho, Sung Min; Jeong, Seong Eun; Lee, Kyu Ri; Sudhani, Hemanth P K; Kim, Myunghee; Hong, Sung-Yong; Chung, Soo Hyun

2016-10-28

Ochratoxin A (OTA), a mycotoxin, contaminates agricultural products and poses a serious threat to public health worldwide. Microbiological methods are known to be a promising approach for OTA biodegradation because physical and chemical methods have practical limitations. In the present study, a total of 130 fungal isolates obtained from 65 traditional Korean meju (a fermented starter for fermentation of soybeans) samples were examined for OTA-biodegradation activity using thin-layer chromatography. Two fungal isolates were selected for OTA-biodegradation activity and were identified as Aspergillus tubingensis M036 and M074 through sequence analysis of the beta-tubulin gene. After culturing both A. tubingensis isolates in Soytone-Czapek medium containing OTA (40 ng/ml), OTA-biodegradation activity was analyzed using high-performance liquid chromatography (HPLC). Both A. tubingensis strains degraded OTA by more than 95.0% after 14 days, and the HPLC analysis showed that the OTA biodegradation by the A. tubingensis strains led to the production of ochratoxin α, which is much less toxic than OTA. Moreover, crude enzymes from the cultures of A. tubingensis M036 and M074 led to OTA biodegradation of 97.5% and 91.3% at pH 5, and 80.3% and 75.3% at pH 7, respectively, in a buffer solution containing OTA (40 ng/ml) after 24 h. In addition, the OTA-biodegrading fungi did not exhibit OTA production activity. Our data suggest that A. tubingensis isolates and their enzymes have the potential for practical application to reduce levels of OTA in food and feed.

Determination of biodegradability kinetics of RCRA compounds using respirometry for structure-activity relationships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tabak, H.H.; Desai, S.; Govind, R.

1990-01-01

Electrolytic respirometry is attaining prominence in biodegradation studies and is becoming one of the more suitable experimental methods for measuring the biodegradability and the kinetics of biodegradation of toxic organic compounds by the sewage, sludge, and soil microbiota and for determining substrate inhibitory effects to microorganisms in wastewater treatment systems. The purpose of the study was to obtain information on biological treatability of the benzene, phenol, phthalate, ketone organics and of the Superfund CERCLA organics bearing wastes in wastewater treatment systems which will support the development of an EPA technical guidance document on the discharge of the above organics tomore » POTWs. The paper discusses the experimental design and procedural steps for the respirometric biodegradation and toxicity testing approach for individual organics or specific industrial wastes at different concentration levels in a mineral salts medium. A developed multi-level protocol is presented for determination of the biodegradability, microbial acclimation to toxic substrates and first order kinetic parameters of biodegradation for estimation of the Monod kinetic parameter of toxic organic compounds, in order to correlate the extent and rate of biodegradation with a predictive model based on chemical properties and molecular structure of these compounds. Respirometric biodegradation/inhibition and biokinetic data are provided for representative RCRA alkyl benzene and ketone organics.« less

Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments.

PubMed

Khan, Ali M; Wick, Lukas Y; Harms, Hauke; Thullner, Martin

2016-04-01

Biodegradation of organic chemicals in the vapor phase of soils and vertical flow filters has gained attention as promising approach to clean up volatile organic compounds (VOC). The drivers of VOC biodegradation in unsaturated systems however still remain poorly understood. Here, we analyzed the processes controlling aerobic VOC biodegradation in a laboratory setup mimicking the unsaturated zone above a shallow aquifer. The setup allowed for diffusive vapor-phase transport and biodegradation of three VOC: non-deuterated and deuterated toluene as two compounds of highly differing biodegradability but (nearly) identical physical and chemical properties, and MTBE as (at the applied experimental conditions) non-biodegradable tracer and internal control. Our results showed for toluene an effective microbial degradation within centimeter VOC transport distances despite high gas-phase diffusivity. Degradation rates were controlled by the reactivity of the compounds while oxic conditions were found everywhere in the system. This confirms hypotheses that vadose zone biodegradation rates can be extremely high and are able to prevent the outgassing of VOC to the atmosphere within a centimeter range if compound properties and site conditions allow for sufficiently high degradation rates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of diclofenac from a non-sterile aqueous system using Trametes versicolor with an emphasis on adsorption and biodegradation mechanisms.

PubMed

Stenholm, Åke; Hedeland, Mikael; Arvidsson, Torbjörn; Pettersson, Curt E

2018-03-04

This paper describes the search for procedures through which the xenobiotic pollutant diclofenac can be removed from non-sterile aquatic systems. Specifically, adsorption to solid supports (carriers) in combination with biodegradation by non-immobilized and immobilized white rot fungus Trametes versicolor were investigated. Batch experiments using polyurethane foam (PUF)-carriers resulted in 99.9% diclofenac removal after 4 h, with monolayer adsorption of diclofenac to carrier and glass surfaces accounting for most of the diclofenac decrease. Enzymatic reactions contributed less, accounting for approximately < 0.5% of this decrease. In bioreactor experiments using PUF-carriers, an initial 100% removal was achieved with biodegradation contributing approximately 7%. In batch experiments that utilized polyethylene-carriers with negligible immobilization of Trametes versicolor, a 98% total diclofenac removal was achieved after one week, with a biodegradation contribution of approximately 14%. Five novel enzyme-catalyzed biodegradation products were tentatively identified in the batch-wise and bioreactor experiments using full scan ultra-high-performance liquid chromatography-quadrupole/time of flight mass spectrometry. Both reduction and oxidation products were found, with the contents estimated to be at µg L -1 concentration levels.

Impact of formation water geochemistry and crude oil biodegradation on microbial methanogenesis

USGS Publications Warehouse

Shelton, Jenna L.; McIntosh, Jennifer C.; Warwick, Peter D.; McCray, John E.

2016-01-01

Shallow wells (393–442 m depth) contained highly biodegraded oils associated with low extent of methanogenesis, while the deepest (> 1208 m) wells contained minimally degraded oils and produced fluids suggesting a low extent of methanogenesis. Mid-depth wells (666–857 m) in the central field had the highest indicators of methanogenesis and contained moderately biodegraded oils. Little correlation existed between extents of crude oil biodegradation and methanogenesis across the whole transect (avg.R2 = 0.13). However, when wells with the greatest extent of crude oil biodegradation were eliminated (3 of 6 oilfields), better correlation between extent of methanogenesis and biodegradation (avg. R2 = 0.53) was observed. The results suggest that oil quality and salinity impact methanogenic crude oil biodegradation. Reservoirs indicating moderate extent of crude oil biodegradation and high extent of methanogenesis, such as the central field, would be good candidates for attempting to enhance methanogenic crude oil biodegradation as a result of the observations from the study.

Review of Concrete Biodeterioration in Relation to Buried Nuclear Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turick, C; Berry, C.

Long-term storage of low level radioactive material in below ground concrete disposal units (DUs) (Saltstone Disposal Facility) is a means of depositing wastes generated from nuclear operations of the U.S. Department of Energy. Based on the currently modeled degradation mechanisms, possible microbial induced effects on the structural integrity of buried low level wastes must be addressed. Previous international efforts related to microbial impacts on concrete structures that house low level radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the recent research in thismore » field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete vaults housing stored wastes and the wastes themselves. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources like components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The results of this review suggest that microbial activity in Saltstone, (grouted low level radioactive waste) is unlikely due to very high pH and osmotic pressure. Biodegradation of the concrete vaults housing the radioactive waste however, is a possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Results from this review point to parameters to focus on for modeling activities and also, possible options for mitigation that would minimize concrete biodegradation. In addition, key chemical components that drive microbial activity on concrete surfaces are discussed.« less

Enhancing biodegradation of C16-alkyl quaternary ammonium compounds using an oxygen-based membrane biofilm reactor.

PubMed

Lai, YenJung Sean; Ontiveros-Valencia, Aura; Ilhan, Zehra Esra; Zhou, Yun; Miranda, Evelyn; Maldonado, Juan; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

2017-10-15

Quaternary ammonium compounds (QACs) (e.g., hexadecyltrimethyl-ammonium bromide, CTAB) are emerging contaminants with widespread use as surfactants and disinfectants. Because the initial step of QAC biodegradation is mono-oxygenation, QAC degraders require O 2 , but normal aeration leads to serious foaming. Here, we developed and tested an oxygen-based membrane biofilm reactor (O 2 -MBfR) that delivers O 2 by diffusion through the walls of hollow-membranes to a biofilm accumulating on the outer surface of membranes. The O 2 -MBfR sustained QAC biodegradation even with high and toxic QAC input concentrations, up to 400 mg/L CTAB. Bubbleless O 2 transfer completely eliminated foaming, and biofilm accumulation helped the QAC biodegraders resist toxicity. Pseudomonas, Achromobacter, Stenotrophomonas, and members of the Xanthomonadaceae family were dominant in the biofilm communities degrading CTAB, and their proportions depended on the O 2 -delivery capacity of the membranes. Bacteria capable of biodegrading QACs often harbor antibiotic resistance genes (ARGs) that help them avoid QAC toxicity. Gene copies of ARGs were detected in biofilms and liquid, but the levels of ARGs were 5- to 35-fold lower in the liquid than in the biofilm. In summary, the O 2 -MBfR achieved aerobic biodegradation of CTAB with neither foaming nor toxicity, and it also minimized the spread of ARGs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradation of PAHs and PCBs in soils and sludges

USGS Publications Warehouse

Liu, L.; Tindall, J.A.; Friedel, M.J.

2007-01-01

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in soil/water systems, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals on remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges during long-term biotreatment, this model comprises a kinetic equation for organic chemical intraparticle sequestration process. Model responses were verified by comparison to measurements of biodegradation of PAHs and PCBs in land treatment units; a favorable match was found between them. Model simulations were performed to predict on-going biodegradation behavior of PAHs and PCBs in land treatment units. Simulation results indicate that complete biostabilization will be achieved when the concentration of reversibly sorbed chemical (S RA) reduces to undetectable levels, with a certain amount of irreversibly sequestrated residual chemical (S IA) remaining within the soil particle solid phase. The residual fraction (S IA) tends to lose its original chemical and biological activity, and hence, is much less available, toxic, and mobile than the "free" compounds. Therefore, little or no PAHs and PCBs will leach from the treatment site and constitutes no threat to human health or the environment. Biotreatment of PAHs and PCBs can be terminated accordingly. Results from the pilot-scale testing data and model calculations also suggest that a significant fraction (10-30%) of high-molecular-weight PAHs and PCBs could be sequestrated and become unavailable for biodegradation. Bioavailability (large K d , i.e., slow desorption rate) is the key factor limiting the PAHs degradation. However, both bioavailability and bioactivity (K in Monod kinetics, i.e., number of microbes, nutrients, and electron acceptor, etc.) regulate PCBs biodegradation. The sequential active-passive biotreatment can be a cost-effective approach for remediation of highly hydrophobic organic contaminants. The mathematical model proposed here would be useful in the design and operation of such organic chemical biodegradation processes on remediation sites. ?? 2007 Springer Science+Business Media B.V.

Comparison of methane production potential, biodegradability, and kinetics of different organic substrates.

PubMed

Li, Yeqing; Zhang, Ruihong; Liu, Guangqing; Chen, Chang; He, Yanfeng; Liu, Xiaoying

2013-12-01

The methane production potential, biodegradability, and kinetics of a wide range of organic substrates were determined using a unified and simple method. Results showed that feedstocks that contained high energy density and easily degradable substrates exhibited high methane production potential and biodegradability. Lignocellulosic biomass with high content of fibrous compositions had low methane yield and biodegradability. Feedstocks with high lignin content (≥ 15%, on a TS basis) had low first-order rate constant (0.05-0.06 1/d) compared to others. A negative linear correlation between lignin content and experimental methane yield (or biodegradability) was found for lignocellulosic and manure wastes. This could be used as a fast method to predict the methane production potential and biodegradability of fiber-rich substrates. The findings of this study provided a database for the conversion efficiency of different organic substrates and might be useful for applications of biomethane potential assay and anaerobic digestion in the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Progress on biodegradation of polylactic acid--a review].

PubMed

Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

2008-02-01

Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes.

Biodegradability of organic nanoparticles in the aqueous environment.

PubMed

Kümmerer, Klaus; Menz, Jakob; Schubert, Thomas; Thielemans, Wim

2011-03-01

Synthetic nanoparticles have already been detected in the aquatic environment. Therefore, knowledge on their biodegradability is of utmost importance for risk assessment but such information is currently not available. Therefore, the biodegradability of fullerenes, single, double, multi-walled as well as COOH functionalized carbon nanotubes and cellulose and starch nanocrystals in aqueous environment has been investigated according to OECD standards. The biodegradability of starch and cellulose nanoparticles was also compared with the biodegradability of their macroscopic counterparts. Fullerenes and all carbon nanotubes did not biodegrade at all, while starch and cellulose nanoparticles biodegrade to similar levels as their macroscopic counterparts. However, neither comfortably met the criterion for ready biodegradability (60% after 28 days). The cellulose and starch nanoparticles were also found to degrade faster than their macroscopic counterparts due to their higher surface area. These findings are the first report of biodegradability of organic nanoparticles in the aquatic environment, an important accumulation environment for manmade compounds. Copyright © 2010 Elsevier Ltd. All rights reserved.

Mechanical properties, biocompatibility, and biodegradation of cross-linked cellulose acetate-reinforced polyester composites.

PubMed

Wu, Chin-San

2014-05-25

Composites of treated (cross-linked) cellulose acetate (t-CA) and acrylic acid-grafted poly(hydroxyalkanoate) (PHA-g-AA/t-CA) exhibited noticeably superior mechanical properties compared with PHA/CA composites due to greater compatibility between the two components. The dispersion covering of t-CA in the PHA-g-AA matrix was highly homogeneous as a result of condensation reactions. Human lung fibroblasts (FBs) were seeded on these two series of composites to characterize the biocompatibility properties. In a time-dependent course, the FB proliferation results demonstrated higher performance from the PHA/CA series of composites than from the PHA-g-AA/t-CA composites. The water resistance of PHA-g-AA/t-CA was higher than that of PHA/CA, although the weight loss of both composites buried in Acetobacter pasteurianus (A. pasteurianus) indicated that they were both biodegradable, especially at higher levels of cellulose acetate substitution. The PHA/CA and PHA-g-AA/t-CA composites were more biodegradable than pure PHA, implying a strong connection between cellulose acetate content and biodegradability. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biodegradable nanostructures with selective lysis of microbial membranes

NASA Astrophysics Data System (ADS)

Nederberg, Fredrik; Zhang, Ying; Tan, Jeremy P. K.; Xu, Kaijin; Wang, Huaying; Yang, Chuan; Gao, Shujun; Guo, Xin Dong; Fukushima, Kazuki; Li, Lanjuan; Hedrick, James L.; Yang, Yi-Yan

2011-05-01

Macromolecular antimicrobial agents such as cationic polymers and peptides have recently been under an increased level of scrutiny because they can combat multi-drug-resistant microbes. Most of these polymers are non-biodegradable and are designed to mimic the facially amphiphilic structure of peptides so that they may form a secondary structure on interaction with negatively charged microbial membranes. The resulting secondary structure can insert into and disintegrate the cell membrane after recruiting additional polymer molecules. Here, we report the first biodegradable and in vivo applicable antimicrobial polymer nanoparticles synthesized by metal-free organocatalytic ring-opening polymerization of functional cyclic carbonate. We demonstrate that the nanoparticles disrupt microbial walls/membranes selectively and efficiently, thus inhibiting the growth of Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and fungi, without inducing significant haemolysis over a wide range of concentrations. These biodegradable nanoparticles, which can be synthesized in large quantities and at low cost, are promising as antimicrobial drugs, and can be used to treat various infectious diseases such as MRSA-associated infections, which are often linked with high mortality.

An assessment of biodegradability of quaternary carbon-containing fragrance compounds: comparison of experimental OECD screening test results and in silico prediction data.

PubMed

Seyfried, Markus; Boschung, Alain

2014-05-01

An assessment of biodegradability was carried out for fragrance substances containing quaternary carbons by using data obtained from Organisation for Economic Co-operation and Development (OECD) 301F screening tests for ready biodegradation and from Biowin and Catalogic prediction models. Despite an expected challenging profile, a relatively high percentage of common-use fragrance substances showed significant biodegradation under the stringent conditions applied in the OECD 301F test. Among 27 test compounds, 37% met the pass level criteria after 28 d, while another 26% indicated partial breakdown (≥20% biodegradation). For several compounds for which structural analogs were available, the authors found that structures that were rendered less water soluble by either the presence of an acetate ester or the absence of oxygen tended to degrade to a lesser extent compared to the primary alcohols or oxygenated counterparts under the test conditions applied. Difficulties were encountered when attempting to correlate experimental with in silico data. Whereas the Biowin model combinations currently recommended by regulatory agencies did not allow for a reliable discrimination between readily and nonbiodegradable compounds, only a comparably small proportion of the chemicals studied (30% and 63% depending on the model) fell within the applicability domain of Catalogic, a factor that critically reduced its predictive power. According to these results, currently neither Biowin nor Catalogic accurately reflects the potential for biodegradation of fragrance compounds containing quaternary carbons. © 2014 SETAC.

High Throughput Biodegradation-Screening Test To Prioritize and Evaluate Chemical Biodegradability.

PubMed

Martin, Timothy J; Goodhead, Andrew K; Acharya, Kishor; Head, Ian M; Snape, Jason R; Davenport, Russell J

2017-06-20

Comprehensive assessment of environmental biodegradability of pollutants is limited by the use of low throughput systems. These are epitomized by the Organisation for Economic Cooperation and Development (OECD) Ready Biodegradability Tests (RBTs), where one sample from an environment may be used to assess a chemical's ability to readily biodegrade or persist universally in that environment. This neglects the considerable spatial and temporal microbial variation inherent in any environment. Inaccurate designations of biodegradability or persistence can occur as a result. RBTs are central in assessing the biodegradation fate of chemicals and inferring exposure concentrations in environmental risk assessments. We developed a colorimetric assay for the reliable quantification of suitable aromatic compounds in a high throughput biodegradation screening test (HT-BST). The HT-BST accurately differentiated and prioritized a range of structurally diverse aromatic compounds on the basis of their assigned relative biodegradabilities and quantitative structure-activity relationship (QSAR) model outputs. Approximately 20 000 individual biodegradation tests were performed, returning analogous results to conventional RBTs. The effect of substituent group structure and position on biodegradation potential demonstrated a significant correlation (P < 0.05) with Hammett's constant for substituents on position 3 of the phenol ring. The HT-BST may facilitate the rapid screening of 100 000 chemicals reportedly manufactured in Europe and reduce the need for higher-tier fate and effects tests.

Adsorption and biodegradation of antidiabetic pharmaceuticals in soils.

PubMed

Mrozik, Wojciech; Stefańska, Justyna

2014-01-01

Pharmaceuticals are emerging contaminants in the natural environment. Most studies of the environmental fate of these chemicals focus on their behavior in wastewater treatment processes and in sewage sludge. Little is known about their behavior in soils. In this study adsorption and biodegradation of four antidiabetic pharmaceuticals - glimepiride, glibenclamide, gliclazide and metformin - were examined in three natural soils. The sorption of sulfonylurea derivatives was high (higher than sulfonylurea herbicides for example), whereas metformin showed high mobility. Desorption rates were highest for metformin. Sorption isotherms in two of three soils fitted best to the Freundlich model. Despite their high affinity to for soil surfaces, biodegradation studies revealed that transformation of the drugs occurred. Biodegradation results were described by pseudo-first order kinetics with half-life values from 5 to over 120 d (under aerobic conditions) and indicate that none of the tested drugs can be classified as quickly biodegradable. Biodegradation under anoxic conditions was much slower; often degrading by less than 50% during time of the experiment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons under anaerobic conditions: Overview of studies, proposed pathways and future perspectives.

PubMed

Nzila, Alexis

2018-05-07

The biodegradation of low- and high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) (LWM-PAHs and HMW-PAHs, respectively) has been studied extensively under aerobic conditions. Molecular O 2 plays 2 critical roles in this biodegradation process. O 2 activates the aromatic rings through hydroxylation prior to ring opening and serves as a terminal electron acceptor (TEA). However, several microorganisms have devised ways of activating aromatic rings, leading to ring opening (and thus biodegradation) when TEAs other than O 2 are used (under anoxic conditions). These microorganisms belong to the sulfate-, nitrate-, and metal-ion-reducing bacteria and the methanogens. Although the anaerobic biodegradation of monocyclic aromatic hydrocarbons and LWM-PAH naphthalene have been studied, little information is available about the biodegradation of HMW-PAHs. This manuscript reviews studies of the anaerobic biodegradation of HMW-PAHs and identifies gaps that limit both our understanding and the efficiency of this biodegradation process. Strategies that can be employed to overcome these limitations are also discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Drug-laden 3D biodegradable label using QR code for anti-counterfeiting of drugs.

PubMed

Fei, Jie; Liu, Ran

2016-06-01

Wiping out counterfeit drugs is a great task for public health care around the world. The boost of these drugs makes treatment to become potentially harmful or even lethal. In this paper, biodegradable drug-laden QR code label for anti-counterfeiting of drugs is proposed that can provide the non-fluorescence recognition and high capacity. It is fabricated by the laser cutting to achieve the roughness over different surface which causes the difference in the gray levels on the translucent material the QR code pattern, and the micro mold process to obtain the drug-laden biodegradable label. We screened biomaterials presenting the relevant conditions and further requirements of the package. The drug-laden microlabel is on the surface of the troches or the bottom of the capsule and can be read by a simple smartphone QR code reader application. Labeling the pill directly and decoding the information successfully means more convenient and simple operation with non-fluorescence and high capacity in contrast to the traditional methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Degradation of Nitroguanidine in Soils

DTIC Science & Technology

1985-01-01

columns. Nitroguanidine was biodegraded if sufficient supplemental carbon was provided in the wastewater. The primary product formed during the... biodegradation of nitroguanidine in soil was ammonia. Only trace concentration of nitrosoguanidine were detected and no significant levels of other organic...low cost treatment option for these wastewaters. In addition, preliminary work was performed to evaluate the biodegradability of guanidine nitrate

Characterization and prediction of organic nitrogen biodegradability during anaerobic digestion: A bioaccessibility approach.

PubMed

Bareha, Y; Girault, R; Jimenez, J; Trémier, A

2018-04-26

Prediction of organic nitrogen mineralization into ammonium during anaerobic digestion is required for optimizing substitution of mineral fertilizer by digestates. The aim of this study was to understand organic nitrogen biodegradability and to investigate how it can be predicted from carbon biodegradability, and nitrogen bioaccessibility, respectively. Bioaccessibility was assessed using fractionation methods based on sequential extractions. Results showed that organic nitrogen was present in fractions whose bioaccessibility levels differed. Organic nitrogen and carbon biodegradability were also determined and compared. Results highlighted two groups of substrates: the first with an initial NH 4 + /TKN < 30%, whose carbon and nitrogen biodegradability are similar; the second with an initial NH 4 + /TKN > 30%, whose carbon and nitrogen biodegradability differ significantly. To enable prediction on all substrates, partial least square (PLS) regressions were carried out to link organic nitrogen bioaccessibility indicators to biodegradability. The models successfully predicted organic nitrogen biodegradability with a maximum prediction error of 10%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Organic wastes decomposition technology, perspective for long-term autonomous missions

NASA Astrophysics Data System (ADS)

Viacheslav, Ilyin; Korshunov, Denis; Mardanov, Robert; Starkova, Lyubov; Deshevaya, Elena; Smirnov, Igor

At present time there is no large problem in waste management in ISS space flight conditions, since spacecrafts "Progress" is used for it's removal from orbital station and the wastes burns in dense layers of Earth's atmosphere. However such method does not approach for far inter-planetary flights since interplanetary quarantine desires do not allow to deposit contaminated wastes outside the spacecraft. Essential part of wastes is formed by disposed means of personal hygiene and greenhouse wastes which are not safe from sanitary-epidemiological aspect. Above mentioned materials have one common feature: they can be subjected to biodegradation using different microbial compositions. Microbial decomposition of wastes as meets the main crite-ria of safety and power consumption. We investigated the effectiveness of method of disposed personal hygiene means biodegradation by anaerobic thermophiles with further purification of obtained decomposition products from chemical solvents with the help of mesophilic isolates in microaerophile conditions. Bacteria of Clostridium genera were selected for cellulolysis be-cause of their high specific endoglucanasic activity which less depends on substrate nature and relatively high growth rate on cellulose contaning substrates. As result some strains in case of optimal conditions (substrata pretreating, pH correction) decomposed means of personal hygiene with level of biodegradation up to 90With the purpose of purification, liqiud medi-ums originating from Closrtidium sp. exhibiting used like substrates for cellololitic fungi. It was shown that the cultures are able to change pH of media from slow-acid to neutral. Also the effectiveness of plant wastes biodegradation (vegetables homogenates) was studied using associations of mesophile aerobes trophically adapted to substrates. Rate of biodestruction of dry mass varied near 76To purify liquid products of biodegradation from chemicals cellulolytic fungal strains as well as bacterial mesophylic association was used. Prevalence of cultures for purification was depended on pH of culture liquors. Chemical content of gaseous phase of cul-ture liquors was also studied. As it comes from chromatomass spectrometry data there was tremendous decrease of organic admixtures in liquid products of biodegradation after purifi-cation by fungal and bacterial cultures. These cultures were capable to support sustainable growth, feeding by metabolites of bacteria, which perform primary biodegradation. Also there was evaluated prospective of application of biofuel cells in the process of biotransformation of different substrates. Application of electrogenic bacteria could be perspective approach in wastes biodegradation technology.

[Biodegradation of polyethylene].

PubMed

Yang, Jun; Song, Yi-ling; Qin, Xiao-yan

2007-05-01

Plastic material is one of the most serious solid wastes pollution. More than 40 million tons of plastics produced each year are discarded into environment. Plastics accumulated in the environment is highly resistant to biodegradation and not be able to take part in substance recycle. To increase the biodegradation efficiency of plastics by different means is the main research direction. This article reviewed the recent research works of polyethylene biodegradation that included the modification and pretreatment of polyethylene, biodegradation pathway, the relevant microbes and enzymes and the changes of physical, chemical and biological properties after biodegradation. The study directions of exploiting the kinds of life-forms of biodegradation polyethylene except the microorganisms, isolating and cloning the key enzymes and gene that could produce active groups, and enhancing the study on polyethylene biodegradation without additive were proposed.

Effect of EOR-systems on the oil composition at biooxidation with native microflora of the oil reservoir

NASA Astrophysics Data System (ADS)

Ovsyannikova, Varvara S.; Shcherbakova, Anastasia G.; Altunina, Lyubov K.; Filatov, Dmitry A.

2017-12-01

The paper presents the results of laboratory experiments on the biodegradation of different oil compositions from the Usinskoye oil field in the presence of systems for enhanced oil recovery. It is shown that the oil-displacing IKhN-PRO system could be an optimal stimulating substrate to activate the biooxidation of oil with a high content of aromatic hydrocarbons, while the maximum conversion of oil with a high content of n-alkanes is observed in the presence of the oil-displacing sol-forming NINKA 3 system. A stimulating effect of the systems on the hydrocarbon-oxidizing native microflora of the oil reservoir, promoting its growth and increasing the level of oil biodegradation, could be used to enhance oil recovery, in addition to physicochemical methods.

Molecularly organic/inorganic hybrid hollow mesoporous organosilica nanocapsules with tumor-specific biodegradability and enhanced chemotherapeutic functionality.

PubMed

Huang, Ping; Chen, Yu; Lin, Han; Yu, Luodan; Zhang, Linlin; Wang, Liying; Zhu, Yufang; Shi, Jianlin

2017-05-01

Based on the intrinsic features of high stability and unique multifunctionality, inorganic nanoparticles have shown remarkable potentials in combating cancer, but their biodegradability and biocompatibility are still under debate. As a paradigm, this work successfully demonstrates that framework organic-inorganic hybridization can endow the inorganic mesoporous silica nanocarriers with unique tumor-sensitive biodegradability and high biocompatibility. Based on a "chemical homology" mechanism, molecularly organic-inorganic hybridized hollow mesoporous organosilica nanocapsules (HMONs) with high dispersity and sub-50 nm particle dimension were constructed in mass production. A physiologically active disulfide bond (SS) was directly incorporated into the silica framework, which could break up upon contacting the reducing microenvironment of tumor tissue and biodegrade accordingly. Such a tumor-specific biodegradability is also responsible for the tumor-responsive drug releasing by the fast biodegradation and disintegration of the framework. The ultrasmall particle size of HMONs guarantees their high accumulation into tumor tissue, thus causing the high chemotherapeutic outcome. This research provides a paradigm that framework organic-inorganic hybridization can endow the inorganic nanocarrier with unique biological effects suitable for biomedical application, benefiting the development of novel nanosystems with the unique bio-functionality and performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper

PubMed Central

Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W.; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

2015-01-01

Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials. PMID:26006731

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper.

PubMed

Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

2015-05-26

Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials.

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper

NASA Astrophysics Data System (ADS)

Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W.; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

2015-05-01

Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials.

Predicting ready biodegradability of premanufacture notice chemicals.

PubMed

Boethling, Robert S; Lynch, David G; Thom, Gary C

2003-04-01

Chemical substances other than pesticides, drugs, and food additives are regulated by the U.S. Environmental Protection Agency (U.S. EPA) under the Toxic Substances Control Act (TSCA), but the United States does not require that new substances be tested automatically for such critical properties as biodegradability. The resulting lack of submitted data has fostered the development of estimation methods, and the BioWIN models for predicting biodegradability from chemical structure have played a prominent role in premanufacture notice (PMN) review. Until now, validation efforts have used only the Japanese Ministry of International Trade and Industry (MITI) test data and have not included all models. To assess BioWIN performance with PMN substances, we assembled a database of PMNs for which ready biodegradation data had been submitted over the period 1995 through 2001. The 305 PMN structures are highly varied and pose major challenges to chemical property estimation. Despite the variability of ready biodegradation tests, the use of at least six different test methods, and widely varying quality of submitted data, accuracy of four of six BioWIN models (MITI linear, MITI nonlinear, survey ultimate, survey primary) was in the 80+% range for predicting ready biodegradability. Greater accuracy (>90%) can be achieved by using model estimates only when the four models agree (true for 3/4 of the PMNs). The BioWIN linear and nonlinear probability models did not perform as well even when classification criteria were optimized. The results suggest that the MITI and survey BioWIN models are suitable for use in screening-level applications.

Dilation or biodegradable stent placement for recurrent benign esophageal strictures: a randomized controlled trial.

PubMed

Walter, Daisy; van den Berg, Maarten W; Hirdes, Meike M; Vleggaar, Frank P; Repici, Alessandro; Deprez, Pierre H; Viedma, Bartolomé L; Lovat, Laurence B; Weusten, Bas L; Bisschops, Raf; Haidry, Rehan; Ferrara, Elisa; Sanborn, Keith J; O'Leary, Erin E; van Hooft, Jeanin E; Siersema, Peter D

2018-06-08

 Dilation is the standard of care for recurrent benign esophageal strictures (BES). Biodegradable stents may prolong the effect of dilation and reduce recurrences. Efficacy and safety of dilation and biodegradable stent placement early in the treatment algorithm of recurrent BES were compared.  This multicenter, randomized study enrolled patients with BES treated with previous dilations to ≥ 16 mm. The primary end point was number of repeat endoscopic dilations for recurrent stricture within 3 and 6 months. Secondary outcomes through 12 months included safety, time to first dilation for recurrent stricture, dysphagia, and level of activity.  At 3 months, the biodegradable stent group (n = 32) underwent significantly fewer endoscopic dilations for recurrent stricture compared with the dilation group (n = 34; P  < 0.001). By 6 months, the groups were similar. The number of patients experiencing adverse events was similar between the groups. Two patients in the biodegradable stent group died after developing tracheoesophageal fistulas at 95 and 96 days post-placement; no deaths were attributed to the stent. Median time to first dilation of recurrent stricture for the biodegradable stent group was significantly longer (106 vs. 41.5 days; P  = 0.003). Dysphagia scores improved for both groups. Patients in the biodegradable stent group had a significantly higher level of activity through 12 months ( P  < 0.001).  Biodegradable stent placement is associated with temporary reduction in number of repeat dilations and prolonged time to recurrent dysphagia compared with dilation. Additional studies are needed to better define the exact role of biodegradable stent placement to treat recurrent BES. © Georg Thieme Verlag KG Stuttgart · New York.

Metabolic efficiency and turnover of soil microbial communities in biodegradation tests.

PubMed Central

Shen, J; Bartha, R

1996-01-01

Biodegradability screening tests of soil commonly measure 14CO2 evolution from radiolabeled test compounds, and glucose has often served as a positive control. When constant amounts of radiolabel were added to soil in combination with increasing amounts of unlabeled substrates, glucose and some related hexoses behaved in an anomalous manner. In contrast to that of formate, benzoate, n-hexadecane, or bis(2-ethylhexyl) phthalate, dilution of glucose radiocarbon with unlabeled glucose increased rather than decreased the rate and extent of 14CO2 evolution. [14C]glucose incorporation into biomass and Vmax values were consistent with the interpretation that application of relatively high concentrations of glucose to soil shifts the balance of the soil microbial community from the autochthonous (humus-degrading) to the zymogeneous (opportunistic) segment. The higher growth and turnover rates that define zymogeneous microorganisms, combined with a lower level of carbon incorporation into their biomass, result in the evolution of disproportionate percentages of 14CO2. When used as positive controls, glucose and related hexoses may raise the expectations for percent 14CO2 evolution to levels that are not realistic for other biodegradable compounds. PMID:8779580

Characterization of the biodegradation, bioremediation and detoxification capacity of a bacterial consortium able to degrade the fungicide thiabendazole.

PubMed

Perruchon, Chiara; Pantoleon, Anastasios; Veroutis, Dimitrios; Gallego-Blanco, Sara; Martin-Laurent, F; Liadaki, Kalliopi; Karpouzas, Dimitrios G

2017-12-01

Thiabendazole (TBZ) is a persistent fungicide used in the post-harvest treatment of fruits. Its application results in the production of contaminated effluents which should be treated before their environmental discharge. In the absence of efficient treatment methods in place, biological systems based on microbial inocula with specialized degrading capacities against TBZ could be a feasible treatment approach. Only recently the first bacterial consortium able to rapidly transform TBZ was isolated. This study aimed to characterize its biodegradation, bioremediation and detoxification potential. The capacity of the consortium to mineralize 14 C-benzyl-ring labelled TBZ was initially assessed. Subsequent tests evaluated its degradation capacity under various conditions (range of pH, temperatures and TBZ concentration levels) and relevant practical scenarios (simultaneous presence of other postharvest compounds) and its bioaugmentation potential in soils contaminated with increasing TBZ levels. Finally cytotoxicity assays explored its detoxification potential. The consortium effectively mineralized the benzoyl ring of the benzimidazole moiety of TBZ and degraded spillage level concentrations of the fungicide in aqueous cultures (750 mg L -1 ) and in soil (500 mg kg -1 ). It maintained its high degradation capacity in a wide range of pH (4.5-7.5) and temperatures (15-37 °C) and in the presence of other pesticides (ortho-phenylphenol and diphenylamine). Toxicity assays using the human liver cancer cell line HepG2 showed a progressive decrease in cytotoxicity, concomitantly with the biodegradation of TBZ, pointing to a detoxification process. Overall, the bacterial consortium showed high potential for future implementation in bioremediation and biodepuration applications.

Enhanced micropollutant biodegradation and assessment of nitrous oxide concentration reduction in wastewater treated by acclimatized sludge bioaugmentation.

PubMed

Boonnorat, Jarungwit; Techkarnjanaruk, Somkiet; Honda, Ryo; Ghimire, Anish; Angthong, Sivakorn; Rojviroon, Thammasak; Phanwilai, Supaporn

2018-05-11

This research investigated the micropollutant biodegradation and nitrous oxide (N 2 O) concentration reduction in high strength wastewater treated by two-stage activated sludge (AS) systems with (bioaugmented) and without (non-bioaugmented) acclimatized sludge bioaugmentation. The bioaugmented and non-bioaugmented systems were operated in parallel for 228 days, with three levels of concentrations of organics, nitrogen, and micropollutants in the influent: conditions 1 (low), 2 (moderate), and 3 (high). The results showed that, under condition 1, both systems efficiently removed the organic and nitrogen compounds. However, the bioaugmented system was more effective in the micropollutant biodegradation and N 2 O concentration reduction than the non-bioaugmented one. Under condition 2, the nitrogen and micropollutant biodegradation efficiency of the non-bioaugmented system slightly decreased, while the N 2 O concentration declined in the bioaugmented system. Under condition 3, the treatment performance and N 2 O concentration abatement were substantially lowered as the compounds concentration increased. Further analysis also showed that the acclimatized sludge bioaugmentation increased the bacterial diversity in the system. In essence, the acclimatized sludge bioaugmentation strategy was highly effective for the influent with low compounds concentration, achieving the organics and nitrogen removal efficiencies of 92-97%, relative to 71-97% of the non-bioaugmented system. The micropollutant treatment efficiency of the bioaugmented system under condition 1 was 75-92%, indicating significant improvement in the treatment performance (p < 0.05), compared with 60-79% of the non-bioaugmented system. Copyright © 2018 Elsevier B.V. All rights reserved.

Biodegradability study of high-erucic-acid-rapeseed-oil-based lubricant additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, E.; Crawford, R.L.; Shanahan, A.

1995-12-31

A variety of high-erucic-acid-rapeseed (HEAR)-oil-based lubricants, lubricant additives, and greases were examined for biodegradability at the University of Idaho Center for Hazardous Waste Remediation Research. Two standard biodegradability tests were employed, a currently accepted US Environmental Protection Agency (EPA) protocol and the Sturm Test. As is normal for tests that employ variable inocula such as sewage as a source of microorganisms, these procedures yielded variable results from one repetition to another. However, a general trend of rapid and complete biodegradability of the HEAR-oil-based materials was observed.

The peroxidase-mediated biodegradation of petroleum hydrocarbons in a H2O2-induced SBR using in-situ production of peroxidase: Biodegradation experiments and bacterial identification.

PubMed

Shekoohiyan, Sakine; Moussavi, Gholamreza; Naddafi, Kazem

2016-08-05

A bacterial peroxidase-mediated oxidizing process was developed for biodegrading total petroleum hydrocarbons (TPH) in a sequencing batch reactor (SBR). Almost complete biodegradation (>99%) of high TPH concentrations (4g/L) was attained in the bioreactor with a low amount (0.6mM) of H2O2 at a reaction time of 22h. A specific TPH biodegradation rate as high as 44.3mgTPH/gbiomass×h was obtained with this process. The reaction times required for complete biodegradation of TPH concentrations of 1, 2, 3, and 4g/L were 21, 22, 28, and 30h, respectively. The catalytic activity of hydrocarbon catalyzing peroxidase was determined to be 1.48U/mL biomass. The biodegradation of TPH in seawater was similar to that in fresh media (no salt). A mixture of bacteria capable of peroxidase synthesis and hydrocarbon biodegradation including Pseudomonas spp. and Bacillus spp. were identified in the bioreactor. The GC/MS analysis of the effluent indicated that all classes of hydrocarbons could be well-degraded in the H2O2-induced SBR. Accordingly, the peroxidase-mediated process is a promising method for efficiently biodegrading concentrated TPH-laden saline wastewater. Copyright © 2016 Elsevier B.V. All rights reserved.

Factors affecting the distribution of hydrocarbon contaminants and hydrogeochemical parameters in a shallow sand aquifer

NASA Astrophysics Data System (ADS)

Lee, Jin-Yong; Cheon, Jeong-Yong; Lee, Kang-Kun; Lee, Seok-Young; Lee, Min-Hyo

2001-07-01

The distributions of hydrocarbon contaminants and hydrogeochemical parameters were investigated in a shallow sand aquifer highly contaminated with petroleum hydrocarbons leaked from solvent storage tanks. For these purposes, a variety of field investigations and studies were performed, which included installation of over 100 groundwater monitoring wells and piezometers at various depths, soil logging and analyses during well and piezometer installation, chemical analysis of groundwater, pump tests, and slug tests. Continuous water level monitoring at three selected wells using automatic data-logger and manual measuring at other wells were also conducted. Based on analyses of the various investigations and tests, a number of factors were identified to explain the distribution of the hydrocarbon contaminants and hydrogeochemical parameters. These factors include indigenous biodegradation, hydrostratigraphy, preliminary pump-and-treat remedy, recharge by rainfall, and subsequent water level fluctuation. The permeable sandy layer, in which the mean water table elevation is maintained, provided a dominant pathway for contaminant transport. The preliminary pump-and-treat action accelerated the movement of the hydrocarbon contaminants and affected the redox evolution pattern. Seasonal recharge by rain, together with indigenous biodegradation, played an important role in the natural attenuation of the petroleum hydrocarbons via mixing/dilution and biodegradation. The water level fluctuations redistributed the hydrocarbon contaminants by partitioning them into the soil and groundwater. The identified factors are not independent but closely inter-correlated.

The effect of biodegradation on gammacerane in crude oils.

PubMed

Huang, Haiping

2017-08-01

Gammacerane is one of the major biomarkers widely used in depositional environment diagnosis, oil family classification, and oil-source correlation. It is generally accepted that gammacerane is more resistant to biodegradation than regular hopanes. However, whether it is biodegradable as well has not been reported in literatures. In order to investigate the effect of biodegradation on gammacerane in crude oils, 69 core samples from two biodegraded petroleum accumulations were geochemically characterized by quantitative GC-MS analysis. All samples are originated from lacustrine source rocks in China and have experienced at least level 8 degree of biodegradation on the scale of Peters and Moldowan (The biomarker guide: interpreting molecular fossils in petroleum and ancient sediments, Prentice Hall, Englewood Cliffs, 1993). Both case histories showed the concentration of gammacerane decrease with increasing severity of biodegradation, indicating the destruction of gammacerane by biodegradation. A whole series of 25-norhopanes paralleling the 17α,21β-hopanes (up to C 34 ), together with C 28 18-α-25,30-bisnorneohopane, C 29 25-nordiahopane and C 29 25-norgammacerane, is found in the Liaohe sample suite but C 33 , C 34 25-norhopane and 25-norgammacerane are almost undetectable in the Junggar case. The gammacerane in the Liaohe case study appear to be altered simultaneously with hopanes, although the rate of gammacerane alteration is slower. Its susceptibility to biodegradation is similar to 18α(H)-22,29,30-trisnorneohopane (Ts) and 17α(H)-22,29,30-trisnorhopane (Tm) but more vulnerable than 18α-30-norneohopane (C 29 Ts), 15α-methyl-17α(H)-27-norhopane (C 30 diahopane) and pregnanes. The gammacerane in the Junggar oils appear to be less biodegradable than the Liaohe case history. It was altered simultaneously with pregnanes and C 29 Ts but faster than C 30 diahopane. The present data suggest that biodegradation sequence is not universal since the relative rates of biodegradation of different compound classes depend upon specific environmental conditions. Like the case of hopane demethylation, the mechanism of gammacerane biodegradation is not straightforward. While the conversion of gammacerane to 25-norgammacerane is not quantitatively balanced in the Liaohe case history, no 25-norgammacerane has been formed from the degradation of gammacerane in the Junggar case history. The ratio of gammacerane to regular hopanes increases with biodegradation degree especially at extreme levels of degradation, gammacerane index is no longer valid for depositional environment assessment or oil-source correlation.

The primary biodegradation of dispersed crude oil in the sea.

PubMed

Prince, Roger C; McFarlin, Kelly M; Butler, Josh D; Febbo, Eric J; Wang, Frank C Y; Nedwed, Tim J

2013-01-01

Dispersants are important tools for stimulating the biodegradation of large oil spills. They are essentially a bioremediation tool - aiming to stimulate the natural process of aerobic oil biodegradation by dispersing oil into micron-sized droplets that become so dilute in the water column that the natural levels of biologically available nitrogen, phosphorus and oxygen are sufficient for microbial growth. Many studies demonstrate the efficacy of dispersants in getting oil off the water surface. Here we show that biodegradation of dispersed oil is prompt and extensive when oil is present at the ppm levels expected from a successful application of dispersants - more than 80% of the hydrocarbons of lightly weathered Alaska North Slope crude oil were degraded in 60 d at 8 °C in unamended New Jersey (USA) seawater when the oil was present at 2.5 ppm by volume. The apparent halftime of the biodegradation of the hydrocarbons was 13.8 d in the absence of dispersant, and 11 d in the presence of Corexit 9500 - similar to rates extrapolated from the field in the Deepwater Horizon response. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biodegradation of o-Benzyl-p-Chlorophenol

PubMed Central

Swisher, R. D.; Gledhill, W. E.

1973-01-01

The extent of biodegradation of o-benzyl-p-chlorophenol, marketed as a germicide under the name Santophen® 1 (Monsanto Co.), in river water, sewage, and activated sludge was determined. Biodegradation was assessed by use of a colorimetric procedure for phenolic materials, carbon analysis, and CO2 evolution. In unacclimated river water, 0.1 mg of Santophen 1 per liter was degraded within 6 days. In sewage, 0.5 and 1.0 mg/liter levels of Santophen 1 were degraded in 1 day. Acclimated activated sludge achieved 80% biodegradation of 1.0 mg/liter Santophen 1 in 8 h and 100% in 24 h. When effluent from a semicontinuous activated sludge unit, acclimated to 20 mg of Santophen 1 per liter was used as the inoculum for the CO2 evolution procedure, 60% of the total theoretical CO2 was evolved from Santophen 1. Based on the results of these studies, indicating Santophen 1 to be readily biodegraded in at least four biological systems, the continued use of present levels of Santophen 1 should present no significant environmental problems. PMID:4356462

Control of Boreal Forest Soil Microbial Communities and Processes by Plant Secondary Compounds

NASA Astrophysics Data System (ADS)

Leewis, M. C.; Leigh, M. B.

2016-12-01

Plants release an array of secondary plant metabolites (SPMEs), which vary widely between plant species/progenies and may drive shifts in soil microbial community structure and function. We hypothesize that SPMEs released through litterfall and root turnover in the boreal forest control ecosystem carbon cycling by inhibiting microbial decomposition processes, which are overcome partially by increased aromatic biodegradation of microbial communities that also fortuitously prime soils for accelerated biodegradation of contaminants. Soils and litter (stems, roots, senescing leaves) were collected from 3 different birch progenies from Iceland, Finland, and Siberia that have been reported to contain different SPME content (low, medium, high, respectively) due to differences in herbivory pressure over their natural history, as well as black spruce, all growing in a long-term common tree garden at the Kevo Subarctic Field Research Institute, Finland. We characterized the SPME content of these plant progenies and used a variety of traditional microbiological techniques (e.g., enzyme assays, litter decomposition and contaminant biodegradation rates) and molecular techniques (e.g., high-throughput amplicon sequencing for bacteria and fungi) to assess how different levels of SPMEs may correlate to shifts in microbial community structure and function. Microbial communities (bacterial and fungal) significantly varied in composition as well as leaf litter and diesel biodegradation rates, in accordance with the phytochemistry of the trees present. This study offers novel, fundamental information about phytochemical controls on ecosystem processes, resilience to contaminants, and microbial decomposition processes.

Field Investigation of Natural Attenuation of a Petroleum Hydrocarbon Contaminated Aquifer, Gyeonggi Province, Korea

NASA Astrophysics Data System (ADS)

Yang, J.; Lee, K.; Bae, G.

2004-12-01

In remediation of a petroleum hydrocarbon contaminated aquifer, natural attenuation may be significant as a remedial alternative. Therefore, natural attenuation should be investigated in the field in order to effectively design and evaluate the remediation strategy at the contaminated site. This study focused on evaluating the natural attenuation for benzene, toluene, ethylbenzene, and xylene (BTEX) at a contaminated site in South Korea. At the study site, the aquifer is composed of a high permeable gravel layer and relatively low permeable sandy-silt layers. Groundwater level vertically fluctuated between 1m and 2m throughout the year (April, 2003~June, 2004) and showed direct response to rainfall events. Chemical analyses of sampled groundwater were performed to investigate the concentrations of various chemical species which are associated with the natural attenuation processes. To evaluate the degree of the biodegradation, the expressed biodegradation capacity (EBC) analysis was done using aerobic respiration, nitrate reduction, manganese reduction, ferric iron reduction, and sulfate reduction as an indicator. High EBC value of sulfate indicate that anaerobic biodegradation by sulfate reduction was a dominant process of mineralization of BTEX at this site. The EBC values decrease sensitively when heavy rainfall occurs due to the dilution and inflow of electron acceptors through a gravel layer. The first-order biodegradation rates of BTEX were estimated by means of the Buscheck and Alcantar method (1995). Results show that the natural attenuation rate of benzene was the highest among the BTEX.

Biodegradation of chloro- and bromobenzoic acids: effect of milieu conditions and microbial community analysis.

PubMed

Gaza, Sarah; Felgner, Annika; Otto, Johannes; Kushmaro, Ariel; Ben-Dov, Eitan; Tiehm, Andreas

2015-04-28

Monohalogenated benzoic acids often appear in industrial wastewaters where biodegradation can be hampered by complex mixtures of pollutants and prevailing extreme milieu conditions. In this study, the biodegradation of chlorinated and brominated benzoic acids was conducted at a pH range of 5.0-9.0, at elevated salt concentrations and with pollutant mixtures including fluorinated and iodinated compounds. In mixtures of the isomers, the degradation order was primarily 4-substituted followed by 3-substituted and then 2-substituted halogenated benzoic acids. If the pH and salt concentration were altered simultaneously, long adaptation periods were required. Community analyses were conducted in liquid batch cultures and after immobilization on sand columns. The Alphaproteobacteria represented an important fraction in all of the enrichment cultures. On the genus level, Afipia sp. was detected most frequently. In particular, Bacteroidetes were detected in high numbers with chlorinated benzoic acids. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser sclerectomy and 5-FU controlled-drug-release biodegradable implant for glaucoma therapy

NASA Astrophysics Data System (ADS)

Villain, Franck L.; Parel, Jean-Marie A.; Kiss, Katalin; Parrish, Richard K.; Kuhne, Francois; Takesue, Yoshiko; Hostyn, Patrick

1993-06-01

Laser sclerectomy, a simple filtering procedure performed to alleviate high intraocular pressure in glaucoma patients, was taught to offer longer lasting effect and therefore improve the patient's outcome when compared with the standard trabeculectomy procedure. Recent clinical trials have shown that this was not the case and pharmacologic wound healing modulation is also required with this new procedure. Five-Fluorouracil (5-FU) is useful as an adjunct treatment for glaucoma filtering surgery. However, efficacy depends upon maintaining sustained drug levels, currently achieved by repeated daily injection of the drug for several weeks. To overcome this limitation, we designed a biodegradable implant for the sustained release of 5-FU. After laser sclerectomy, the implant is inserted through the same 1 mm wide conjunctival snip incision and positioned below the open channel. Implantation takes less than a minute. The implant releases the drug for over 15 days and totally biodegrades in less than 100 days. The combined laser surgery and implantation procedure show great potentials for the treatment of glaucoma.

Manufacturing of biodegradable polyurethane scaffolds based on polycaprolactone using a phase separation method: physical properties and in vitro assay

PubMed Central

Asefnejad, Azadeh; Khorasani, Mohammad Taghi; Behnamghader, Aliasghar; Farsadzadeh, Babak; Bonakdar, Shahin

2011-01-01

Background Biodegradable polyurethanes have found widespread use in soft tissue engineering due to their suitable mechanical properties and biocompatibility. Methods In this study, polyurethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and a copolymer of 1,4-butanediol as a chain extender. Polyurethane scaffolds were fabricated by a combination of liquid–liquid phase separation and salt leaching techniques. The effect of the NCO:OH ratio on porosity content and pore morphology was investigated. Results Scanning electron micrographs demonstrated that the scaffolds had a regular distribution of interconnected pores, with pore diameters of 50–300 μm, and porosities of 64%–83%. It was observed that, by increasing the NCO:OH ratio, the average pore size, compressive strength, and compressive modulus increased. L929 fibroblast and chondrocytes were cultured on the scaffolds, and all samples exhibited suitable cell attachment and growth, with a high level of biocompatibility. Conclusion These biodegradable polyurethane scaffolds demonstrate potential for soft tissue engineering applications. PMID:22072874

Biodegradation of crude oil saturated fraction supported on clays.

PubMed

Ugochukwu, Uzochukwu C; Jones, Martin D; Head, Ian M; Manning, David A C; Fialips, Claire I

2014-02-01

The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.

Interaction effects of metals and salinity on biodegradation of a complex hydrocarbon waste.

PubMed

Amatya, Prasanna L; Hettiaratchi, Joseph Patrick A; Joshi, Ramesh C

2006-02-01

The presence of high levels of salts because of produced brine water disposal at flare pits and the presence of metals at sufficient concentrations to impact microbial activity are of concern to bioremediation of flare pit waste in the upstream oil and gas industry. Two slurry-phase biotreatment experiments based on three-level factorial statistical experimental design were conducted with a flare pit waste. The experiments separately studied the primary effect of cadmium [Cd(II)] and interaction effect between Cd(II) and salinity and the primary effect of zinc [Zn(II)] and interaction effect between Zn(II) and salinity on hydrocarbon biodegradation. The results showed 42-52.5% hydrocarbon removal in slurries spiked with Cd and 47-62.5% in the slurries spiked with Zn. The analysis of variance showed that the primary effects of Cd and Cd-salinity interaction were statistically significant on hydrocarbon degradation. The primary effects of Zn and the Zn-salinity interaction were statistically insignificant, whereas the quadratic effect of Zn was highly significant on hydrocarbon degradation. The study on effects of metallic chloro-complexes showed that the total aqueous concentration of Cd or Zn does not give a reliable indication of overall toxicity to the microbial activity in the presence of high salinity levels.

Development and application of screening tools for biodegradation in water-sediment systems and soil.

PubMed

Junker, Thomas; Coors, Anja; Schüürmann, Gerrit

2016-02-15

Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301. Copyright © 2015 Elsevier B.V. All rights reserved.

High-performance green semiconductor devices: materials, designs, and fabrication

NASA Astrophysics Data System (ADS)

Jung, Yei Hwan; Zhang, Huilong; Gong, Shaoqin; Ma, Zhenqiang

2017-06-01

From large industrial computers to non-portable home appliances and finally to light-weight portable gadgets, the rapid evolution of electronics has facilitated our daily pursuits and increased our life comforts. However, these rapid advances have led to a significant decrease in the lifetime of consumer electronics. The serious environmental threat that comes from electronic waste not only involves materials like plastics and heavy metals, but also includes toxic materials like mercury, cadmium, arsenic, and lead, which can leak into the ground and contaminate the water we drink, the food we eat, and the animals that live around us. Furthermore, most electronics are comprised of non-renewable, non-biodegradable, and potentially toxic materials. Difficulties in recycling the increasing amount of electronic waste could eventually lead to permanent environmental pollution. As such, discarded electronics that can naturally degrade over time would reduce recycling challenges and minimize their threat to the environment. This review provides a snapshot of the current developments and challenges of green electronics at the semiconductor device level. It looks at the developments that have been made in an effort to help reduce the accumulation of electronic waste by utilizing unconventional, biodegradable materials as components. While many semiconductors are classified as non-biodegradable, a few biodegradable semiconducting materials exist and are used as electrical components. This review begins with a discussion of biodegradable materials for electronics, followed by designs and processes for the manufacturing of green electronics using different techniques and designs. In the later sections of the review, various examples of biodegradable electrical components, such as sensors, circuits, and batteries, that together can form a functional electronic device, are discussed and new applications using green electronics are reviewed.

Comparison of biodegradation performance of OECD test guideline 301C with that of other ready biodegradability tests.

PubMed

Kayashima, Takakazu; Taruki, Masanori; Katagiri, Kazuomi; Nabeoka, Ryosuke; Yoshida, Tomohiko; Tsuji, Toshiaki

2014-02-01

The Organisation for Economic Co-operatoin and development (OECD) Guidelines for the Testing of Chemicals list 7 types of tests for determining the ready biodegradability of chemical compounds (301A-F and 310). The present study compares the biodegradation performance of test guideline 301C, which is applied in Japan's Chemical Substances Control Law, with the performance of the other 6 ready biodegradability tests (RBTs) listed in the guidelines. Test guideline 301C specifies use of activated sludge precultured with synthetic sewage containing glucose and peptone (301C sludge) as a test inoculum; in the other RBTs, however, activated sludge from wastewater treatment plants (WWTP sludge) is frequently employed. Analysis based on percentage of biodegradation and pass levels revealed that the biodegradation intensity of test guideline 301C is relatively weak compared with the intensities of RBTs using WWTP sludge, and the following chemical compounds are probably not biodegraded under test guideline 301C conditions: phosphorus compounds; secondary, tertiary, and quaternary amines; and branched quaternary carbon compounds. The relatively weak biodegradation intensity of test guideline 301C may be related to the markedly different activities of the 301C and WWTP sludges. These findings will be valuable for evaluating RBT data in relation to Japan's Chemical Substances Control Law. © 2013 SETAC.

Biodegradation of hydrocarbon mixtures in surface waters at environmentally relevant levels - Effect of inoculum origin on kinetics and sequence of degradation.

PubMed

Birch, Heidi; Hammershøj, Rikke; Comber, Mike; Mayer, Philipp

2017-10-01

Biodegradation is a dominant removal process for many organic pollutants, and biodegradation tests serve as tools for assessing their environmental fate within regulatory risk assessment. In simulation tests, the inoculum is not standardized, varying in microbial quantity and quality, thereby potentially impacting the observed biodegradation kinetics. In this study we investigated the effect of inoculum origin on the biodegradation kinetics of hydrocarbons for five inocula from surface waters varying in urbanization and thus expected pre-exposure to petroleum hydrocarbons. A new biodegradation method for testing mixtures of hydrophobic chemicals at trace concentrations was demonstrated: Aqueous solutions containing 9 hydrocarbons were generated by passive dosing and diluted with surface water resulting in test systems containing native microorganisms exposed to test substances at ng-μg/L levels. Automated Headspace Solid Phase Microextraction coupled to GC-MS was applied directly to these test systems to determine substrate depletion relative to abiotic controls. Lag phases were generally less than 8 days. First order rate constants were within one order of magnitude for each hydrocarbon in four of the five waters but lower in water from a rural lake. The sequence of degradation between the 9 hydrocarbons showed similar patterns in the five waters indicating the potential for using selected hydrocarbons for benchmarking between biodegradation tests. Degradation half-times were shorter than or within one order of magnitude of BioHCwin predictions for 8 of 9 hydrocarbons. These results showed that location choice is important for biodegradation kinetics and can provide a relevant input to aquatic exposure and fate models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fate and Tranport of MTBE in Clay-Rich Materials

NASA Astrophysics Data System (ADS)

lenczewski, m e

2001-12-01

A recent report by the U.S. Geological Survey identified methyl tert-butyl ether (MTBE), a constituent of reformulated gasoline, as the most common contaminant of urban aquifers in the United States. MTBE has been released into groundwater supplies by leaking underground fuel tanks. In Illinois, it has been found in 26 of the 1,800 public water supplies and although detection was intermittent, levels were high enough to be offensive to users in some Illinois communities. MTBE is also being used in Mexico to solve the problem of air quality; however, it has the potential to harm the drinking water quality in the process. Early research on MTBE considered it resistant to biodegradation and unable to adsorb to soils and sediments. However, recent evidence indicates that biodegradation does occur under certain conditions and that sorption can occur to organic materials. This research project will investigate the biodegradation of MTBE and its sorption to the clay-rich glacial till found in northern Illinois and lacustrine clays found in the Chalco Basin, Mexico City, Mexico whose interaction with MTBE has not previously been studied. The principal hypothesis of this research is that the microorganisms and environmental factors in clay-rich materials will increase the biodegradation and sorption of MTBE as compared to sandy materials. The experiments will simulate a spill of MTBE or downgradient from a gasoline spill. Microcosms and batch isotherm experiments will be used to demonstrate the potential for biodegradation and sorption in these materials; however, laboratory results are not considered reliable estimates of actual field sorption and biodegradation rates. Therefore long-term column experiments will also be conducted in which large sample volumes of material that simulate the heterogeneities naturally observed in the environment. This research will increase understanding of the biodegradation and sorption of MTBE and lay the necessary groundwork to implement the optimal remediation method for sites contaminated by MTBE, helping to ensure a sustainable groundwater resource.

Redox conditions and the efficiency of chlorinated ethene biodegradation: Field studies

USGS Publications Warehouse

Chapelle, F.H.; Bradley, P.M.

2000-01-01

The effect of redox conditions on the efficiency of chlorinated ethene biodegradation was investigated at two field sites. One site (NAS Cecil Field, FL) is characterized by predominantly Fe(III)-reducing conditions in the contaminant source area, grading to predominantly sulfate- reducing conditions downgradient. This sequence of redox conditions led to relatively inefficient biodegradation of chlorinated ethenes, with high concentrations of trichloroethene extending more than 400 meters downgradient of the source area. In contrast, a second site (NBS Kings Bay, GA) characterized by predominantly sulfate-reducing conditions in the source area followed by Fe(III)-reducing conditions downgradient. In this system perchloroethene (PCE) and TCE were rapidly biodegraded and extended less than 100 meters downgradient. Rates of ground- water transport are similar at the two sites (???0.2 m/d) indicating that the succession of redox processes, rather than other hydrologic factors, is the principal control on biodegradation. In particular, redox conditions that favor the initial reduction of highly chlorinated ethenes (methanogenic or sulfate-reducing conditions) followed by more oxidizing conditions (Fe(III)- reducing or oxic conditions) favors efficient biodegradation. Thus, documenting the succession of redox processes is an important step in understanding the efficiency of chlorinated ethene biodegradation in ground-water systems.

Influence of drying restraint on physical and mechanical properties of nanofibrillated cellulose films

Treesearch

Carlos Baez; John Considine; Robert Rowlands

2014-01-01

Nanofibrillated cellulose (NFC) is a renewable and biodegradable fibril that possesses high strength and stiffness resulting from high level hydrogen bonding. Films made from NFC shrink and distort as they transition from a wet state (20 wt% solids) to a state of moisture equilibrium (90 wt% solids at 50 % RH, 23 °C). Material distortions are driven by development of...

Biodegradability of plastics.

PubMed

Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

2009-08-26

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

Biodegradability of Plastics

PubMed Central

Tokiwa, Yutaka; Calabia, Buenaventurada P.; Ugwu, Charles U.; Aiba, Seiichi

2009-01-01

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed. PMID:19865515

Degradation of terbuthylazine, difenoconazole and pendimethalin pesticides by selected fungi cultures.

PubMed

Pinto, A P; Serrano, C; Pires, T; Mestrinho, E; Dias, L; Teixeira, D Martins; Caldeira, A T

2012-10-01

Contamination of waters by xenobiotic compounds such as pesticides presents a serious environmental problem with substantial levels of pesticides now contaminating European water resources. The aim of this work was to evaluate the ability of the fungi Fusarium oxysporum, Aspergillus oryzae, Lentinula edodes, Penicillium brevicompactum and Lecanicillium saksenae, for the biodegradation of the pesticides terbuthylazine, difenoconazole and pendimethalin in batch liquid cultures. These pesticides are common soil and water contaminants and terbuthylazine is considered the most persistent triazine herbicide in surface environments. P. brevicompactum and L. saksenae were achieved by enrichment, isolation and screening of fungi capable to metabolize the pesticides studied. The isolates were obtained from two pesticide-primed materials (soil and biomixture). Despite the relatively high persistence of terbuthylazine, the results obtained in this work showed that the fungi species studied have a high capability of biotransformation of this xenobiotic, comparatively the results obtained in other similar studies. The highest removal percentage of terbuthylazine from liquid medium was achieved with A. oryzae (~80%), although the major biodegradation has been reached with P. brevicompactum. The higher ability of P. brevicompactum to metabolize terbuthylazine was presumably acquired through chronic exposure to contamination with the herbicide. L. saksenae could remove 99.5% of the available pendimethalin in batch liquid cultures. L. edodes proved to be a fungus with a high potential for biodegradation of pesticides, especially difenoconazole and pendimethalin. Furthermore, the metabolite desethyl-terbuthylazine was detected in L. edodes liquid culture medium, indicating terbuthylazine biodegradation by this fungus. The fungi strains investigated could prove to be valuable as active pesticide-degrading microorganisms, increasing the efficiency of biopurification systems containing wastewaters contaminated with the xenobiotics studied or compounds with similar intrinsic characteristics. Copyright © 2012 Elsevier B.V. All rights reserved.

Sustained Release of Antibacterial Lipopeptides from Biodegradable Polymers against Oral Pathogens

PubMed Central

Eckhard, Lea H.; Houri-Haddad, Yael; Sol, Asaf; Zeharia, Rotem; Shai, Yechiel; Beyth, Shaul; Domb, Abraham J.

2016-01-01

The development of antibacterial drugs to overcome various pathogenic species, which inhabit the oral cavity, faces several challenges, such as salivary flow and enzymatic activity that restrict dosage retention. Owing to their amphipathic nature, antimicrobial peptides (AMPs) serve as the first line of defense of the innate immune system. The ability to synthesize different types of AMPs enables exploitation of their advantages as alternatives to antibiotics. Sustained release of AMPs incorporated in biodegradable polymers can be advantageous in maintaining high levels of the peptides. In this study, four potent ultra-short lipopeptides, conjugated to an aliphatic acid chain (16C) were incorporated in two different biodegradable polymers: poly (lactic acid co castor oil) (PLACO) and ricinoleic acid-based poly (ester-anhydride) (P(SA-RA)) for sustained release. The lipopeptide and polymer formulations were tested for antibacterial activity during one week, by turbidometric measurements of bacterial outgrowth, anti-biofilm activity by live/dead staining, biocompatibility by hemolysis and XTT colorimetric assays, mode of action by fluorescence-activated cell sorting (FACS) and release profile by a fluorometric assay. The results show that an antibacterial and anti-biofilm effect, as well as membrane disruption, can be achieved by the use of a formulation of lipopeptide incorporated in biodegradable polymer. PMID:27606830

Chemical structure-based predictive model for methanogenic anaerobic biodegradation potential.

PubMed

Meylan, William; Boethling, Robert; Aronson, Dallas; Howard, Philip; Tunkel, Jay

2007-09-01

Many screening-level models exist for predicting aerobic biodegradation potential from chemical structure, but anaerobic biodegradation generally has been ignored by modelers. We used a fragment contribution approach to develop a model for predicting biodegradation potential under methanogenic anaerobic conditions. The new model has 37 fragments (substructures) and classifies a substance as either fast or slow, relative to the potential to be biodegraded in the "serum bottle" anaerobic biodegradation screening test (Organization for Economic Cooperation and Development Guideline 311). The model correctly classified 90, 77, and 91% of the chemicals in the training set (n = 169) and two independent validation sets (n = 35 and 23), respectively. Accuracy of predictions of fast and slow degradation was equal for training-set chemicals, but fast-degradation predictions were less accurate than slow-degradation predictions for the validation sets. Analysis of the signs of the fragment coefficients for this and the other (aerobic) Biowin models suggests that in the context of simple group contribution models, the majority of positive and negative structural influences on ultimate degradation are the same for aerobic and methanogenic anaerobic biodegradation.

High throughput and miniaturised systems for biodegradability assessments.

PubMed

Cregut, Mickael; Jouanneau, Sulivan; Brillet, François; Durand, Marie-José; Sweetlove, Cyril; Chenèble, Jean-Charles; L'Haridon, Jacques; Thouand, Gérald

2014-01-01

The society demands safer products with a better ecological profile. Regulatory criteria have been developed to prevent risks for human health and the environment, for example, within the framework of the European regulation REACH (Regulation (EC) No 1907, 2006). This has driven industry to consider the development of high throughput screening methodologies for assessing chemical biodegradability. These new screening methodologies must be scalable for miniaturisation, reproducible and as reliable as existing procedures for enhanced biodegradability assessment. Here, we evaluate two alternative systems that can be scaled for high throughput screening and conveniently miniaturised to limit costs in comparison with traditional testing. These systems are based on two dyes as follows: an invasive fluorescent dyes that serves as a cellular activity marker (a resazurin-like dye reagent) and a noninvasive fluorescent oxygen optosensor dye (an optical sensor). The advantages and limitations of these platforms for biodegradability assessment are presented. Our results confirm the feasibility of these systems for evaluating and screening chemicals for ready biodegradability. The optosensor is a miniaturised version of a component already used in traditional ready biodegradability testing, whereas the resazurin dye offers an interesting new screening mechanism for chemical concentrations greater than 10 mg/l that are not amenable to traditional closed bottle tests. The use of these approaches allows generalisation of high throughput screening methodologies to meet the need of developing new compounds with a favourable ecological profile and also assessment for regulatory purpose.

Microcosm assays and Taguchi experimental design for treatment of oil sludge containing high concentration of hydrocarbons.

PubMed

Castorena-Cortés, G; Roldán-Carrillo, T; Zapata-Peñasco, I; Reyes-Avila, J; Quej-Aké, L; Marín-Cruz, J; Olguín-Lora, P

2009-12-01

Microcosm assays and Taguchi experimental design was used to assess the biodegradation of an oil sludge produced by a gas processing unit. The study showed that the biodegradation of the sludge sample is feasible despite the high level of pollutants and complexity involved in the sludge. The physicochemical and microbiological characterization of the sludge revealed a high concentration of hydrocarbons (334,766+/-7001 mg kg(-1) dry matter, d.m.) containing a variety of compounds between 6 and 73 carbon atoms in their structure, whereas the concentration of Fe was 60,000 mg kg(-1) d.m. and 26,800 mg kg(-1) d.m. of sulfide. A Taguchi L(9) experimental design comprising 4 variables and 3 levels moisture, nitrogen source, surfactant concentration and oxidant agent was performed, proving that moisture and nitrogen source are the major variables that affect CO(2) production and total petroleum hydrocarbons (TPH) degradation. The best experimental treatment yielded a TPH removal of 56,092 mg kg(-1) d.m. The treatment was carried out under the following conditions: 70% moisture, no oxidant agent, 0.5% of surfactant and NH(4)Cl as nitrogen source.

Water absorption and biodegradation kinetics of highly filled EOC-FS biocomposites

NASA Astrophysics Data System (ADS)

Zykova, A. K.; Pantyukhov, P. V.; Platov, Yu. T.; Bobojonova, G. A.; Ramos, C. Chaverri; Popov, A. A.

2017-12-01

The paper analyzes the water absorption and biodegradation kinetics in highly filled biocomposites based on ethylene-octene copolymer (EOC) and oil flax straw (FS). It is shown that adding the filler to EOC increases the water absorption from 0 to 22%. The tendency can be explained both by the low interfacial adhesion of EOC to FS and by the hydrophilic nature of the filler. According to biodegradation tests (10 months), the mass of pure EOC remains unchanged, suggesting that it fails to biodegrade in the environment. Increasing the filler content increases the weight loss of the composites and the degree of microbiological contamination (fungi filaments, bacteria) as evidenced by optical microscopy.

BIOB: a mathematical model for the biodegradation of low solubility hydrocarbons.

PubMed

Geng, Xiaolong; Boufadel, Michel C; Personna, Yves R; Lee, Ken; Tsao, David; Demicco, Erik D

2014-06-15

Modeling oil biodegradation is an important step in predicting the long term fate of oil on beaches. Unfortunately, existing models do not account mechanistically for environmental factors, such as pore water nutrient concentration, affecting oil biodegradation, rather in an empirical way. We present herein a numerical model, BIOB, to simulate the biodegradation of insoluble attached hydrocarbon. The model was used to simulate an experimental oil spill on a sand beach. The biodegradation kinetic parameters were estimated by fitting the model to the experimental data of alkanes and aromatics. It was found that parameter values are comparable to their counterparts for the biodegradation of dissolved organic matter. The biodegradation of aromatics was highly affected by the decay of aromatic biomass, probably due to its low growth rate. Numerical simulations revealed that the biodegradation rate increases by 3-4 folds when the nutrient concentration is increased from 0.2 to 2.0 mg N/L. Published by Elsevier Ltd.

Biodegradation of disinfection byproducts as a potential removal process during aquifer storage recovery

USGS Publications Warehouse

Landmeyer, J.E.; Bradley, P.M.; Thomas, J.M.

2000-01-01

The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of tri-halomethanes in drinking water.The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water.Aquifer-storage-recovery injection water often contains disinfection byproducts. Results are presented from a study in which two model disinfection byproducts, chloroform and chloroacetic acid, were used to examine biodegradation by indigenous microorganisms. The recharge system studied was near Las Vegas, NV, where the aquifers are recharged artificially during the winter months. Microcosms were constructed using aquifer material recovered from two layers. Results showed that no significant biodegradation of chloroform occurred under aerobic or anaerobic conditions, but chloroacetic acid was biodegraded under both aerobic and anaerobic conditions.

Persistence assessment of cyclohexyl- and norbornyl-derived ketones and their degradation products in different OECD screening tests.

PubMed

Seyfried, M; van Ginkel, C G; Boschung, A; Miffon, F; Fantini, P; Tissot, E; Baroux, L; Merle, P; Chaintreau, A

2015-07-01

The persistence of synthetic cyclohexyl- and norbornyl-derived ketones was assessed by using OECD 301F and 301D biodegradation tests. While cyclohexyl-derived ketones either reached or came close to the pass level (60%) after 60 d, the corresponding norbornyl derivatives yielded significantly less biodegradation (<40%). By analyzing extracts at 60 d, the key degradation products of four norbornyl derivatives were identified. Consistently, 2-bicyclo[2.2.1]heptane carboxylic acid was found as a principal degradation product with minor quantities of bicyclo[2.2.1]heptan-2-one and 2-bicyclo[2.2.1]heptane acetic acid. When the three degradation products were re-synthesized and tested individually for biodegradability, the former two were found to be ultimately biodegradable after 60 d in OECD 301D tests, thus proving non-persistence. Similarly, 2-bicyclo[2.2.1]heptane acetic acid was found to be degraded significantly, albeit with long lag phases exceeding 60 d in the case of freshwater inoculum, then ultimately reaching the pass level. On the other hand, norbornyl ketones were still only partially biodegradable in the same test. We conclude that despite the potential for ultimate biodegradation of norbornyl-derived ketones, current screening tests yield an incomplete picture of their biodegradability, particularly when applying strict OECD criteria. The appearance of long lag phases when re-testing norbornyl ketone degradation products underlines the importance of extending tests to well beyond 28 and even 60 d in the case of freshwater inocula. Copyright © 2015 Elsevier Ltd. All rights reserved.

UTILIZATION OF THE CARBON AND HYDROGEN ISOTOPIC COMPOSITION OF INDIVIDUAL COMPOUNDS IN REFINED HYDROCARBON PRODUCTS TO MONITOR THEIR FATE IN THE ENVIRONMENT

EPA Science Inventory

Isotope effects resulting from biodegradation of MTBE
To conduct the microcosm biodegradation study, sediment samples were collected from sites offering high potential of MTBE biodegradation. Sites where sediment samples were collected for the MTBE microcosm c...

Modeling the Impact of Heterogeneous Spatial Distribution of Soil Microbes on Pesticide Biodegradation at the Centimeter Scale

NASA Astrophysics Data System (ADS)

Babey, T.; De Dreuzy, J. R.; Pinheiro, M.; Garnier, P.; Vieublé-Gonod, L.; Rapaport, A.

2015-12-01

Micro-organisms and substrates may be heterogeneously distributed in soils. This repartition as well as transport mechanisms bringing them into contact are expected to impact the biodegradation rates. Pinheiro et al [2015] have measured in cm-large reconstructed soil cores the fate of an injection of 2,4-D pesticide for different injection conditions and initial distributions of soil pesticide degraders. Through the calibration of a reactive transport model of these experiments, we show that: i) biodegradation of diffusion-controlled pesticide fluxes is favored by a high Damköhler number (high reaction rate compared to flux rate); ii) abiotic sorption processes are negligible and do not interact strongly with biodegradation; iii) biodegradation is primarily governed by the initial repartition of pesticide and degraders for diffusion-controlled transport, as diffusion greatly limits the flux of pesticide reaching the microbial hotspot due to dilution. These results suggest that for biodegradation to be substantial, a spatial heterogeneity in the repartition of microbes and substrate has to be associated with intermittent and fast transport processes to mix them.

Current approaches for the assessment of in situ biodegradation.

PubMed

Bombach, Petra; Richnow, Hans H; Kästner, Matthias; Fischer, Anko

2010-04-01

Considering the high costs and technical difficulties associated with conventional remediation strategies, in situ biodegradation has become a promising approach for cleaning up contaminated aquifers. To verify if in situ biodegradation of organic contaminants is taking place at a contaminated site and to determine if these processes are efficient enough to replace conventional cleanup technologies, a comprehensive characterization of site-specific biodegradation processes is essential. In recent years, several strategies including geochemical analyses, microbial and molecular methods, tracer tests, metabolite analysis, compound-specific isotope analysis, and in situ microcosms have been developed to investigate the relevance of biodegradation processes for cleaning up contaminated aquifers. In this review, we outline current approaches for the assessment of in situ biodegradation and discuss their potential and limitations. We also discuss the benefits of research strategies combining complementary methods to gain a more comprehensive understanding of the complex hydrogeological and microbial interactions governing contaminant biodegradation in the field.

Insight into metabolic and cometabolic activities of autotrophic and heterotrophic microorganisms in the biodegradation of emerging trace organic contaminants.

PubMed

Tran, Ngoc Han; Urase, Taro; Ngo, Huu Hao; Hu, Jiangyong; Ong, Say Leong

2013-10-01

Many efforts have been made to understand the biodegradation of emerging trace organic contaminants (EOCs) in the natural and engineered systems. This review summarizes the current knowledge on the biodegradation of EOCs while having in-depth discussion on metabolism and cometabolism of EOCs. Biodegradation of EOCs is mainly attributed to cometabolic activities of both heterotrophic and autotrophic microorganisms. Metabolism of EOCs can only be observed by heterotrophic microbes. Autotrophic ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaeal (AOA) cometabolize a variety of EOCs via the non-specific enzymes, such as ammonia monooxygenase (AMO). Higher biodegradation of EOCs is often noted under nitrification at high ammonia loading rate. The presence of a growth substrate promotes cometabolic biodegradation of EOCs. Potential strategies for enhancing the biodegradation of EOCs were also proposed in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioremediation of Petroleum Hydrocarbon Contaminated Sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fallgren, Paul

Bioremediation has been widely applied in the restoration of petroleum hydrocarbon-contaminated. Parameters that may affect the rate and efficiency of biodegradation include temperature, moisture, salinity, nutrient availability, microbial species, and type and concentration of contaminants. Other factors can also affect the success of the bioremediation treatment of contaminants, such as climatic conditions, soil type, soil permeability, contaminant distribution and concentration, and drainage. Western Research Institute in conjunction with TechLink Environmental, Inc. and the U.S. Department of Energy conducted laboratory studies to evaluate major parameters that contribute to the bioremediation of petroleum-contaminated drill cuttings using land farming and to develop amore » biotreatment cell to expedite biodegradation of hydrocarbons. Physical characteristics such as soil texture, hydraulic conductivity, and water retention were determined for the petroleum hydrocarbon contaminated soil. Soil texture was determined to be loamy sand to sand, and high hydraulic conductivity and low water retention was observed. Temperature appeared to have the greatest influence on biodegradation rates where high temperatures (>50 C) favored biodegradation. High nitrogen content in the form of ammonium enhanced biodegradation as well did the presence of water near field water holding capacity. Urea was not a good source of nitrogen and has detrimental effects for bioremediation for this site soil. Artificial sea water had little effect on biodegradation rates, but biodegradation rates decreased after increasing the concentrations of salts. Biotreatment cell (biocell) tests demonstrated hydrocarbon biodegradation can be enhanced substantially when utilizing a leachate recirculation design where a 72% reduction of hydrocarbon concentration was observed with a 72-h period at a treatment temperature of 50 C. Overall, this study demonstrates the investigation of the effects of environmental parameters on bioremediation is important in designing a bioremediation system to reduce petroleum hydrocarbon concentrations in impacted soils.« less

Optimizing contaminant desorption and bioavailability in dense slurry systems. 2. PAH bioavailability and rates of degradation.

PubMed

Kim, Han S; Weber, Walter J

2005-04-01

The effects of mechanical mixing on rates of polycyclic aromatic hydrocarbon (PAH) biodegradation in dense geosorbent slurry (67% solids content, w/w) systems were evaluated using laboratory-scale intermittently mixed batch bioreactors. A PAH-contaminated soil and a phenanthrene-sorbed mineral sorbent (alpha-Al2O3) were respectively employed as slurry solids in aerobic and anaerobic biodegradation studies. Both slurries exhibited a characteristic behavior of pseudoplastic non-Newtonian fluids, and the impeller revolution rate and its diameter had dramatic impacts on power and torque requirements in their laminar flow mixing. Rates of phenanthrene biodegradation were markedly enhanced by relatively low-level auger mixing under both aerobic and anaerobic (denitrifying) conditions. Parameters for empirical models correlating biodegradation rate coefficient (k(b)) values to the degree of mixing were similar to those for correlations between mass transfer (desorption) rate coefficient (k(r)) values for rapidly desorbing fractions of soil organic matter and degree of mixing reported in a companion study, supporting a conclusion that performance-efficient and cost-effective enhancements of PAH mass transfer (desorption) and its biodegradation processes can be achieved by the introduction of optimal levels of reactor-scale mechanical mixing.

Biodegradable and biocompatible high elastic chitosan scaffold is cell-friendly both in vitro and in vivo

PubMed Central

Lin, Xianfeng; Yang, Lin; Wang, Qiang; Wang, Zhengke; Shan, Zhi; Li, Shengyun; Wang, Jiying; Fan, Shunwu; Hu, Qiaoling

2017-01-01

Biodegradable and biocompatible macromolecule chitosan has been favored for a variety of clinical applications. We reported herein the fabrication of a novel chitosan scaffold with high elasticity. This scaffold can be easily compressed and thus enable the insertion of such scaffold into surgical lesions during minimal invasive surgeries. In addition, this novel scaffold can restore its shape when released. We evidenced that this high elastic scaffold has better biocompatibility than traditional chitosan scaffold. Therefore, this new chitosan material might lead to the manufacture of a variety of novel biodegradable biomedical materials and devices. PMID:28103580

Use of fugacity model to analyze temperature-dependent removal of micro-contaminants in sewage treatment plants.

PubMed

Thompson, Kelly; Zhang, Jianying; Zhang, Chunlong

2011-08-01

Effluents from sewage treatment plants (STPs) are known to contain residual micro-contaminants including endocrine disrupting chemicals (EDCs) despite the utilization of various removal processes. Temperature alters the efficacy of removal processes; however, experimental measurements of EDC removal at various temperatures are limited. Extrapolation of EDC behavior over a wide temperature range is possible using available physicochemical property data followed by the correction of temperature dependency. A level II fugacity-based STP model was employed by inputting parameters obtained from the literature and estimated by the US EPA's Estimations Programs Interface (EPI) including EPI's BIOWIN for temperature-dependent biodegradation half-lives. EDC removals in a three-stage activated sludge system were modeled under various temperatures and hydraulic retention times (HRTs) for representative compounds of various properties. Sensitivity analysis indicates that temperature plays a significant role in the model outcomes. Increasing temperature considerably enhances the removal of β-estradiol, ethinyestradiol, bisphenol, phenol, and tetrachloroethylene, but not testosterone with the highest biodegradation rate. The shortcomings of BIOWIN were mitigated by the correction of highly temperature-dependent biodegradation rates using the Arrhenius equation. The model predicts well the effects of operating temperature and HRTs on the removal via volatilization, adsorption, and biodegradation. The model also reveals that an impractically long HRT is needed to achieve a high EDC removal. The STP model along with temperature corrections is able to provide some useful insight into the different patterns of STP performance, and useful operational considerations relevant to EDC removal at winter low temperatures. Copyright © 2011 Elsevier Ltd. All rights reserved.

A strategy for aromatic hydrocarbon bioremediation under anaerobic conditions and the impacts of ethanol: A microcosm study

NASA Astrophysics Data System (ADS)

Chen, Yu Dao; Barker, James F.; Gui, Lai

2008-02-01

Increased use of ethanol-blended gasoline (gasohol) and its potential release into the subsurface have spurred interest in studying the biodegradation of and interactions between ethanol and gasoline components such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) in groundwater plumes. The preferred substrate status and the high biological oxygen demand (BOD) posed by ethanol and its biodegradation products suggests that anaerobic electron acceptors (EAs) will be required to support in situ bioremediation of BTEX. To develop a strategy for aromatic hydrocarbon bioremediation and to understand the impacts of ethanol on BTEX biodegradation under strictly anaerobic conditions, a microcosm experiment was conducted using pristine aquifer sand and groundwater obtained from Canadian Forces Base Borden, Canada. The initial electron accepter pool included nitrate, sulfate and/or ferric iron. The microcosms typically contained 400 g of sediment, 600˜800 ml of groundwater, and with differing EAs added, and were run under anaerobic conditions. Ethanol was added to some at concentrations of 500 and 5000 mg/L. Trends for biodegradation of aromatic hydrocarbons for the Borden aquifer material were first developed in the absence of ethanol, The results showed that indigenous microorganisms could degrade all aromatic hydrocarbons (BTEX and trimethylbenzene isomers-TMB) under nitrate- and ferric iron-combined conditions, but not under sulfate-reducing conditions. Toluene, ethylbenzene and m/p-xylene were biodegraded under denitrifying conditions. However, the persistence of benzene indicated that enhancing denitrification alone was insufficient. Both benzene and o-xylene biodegraded significantly under iron-reducing conditions, but only after denitrification had removed other aromatics. For the trimethylbenzene isomers, 1,3,5-TMB biodegradation was found under denitrifying and then iron-reducing conditions. Biodegradation of 1,2,3-TMB or 1,2,4-TMB was slower under iron-reducing conditions. This study suggests that addition of excess ferric iron combined with limited nitrate has promise for in situ bioremediation of BTEX and TMB in the Borden aquifer and possibly for other sites contaminated by hydrocarbons. This study is the first to report 1,2,3-TMB biodegradation under strictly anaerobic condition. With the addition of 500 mg/L ethanol but without EA addition, ethanol and its main intermediate, acetate, were quickly biodegraded within 41 d with methane as a major product. Ethanol initially present at 5000 mg/L without EA addition declined slowly with the persistence of unidentified volatile fatty acids, likely propionate and butyrate, but less methane. In contrast, all ethanol disappeared with repeated additions of either nitrate or ferric iron, but acetate and unidentified intermediates persisted under iron-enhanced conditions. With the addition of 500 mg/L ethanol and nitrate, only minor toluene biodegradation was observed under denitrifying conditions and only after ethanol and acetate were utilized. The higher ethanol concentration (5000 mg/L) essentially shut down BTEX biodegradation likely due to high EA demand provided by ethanol and its intermediates. The negative findings for anaerobic BTEX biodegradation in the presence of ethanol and/or its biodegradation products are in contrast to recent research reported by Da Silva et al. [Da Silva, M.L.B., Ruiz-Aguilar, G.M.L., Alvarez, P.J.J., 2005. Enhanced anaerobic biodegradation of BTEX-ethanol mixtures in aquifer columns amended with sulfate, chelated ferric iron or nitrate. Biodegradation. 16, 105-114]. Our results suggest that the apparent conservation of high residual labile carbon as biodegradation products such as acetate makes natural attenuation of aromatics less effective, and makes subsequent addition of EAs to promote in situ BTEX biodegradation problematic.

Enhancement of in vitro high-density polyethylene (HDPE) degradation by physical, chemical, and biological treatments.

PubMed

Balasubramanian, V; Natarajan, K; Rajeshkannan, V; Perumal, P

2014-11-01

Partially degraded high-density polyethylene (HDPE) was collected from plastic waste dump yard for biodegradation using fungi. Of various fungi screened, strain MF12 was found efficient in degrading HDPE by weight loss and Fourier transform infrared (FT-IR) spectrophotometric analysis. Strain MF12 was selected as efficient HDPE degraders for further studies, and their growth medium composition was optimized. Among those different media used, basal minimal medium (BMM) was suitable for the HDPE degradation by strain MF12. Strain MF12 was subjected to 28S rRNA sequence analysis and identified as Aspergillus terreus MF12. HDPE degradation was carried out using combinatorial physical and chemical treatments in conjunction to biological treatment. The high level of HDPE degradation was observed in ultraviolet (UV) and KMnO4/HCl with A. terreus MF12 treatment, i.e., FT10. The abiotic physical and chemical factors enhance the biodegradation of HDPE using A. terreus MF12.

Aerobic biodegradation of sludge with high hydrocarbon content generated by a Mexican natural gas processing facility.

PubMed

Roldán-Carrillo, T; Castorena-Cortés, G; Zapata-Peñasco, I; Reyes-Avila, J; Olguín-Lora, P

2012-03-01

The biodegradation of oil sludge from Mexican sour gas and petrochemical facilities contaminated with a high content of hydrocarbons, 334.7 ± 7.0 g kg(-1) dry matter (dm), was evaluated. Studies in microcosm systems were carried out in order to determine the capacity of the native microbiota in the sludge to reduce hydrocarbon levels under aerobic conditions. Different carbon/nitrogen/phosphorous (C/N/P) nutrient ratios were tested. The systems were incubated at 30 °C and shaken at 100 rpm. Hydrocarbon removals from 32 to 51% were achieved in the assays after 30 days of incubation. The best assay had C/N/P ratio of 100/1.74/0.5. The results of the Microtox(®) and Ames tests indicated that the original sludge was highly toxic and mutagenic, whereas the best assay gave a final product that did not show toxicity or mutagenicity. Copyright © 2011 Elsevier Ltd. All rights reserved.

77 FR 28340 - Revocation of TSCA Section 4 Testing Requirements for One High Production Volume Chemical Substance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... a result, a biodegradation study of C.I. Pigment Blue 56, found adequate by an EPA review, satisfies the need for biodegradation data on C.I. Pigment Blue 61 (Ref. 5). Likewise, a fish acute toxicity..., water solubility, biodegradation, fish acute toxicity, mammalian acute toxicity, bacterial reverse...

Biodegradability of fluoxetine, mefenamic acid, and metoprolol using different microbial consortiums.

PubMed

Velázquez, Yolanda Flores; Nacheva, Petia Mijaylova

2017-03-01

The biodegradation of fluoxetine, mefenamic acid, and metoprolol using ammonium-nitrite-oxidizing consortium, nitrite-oxidizing consortium, and heterotrophic biomass was evaluated in batch tests applying different retention times. The ammonium-nitrite-oxidizing consortium presented the highest biodegradation percentages for mefenamic acid and metoprolol, of 85 and 64% respectively. This consortium was also capable to biodegrade 79% of fluoxetine. The heterotrophic consortium showed the highest ability to biodegrade fluoxetine reaching 85%, and it also had a high potential for biodegrading mefenamic acid and metoprolol, of 66 and 58% respectively. The nitrite-oxidizing consortium presented the lowest biodegradation of the three pharmaceuticals, of less than 48%. The determination of the selected pharmaceuticals in the dissolved phase and in the biomass indicated that biodegradation was the major removal mechanism of the three compounds. Based on the obtained results, the biodegradation kinetics was adjusted to pseudo-first-order for the three pharmaceuticals. The values of k biol for fluoxetine, mefenamic acid, and metoprolol determined with the three consortiums indicated that ammonium-nitrite-oxidizing and heterotrophic biomass allow a partial biodegradation of the compounds, while no substantial biodegradation can be expected using nitrite-oxidizing consortium. Metoprolol was the less biodegradable compound. The sorption of fluoxetine and mefenamic acid onto biomass had a significant contribution for their removal (6-14%). The lowest sorption coefficients were obtained for metoprolol indicating that the sorption onto biomass is poor (3-4%), and the contribution of this process to the global removal can be neglected.

Biodegradable compounds: Rheological, mechanical and thermal properties

NASA Astrophysics Data System (ADS)

Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

2015-12-01

Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

Scale up of diesel oil biodegradation in a baffled roller bioreactor.

PubMed

Nikakhtari, Hossein; Song, Wanning; Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2010-05-01

Diesel oil is a suitable substance to represent petroleum contamination from accidental spills in operating and transportation facilities. Using a microbial culture enriched from a petroleum contaminated soil, biodegradation of diesel oil was carried out in 2.2, 55, and 220 L roller baffled bioreactors. The effects of bioreactor rotation speed (from 5 to 45 rpm) and liquid loading (from 18% to 73% of total volume) on the biodegradation of diesel oil were studied. In the small scale bioreactor (2.2L), the maximum rotation speed of 45 rpm resulted in the highest biodegradation rate with a first order biodegradation kinetic constant of 0.095 d(-1). In the larger scale bioreactors, rotation speed did not affect the biodegradation rate. Liquid loadings higher than 64% resulted in reduced biodegradation rates in the small scale bioreactor; however, in the larger roller bioreactors liquid loading did not affect the biodegradation rate. Biodegradation of diesel oil at 5 rpm and 73% loading is recommended for operating large scale roller baffled bioreactors. Under these conditions, high diesel oil concentrations up to 50 gL(-1) can be bioremediated at a rate of 1.61 gL(-1)d(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Biodegradable and compostable alternatives to conventional plastics.

PubMed

Song, J H; Murphy, R J; Narayan, R; Davies, G B H

2009-07-27

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.

Enhanced crude oil biodegradation in soil via biostimulation.

PubMed

Al-Saleh, Esmaeil; Hassan, Ali

2016-08-02

Research on feasible methods for the enhancement of bioremediation in soil contaminated by crude oil is vital in oil-exporting countries such as Kuwait, where crude oil is a major pollutant and the environment is hostile to biodegradation. This study investigated the possibility of enhancing crude oil bioremediation by supplementing soil with cost-effective organic materials derived from two widespread locally grown trees, Conocarpus and Tamarix. Amendments in soils increased the counts of soil microbiota by up to 98% and enhanced their activity by up to 95.5%. The increase in the biodegradation of crude oil (75%) and high levels of alkB expression substantiated the efficiency of the proposed amendment technology for the bioremediation of hydrocarbon-contaminated sites. The identification of crude-oil-degrading bacteria revealed the dominance of the genus Microbacterium (39.6%), Sphingopyxis soli (19.3%), and Bordetella petrii (19.6%) in unamended, Conocarpus-amended, and Tamarix-amended contaminated soils, respectively. Although soil amendments favored the growth of Gram-negative bacteria and reduced bacterial diversity, the structures of bacterial communities were not significantly altered.

Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

PubMed

Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

2016-03-01

Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of the effect of reprocessing on the structure and properties of low density polyethylene/thermoplastic starch blends.

PubMed

Peres, Anderson M; Pires, Ruthe R; Oréfice, Rodrigo L

2016-01-20

The great quantity of synthetic plastic discarded inappropriately in the environment is forcing the search for materials that can be reprocessable and biodegradable. Blends between synthetic polymers and natural and biodegradable polymers can be good candidates of such novel materials because they can combine processability with biodegradation and the use of renewable raw materials. However, traditional polymers usually present high levels of recyclability and use the well-established recycling infrastructure that can eventually be affected by the introduction of systems containing natural polymers. Thus, this work aims to evaluate the effect of reprocessing (simulated here by multiple extrusions) on the structure and properties of a low density polyethylene/thermoplastic starch (LDPE/TPS) blend compared to LDPE. The results indicated that multiple extrusion steps led to a reduction in the average size of the starch-rich phases of LDPE/TPS blends and minor changes in the mechanical and rheological properties of the materials. Such results suggest that the LDPE/TPS blend presents similar reprocessability to the LDPE for the experimental conditions used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nano/bio treatment of polychlorinated biphenyls with evaluation of comparative toxicity

DOE PAGES

Le, Thao Thanh; Francis, Arokiasamy J.; Nguyen, Hoang Khanh; ...

2015-02-03

The persistence of polychlorinated biphenyl (PCB) Aroclor 1248 in soils and sediments is a major concern because of its toxicity and presence at high concentrations. In this study, we developed an integrated remediation system for PCBs using chemical catalysis and biodegradation. The dechlorination of Aroclor 1248 was achieved by treatment with bimetallic nanoparticles Pd/nFe under anoxic conditions. Among the 32 PCB congeners of Aroclor 1248 examined, our process dechlorinated 99%, 92%, 84%, and 28% of tri-, tetra-, penta-, and hexachlorinated biphenyls, respectively. The resulting biphenyl was biodegraded rapidly by Burkholderia xenovorans LB400. Benzoic acid was detected as an intermediate duringmore » the biodegradation process. The toxicity of the residual PCBs after nano-bio treatment was evaluated in terms of toxic equivalent values which decreased from 33.8 × 10 -5 μg g -1 to 9.5 × 10 -5 μg g -1. The residual PCBs also had low cytotoxicity toward Escherichia coli as demonstrated by lower reactive oxygen species levels, lower glutathione peroxidase activity, and a reduced number of dead bacteria.« less

Nano/bio treatment of polychlorinated biphenyls with evaluation of comparative toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le, Thao Thanh; Francis, Arokiasamy J.; Nguyen, Hoang Khanh

The persistence of polychlorinated biphenyl (PCB) Aroclor 1248 in soils and sediments is a major concern because of its toxicity and presence at high concentrations. In this study, we developed an integrated remediation system for PCBs using chemical catalysis and biodegradation. The dechlorination of Aroclor 1248 was achieved by treatment with bimetallic nanoparticles Pd/nFe under anoxic conditions. Among the 32 PCB congeners of Aroclor 1248 examined, our process dechlorinated 99%, 92%, 84%, and 28% of tri-, tetra-, penta-, and hexachlorinated biphenyls, respectively. The resulting biphenyl was biodegraded rapidly by Burkholderia xenovorans LB400. Benzoic acid was detected as an intermediate duringmore » the biodegradation process. The toxicity of the residual PCBs after nano-bio treatment was evaluated in terms of toxic equivalent values which decreased from 33.8 × 10 -5 μg g -1 to 9.5 × 10 -5 μg g -1. The residual PCBs also had low cytotoxicity toward Escherichia coli as demonstrated by lower reactive oxygen species levels, lower glutathione peroxidase activity, and a reduced number of dead bacteria.« less

Anaerobic biodegradation of dissolved ethanol in a pilot-scale sand aquifer: Variability in plume (redox) biogeochemistry

NASA Astrophysics Data System (ADS)

McLeod, Heather C.; Roy, James W.; Slater, Gregory F.; Smith, James E.

2018-01-01

The use of ethanol in alternative fuels has led to contamination of groundwater with high concentrations of this easily biodegradable organic compound. Previous laboratory and field studies have shown vigorous biodegradation of ethanol plumes, with prevalence of reducing conditions and methanogenesis. The objective of this study was to further our understanding of the dynamic biogeochemistry processes, especially dissolved gas production, that may occur in developing and aging plume cores at sites with ethanol or other organic contamination of groundwater. The experiment performed involved highly-detailed spatial and temporal monitoring of ethanol biodegradation in a 2-dimensional (175 cm high × 525 cm long) sand aquifer tank for 330 days, with a vertical shift in plume position and increased nutrient inputs occurring at Day 100. Rapid onset of fermentation, denitrification, sulphate-reduction and iron(III)-reduction occurred following dissolved ethanol addition, with the eventual widespread development of methanogenesis. The detailed observations also demonstrate a redox zonation that supports the plume fringe concept, secondary reactions resulting from a changing/moving plume, and time lags for the various biodegradation processes. Additional highlights include: i) the highest dissolved H2 concentrations yet reported for groundwater, possibly linked to vigorous fermentation in the absence of common terminal electron-acceptors (i.e., dissolved oxygen, nitrate, and sulphate, and iron(III)-minerals) and methanogenesis; ii) evidence of phosphorus nutrient limitation, which stalled ethanol biodegradation and perhaps delayed the onset of methanogenesis; and iii) the occurrence of dissimilatory nitrate reduction to ammonium, which has not been reported for ethanol biodegradation to date.

Impact of initial biodegradability on sludge anaerobic digestion enhancement by thermal pretreatment.

PubMed

Carrère, Hélène; Bougrier, Claire; Castets, Delphine; Delgenès, Jean Philippe

2008-11-01

Thermal treatments with temperature ranging from 60 to 210 degrees C were applied to 6 waste-activated sludge samples originating from high or medium load, extended aeration wastewater treatment processes that treated different wastewaters (urban, urban and industrial or slaughterhouse). COD sludge solubilisation was linearly correlated with the treatment temperature on the whole temperature range and independently of the sludge samples. Sludge batch mesophilic biodegradability increased with treatment temperature up to 190 degrees C. In this temperature range, biodegradability enhancement or methane production increase by thermal hydrolysis was shown to be a function of sludge COD solubilisation but also of sludge initial biodegradability. The lower the initial biodegradability means the higher efficiency of thermal treatment.

Controllable stearic acid crystal induced high hydrophobicity on cellulose film surface.

PubMed

He, Meng; Xu, Min; Zhang, Lina

2013-02-01

A novel, highly hydrophobic cellulose composite film (RCS) with biodegradability was fabricated via solvent-vaporized controllable crystallization of stearic acid in the porous structure of cellulose films (RC). The interface structure and properties of the composite films were investigated with wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), FT-IR, solid-state (13)C NMR, water uptake, tensile testing, water contact angle, and biodegradation tests. The results indicated that the RCS films exhibited high hydrophobicity (water contact angle achieved to 145°), better mechanical properties in the humid state and lower water uptake ratio than RC. Interestingly, the stearic acid crystallization was induced by the pore wall of the cellulose matrix to form a micronano binary structure, resulting in a rough surface. The rough surface with a hierarchical structure containing micronanospace on the RCS film surface could trap abundant air, leading to the high hydrophobicity. Moreover, the RCS films were flexible, biodegradable, and low-cost, showing potential applications in biodegradable water-proof packaging.

Biodegradation potential of MTBE in a fractured chalk aquifer under aerobic conditions in long-term uncontaminated and contaminated aquifer microcosms.

PubMed

Shah, Nadeem W; Thornton, Steven F; Bottrell, Simon H; Spence, Michael J

2009-01-26

The potential for aerobic biodegradation of MTBE in a fractured chalk aquifer is assessed in microcosm experiments over 450 days, under in situ conditions for a groundwater temperature of 10 degrees C, MTBE concentration between 0.1 and 1.0 mg/L and dissolved O2 concentration between 2 and 10 mg/L. Following a lag period of up to 120 days, MTBE was biodegraded in uncontaminated aquifer microcosms at concentrations up to 1.2 mg/L, demonstrating that the aquifer has an intrinsic potential to biodegrade MTBE aerobically. The MTBE biodegradation rate increased three-fold from a mean of 6.6+/-1.6 microg/L/day in uncontaminated aquifer microcosms for subsequent additions of MTBE, suggesting an increasing biodegradation capability, due to microbial cell growth and increased biomass after repeated exposure to MTBE. In contaminated aquifer microcosms which also contained TAME, MTBE biodegradation occurred after a shorter lag of 15 or 33 days and MTBE biodegradation rates were higher (max. 27.5 microg/L/day), probably resulting from an acclimated microbial population due to previous exposure to MTBE in situ. The initial MTBE concentration did not affect the lag period but the biodegradation rate increased with the initial MTBE concentration, indicating that there was no inhibition of MTBE biodegradation related to MTBE concentration up to 1.2 mg/L. No minimum substrate concentration for MTBE biodegradation was observed, indicating that in the presence of dissolved O2 (and absence of inhibitory factors) MTBE biodegradation would occur in the aquifer at MTBE concentrations (ca. 0.1 mg/L) found at the front of the ether oxygenate plume. MTBE biodegradation occurred with concomitant O2 consumption but no other electron acceptor utilisation, indicating biodegradation by aerobic processes only. However, O2 consumption was less than the stoichiometric requirement for complete MTBE mineralization, suggesting that only partial biodegradation of MTBE to intermediate organic metabolites occurred. The availability of dissolved O2 did not affect MTBE biodegradation significantly, with similar MTBE biodegradation behaviour and rates down to ca. 0.7 mg/L dissolved O2 concentration. The results indicate that aerobic MTBE biodegradation could be significant in the plume fringe, during mixing of the contaminant plume and uncontaminated groundwater and that, relative to the plume migration, aerobic biodegradation is important for MTBE attenuation. Moreover, should the groundwater dissolved O2 concentration fall to zero such that MTBE biodegradation was inhibited, an engineered approach to enhance in situ bioremediation could supply O2 at relatively low levels (e.g. 2-3 mg/L) to effectively stimulate MTBE biodegradation, which has significant practical advantages. The study shows that aerobic MTBE biodegradation can occur at environmentally significant rates in this aquifer, and that long-term microcosm experiments (100s days) may be necessary to correctly interpret contaminant biodegradation potential in aquifers to support site management decisions.

78 FR 27860 - Revocation of TSCA Section 4 Testing Requirements for One High Production Volume Chemical Substance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-13

... for C.I. Pigment Blue 61 (Ref. 8). As a result, a biodegradation study of C.I. Pigment Blue 56, found adequate by an EPA review, satisfies the need for biodegradation data on C.I. Pigment Blue 61 (Ref. 8..., boiling point, vapor pressure, water solubility, biodegradation, fish acute toxicity, mammalian acute...

Development of dopant-free conductive bioelastomers

PubMed Central

Xu, Cancan; Huang, Yihui; Yepez, Gerardo; Wei, Zi; Liu, Fuqiang; Bugarin, Alejandro; Tang, Liping; Hong, Yi

2016-01-01

Conductive biodegradable materials are of great interest for various biomedical applications, such as tissue repair and bioelectronics. They generally consist of multiple components, including biodegradable polymer/non-degradable conductive polymer/dopant, biodegradable conductive polymer/dopant or biodegradable polymer/non-degradable inorganic additives. The dopants or additives induce material instability that can be complex and possibly toxic. Material softness and elasticity are also highly expected for soft tissue repair and soft electronics. To address these concerns, we designed a unicomponent dopant-free conductive polyurethane elastomer (DCPU) by chemically linking biodegradable segments, conductive segments, and dopant molecules into one polymer chain. The DCPU films which had robust mechanical properties with high elasticity and conductivity can be degraded enzymatically and by hydrolysis. It exhibited great electrical stability in physiological environment with charge. Mouse 3T3 fibroblasts survived and proliferated on these films exhibiting good cytocompatibility. Polymer degradation products were non-toxic. DCPU could also be processed into a porous scaffold and in an in vivo subcutaneous implantation model, exhibited good tissue compatibility with extensive cell infiltration over 2 weeks. Such biodegradable DCPU with good flexibility and elasticity, processability, and electrical stability may find broad applications for tissue repair and soft/stretchable/wearable bioelectronics. PMID:27686216

Biodegradable sizing agents from soy protein via controlled hydrolysis and dis-entanglement for remediation of textile effluents.

PubMed

Yang, Maiping; Xu, Helan; Hou, Xiuliang; Zhang, Jie; Yang, Yiqi

2017-03-01

Fully biodegradable textile sizes with satisfactory performance properties were developed from soy protein with controlled hydrolysis and dis-entanglement to tackle the intractable environmental issues associated with the non-biodegradable polyvinyl alcohol (PVA) in textile effluents. PVA derived from petroleum is the primary sizing agent due to its excellent sizing performance on polyester-containing yarns, especially in increasingly prevailing high-speed weaving. However, due to the poor biodegradability, PVA causes serious environmental pollution, and thus, should be substituted with more environmentally friendly polymers. Soy protein treated with high amount of triethanolamine was found with acceptable sizing properties. However, triethanolamine is also non-biodegradable and originated from petroleum, therefore, is not an ideal additive. In this research, soy sizes were developed from soy protein treated with glycerol, the biodegradable triol that could also be obtained from soy. The soy sizes had good film properties, adhesion to polyester and abrasion resistance close to PVA, rendering them qualified for sizing applications. Regarding desizing, consumption of water and energy for removal of soy size could be remarkably decreased, comparing to removal of PVA. Moreover, with satisfactory degradability, the wastewater containing soy sizes was readily dischargeable after treated in activated sludge for two days. In summary, the fully biodegradable soy sizes had potential to substitute PVA for sustainable textile processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development and Evaluation of an Online CO2 Evolution Test and a Multicomponent Biodegradation Test System

PubMed Central

Strotmann, Uwe; Reuschenbach, Peter; Schwarz, Helmut; Pagga, Udo

2004-01-01

Well-established biodegradation tests use biogenously evolved carbon dioxide (CO2) as an analytical parameter to determine the ultimate biodegradability of substances. A newly developed analytical technique based on the continuous online measurement of conductivity showed its suitability over other techniques. It could be demonstrated that the method met all criteria of established biodegradation tests, gave continuous biodegradation curves, and was more reliable than other tests. In parallel experiments, only small variations in the biodegradation pattern occurred. When comparing the new online CO2 method with existing CO2 evolution tests, growth rates and lag periods were similar and only the final degree of biodegradation of aniline was slightly lower. A further test development was the unification and parallel measurement of all three important summary parameters for biodegradation—i.e., CO2 evolution, determination of the biochemical oxygen demand (BOD), and removal of dissolved organic carbon (DOC)—in a multicomponent biodegradation test system (MCBTS). The practicability of this test method was demonstrated with aniline. This test system had advantages for poorly water-soluble and highly volatile compounds and allowed the determination of the carbon fraction integrated into biomass (heterotrophic yield). The integrated online measurements of CO2 and BOD systems produced continuous degradation curves, which better met the stringent criteria of ready biodegradability (60% biodegradation in a 10-day window). Furthermore the data could be used to calculate maximal growth rates for the modeling of biodegradation processes. PMID:15294794

Co-biodegradation of anthracene and naphthalene by the bacterium Acinetobacter johnsonii.

PubMed

Jiang, Yan; Qi, Hui; Zhang, Xian M

2018-04-16

NAP (Naphthalene) and ANT (anthracene) usually co-exist in environment and possessed interactional effects on their biodegradation in environment. Presently, a strain of Acinetobacter johnsonii was employed to degrade NAP and ANT in single- and dual-substrate systems. NAP was utilized as prefer substrate by cells to accelerate ANT biodegradation. As much as 200 mg L -1 ANT could be entirely degraded with 1,500 mg L -1 NAP, which was beyond bacterial potential in single substrate system. Especially, the shortest biodegradation period (103 h) for ANT was observed with the presence of 50 mg L -1 NAP. By contrast, ANT showed strong inhibition on NAP degradation, while the peak biodegradation of 1,950 mg L -1 NAP with 50 mg L -1 ANT could still proceed. By introducing an inhibition constant parameter to fit the inhibition on cells, modeling indicated the substrate inhibition for NAP and ANT over the concentrations of 174 and 49 mg L -1 , respectively. Furthermore, enzyme assay revealed the pathway of meta fission in NAP biodegradation due to the appearance of catechol 2,3-dioxygenase activity, and low-level lipase excretion was also found in both NAP and ANT biodegradation, but hardly affect NAP and ANT biodegradation in the present study. To research the interplay of NAP and ANT is conducive to targeted decontamination.

Biodegradation of plastics: current scenario and future prospects for environmental safety.

PubMed

Ahmed, Temoor; Shahid, Muhammad; Azeem, Farrukh; Rasul, Ijaz; Shah, Asad Ali; Noman, Muhammad; Hameed, Amir; Manzoor, Natasha; Manzoor, Irfan; Muhammad, Sher

2018-03-01

Plastic is a general term used for a wide range of high molecular weight organic polymers obtained mostly from the various hydrocarbon and petroleum derivatives. There is an ever-increasing trend towards the production and consumption of plastics due to their extensive industrial and domestic applications. However, a wide spectrum of these polymers is non-biodegradable with few exceptions. The extensive use of plastics, lack of waste management, and casual community behavior towards their proper disposal pose a significant threat to the environment. This has raised growing concerns among various stakeholders to devise policies and innovative strategies for plastic waste management, use of biodegradable polymers especially in packaging, and educating people for their proper disposal. Current polymer degradation strategies rely on chemical, thermal, photo, and biological procedures. In the presence of proper waste management strategies coupled with industrially controlled biodegradation facilities, the use of biodegradable plastics for some applications such as packaging or health industry is a promising and attractive option for economic, environmental, and health benefits. This review highlights the classification of plastics with special emphasis on biodegradable plastics and their rational use, the identified mechanisms of plastic biodegradation, the microorganisms involved in biodegradation, and the current insights into the research on biodegradable plastics. The review has also identified the research gaps in plastic biodegradation followed by future research directions.

Microbial degradation of microcystin in Florida’s freshwaters

PubMed Central

Ramani, A.; Rein, K.; Shetty, K. G.

2012-01-01

Presence of microcystin (MC), a predominant freshwater algal toxin and a suspected liver carcinogen, in Florida’s freshwaters poses serious health threat to humans and aquatic species. Being recalcitrant to conventional physical and chemical water treatment methods, biological methods of MC removal is widely researched. Water samples collected from five sites of Lake Okeechobee (LO) frequently exposed to toxic Microcystis blooms were used as inoculum for enrichment with microcystin LR (MC-LR) supplied as sole C and N source. After 20 days incubation, MC levels were analyzed using high performance liquid chromatography (HPLC). A bacterial consortium consisting of two isolates DC7 and DC8 from the Indian Prairie Canal sample showed over 74% toxin degradation at the end of day 20. Optimal temperature requirement for biodegradation was identified and phosphorus levels did not affect the MC biodegradation. Based on 16S rRNA sequence similarity the isolate DC8 was found to have a match with Microbacterium sp. and the DC7 isolate with Rhizobium gallicum (AY972457). PMID:21611743

Anoxic biodegradation of petroleum hydrocarbons in saline media using denitrifier biogranules.

PubMed

Moussavi, Gholamreza; Shekoohiyan, Sakine; Naddafi, Kazem

2016-07-01

The total petroleum hydrocarbons (TPH) biodegradation was examined using biogranules at different initial TPH concentration and contact time under anoxic condition in saline media. The circular compact biogranules having the average diameter between 2 and 3mm were composed of a dense population of Bacillus spp. capable of biodegrading TPH under anoxic condition in saline media were formed in first step of the study. The biogranules could biodegrade over 99% of the TPH at initial concentration up to 2g/L at the contact time of 22h under anoxic condition in saline media. The maximum TPH biodegradation rate of 2.6 gTPH/gbiomass.d could be obtained at initial TPH concentration of 10g/L. Accordingly, the anoxic biogranulation is a possible and promising technique for high-rate biodegradation of petroleum hydrocarbons in saline media. Copyright © 2016 Elsevier Inc. All rights reserved.

Biodegradable and compostable alternatives to conventional plastics

PubMed Central

Song, J. H.; Murphy, R. J.; Narayan, R.; Davies, G. B. H.

2009-01-01

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all ‘good’ or petrochemical-based products are all ‘bad’. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated ‘home’ composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted. PMID:19528060

Investigation of the Spectroscopic Information on Functional Groups Related to Carbohydrates in Different Morphological Fractions of Corn Stover and Their Relationship to Nutrient Supply and Biodegradation Characteristics.

PubMed

Xin, Hangshu; Ding, Xue; Zhang, Liyang; Sun, Fang; Wang, Xiaofan; Zhang, Yonggen

2017-05-24

The objectives of this study were to investigate (1) nutritive values and biodegradation characteristics and (2) mid-IR spectroscopic features within the regions associated with carbohydrate functional groups (including cellulosic component (CELC), structural carbohydrate (STCHO), and total carbohydrate (CHO)) in different morphological fractions of corn stover. Furthermore, correlation and regression analyses were also applied to determine the relationship between nutritional values and spectroscopic parameters. The results showed that different morphological sections of corn stover had different nutrient supplies, in situ biodegradation characteristics, and spectral structural features within carbohydrate regions. The stem rind and ear husk were both high in fibrous content, which led to the lowest effective degradabilities (ED) among these stalk fractions. The ED values of NDF were ranked ear husk > stem pith > leaf blade > leaf sheath > whole plant > stem rind. Intensities of peak height and area within carbohydrate regions were relatively more stable compared with spectral ratio profiles. Significant difference was found only in peak area intensity of CELC, which was at the highest level for stem rind, followed by stem pith, leaf sheath, whole plant, leaf blade, and ear husk. Correlation results showed that changes in some carbohydrate spectral ratios were highly associated with carbohydrate chemical profiles and in situ rumen degradation kinetics. Among the various carbohydrate molecular spectral parameters that were tested in multiple regression analysis, CHO height ratios, and area ratios of CELC:CHO and CELC:STCHO as well as CELC area were mostly sensitive to nutrient supply and biodegradation characteristics in different morphological fractions of corn stover.

Biological Activity Assessment in Mexican Tropical Soils with Different Hydrocarbon Contamination Histories.

PubMed

Riveroll-Larios, Jessica; Escalante-Espinosa, Erika; Fócil-Monterrubio, Reyna L; Díaz-Ramírez, Ildefonso J

The use of soil health indicators linked to microbial activities, such as key enzymes and respirometric profiles, helps assess the natural attenuation potential of soils contaminated with hydrocarbons. In this study, the intrinsic physicochemical characteristics, biological activity and biodegradation potential were recorded for two soils with different contamination histories (>5 years and <1 months). The enzymatic activity (lipase and dehydrogenase) as well as microbiological and mineralisation profiles were measured in contaminated soil samples. Soil suspensions were tested as microbial inocula in biodegradation potential assays using contaminated perlite as an inert support. The basal respiratory rate of the recently contaminated soil was 15-38 mg C-CO 2  kg -1 h -1 , while the weathered soil presented a greater basal mineralisation capacity of 55-70 mg C-CO 2 kg -1 h -1 . The basal levels of lipase and dehydrogenase were significantly greater than those recorded in non-contaminated soils (551 ± 21 μg pNP g -1 ). Regarding the biodegradation potential assessment, the lipase (1000-3000 μg pNP g -1 of perlite) and dehydrogenase (~3000 μg INF g -1 of perlite) activities in the inoculum of the recently contaminated soil were greater than those recorded in the inoculum of the weathered soil. This was correlated with a high mineralisation rate (~30 mg C-CO 2 kg -1 h -1 ) in the recently contaminated soil and a reduction in hydrocarbon concentration (~30 %). The combination of an inert support and enzymatic and respirometric analyses made it possible to detect the different biodegradation capacities of the studied inocula and the natural attenuation potential of a recently contaminated soil at high hydrocarbon concentrations.

Geobacteraceae Community Composition Is Related to Hydrochemistry and Biodegradation in an Iron-Reducing Aquifer Polluted by a Neighboring Landfill†

PubMed Central

Lin, Bin; Braster, Martin; van Breukelen, Boris M.; van Verseveld, Henk W.; Westerhoff, Hans V.; Röling, Wilfred F. M.

2005-01-01

Relationships between community composition of the iron-reducing Geobacteraceae, pollution levels, and the occurrence of biodegradation were established for an iron-reducing aquifer polluted with landfill leachate by using cultivation-independent Geobacteraceae 16S rRNA gene-targeting techniques. Numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles and sequencing revealed a high Geobacteraceae diversity and showed that community composition within the leachate plume differed considerably from that of the unpolluted aquifer. This suggests that pollution has selected for specific species out of a large pool of Geobacteraceae. DGGE profiles of polluted groundwater taken near the landfill (6- to 39-m distance) clustered together. DGGE profiles from less-polluted groundwater taken further downstream did not fall in the same cluster. Several individual DGGE bands were indicative of either the redox process or the level of pollution. This included a pollution-indicative band that dominated the DGGE profiles from groundwater samples taken close to the landfill (6 to 39 m distance). The clustering of these profiles and the dominance by a single DGGE band corresponded to the part of the aquifer where organic micropollutants and reactive dissolved organic matter were attenuated at relatively high rates. PMID:16204512

Biodegradation of hydrocarbon cuts used for diesel oil formulation.

PubMed

Penet, Sophie; Marchal, Rémy; Sghir, Abdelghani; Monot, Frédéric

2004-11-01

The biodegradability of various types of diesel oil (DO), such as straight-run DO, light-cycle DO, hydrocracking DO, Fischer-Tropsch DO and commercial DO, was investigated in biodegradation tests performed in closed-batch systems using two microflorae. The first microflora was an activated sludge from an urban wastewater treatment plant as commonly used in biodegradability tests of commercial products and the second was a microflora from a hydrocarbon-polluted soil with possible specific capacities for hydrocarbon degradation. Kinetics of CO(2) production and extent of DO biodegradation were obtained by chromatographic procedures. Under optimised conditions, the polluted-soil microflora was found to extensively degrade all the DO types tested, the degradation efficiencies being higher than 88%. For all the DOs tested, the biodegradation capacities of the soil microflora were significantly higher than those of the activated sludge. Using both microflora, the extent of biodegradation was highly dependent upon the type of DO used, especially its hydrocarbon composition. Linear alkanes were completely degraded in each test, whereas identifiable branched alkanes such as farnesane, pristane or phytane were degraded to variable extents. Among the aromatics, substituted mono-aromatics were also variably biodegraded.

Recent state-of-the-art of biodegradable scale inhibitors for cooling-water treatment applications (Review)

NASA Astrophysics Data System (ADS)

Popov, K. I.; Kovaleva, N. E.; Rudakova, G. Ya.; Kombarova, S. P.; Larchenko, V. E.

2016-02-01

Scale formation is a challenge worldwide. Recently, scale inhibitors represent the best solution of this problem. The polyaminocarboxylic acids have been the first to be successfully applied in the field, although their efficacy was rather low. The next generation was developed on the grounds of polyphosphonic acids. The main disadvantage of these is associated with low biodegradation level. Polyacrylate-based phosphorous free inhibitors proposed as an alternative to phosphonates all also had low biodegradability. Thus, the main trend of recent R&D is the development of a new generation: environmentally friendly biodegradable scale inhibitors. The recent state of the word and domestic scale inhibitors markets is considered, the main industrial inhibitors manufacturers and marketed substances, as well as the general trends of R&D in the field, are characterized. It is demonstrated that most research is focused on biodegradable polymers and on phosponates with low phosphorus content, as well as on implementation of biodegradable fragments into polyacrylate matrixes for biodegradability enhancement. The problem of research results comparability is indicated along with domestic-made inhibitors quality and the gaps in scale inhibition mechanism. The actuality of fluorescent indicator fragment implementation into the scale inhibitor molecule for the better reagent monitoring in a cooling water system is specially emphasized.

Environmental fate of naproxen, carbamazepine and triclosan in wastewater, surface water and wastewater irrigated soil - Results of laboratory scale experiments.

PubMed

Durán-Álvarez, J C; Prado, B; González, D; Sánchez, Y; Jiménez-Cisneros, B

2015-12-15

Lab-scale photolysis, biodegradation and transport experiments were carried out for naproxen, carbamazepine and triclosan in soil, wastewater and surface water from a region where untreated wastewater is used for agricultural irrigation. Results showed that both photolysis and biodegradation occurred for the three emerging pollutants in the tested matrices as follows: triclosan>naproxen>carbamazepine. The highest photolysis rate for the three pollutants was obtained in experiments using surface water, while biodegradation rates were higher in wastewater and soil than in surface water. Carbamazepine showed to be recalcitrant to biodegradation both in soil and water; although photolysis occurred at a higher level than biodegradation, this compound was poorly degraded by natural processes. Transport experiments showed that naproxen was the most mobile compound through the first 30cm of the soil profile; conversely, the mobility of carbamazepine and triclosan through the soil was delayed. Biodegradation of target pollutants occurred within soil columns during transport experiments. Triclosan was not detected either in leachates or the soil in columns, suggesting its complete biodegradation. Data of these experiments can be used to develop more reliable fate-on-the-field and environmental risk assessment studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Bench-scale biodegradation tests to assess natural attenuation potential of 1,4-dioxane at three sites in California.

PubMed

Li, Mengyan; Van Orden, E Tess; DeVries, David J; Xiong, Zhong; Hinchee, Rob; Alvarez, Pedro J

2015-02-01

1,4-Dioxane (dioxane) is relatively recalcitrant to biodegradation, and its physicochemical properties preclude effective removal from contaminated groundwater by volatilization or adsorption. Through this microcosm study, we assessed the biodegradation potential of dioxane for three sites in California. Groundwater and sediment samples were collected at various locations at each site, including the presumed source zone, middle and leading edge of the plume. A total of 16 monitoring wells were sampled to prepare the microcosms. Biodegradation of dioxane was observed in 12 of 16 microcosms mimicking natural attenuation within 28 weeks. Rates varied from as high as 3,449 ± 459 µg/L/week in source-zone microcosms to a low of 0.3 ± 0.1 µg/L/week in microcosms with trace level of dioxane (<10 µg/L as initial concentration). The microcosms were spiked with (14)C-labeled dioxane to assess the fate of dioxane. Biological oxidizer-liquid scintillation analysis of bound residue infers that 14C-dioxane was assimilated into cell material only in microcosms exhibiting significant dioxane biodegradation. Mineralization was also observed per (14)CO2 recovery (up to 44% of the amount degraded in 28 weeks of incubation). Degradation and mineralization activity significantly decreased with increasing distance from the contaminant source area (p < 0.05), possibly due to less acclimation. Furthermore, both respiked and repeated microcosms prepared with source-zone samples from Site 1 confirmed relatively rapid dioxane degradation (i.e., 100 % removal by 20 weeks). These results show that indigenous microorganisms capable of degrading dioxane are present at these three sites, and suggest that monitored natural attenuation should be considered as a remedial response.

Natural attenuation of trichloroethylene in fractured shale bedrock.

PubMed

Lenczewski, M; Jardine, P; McKay, L; Layton, A

2003-07-01

This paper describes one of the first well-documented field examples of natural attenuation of trichloroethylene (TCE) in groundwater in a fractured shale bedrock. The study was carried out adjacent to a former waste burial site in Waste Area Grouping 5 (WAG5) on the Oak Ridge Reservation, Oak Ridge, TN. A contaminant plume containing TCE and its daughter products were detected downgradient from the buried waste pits, with most of the contamination occurring in the upper 6 m of the bedrock. The monitoring well array consists of a 35-m-long transect of multilevel sampling wells, situated along a line between the waste pits and a seep which discharges into a small stream. Concentrations of volatile organic carbons (VOCs) were highest in the waste trenches and decreased with distance downgradient towards the seep. Sampling wells indicated the presence of overlapping plumes of TCE, cis-dichloroethylene (cDCE), vinyl chloride (VC), ethylene, ethane, and methane, with the daughter products extending further downgradient than the parent (TCE). This type of distribution suggests anaerobic biodegradation. Measurements of redox potential at the site indicated that iron-reduction, sulfate reduction, and potentially methanogensis were occurring and are conducive to dechlorination of TCE. Bacteria enrichment of groundwater samples revealed the presence of methanotrophs, methanogens, iron-reducing bacteria and sulfate-reducing bacteria, all of which have previously been implicated in anaerobic biodegradation of TCE. 16S rDNA sequence from DNA extracted from two wells were similar to sequences of organisms previously implicated in the anaerobic biodegradation of chlorinated solvents. The combined data strongly suggest that anaerobic biodegradation of the highly chlorinated compounds is occurring. Aerobic biodegradation may also be occurring in oxygenated zones, including near a seep where groundwater exits the site, or in the upper bedrock during seasonal fluctuations in water table elevation and oxygen levels.

Prediction of biodegradability from chemical structure: Modeling or ready biodegradation test data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loonen, H.; Lindgren, F.; Hansen, B.

1999-08-01

Biodegradation data were collected and evaluated for 894 substances with widely varying chemical structures. All data were determined according to the Japanese Ministry of International Trade and Industry (MITI) I test protocol. The MITI I test is a screening test for ready biodegradability and has been described by Organization for Economic Cooperation and Development (OECD) test guideline 301 C and European Union (EU) test guideline C4F. The chemicals were characterized by a set of 127 predefined structural fragments. This data set was used to develop a model for the prediction of the biodegradability of chemicals under standardized OECD and EUmore » ready biodegradation test conditions. Partial least squares (PLS) discriminant analysis was used for the model development. The model was evaluated by means of internal cross-validation and repeated external validation. The importance of various structural fragments and fragment interactions was investigated. The most important fragments include the presence of a long alkyl chain; hydroxy, ester, and acid groups (enhancing biodegradation); and the presence of one or more aromatic rings and halogen substituents (regarding biodegradation). More than 85% of the model predictions were correct for using the complete data set. The not readily biodegradable predictions were slightly better than the readily biodegradable predictions (86 vs 84%). The average percentage of correct predictions from four external validation studies was 83%. Model optimization by including fragment interactions improve the model predicting capabilities to 89%. It can be concluded that the PLS model provides predictions of high reliability for a diverse range of chemical structures. The predictions conform to the concept of readily biodegradable (or not readily biodegradable) as defined by OECD and EU test guidelines.« less

Bioremediation of a weathered and a recently oil-contaminated soils from Brazil: a comparison study.

PubMed

Trindade, P V O; Sobral, L G; Rizzo, A C L; Leite, S G F; Soriano, A U

2005-01-01

The facility with which hydrocarbons can be removed from soils varies inversely with aging of soil samples as a result of weathering. Weathering refers to the result of biological, chemical and physical processes that can affect the type of hydrocarbons that remain in a soil. These processes enhance the sorption of hydrophobic organic contaminants (HOCs) to the soil matrix, decreasing the rate and extent of biodegradation. Additionally, pollutant compounds in high concentrations can more easily affect the microbial population of a recently contaminated soil than in a weathered one, leading to inhibition of the biodegradation process. The present work aimed at comparing the biodegradation efficiencies obtained in a recently oil-contaminated soil (spiked one) from Brazil and an weathered one, contaminated for four years, after the application of bioaugmentation and biostimulation techniques. Both soils were contaminated with 5.4% of total petroleum hydrocarbons (TPHs) and the highest biodegradation efficiency (7.4%) was reached for the weathered contaminated soil. It could be concluded that the low biodegradation efficiencies reached for all conditions tested reflect the treatment difficulty of a weathered soil contaminated with a high crude oil concentration. Moreover, both soils (weathered and recently contaminated) submitted to bioaugmentation and biostimulation techniques presented biodegradation efficiencies approximately twice as higher as the ones without the aforementioned treatment (natural attenuation).

Read-across of ready biodegradability based on the substrate specificity of N-alkyl polypropylene polyamine-degrading microorganisms.

PubMed

Geerts, R; van Ginkel, C G; Plugge, C M

2017-04-01

The biodegradation of N-alkyl polypropylene polyamines (NAPPs) was studied using pure and mixed cultures to enable read-across of ready biodegradability test results. Two Pseudomonas spp. were isolated from activated sludge with N-oleyl alkyl propylene diamine and N-coco alkyl dipropylene triamine, respectively. Both strains utilized all NAPPs tested as the sole source of carbon, nitrogen and energy for growth. Mineralization of NAPPs was independent of the alkyl chain length and the size of the polyamine moiety. NAPPs degraded in closed bottle tests (CBTs) using both river water and activated sludge. However, ready biodegradability of NAPPs with alkyl chain lengths of 16-18 carbon atoms and polyamine moieties with three and four nitrogen atoms could not be demonstrated. Biodegradation in the CBT was hampered by their limited bioavailability, making assessment of the true ready biodegradability of these highly adsorptive surfactants impossible. All NAPPs are therefore classified as readily biodegradable through read-across. Read-across is justified by the broad substrate specificity of NAPP-degrading microorganisms, their omnipresence and the mineralization of NAPPs.

Endocrine activity in an urban river system and the biodegradation of estrogen-like endocrine disrupting chemicals through a bio-analytical approach using DRE- and ERE-CALUX bioassays.

PubMed

Vandermarken, T; Croes, K; Van Langenhove, K; Boonen, I; Servais, P; Garcia-Armisen, T; Brion, N; Denison, M S; Goeyens, L; Elskens, M

2018-06-01

The Zenne River, crossing the Brussels region (Belgium) is an extremely urbanized river impacted by both domestic and industrial effluents. The objective of this study was to monitor the occurrence and activity of Endocrine Active Substances (EAS) in river water and sediments in the framework of the Environmental Quality Standards Directive (2008/105/EC and 2013/39/EU). Activities were determined using Estrogen and Dioxin Responsive Elements (ERE and DRE) Chemical Activated Luciferase Gene Expression (CALUX) bioassays. A potential contamination source of estrogen active compounds was identified in the river at an industrial area downstream from Brussels with a peak value of 938 pg E2 eq./L water (above the EQS of 0.4 ng/L) and 195 pg E2 eq./g sediment. Estrogens are more abundantly present in the sediments than in the dissolved phase. Principal Component Analysis (PCA) showed high correlations between Suspended Particulate Matter (SPM), Particulate (POC) and Dissolved Organic Carbon (DOC) and estrogenic EAS. The dioxin fractions comply with previous data and all were above the United States Environmental Protection Agency (US EPA) low-level risk, with one (42 pg TCDD eq./g sediment) exceeding the high-level risk value for mammals. The self-purifying ability of the Zenne River regarding estrogens was examined with an in vitro biodegradation experiment using the bacterial community naturally present in the river. Hill coefficient and EC 50 values (Effective Concentration at 50%) revealed a process of biodegradation in particulate and dissolved phase. The estrogenic activity was decreased by 80%, demonstrating the ability of self-purification of estrogenic compounds in the Zenne River. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetic and microbial community analysis of methyl ethyl ketone biodegradation in aquifer sediments.

PubMed

Fahrenfeld, N; Pruden, A; Widdowson, M

2017-02-01

Methyl ethyl ketone (MEK) is a common groundwater contaminant often present with more toxic compounds of primary interest. Because of this, few studies have been performed to determine the effect of microbial community structure on MEK biodegradation rates in aquifer sediments. Here, microcosms were prepared with aquifer sediments containing MEK following a massive spill event and compared to laboratory-spiked sediments, with MEK biodegradation rates quantified under mixed aerobic/anaerobic conditions. Biodegradation was achieved in MEK-contaminated site sediment microcosms at about half of the solubility (356 mg/L) with largely Firmicutes population under iron-reducing conditions. MEK was biodegraded at a higher rate [4.0 ± 0.74 mg/(L days)] in previously exposed site samples compared to previously uncontaminated sediments [0.51 ± 0.14 mg/(L days)]. Amplicon sequencing and denaturing gradient gel electrophoresis of 16S rRNA genes were combined to understand the relationship between contamination levels, biodegradation, and community structure across the plume. More heavily contaminated sediments collected from an MEK-contaminated field site had the most similar communities than less contaminated sediments from the same site despite differences in sediment texture. The more diverse microbial community observed in the laboratory-spiked sediments reduced MEK concentration 47 % over 92 days. Results of this study suggest lower rates of MEK biodegradation in iron-reducing aquifer sediments than previously reported for methanogenic conditions and biodegradation rates comparable to previously reported nitrate- and sulfate-reducing conditions.

Soil burial biodegradation studies of palm oil-based UV-curable films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tajau, Rida, E-mail: rida@nuclearmalaysia.gov.my; Salleh, Mek Zah, E-mail: mekzah@nuclearmalaysia.gov.my; Salleh, Nik Ghazali Nik, E-mail: nik-ghazali@nuclearmalaysia.gov.my

The palm oil-based ultraviolet (uv)-curable films were subjected to an outdoor soil burial test to investigate the biodegradation under natural environment. The films were burial in the soil experiment plot at the Nuclear Malaysia’s Dengkil complex. The uv-curable films were synthesized from the epoxidized palm oil acrylated (EPOLA) resin and the polyurethane palm oil (POBUA) resin, respectively. Biodegradation tests are more specific to burial film in soil experiments for 12 months under natural conditions. The biodegradability of palm oil resin based uv-curable films were investigated and compared with the petrochemical resin based film. The films properties were compared with respectmore » to properties of the thermal characteristic, the crystallinity, the morphology and the weight loss which are analyzed using the thermogravimetric analysis (TGA), the differential scanning calorimetry (DSC), the scanning electron microscope (SEM), an optical microscope and the weight loss of film calculation. These findings suggested that the palm oil-based uv-curable films show quite satisfactory biodegradation levels.« less

Soil burial biodegradation studies of palm oil-based UV-curable films

NASA Astrophysics Data System (ADS)

Tajau, Rida; Salleh, Mek Zah; Salleh, Nik Ghazali Nik; Abdurahman, Mohamad Norahiman; Salih, Ashraf Mohammed; Fathy, Siti Farhana; Azman, Anis Asmi; Hamidi, Nur Amira

2016-01-01

The palm oil-based ultraviolet (uv)-curable films were subjected to an outdoor soil burial test to investigate the biodegradation under natural environment. The films were burial in the soil experiment plot at the Nuclear Malaysia's Dengkil complex. The uv-curable films were synthesized from the epoxidized palm oil acrylated (EPOLA) resin and the polyurethane palm oil (POBUA) resin, respectively. Biodegradation tests are more specific to burial film in soil experiments for 12 months under natural conditions. The biodegradability of palm oil resin based uv-curable films were investigated and compared with the petrochemical resin based film. The films properties were compared with respect to properties of the thermal characteristic, the crystallinity, the morphology and the weight loss which are analyzed using the thermogravimetric analysis (TGA), the differential scanning calorimetry (DSC), the scanning electron microscope (SEM), an optical microscope and the weight loss of film calculation. These findings suggested that the palm oil-based uv-curable films show quite satisfactory biodegradation levels.

Evolution of biodegradation of deinking by-products used as alternative cover material.

PubMed

Aït-Benichou, Samah; Rodrigues Cabral, Alexandre; Teixeira Panarotto, Claudia

2008-01-01

Deinking by-products (DBP) have been used as alternative cover material for landfills and mine tailings. Since DBP is biodegradable because of its high cellulose and hemicellulose content, a laboratory experimental program was performed to monitor the evolution of biodegradation and changes in the physico-chemical and geotechnical properties of DBP samples submitted to accelerated biodegradation for 1460 days at 38 degrees C. The evolution of gas and leachate production was monitored in terms of both quality and quantity, which allowed for the calculation of mass loss with time. Under the conditions of the tests (no load applied), 19.6% of the mass was lost as gas, whereas 6.1% was leached out. The results show that biodegradation did not significantly alter the compaction behavior of DBP. The void ratio and water content increased significantly, while the volume of the samples slightly decreased. This seem to indicate that the porous structure of the samples was no longer the same after 1460 d of accelerated biodegradation. A slight increase in the relative density indicates that the organic/inorganic matter ratio increased. The results of permeability tests performed with samples at various stages of biodegradation and at various confining stresses show that the saturated hydraulic conductivity of recompacted biodegraded DBP decreased from 7 x 10(-7)cm/s to approximately 2 x 10(-7)cm/s, as biodegradation advanced.

Biodegradability of tannin-containing wastewater from leather industry.

PubMed

He, Qiang; Yao, Kai; Sun, Danhong; Shi, Bi

2007-08-01

Tannins occur commonly in the wastewaters from forestry, plant medicine, paper and leather industries. The treatment of this kind of wastewaters, including settling and biodegradation, is usually difficult because tannins are highly soluble in water and would inhibit the growth of microorganisms in activated sludge. The objective of this study is to investigate biodegradability of tannin-containing wastewaters, so as to characterize the pollution properties of such wastewaters and provide a reference for their biological treatment in wastewater treatment plants. The research was typified by using the wastewater collected from vegetable tanning process in leather industry. A model was developed to describe the activated sludge process, and the biodegradation kinetics of vegetable tanning wastewater (VET wastewater) was studied. It was found that the biodegradability of tannin-containing wastewater varies heavily with the content of tannins in wastewater. The biodegradation of VET wastewater with tannin content around 4,900 mg/l occurred inefficiently due to the inhibition of tannins to the activated sludge process, and only 34.7% of biodegradation extent was reached in 14 days of incubation. The optimal biodegradability of VET wastewater was observed when its tannin content was diluted to 490 mg/l, where the COD and tannin removals reached 51.3% and 45.1% respectively in 6 days. Hence, it is suggested that a proper control of tannin content is necessary to achieve an effective biodegradation of tannin-containing wastewaters in wastewater treatment plants.

Application of molecular docking for the degradation of organic pollutants in the environmental remediation: A review.

PubMed

Liu, Zhifeng; Liu, Yujie; Zeng, Guangming; Shao, Binbin; Chen, Ming; Li, Zhigang; Jiang, Yilin; Liu, Yang; Zhang, Yu; Zhong, Hua

2018-07-01

The molecular docking has been employed successfully to study the mechanism of biodegradation in the environmental remediation in the past few years, although medical science and biology are the main application areas for it. Molecular docking is a very convenient and low cost method to understand the reaction mechanism of proteins or enzymes with ligands with a high accuracy. This paper mainly provides a review for the application of molecular docking between organic pollutants and enzymes. It summarizes the fundamental knowledge of molecular docking, such as its theory, available softwares and main databases. Moreover, five types of pollutants, including phenols, BTEX (benzene, toluene, ethylbenzene, and xylenes), nitrile, polycyclic aromatic hydrocarbons (PAHs), and high polymer (e.g., lignin and cellulose), are discussed from molecular level. Different removal mechanisms are also explained in detail via docking technology. Even though this method shows promising application in the research of biodegradation, further studies are still needed to relate with actual condition. Copyright © 2018 Elsevier Ltd. All rights reserved.

Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

NASA Astrophysics Data System (ADS)

Aras, Neny Rasnyanti M.; Arcana, I. Made

2015-09-01

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate, and followed by thermal treatment at a temperature of 70 °C and the incubation time for 45 days in the activated sludge.

A comparative study of different tests for biodegradability enhancement determination during AOP treatment of recalcitrant toxic aqueous solutions.

PubMed

Ballesteros Martín, M M; Casas López, J L; Oller, I; Malato, S; Sánchez Pérez, J A

2010-09-01

Four biodegradability tests (Pseudomonas putida bioassay, Zahn-Wellens test, BOD5/COD ratio and respirometry assay) have been used to determine the biodegradability enhancement during the treatment of wastewater containing 200 mg L(-1) of dissolved organic carbon (DOC) of a five commercial pesticides mixture (Vydate, Metomur, Couraze, Ditumur and Scala) by an advanced oxidation process (AOP). A comparative study was carried out taking into account repeatability and precision of each biodegradability test. Solar photo-Fenton was the AOP selected for pesticide degradation up to three levels of mineralization: 20%, 40% and 60% of initial DOC. Intra- and interday precisions were evaluated conducting each biodegradability test by triplicate and they were applied three times on different dates over a period of three months. Fisher's least significant difference method was applied to the means, P. putida and Zahn-Wellens tests giving higher repeatability and precision. The P. putida test requires a shorter time to obtain reliable results using a standardized inoculum and constitutes a worthwhile alternative to estimate biodegradability in contrast to other less accurate or more time consuming methods. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Lactic acid polymers as biodegradable carriers of fluoroquinolones: an in vitro study.

PubMed

Kanellakopoulou, K; Kolia, M; Anastassiadis, A; Korakis, T; Giamarellos-Bourboulis, E J; Andreopoulos, A; Dounis, E; Giamarellou, H

1999-03-01

A biodegradable polymer of DL-dilactide that facilitates release of ciprofloxacin or pefloxacin at levels exceeding MICs for the causative microorganisms of chronic osteomyelitis is described. Duration and peak of release were found to depend on the molecular weight of the polymer. Its characteristics make it promising for treating chronic bone infections.

Methanogenic biodegradation of charcoal production wastes in groundwater at Kingsford, Michigan, USA

USGS Publications Warehouse

Michael, Godsy E.; Warren, E.; Westjohn, D.B.

2001-01-01

A house exploded in the City of Kingsford, Michigan USA. The explosion was caused by CH4 that leaked into the basement from the surrounding soil. Evidence suggests that biodegradation of products from the distillation and spillage at or near a former wood carbonization plant site was the major source of CH4 and CO2 in the groundwater system. The plant area is directly upgradient from deep groundwater, samples of which are green-yellow in colour, have a very strong odour of burnt wood, contain high concentrations of mononuclear aromatic and phenolic compounds, and extremely high concentrations of volatile fatty acids. The majority of the dissolved compounds in these groundwater samples have been shown, using laboratory microcosms, to be anaerobically biodegradable to CH4 and CO2. The biodegradable compounds, and the amounts of CH4 and CO2 produced in the microcosms, are consistent with observations from field samples.

Effects of carbon nanotubes on atrazine biodegradation by Arthrobacter sp.

PubMed

Zhang, Chengdong; Li, Mingzhu; Xu, Xu; Liu, Na

2015-04-28

The environmental risks of engineered nanoparticles have attracted attention. However, little is known regarding the effects of carbon nanotubes (CNTs) on the biodegradation and persistence of organic contaminants in water. We investigated the impacts of pristine and oxidized multiwalled CNTs on the atrazine biodegradation rate and efficiency using Arthrobacter sp. At a concentration of 25mg/L, the CNTs enhanced the biodegradation rate by up to 20%; however, at a concentration of 100mg/L, the CNTs decreased the biodegradation rate by up to 50%. The stimulation effects resulted from enhanced bacterial growth and the overexpression of degradation genes. The inhibitory effects resulted from the toxicity of the CNTs at high concentrations. The differences between the two CNTs at tested concentrations were not significant. The biodegradation efficiency was not impacted by adsorption, and the pre-adsorbed atrazine on the CNTs was fully biodegraded when the CNT concentration was ≤25mg/L. This finding was consistent with the lack of observable desorption hysteresis for atrazine on the tested CNTs. Our results indicate that CNTs can enhance or inhibit biodegradation through a balance of two effects: the toxic effects on microbial activity and the effects of the changing bioavailability that result from adsorption and desorption. Copyright © 2015 Elsevier B.V. All rights reserved.

Aerobic biodegradation of amphoteric amine-oxide-based surfactants: Effect of molecular structure, initial surfactant concentration and pH.

PubMed

Ríos, Francisco; Lechuga, Manuela; Fernández-Serrano, Mercedes; Fernández-Arteaga, Alejandro

2017-03-01

The present study was designed to provide information regarding the effect of the molecular structure of amphoteric amine-oxide-based surfactants and the initial surfactant concentration on their ultimate biodegradation. Moreover, given this parameter's pH-dependence, the effect of pH was also investigated. Three amine-oxide-based surfactants with structural differences in their hydrophobic alkyl chain were tested: Lauramine oxide (AO-R 12 ), Myristamine oxide (AO-R 14 ) and Cocamidopropylamine oxide (AO-Cocoamido). We studied the ultimate biodegradation using the Modified OECD Screening Test at initial surfactant concentrations ranged from 5 to 75 mg L -1 and at pH levels from 5 to 7.4. The results demonstrate that at pH 7.4, amine-oxide-based surfactants are readily biodegradable. In this study, we concluded that ω-oxidation can be assumed to be the main biodegradation pathway of amine-oxides and that differences in the biodegradability between them can be explained by the presence of an amide group in the alkyl chain of AO-Cocoamido; the CN fission of the amide group slows down their mineralization process. In addition, the increase in the concentration of the surfactant from 5 to 75 mg L -1 resulted in an increase in the final biodegradation of AO-R 12 and AO-R 14 . However, in the case of AO-Cocoamido, a clear relationship between the concentration and biodegradation cannot be stated. Conversely, the biodegradability of AO-R 12 and AO-R 14 was considerably lower in an acid condition than at a pH of 7.4, whereas AO-Cocoamido reached similar percentages in acid conditions and at a neutral pH. However, microorganisms required more time to acclimate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil.

PubMed

Won, Jongho; Borden, Robert C

2016-11-01

Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate >200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20g/m 3 /d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil. Copyright © 2016 Elsevier B.V. All rights reserved.

An adsorption-release-biodegradation system for simultaneous biodegradation of phenol and ammonium in phenol-rich wastewater.

PubMed

Wang, Ying; Chen, Hu; Liu, Yu-Xiang; Ren, Rui-Peng; Lv, Yong-Kang

2016-07-01

The feasibility of simultaneous biodegradation of phenol and ammonium in phenol-rich wastewater was evaluated in a reusable system, which contained macroporous adsorption resin and Alcaligenes faecalis strain WY-01. In the system, up to 6000mg/L phenol could be completely degraded by WY-01; meanwhile, 99.03±3.95% of ammonium was removed from the initial concentration of 384mg/L. This is the first study to show the capability of single strain in simultaneous removal of ammonium and phenol in wastewater containing such high concentrations of phenol. Moreover, the resin was regenerated during the biodegradation process without any additional manipulations, indicating the system was reusable. Furthermore, enzyme assay, gene expression patterns, HPLC-MS and gas chromatography analysis confirmed that phenol biodegradation accompanied with aerobic nitrifier denitrification process. Results imply that the reusable system provides a novel strategy for more efficient biodegradation of phenol and ammonium contained in some particular industrial wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biocompatibility and characterization of renewable agricultural residues and polyester composites.

PubMed

Wu, Chin-San; Hsu, Yi-Chiang; Yeh, Jen-taut; Liao, Hsin-Tzu; Jhang, Jheng-Jie; Sie, Yong-Yu

2013-04-15

Composites of sesame husk and glycidyl methacrylate-grafted polytrimethylene terephthalate (PTT-g-GMA/SH) exhibit noticeably superior mechanical properties compared to PTT/SH composites due to greater compatibility between the two components. The dispersion of SH in the PTT-g-GMA matrix is highly homogeneous as a result of condensation reaction formations. Human lung fibroblasts (FBs) were seeded on these two series of composites to characterize the biocompatibility properties. In a time-dependent course, the FB proliferation results demonstrated higher performance from the PTT/SH series of composites than from the PTT-g-GMA/SH composites. In addition, collagen production by FBs present in the PTT/SH series was 20% higher than in regular culture-plates after 7 days of incubation. The water resistance of PTT-g-GMA/SH was higher than that of PTT/SH, although the weight loss of both composites buried in soil compost indicated that they were both biodegradable, especially at higher levels of SH substitution. The PTT/SH and PTT-g-GMA/SH composites were more biodegradable than pure PTT, implying a strong connection between SH content and biodegradability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fate of pharmaceutical compounds in hydroponic mesocosms planted with Scirpus validus.

PubMed

Zhang, Dong Qing; Gersberg, Richard M; Hua, Tao; Zhu, Junfei; Goyal, Manish Kumar; Ng, Wun Jern; Tan, Soon Keat

2013-10-01

A systematic approach to assess the fate of selected pharmaceuticals (carbamazepine, naproxen, diclofenac, clofibric acid and caffeine) in hydroponic mesocosms is described. The overall objective was to determine the kinetics of depletion (from solution) and plant uptake for these compounds in mesocosms planted with S. validus growing hydroponically. The potential for translocation of these pharmaceuticals from the roots to the shoots was also assessed. After 21 days of incubation, nearly all of the caffeine, naproxen and diclofenac were eliminated from solution, whereas carbamazepine and clofibric acid were recalcitrant to both photodegradation and biodegradation. The fact that the BAFs for roots for carbamazepine and clofibric acid were greater than 5, while the BAFs for naproxen, diclofenac and caffeine were less than 5, implied that the latter two compounds although recalcitrant to biodegradation, still had relatively high potential for plant uptake. Naproxen was sensitive to both photodegradation (30-42%) and biodegradation (>50%), while diclofenac was particularly sensitive (>70%) to photodegradation alone. No significant correlations (p > 0.05) were found between the rate constants of depletion or plant tissue levels of the pharmaceuticals and either log Kow or log Dow. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodegradation Mechanisms of Patulin in Candida guilliermondii: An iTRAQ-Based Proteomic Analysis

PubMed Central

Chen, Yong; Peng, Huai-Min; Wang, Xiao; Li, Bo-Qiang; Long, Man-Yuan; Tian, Shi-Ping

2017-01-01

Patulin, a potent mycotoxin, contaminates fruits and derived products worldwide, and is a serious health concern. Several yeast strains have shown the ability to effectively degrade patulin. However, the mechanisms of its biodegradation still remain unclear at this time. In the present study, biodegradation and involved mechanisms of patulin by an antagonistic yeast Candida guilliermondii were investigated. The results indicated that C. guilliermondii was capable of not only multiplying to a high population in medium containing patulin, but also effectively reducing patulin content in culture medium. Degradation of patulin by C. guilliermondii was dependent on the yeast cell viability, and mainly occurred inside cells. E-ascladiol was the main degradation product of patulin. An iTRAQ-based proteomic analysis revealed that the responses of C. guilliermondii to patulin were complex. A total of 30 differential proteins involved in 10 biological processes were identified, and more than two-thirds of the differential proteins were down-accumulated. Notably, a short-chain dehydrogenase (gi|190348612) was markedly induced by patulin at both the protein and mRNA levels. Our findings will provide a foundation to help enable the commercial development of an enzyme formulation for the detoxification of patulin in fruit-derived products. PMID:28208714

Solar photocatalytic treatment of landfill leachate using a solid mineral by-product as a catalyst.

PubMed

Poblete, Rodrigo; Prieto-Rodríguez, Lucia; Oller, Isabel; Maldonado, Manuel I; Malato, Sixto; Otal, Emilia; Vilches, Luis F; Fernández-Pereira, Constantino

2012-08-01

The treatment of municipal solid waste landfill leachate in a pilot plant made up of solar compound parabolic collectors, using a solid industrial titanium by-product (WTiO(2)) containing TiO(2) and Fe(III) as a photocatalyst, was investigated. In the study evidence was found showing that the degradation performed with WTiO(2) was mainly due to the Fe provided by this by-product, instead of TiO(2). However, although TiO(2) had very little effect by itself, a synergistic effect was observed between Fe and TiO(2). The application of WTiO(2), which produced coupled photo-Fenton and heterogeneous catalysis reactions, achieved a surprisingly high depuration level (86% of COD removal), higher than that reached by photo-Fenton using commercial FeSO(4) (43%) in the same conditions. After the oxidation process the biodegradability and toxicity of the landfill leachate were studied. The results showed that the leachate biodegradability was substantially increased, at least in the first stages of the process, and again that WTiO(2) was more efficient than FeSO(4) in terms of increasing biodegradability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Importance of Xanthobacter autotrophicus in toluene biodegradation within a contaminated stream.

PubMed

Tay, S T; Hemond, H F; Polz, M F; Cavanaugh, C M; Krumholz, L R

1999-02-01

Toluene-degrading strains T101 and T102 were isolated from rock surface biomass in a toluene-contaminated freshwater stream. These organisms were present at a density of 5.5 x 10(6) cells/g of rock surface biomass. Both are aerobic, rod-shaped, Gram-negative, non-motile, catalase-positive, oxidase-positive, with yellow pigments, and can grow on benzene. Phylogenetic analyses show that strains T101 and T102 have 16S rDNA sequences identical to Xanthobacter autotrophicus. Fatty acid analyses indicate that they are different strains of the same species Xanthobacter autotrophicus, and that they have high levels of cis-11-octadecenoic acid and cis-9-hexadecenoic acid; 3-hydroxyhexadecanoic acid is the major hydroxy fatty acid present. Strains T101 and T102 had maximal velocities (Vmax) for toluene biodegradation of 3.8 +/- 0.5 and 28.3 +/- 2.2 mumoles toluene/mgprotein-hr, and half-saturation constants (Ks) of 0.8 +/- 0.5 and 11.5 +/- 2.4 microM, respectively. Strain T102 has a higher capacity than strain T101 to degrade toluene, and kinetic calculations suggest that strain T102 may be a major contributor to toluene biodegradation in the stream.

Oil Biodegradation and Oil-Degrading Microbial Populations in Marsh Sediments Impacted by Oil from the Deepwater Horizon Well Blowout.

PubMed

Atlas, Ronald M; Stoeckel, Donald M; Faith, Seth A; Minard-Smith, Angela; Thorn, Jonathan R; Benotti, Mark J

2015-07-21

To study hydrocarbon biodegradation in marsh sediments impacted by Macondo oil from the Deepwater Horizon well blowout, we collected sediment cores 18-36 months after the accident at the marshes in Bay Jimmy (Upper Barataria Bay), Louisiana, United States. The highest concentrations of oil were found in the top 2 cm of sediment nearest the waterline at the shorelines known to have been heavily oiled. Although petroleum hydrocarbons were detectable, Macondo oil could not be identified below 8 cm in 19 of the 20 surveyed sites. At the one site where oil was detected below 8 cm, concentrations were low. Residual Macondo oil was already highly weathered at the start of the study, and the concentrations of individual saturated hydrocarbons and polycyclic aromatic hydrocarbons continued to decrease over the course of the study due to biodegradation. Desulfococcus oleovorans, Marinobacter hydrocarbonoclasticus, Mycobacterium vanbaalenii, and related mycobacteria were the most abundant oil-degrading microorganisms detected in the top 2 cm at the oiled sites. Relative populations of these taxa declined as oil concentrations declined. The diversity of the microbial community was low at heavily oiled sites compared to that of the unoiled reference sites. As oil concentrations decreased over time, microbial diversity increased and approached the diversity levels of the reference sites. These trends show that the oil continues to be biodegraded, and microbial diversity continues to increase, indicating ongoing overall ecological recovery.

Remediation of soil co-contaminated with petroleum and heavy metals by the integration of electrokinetics and biostimulation.

PubMed

Dong, Zhi-Yong; Huang, Wen-Hui; Xing, Ding-Feng; Zhang, Hong-Feng

2013-09-15

Successful remediation of soil co-contaminated with high levels of organics and heavy metals is a challenging task, because that metal pollutants in soil can partially or completely suppress normal heterotrophic microbial activity and thus hamper biodegradation of organics. In this study, the benefits of integrating electrokinetic (EK) remediation with biodegradation for decontaminating soil co-contaminated with crude oil and Pb were evaluated in laboratory-scale experiments lasting for 30 days. The treated soil contained 12,500 mg/kg of total petroleum hydrocarbons (TPH) and 450 mg/kg Pb. The amendments of EDTA and Tween 80, together with a regular refreshing of electrolyte showed the best performance to remediate this contaminated soil. An important function of EDTA-enhanced EK treatment was to eliminate heavy metal toxicity from the soil, thus activating microbial degradation of oil. Although Tween 80 reduced current, it could serve as a second substrate for enhancing microbial growth and biodegradation. It was found that oil biodegradation degree and microbial numbers increased toward the anode and cathode. Microbial metabolism was found to be beneficial to metal release from the soil matrix. Under the optimum conditions, the soil Pb and TPH removal percentages after 30 days of running reached 81.7% and 88.3%, respectively. After treatment, both the residual soil Pb and TPH concentrations met the requirement of the Chinese soil environmental quality standards. Copyright © 2013 Elsevier B.V. All rights reserved.

A new biostimulation approach based on the concept of remaining P for soil bioremediation.

PubMed

Júlio, Aline Daniela Lopes; Fernandes, Rita de Cássia Rocha; Costa, Maurício Dutra; Neves, Júlio César Lima; Rodrigues, Edmo Montes; Tótola, Marcos Rogério

2018-02-01

C:N:P ratio is generally adopted to estimate the amount of nitrogen and phosphorus to be added to soils to accelerate biodegradation of organic contaminants. However, differences in P fixation among soils lead to varying amounts of available P when a specific dose of the element is applied to different soils. Thus, the application of fertilizers to achieve a previously established C:P ratio leads to biodegradation rates that can be lower than the theoretical maximum. In this study, we developed an equation to estimate the dose of P required to maximize organic contaminant biodegradation in soils as a function of remaining P (P-rem), using diesel as a model contaminant. The soils were contaminated with diesel and received six doses of P. CO 2 emission was used to estimate biodegradation of hydrocarbons. Biodegradation increased with P doses. The P level that provided the highest hydrocarbon biodegradation rate showed linear and negative correlation with P-rem. The result shows that the requirement for P decreases as the P-rem of the soil increases (or the P-fixing capacity decreases). The dose of P recommended to maximize hydrocarbon biodegradation rate in soil can be estimated by the formula P (mg/dm 3 ) = 436.5-5.39 × P-rem (mg/L). Copyright © 2017 Elsevier Ltd. All rights reserved.

Trichloroethylene Biodegradation by a Methane-Oxidizing Bacterium †

PubMed Central

Little, C. Deane; Palumbo, Anthony V.; Herbes, Stephen E.; Lidstrom, Mary E.; Tyndall, Richard L.; Gilmer, Penny J.

1988-01-01

Trichloroethylene (TCE), a common groundwater contaminant, is a suspected carcinogen that is highly resistant to aerobic biodegradation. An aerobic, methane-oxidizing bacterium was isolated that degrades TCE in pure culture at concentrations commonly observed in contaminated groundwater. Strain 46-1, a type I methanotrophic bacterium, degraded TCE if grown on methane or methanol, producing CO2 and water-soluble products. Gas chromatography and 14C radiotracer techniques were used to determine the rate, methane dependence, and mechanism of TCE biodegradation. TCE biodegradation by strain 46-1 appears to be a cometabolic process that occurs when the organism is actively metabolizing a suitable growth substrate such as methane or methanol. It is proposed that TCE biodegradation by methanotrophs occurs by formation of TCE epoxide, which breaks down spontaneously in water to form dichloroacetic and glyoxylic acids and one-carbon products. Images PMID:16347616

In vivo characterization of magnesium alloy biodegradation using electrochemical H2 monitoring, ICP-MS, and XPS.

PubMed

Zhao, Daoli; Wang, Tingting; Nahan, Keaton; Guo, Xuefei; Zhang, Zhanping; Dong, Zhongyun; Chen, Shuna; Chou, Da-Tren; Hong, Daeho; Kumta, Prashant N; Heineman, William R

2017-03-01

The effect of widely different corrosion rates of Mg alloys on four parameters of interest for in vivo characterization was evaluated: (1) the effectiveness of transdermal H 2 measurements with an electrochemical sensor for noninvasively monitoring biodegradation compared to the standard techniques of in vivo X-ray imaging and weight loss measurement of explanted samples, (2) the chemical compositions of the corrosion layers of the explanted samples by XPS, (3) the effect on animal organs by histology, and (4) the accumulation of corrosion by-products in multiple organs by ICP-MS. The in vivo biodegradation of three magnesium alloys chosen for their widely varying corrosion rates - ZJ41 (fast), WKX41 (intermediate) and AZ31 (slow) - were evaluated in a subcutaneous implant mouse model. Measuring H 2 with an electrochemical H 2 sensor is a simple and effective method to monitor the biodegradation process in vivo by sensing H 2 transdermally above magnesium alloys implanted subcutaneously in mice. The correlation of H 2 levels and biodegradation rate measured by weight loss shows that this non-invasive method is fast, reliable and accurate. Analysis of the insoluble biodegradation products on the explanted alloys by XPS showed all of them to consist primarily of Mg(OH) 2 , MgO, MgCO 3 and Mg 3 (PO 4 ) 2 with ZJ41 also having ZnO. The accumulation of magnesium and zinc were measured in 9 different organs by ICP-MS. Histological and ICP-MS studies reveal that there is no significant accumulation of magnesium in these organs for all three alloys; however, zinc accumulation in intestine, kidney and lung for the faster biodegrading alloy ZJ41 was observed. Although zinc accumulates in these three organs, no toxicity response was observed in the histological study. ICP-MS also shows higher levels of magnesium and zinc in the skull than in the other organs. Biodegradable devices based on magnesium and its alloys are promising because they gradually dissolve and thereby avoid the need for subsequent removal by surgery if complications arise. In vivo biodegradation rate is one of the crucial parameters for the development of these alloys. Promising alloys are first evaluated in vivo by being implanted subcutaneously in mice for 1month. Here, we evaluated several magnesium alloys with widely varying corrosion rates in vivo using multiple characterization techniques. Since the alloys biodegrade by reacting with water forming H 2 gas, we used a recently demonstrated, simple, fast and noninvasive method to monitor the biodegradation process by just pressing the tip of a H 2 sensor against the skin above the implant. The analysis of 9 organs (intestine, kidney, spleen, lung, heart, liver, skin, brain and skull) for accumulation of Mg and Zn revealed no significant accumulation of magnesium in these organs. Zinc accumulation in intestine, kidney and lung was observed for the faster corroding implant ZJ41. The surfaces of explanted alloys were analyzed to determine the composition of the insoluble biodegradation products. The results suggest that these tested alloys are potential candidates for biodegradable implant applications. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of inorganic nanoparticles on viability and catabolic activities of Agrobacterium sp. PH-08 during biodegradation of dibenzofuran.

PubMed

Le, Thao Thanh; Murugesan, Kumarasamy; Kim, Eun-Ju; Chang, Yoon-Seok

2014-09-01

This study investigated the cytotoxicity, genotoxicity, and growth inhibition effects of four different inorganic nanoparticles (NPs) such as aluminum (nAl), iron (nFe), nickel (nNi), and zinc (nZn) on a dibenzofuran (DF) degrading bacterium Agrobacterium sp. PH-08. NP (0-1,000 mg L(-1)) -treated bacterial cells were assessed for cytotoxicity, genotoxicity, growth and biodegradation activities at biochemical and molecular levels. In an aqueous system, the bacterial cells treated with nAl, nZn and nNi at 500 mg L(-1) showed significant reduction in cell viability (30-93.6 %, p < 0.05), while nFe had no significant inhibition on bacterial cell viability. In the presence of nAl, nZn and nNi, the cells exhibited elevated levels of reactive oxygen species (ROS), DNA damage and cell death. Furthermore, NP exposure showed significant (p < 0.05) impairment in DF and catechol biodegradation activities. The reduction in DF biodegradation was ranged about 71.7-91.6 % with single NPs treatments while reached up to 96.3 % with a mixture of NPs. Molecular and biochemical investigations also clearly revealed that NP exposure drastically affected the catechol-2,3-dioxygenase activities and its gene (c23o) expression. However, no significant inhibition was observed in nFe treatment. The bacterial extracellular polymeric materials and by-products from DF degradation can be assumed as key factors in diminishing the toxic effects of NPs, especially for nFe. This study clearly demonstrates the impact of single and mixed NPs on the microbial catabolism of xenobiotic-degrading bacteria at biochemical and molecular levels. This is the first study on estimating the impact of mixed NPs on microbial biodegradation.

Intrinsic bioremediation of MTBE-contaminated groundwater at a petroleum-hydrocarbon spill site

NASA Astrophysics Data System (ADS)

Chen, K. F.; Kao, C. M.; Chen, T. Y.; Weng, C. H.; Tsai, C. T.

2006-06-01

An oil-refining plant site located in southern Taiwan has been identified as a petroleum-hydrocarbon [mainly methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX)] spill site. In this study, groundwater samples collected from the site were analyzed to assess the occurrence of intrinsic MTBE biodegradation. Microcosm experiments were conducted to evaluate the feasibility of biodegrading MTBE by indigenous microorganisms under aerobic, cometabolic, iron reducing, and methanogenic conditions. Results from the field investigation and microbial enumeration indicate that the intrinsic biodegradation of MTBE and BTEX is occurring and causing the decrease in MTBE and BTEX concentrations. Microcosm results show that the indigenous microorganisms were able to biodegrade MTBE under aerobic conditions using MTBE as the sole primary substrate. The detected biodegradation byproduct, tri-butyl alcohol (TBA), can also be biodegraded by the indigenous microorganisms. In addition, microcosms with site groundwater as the medium solution show higher MTBE biodegradation rate. This indicates that the site groundwater might contain some trace minerals or organics, which could enhance the MTBE biodegradation. Results show that the addition of BTEX at low levels could also enhance the MTBE removal. No MTBE removal was detected in iron reducing and methanogenic microcosms. This might be due to the effects of low dissolved oxygen (approximately 0.3 mg/L) within the plume. The low iron reducers and methanogens (<1.8×103 cell/g of soil) observed in the aquifer also indicate that the iron reduction and methanogenesis are not the dominant biodegradation patterns in the contaminant plume. Results from the microcosm study reveal that preliminary laboratory study is required to determine the appropriate substrates and oxidation-reduction conditions to enhance the biodegradation of MTBE. Results suggest that in situ or on-site aerobic bioremediation using indigenous microorganisms would be a feasible technology to clean up this MTBE-contaminated site.

Biodegradation kinetics of 1,4-benzoquinone in batch and continuous systems.

PubMed

Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2011-11-01

Combining chemical and biological treatments is a potentially economic approach to remove high concentration of recalcitrant compounds from wastewaters. In the present study, the biodegradation of 1,4-benzoquinone, an intermediate compound formed during phenol oxidation by chlorine dioxide, was investigated using Pseudomonas putida (ATCC 17484) in batch and continuous bioreactors. Batch experiments were conducted to determine the effects of 1,4-benzoquinone concentration and temperature on the microbial activity and biodegradation kinetics. Using the generated data, the maximum specific growth rate and biodegradation rate were determined as 0.94 h(-1) and 6.71 mg of 1,4-benzoquinone l(-1) h(-1). Biodegradation in a continuous bioreactor indicated a linear relationship between substrate loading and biodegradation rates prior to wash out of the cells, with a maximum biodegradation rate of 246 mg l(-1) h(-1) observed at a loading rate of 275 mg l(-1) h(-1) (residence time: 1.82 h). Biokinetic parameters were also determined using the steady state substrate and biomass concentrations at various dilution rates and compared to those obtained in batch cultures.

Additively manufactured biodegradable porous magnesium.

PubMed

Li, Y; Zhou, J; Pavanram, P; Leeflang, M A; Fockaert, L I; Pouran, B; Tümer, N; Schröder, K-U; Mol, J M C; Weinans, H; Jahr, H; Zadpoor, A A

2018-02-01

An ideal bone substituting material should be bone-mimicking in terms of mechanical properties, present a precisely controlled and fully interconnected porous structure, and degrade in the human body to allow for full regeneration of large bony defects. However, simultaneously satisfying all these three requirements has so far been highly challenging. Here we present topologically ordered porous magnesium (WE43) scaffolds based on the diamond unit cell that were fabricated by selective laser melting (SLM) and satisfy all the requirements. We studied the in vitro biodegradation behavior (up to 4 weeks), mechanical properties and biocompatibility of the developed scaffolds. The mechanical properties of the AM porous WE43 (E = 700-800 MPa) scaffolds were found to fall into the range of the values reported for trabecular bone even after 4 weeks of biodegradation. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), electrochemical tests and µCT revealed a unique biodegradation mechanism that started with uniform corrosion, followed by localized corrosion, particularly in the center of the scaffolds. Biocompatibility tests performed up to 72 h showed level 0 cytotoxicity (according to ISO 10993-5 and -12), except for one time point (i.e., 24 h). Intimate contact between cells (MG-63) and the scaffolds was also observed in SEM images. The study shows for the first time that AM of porous Mg may provide distinct possibilities to adjust biodegradation profile through topological design and open up unprecedented opportunities to develop multifunctional bone substituting materials that mimic bone properties and enable full regeneration of critical-size load-bearing bony defects. The ideal biomaterials for bone tissue regeneration should be bone-mimicking in terms of mechanical properties, present a fully interconnected porous structure, and exhibit a specific biodegradation behavior to enable full regeneration of bony defects. Recent advances in additive manufacturing have resulted in biomaterials that satisfy the first two requirements but simultaneously satisfying the third requirement has proven challenging so far. Here we present additively manufactured porous magnesium structures that have the potential to satisfy all above-mentioned requirements. Even after 4 weeks of biodegradation, the mechanical properties of the porous structures were found to be within those reported for native bone. Moreover, our comprehensive electrochemical, mechanical, topological, and biological study revealed a unique biodegradation behavior and the limited cytotoxicity of the developed biomaterials. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Toxicity and biodegradability of selected N-substituted phenols under anaerobic conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donlon, B.; Razo-Flores, E.; Hwu, C.S.

1995-12-31

The anaerobic toxicity and biodegradability of N-substituted aromatics were evaluated in order to obtain information on their ultimate biotreatment. The toxicity of selected N-substituted aromatic compounds toward acetoclastic methanogens in granular sludge was measured in batch assays. This toxicity was highly correlated with compound hydrophobicity, indicating that partitioning into the bacterial membranes was an important factor in the toxicity. However, other factors, such as chemical interactions with key cell components, were suggested to be playing an important role. Nitroaromatic compounds were, on the average, over 300-fold more toxic than their amino-substituted counterparts. This finding suggests that the facile reduction ofmore » nitro-groups known to occur in anaerobic environments would result in a high level of detoxification. To test this hypothesis, continuous lab-scale upward-flow anaerobic sludge bed reactors treating 2-nitrophenol and 4-nitrophenol were established. The 4-nitrophenol was readily converted to the corresponding 4-aminophenol, whereas complete mineralization of 2-nitrophenol via intermediate formation of 2-aminophenol was obtained. These conversions led to a dramatic detoxification of the nitrophenols, because it was feasible to treat the highly toxic nitrophenolics at high organic loading rates.« less

Development of Biodegradable Poly(citrate)-Polyhedral Oligomeric Silsesquioxanes Hybrid Elastomers with High Mechanical Properties and Osteogenic Differentiation Activity.

PubMed

Du, Yuzhang; Yu, Meng; Chen, Xiaofeng; Ma, Peter X; Lei, Bo

2016-02-10

Biodegradable elastomeric biomaterials have attracted much attention in tissue engineering due to their biomimetic viscoelastic behavior and biocompatibility. However, the low mechanical stability at hydrated state, fast biodegradation in vivo, and poor osteogenic activity greatly limited bioelastomers applications in bone tissue regeneration. Herein, we develop a series of poly(octanediol citrate)-polyhedral oligomeric silsesquioxanes (POC-POSS) hybrids with highly tunable elastomeric behavior (hydrated state) and biodegradation and osteoblasts biocompatibility through a facile one-pot thermal polymerization strategy. POC-POSS hybrids show significantly improved stiffness and ductility in either dry or hydrated conditions, as well as good antibiodegradation ability (20-50% weight loss in 3 months). POC-POSS hybrids exhibit significantly enhanced osteogenic differentiation through upregulating alkaline phosphatase (ALP) activity, calcium deposition, and expression of osteogenic markers (ALPL, BGLAP, and Runx2). The high mechanical stability at hydrated state and enhanced osteogenic activity make POC-POSS hybrid elastomers promising as scaffolds and nanoscale vehicles for bone tissue regeneration and drug delivery. This study may also provide a new strategy (controlling the stiffness under hydrated condition) to design advanced hybrid biomaterials with high mechanical properties under physiological condition for tissue regeneration applications.

Sensitivity and uncertainty analysis for Abreu & Johnson numerical vapor intrusion model.

PubMed

Ma, Jie; Yan, Guangxu; Li, Haiyan; Guo, Shaohui

2016-03-05

This study conducted one-at-a-time (OAT) sensitivity and uncertainty analysis for a numerical vapor intrusion model for nine input parameters, including soil porosity, soil moisture, soil air permeability, aerobic biodegradation rate, building depressurization, crack width, floor thickness, building volume, and indoor air exchange rate. Simulations were performed for three soil types (clay, silt, and sand), two source depths (3 and 8m), and two source concentrations (1 and 400 g/m(3)). Model sensitivity and uncertainty for shallow and high-concentration vapor sources (3m and 400 g/m(3)) are much smaller than for deep and low-concentration sources (8m and 1g/m(3)). For high-concentration sources, soil air permeability, indoor air exchange rate, and building depressurization (for high permeable soil like sand) are key contributors to model output uncertainty. For low-concentration sources, soil porosity, soil moisture, aerobic biodegradation rate and soil gas permeability are key contributors to model output uncertainty. Another important finding is that impacts of aerobic biodegradation on vapor intrusion potential of petroleum hydrocarbons are negligible when vapor source concentration is high, because of insufficient oxygen supply that limits aerobic biodegradation activities. Copyright © 2015 Elsevier B.V. All rights reserved.

Biodegradation of orthodontic appliances and their effects on the blood level of nickel and chromium. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrett, R.D.

1990-05-01

Austenitic stainless steels containing approximately 18 percent chromium and 8 percent nickel for orthodontic bands, brackets and wires is universally used in orthodontic practices. With the introduction of nickel-titanium alloys as orthodontic archwires in the 1970's an additional source of patient exposure to metal corrosion products has been introduced. Since the oral environment is particularly ideal for the biodegradation of metals due to its ionic, thermal, microbiologic and enzymatic properties some level of patient exposure to the corrosion products of these alloys is assured.

Study on the aerobic biodegradability and degradation kinetics of 3-NP; 2,4-DNP and 2,6-DNP.

PubMed

She, Zonglian; Xie, Tian; Zhu, Yingjie; Li, Leilei; Tang, Gaifeng; Huang, Jian

2012-11-30

Four biodegradability tests (BOD(5)/COD ratio, production of carbon dioxide, relative oxygen uptake rate and relative enzymatic activity) were used to determine the aerobic biodegradability of 3-nitrophenol (3-NP), 2,4-dinitrophenol (2,4-DNP) and 2,6-dinitrophenol (2,6-DNP). Furthermore, biodegradation kinetics of the compounds was investigated in sequencing batch reactors both in the presence of glucose (co-substrate) and with nitrophenol as the sole carbon source. Among the three tested compounds, 3-NP showed the best biodegradability while 2,6-DNP was the most difficult to be biodegraded. The Haldane equation was applied to the kinetic test data of the nitrophenols. The kinetic constants are as follows: the maximum specific degradation rate (K(max)), the saturation constants (K(S)) and the inhibition constants (K(I)) were in the range of 0.005-2.98 mg(mgSS d)(-1), 1.5-51.9 mg L(-1) and 1.8-95.8 mg L(-1), respectively. The presence of glucose enhanced the degradation of the nitrophenols at low glucose concentrations. The degradation of 3-NP was found to be accelerated with the increasing of glucose concentrations from 0 to 660 mg L(-1). At high (1320-2000 mg L(-1)) glucose concentrations, the degradation rate of 3-NP was reduced and the K(max) of 3-NP was even lower than the value obtained in the absence of glucose, suggesting that high concentrations of co-substrate could inhibit 3-NP biodegradation. At 2,4-DNP concentration of 30 mg L(-1), the K(max) of 2,4-DNP with glucose as co-substrate was about 30 times the value with 2,4-DNP as sole substrate. 2,6-DNP preformed high toxicity in the case of sole carbon source degradation and the kinetic data was hardly obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of the degradation of acetaminophen by the filamentous fungus Scedosporium dehoogii using carbon-based modified electrodes.

PubMed

Mbokou, Serge Foukmeniok; Pontié, Maxime; Razafimandimby, Bienvenue; Bouchara, Jean-Philippe; Njanja, Evangéline; Tonle Kenfack, Ignas

2016-08-01

The nonpathogenic filamentous fungus Scedosporium dehoogii was used for the first time to study the electrochemical biodegradation of acetaminophen (APAP). A carbon fiber microelectrode (CFME) modified by nickel tetrasulfonated phthalocyanine (p-NiTSPc) and a carbon paste electrode (CPE) modified with coffee husks (CH) were prepared to follow the kinetics of APAP biodegradation. The electrochemical response of APAP at both electrodes was studied by cyclic voltammetry and square wave voltammetry. p-NiTSPc-CFME was suitable to measure high concentrations of APAP, whereas CH-CPE gave rise to high current densities but was subject to the passivation phenomenon. p-NiTSPc-CFME was then successfully applied as a sensor to describe the kinetics of APAP biodegradation: this was found to be of first order with a kinetics constant of 0.11 day(-1) (at 25 °C) and a half-life of 6.30 days. APAP biodegradation by the fungus did not lead to the formation of p-aminophenol (PAP) and hydroquinone (HQ) that are carcinogenic, mutagenic, and reprotoxic (CMR). Graphical Abstract The kinetics of APAP biodegradation, followed by a poly-nickel tetrasulfonated phtalocyanine modified carbon fiber microelectrode.

Phenolic wastewater treatment through extractive recovery coupled with biodegradation in a two-phase partitioning membrane bioreactor.

PubMed

Praveen, Prashant; Loh, Kai-Chee

2015-12-01

A two-phase partitioning membrane bioreactor (TPPMB) was designed and operated for treatment of high strength phenolic wastewater through extraction/stripping and concomitant biodegradation. Tributyl phosphate dissolved in kerosene was used as the organic phase, sodium hydroxide as the stripping phase and Pseudomonas putida for biodegradation. In a semi-dispersive approach, organic phase dispersed in the stripping solution was contacted with wastewater through semi-permeable membranes for removal of phenol from wastewater, while the microorganisms were inoculated directly into the wastewater for biodegradation. The TPPMB exhibited high phenol removal rates, and phenol concentrations of 1000-3000mg/L were reduced to undetected amounts within 2-4h. Up to 80% phenol was recovered through extraction, while the remaining was metabolized by the microorganisms. Phenol recovery in the TPPMB was enhanced by increasing the mass transfer rate of phenol through the membranes, and it was also estimated that phenol diffusion through the aqueous boundary layer on the tube side was the rate limiting step. The flexibility in adjusting inoculation time in the TPPMB prevented microorganisms from adverse effects of substrate inhibition, which facilitated complete removal of phenol from the wastewater. TPPMB retained the advantages of both solvent extraction and biodegradation, and it can be highly promising for the treatment of toxic industrial wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

Phyllosphere yeasts rapidly break down biodegradable plastics

PubMed Central

2011-01-01

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

Phyllosphere yeasts rapidly break down biodegradable plastics.

PubMed

Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

2011-11-29

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

In Situ Treatment and Management Strategies for 1,4-Dioxane-Contaminated Groundwater

DTIC Science & Technology

2017-05-05

microorganisms thrived during the biodegradation process. This was consistent with oxidation process that biodiversity was inhibited by the chemical reaction ...exhibit a strong inhibitory impact on CB1190-like bacteria (Figure 79). However, in well 8MNW54, inhibitory impacts of chemical reactions were clear...inhibited again, indicating that chemical reactions along with high CVOCs levels had widely-varying impacts on microorganisms. Specifically, under low DX

Assessment of hydrothermal pretreatment of various lignocellulosic biomass with CO2 catalyst for enhanced methane and hydrogen production.

PubMed

Eskicioglu, Cigdem; Monlau, Florian; Barakat, Abdellatif; Ferrer, Ivet; Kaparaju, Prasad; Trably, Eric; Carrère, Hélène

2017-09-01

Hydrothermal pretreatment of five lignocellulosic substrates (i.e. wheat straw, rice straw, biomass sorghum, corn stover and Douglas fir bark) were conducted in the presence of CO 2 as a catalyst. To maximize disintegration and conversion into bioenergy (methane and hydrogen), pretreatment temperatures and subsequent pressures varied with a range of 26-175 °C, and 25-102 bars, respectively. Among lignin, cellulose and hemicelluloses, hydrothermal pretreatment caused the highest reduction (23-42%) in hemicelluloses while delignification was limited to only 0-12%. These reductions in structural integrity resulted in 20-30% faster hydrolysis rates during anaerobic digestion for the pretreated substrates of straws, sorghum, and corn stover while Douglas fir bark yielded 172% faster hydrolysis/digestion due to its highly refractory nature in the control. Furans and phenolic compounds formed in the pretreated hydrolyzates were below the inhibitory levels for methane and hydrogen production which had a range of 98-340 ml CH 4 /g volatile solids (VS) and 5-26 ml H 2 /g VS, respectively. Results indicated that hydrothermal pretreatment is able to accelerate the rate of biodegradation without generating high levels of inhibitory compounds while showing no discernible effect on ultimate biodegradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative proteomics reveal the mechanism of Tween80 enhanced phenanthrene biodegradation by Sphingomonas sp. GY2B.

PubMed

Liu, Shasha; Guo, Chuling; Dang, Zhi; Liang, Xujun

2017-03-01

Previous study concerning the effects of surfactants on phenanthrene biodegradation focused on observing the changes of cell characteristics of Sphingomonas sp. GY2B. However, the impact of surfactants on the expression of bacterial proteins, controlling phenanthrene transport and catabolism, remains obscure. To overcome the knowledge gap, comparative proteomic approaches were used to investigate protein expressions of Sphingomonas sp. GY2B during phenanthrene biodegradation in the presence and absence of a nonionic surfactant, Tween80. A total of 23 up-regulated and 19 down-regulated proteins were detected upon Tween80 treatment. Tween80 could regulate ion transport (e.g. H + ) in cell membrane to provide driving force (ATP) for the transmembrane transport of phenanthrene thus increasing its uptake and biodegradation by GY2B. Moreover, Tween80 probably increased GY2B vitality and growth by inducing the expression of peptidylprolyl isomerase to stabilize cell membrane, increasing the abundances of proteins involved in intracellular metabolic pathways (e.g. TCA cycle), as well as decreasing the abundances of translation/transcription-related proteins and cysteine desulfurase, thereby facilitating phenanthrene biodegradation. This study may facilitate a better understanding of the mechanisms that regulate surfactants-enhanced biodegradation of PAHs at the proteomic level. Copyright © 2016 Elsevier Inc. All rights reserved.

Drug loaded biodegradable load-bearing nanocomposites for damaged bone repair

NASA Astrophysics Data System (ADS)

Gutmanas, E. Y.; Gotman, I.; Sharipova, A.; Psakhie, S. G.; Swain, S. K.; Unger, R.

2017-09-01

In this paper we present a short review-scientific report on processing and properties, including in vitro degradation, of load bearing biodegradable nanocomposites as well as of macroporous 3D scaffolds for bone ingrowth. Biodegradable implantable devices should slowly degrade over time and disappear with ingrown of natural bone replacing the synthetic graft. Compared to low strength biodegradable polymers, and brittle CaP ceramics, biodegradable CaP-polymer and CaP-metal nanocomposites, mimicking structure of natural bone, as well as strong and ductile metal nanocomposites can provide to implantable devices both strengths and toughness. Nanostructuring of biodegradable β-TCP (tricalcium phosphate)-polymer (PCL and PLA), β-TCP-metal (FeMg and FeAg) and of Fe-Ag composites was achieved employing high energy attrition milling of powder blends. Nanocomposite powders were consolidated to densities close to theoretical by high pressure consolidation at ambient temperature—cold sintering, with retention of nanoscale structure. The strength of developed nanocomposites was significantly higher as compared with microscale composites of the same or similar composition. Heat treatment at moderate temperatures in hydrogen flow resulted in retention of nanoscale structure and higher ductility. Degradation of developed biodegradable β-TCP-polymer, β-TCP-metal and of Fe-Ag nanocomposites was studied in physiological solutions. Immersion tests in Ringer's and saline solution for 4 weeks resulted in 4 to 10% weight loss and less than 50% decrease in compression or bending strength, the remaining strength being significantly higher than the values reported for other biodegradable materials. Nanostructuring of Fe-Ag based materials resulted also in an increase of degradation rate because of creation on galvanic Fe-Ag nanocouples. In cell culture experiments, the developed nanocomposites supported the attachment the human osteoblast cells and exhibited no signs of cytotoxicity. Interconnected system of nanopores formed during processing of nanocomposites was used for incorporation of drugs, including antibiotics and anticancer drugs, and can be used for loading of bioactive molecules enhancing bone ingrowth.

Study utilization of extractable petroleum hydrocarbons biodegradation waste as the main material for making solid fuels

NASA Astrophysics Data System (ADS)

Hendrianie, Nuniek; Juliastuti, Sri Rachmania; Ar-rosyidah, Fanny Husna; Rochman, Hilal Abdur

2017-05-01

Nowadays the existence of energy sources of oil and was limited. Therefore, it was important to searching for new innovations of renewable energy sources by utilizing the waste into a source of energy. On the other hand, the process of extractable petroleum hydrocarbons biodegradation generated sludge that had calorific value and untapped. Because of the need for alternative sources of energy innovation with the concept of zero waste and the fuel potential from extractable petroleum hydrocarbons biodegradation waste, so it was necessary to study the use of extractable petroleum hydrocarbons biodegradation waste as the main material for making solid fuel. In addition, sawdust is a waste that had a great quantities and also had a high calorific value to be mixed with extractable petroleum hydrocarbons biodegradation waste. The purpose of this study was to determine the characteristics of the extractable petroleum hydrocarbons biodegradation waste and to determine the potential and a combination of a mixture of extractable petroleum hydrocarbons biodegradation waste and sawdust which has the best calorific value. The variables of this study was the composition of the waste and sawdust as follows 1:1; 1:3; and 3:1 (mass of sawdust : mass of waste) and time of sawdust carbonization was 10, 15 and 20 minutes. Sawdust was carbonized to get the high heating value. The characteristic of main material and fuel analysis performed with proximate analysis. While the calorific value analysis was performed with a bomb calorimeter. From the research, it was known that extractable petroleum hydrocarbons biodegradation waste had a moisture content of 3.06%; volatile matter 19.98%; ash content of 0.56%; fixed carbon content of 76.4% and a calorific value of 717 cal/gram. And a mixture that had the highest calorific value (4286.5 cal/gram) achieved in comparison sawdust : waste (3:1) by carbonization of sawdust for 20 minutes.

Naphthenic acids in athabasca oil sands tailings waters are less biodegradable than commercial naphthenic acids.

PubMed

Scott, Angela C; MacKinnon, Michael D; Fedorak, Phillip M

2005-11-01

Naphthenic acids (NAs) are natural constituents in many petroleum sources, including bitumen in the oil sands of Northern Alberta, Canada. Bitumen extraction processes produce tailings waters that cannot be discharged to the environment because NAs are acutely toxic to aquatic species. However, aerobic biodegradation reduces the toxic character of NAs. In this study, four commercial NAs and the NAs in two oil sands tailings waters were characterized by gas chromatography-mass spectrometry. These NAs were also incubated with microorganisms in the tailings waters under aerobic, laboratory conditions. The NAs in the commercial preparations had lower molecular masses than the NAs in the tailings waters. The commercial NAs were biodegraded within 14 days, but only about 25% of the NAs native to the tailings waters were removed after 40-49 days. These results show that low molecular mass NAs (C < or =17) are more readily biodegraded than high molecular mass NAs (C > or =18). Moreover, the results indicate that biodegradation studies using commercial NAs alone will not accurately reflect the potential biodegradability of NAs in the oil sands tailings waters.

JTEC monograph on biodegradable polymers and plastics in Japan: Research, development, and applications

NASA Technical Reports Server (NTRS)

Lenz, Robert W.

1995-01-01

A fact-finding team of American scientists and engineers visited Japan to assess the status of research and development and applications in biodegradable polymers. The visit was sponsored by the National Science Foundation and industry. In Japan, the team met with representatives of 31 universities, government ministries and institutes, companies, and associations. Japan's national program on biodegradable polymers and plastics evaluates new technologies, testing methods, and potential markets for biodegradables. The program is coordinated by the Biodegradable Plastics Society of Japan, which seeks to achieve world leadership in biodegradable polymer technology and identify commercial opportunities for exploiting this technology. The team saw no major new technology breakthroughs. Japanese scientists and engineers are focusing on natural polymers from renewable resources, synthetic polymers, and bacterially-produced polymers such as polyhydroxyalkanoates, poly(amino acids), and polysaccharides. The major polymers receiving attention are the Zeneca PHBV copolymers, Biopol(registered trademark), poly(lactic acid) from several sources, polycaprolactone, and the new synthetic polyester, Bionolle(registered trademark), from Showa High Polymer. In their present state of development, these polymers all have major deficiencies that inhibit their acceptance for large-scale applications.

BTE-OX biodegradation kinetics with MTBE through bioaugmentation.

PubMed

Acuna-Askar, K; Villarreal-Chiu, J F; Gracia-Lozano, M V; Garza-Gonzalez, M T; Chavez-Gomez, B; Rodriguez-Sanchez, I P; Barrera-Saldana, H A

2004-01-01

The biodegradation kinetics of BTE-oX and MTBE, mixed all together, in the presence of bioaugmented bacterial populations as high as 880 mg/L VSS was evaluated. The effect of soil in aqueous samples and the effect of Tergitol NP-10 on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 36 hours, every 6 hours. Benzene and o-xylene biodegradation followed a first-order one-phase kinetic model, whereas toluene and ethylbenzene biodegradation was well described by a first-order two-phase kinetic model in all samples. MTBE followed a zero-order removal kinetic model in all samples. The presence of soil in aqueous samples retarded BTE-oX removal rates, with the highest negative effect on o-xylene. The presence of soil enhanced MTBE removal rate. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged from 95.4-99.7% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged from 55.9-90.1% and 15.6-30.1%, respectively.

Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aras, Neny Rasnyanti M., E-mail: neny.rasnyanti@gmail.com; Arcana, I Made, E-mail: arcana@chem.itb.ac.id

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearatemore » with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate, and followed by thermal treatment at a temperature of 70 °C and the incubation time for 45 days in the activated sludge.« less

The use of biodegradable mulch for tomato and broccoli production: Crop yield and quality, mulch deterioration, and growers' perceptions

NASA Astrophysics Data System (ADS)

Cowan, Jeremy Scott

Biodegradable mulch may offer the benefits of polyethylene mulch for crop production with the added benefit of biodegradability. Four studies were carried out in Mount Vernon, WA to evaluate biodegradable mulch for tomato (Solanum lycopersicum L.) and broccoli (Brassica oleracea var. italica) production. The first study compared four biodegradable mulch treatments: BioAgri, BioTelo, WeedGuardPlus (cellulose product), and SB-PLA-10/11/12 (experimental, non-woven fabric), to polyethylene mulch and bare ground in high tunnels and in the open field for tomato yield and fruit quality over three growing seasons. Biodegradable plastic films produced yields and fruit quality comparable to polyethylene. Moreover, high tunnels increased total and marketable fruit weight five and eight times, respectively, compared to the open field. The second study quantified relationships among visual assessment parameters and mulch mechanical properties. Visual assessments and mechanical property tests of polyethylene, BioAgri, BioTelo, WeedGuardPlus, and SB-PLA-10/11/12, were made over three growing seasons. Regression analyses found the strongest relationship overall (r2 = 0.41) to be between the percent of initial breaking force in the machine direction and log 10 of percent visual deterioration. However, evaluating mulch products individually and increasing sample frequency are recommended for future research. The third study evaluated three biodegradable mulch products, BioAgri, Crown 1, and SB-PLA-11, after soil-incorporation. The average area of recovered mulch fragments decreased for all mulch products over time. The number of mulch fragments initially increased for all mulch products, with the greatest number of Crown 1 and BioAgri fragments recovered 132 and 299 days after incorporation, respectively. At 397 days after soil-incorporation, the total area of recovered fragments of Crown 1 and BioAgri was 0% and 34% of the theoretical maximum area, respectively. The fourth study used the diffusion of innovations framework to study perceptions about biodegradable mulch and employed the concept of "tactile space" to create sensuously rich learning environments wherein participants could interact with each other and the environment to evaluate biodegradable plastic mulch. Participants' perceptions about biodegradable mulch and attitudes toward adoption improved. Employing tactile space as a diffusion strategy may encourage non-representational learning to supplement and reinforce the knowledge claims being made at outreach/education events.

Controlled delivery of a hydrophilic drug from a biodegradable microsphere system by supercritical anti-solvent precipitation technique.

PubMed

Lee, S; Kim, M S; Kim, J S; Park, H J; Woo, J S; Lee, B C; Hwang, S J

2006-11-01

The purpose of this study was to prepare microspheres loaded with hydrophilic drug, bupivacaine HCl using poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). Microspheres were prepared with varying the PLGA/PLLA ratio with two different levels of bupivacaine HCl (5 and 10%) using a supercritical anti-solvent (SAS) technique. Microspheres ranging from 4-10 microm in geometric mean diameter could be prepared, with high loading efficiency. Powder X-ray diffraction (PXRD) revealed that bupivacaine HCl retained its crystalline state within the polymer and was present as a dispersion within the polymer phase after SAS processing. The release of bupivacaine HCl from biodegradable polymer microspheres was rapid up to 4 h, thereafter bupivacaine HCl was continuously and slowly released for at least 7 days according to the PLGA/PLLA ratio and the molecular weight of PLLA.

Elucidating the impact of micro-scale heterogeneous bacterial distribution on biodegradation

NASA Astrophysics Data System (ADS)

Schmidt, Susanne I.; Kreft, Jan-Ulrich; Mackay, Rae; Picioreanu, Cristian; Thullner, Martin

2018-06-01

Groundwater microorganisms hardly ever cover the solid matrix uniformly-instead they form micro-scale colonies. To which extent such colony formation limits the bioavailability and biodegradation of a substrate is poorly understood. We used a high-resolution numerical model of a single pore channel inhabited by bacterial colonies to simulate the transport and biodegradation of organic substrates. These high-resolution 2D simulation results were compared to 1D simulations that were based on effective rate laws for bioavailability-limited biodegradation. We (i) quantified the observed bioavailability limitations and (ii) evaluated the applicability of previously established effective rate concepts if microorganisms are heterogeneously distributed. Effective bioavailability reductions of up to more than one order of magnitude were observed, showing that the micro-scale aggregation of bacterial cells into colonies can severely restrict the bioavailability of a substrate and reduce in situ degradation rates. Effective rate laws proved applicable for upscaling when using the introduced effective colony sizes.

Cyclodextrin enhanced biodegradation of polycyclic aromatic hydrocarbons and phenols in contaminated soil slurries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ian J. Allan; Kirk T. Semple; Rina Hare

This work aimed to evaluate the relative contribution of soil catabolic activity, contaminant bioaccessibility, and nutrient levels on the biodegradation of field-aged polycyclic aromatic hydrocarbons and phenolic compounds in three municipal gas plant site soils. Extents of biodegradation achieved, in 6 week-long soil slurry assays, under the following conditions were compared: (i) with inoculation of catabolically active PAH and phenol-degrading microorganisms, (ii) with and without hydroxypropyl-{beta}-cyclodextrin supplementation (HPCD; 100 g L{sup -1}), and finally (iii) with the provision of additional inorganic nutrients in combination with HPCD. Results indicated no significant (p {lt} 0.05) differences between biodegradation endpoints attained in treatmentsmore » inoculated with catabolically active microorganisms as compared with the uninoculated control. Amendments with HPCD significantly (p {lt} 0.05) lowered biodegradation endpoints for most PAHs and phenolic compounds. Only in one soil did the combination of HPCD and nutrients consistently achieve better bioremediation endpoints with respect to the HPCD-only treatments. Thus, for most compounds, biodegradation was not limited by the catabolic activity of the indigenous microorganisms but rather by processes resulting in limited availability of contaminants to degraders. It is therefore suggested that the bioremediation of PAH and phenol impacted soils could be enhanced through HPCD amendments. In addition, the biodegradability of in situ and spiked (deuterated analogues) PAHs following 120 days aging of the soils suggested that this contact time was not sufficient to obtain similar partitions to that observed for field-aged contaminants; with the spiked compounds being significantly (p {lt} 0.05) more available for biodegradation. 42 refs., 5 figs., 2 tabs.« less

An equivalent-time-lines model for municipal solid waste based on its compression characteristics.

PubMed

Gao, Wu; Bian, Xuecheng; Xu, Wenjie; Chen, Yunmin

2017-10-01

Municipal solid waste (MSW) demonstrates a noticeable time-dependent stress-strain behavior, which contributes greatly to the settlement of landfills and therefore influences both the storage capacity of landfills and the integrity of internal structures. The long-term compression tests for MSW under different biodegradation conditions were analyzed. It showed that the primary compression can affect the secondary compression due to the biodegradation and mechanical creep. Based on the time-lines model for clays and the compression characteristics of MSW, relationships between MSW's viscous strain rate and equivalent time were established, and then the viscous strain functions of MSW under different biodegradation conditions were deduced, and an equivalent-time-lines model for MSW settlement for two biodegradation conditions was developed, including the Type I model for the enhanced biodegradation condition and the Type II model for the normal biodegradation condition. The simulated compression results of laboratory and field compression tests under different biodegradation conditions were consistent with the measured data, which showed the reliability of both types of the equivalent-time-lines model for MSW. In addition, investigations of the long-term settlement of landfills from the literature indicated that the Type I model is suitable for predicting settlement in MSW landfills with a distinct biodegradation progress of MSW, a high content of organics in MSW, a short fill age or under an enhanced biodegradation environment; while the Type II model is good at predicting settlement in MSW landfills with a distinct progress of mechanical creep compression, a low content of organics in MSW, a long fill age or under a normal biodegradation condition. Furthermore, relationships between model parameters and the fill age of landfills were summarized. Finally, the similarities and differences between the equivalent-time-lines model for MSW and the stress-biodegradation model for MSW were discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Marine Oil Biodegradation.

PubMed

Hazen, Terry C; Prince, Roger C; Mahmoudi, Nagissa

2016-03-01

Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments, and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to "bloom" in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine waters with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.

Marine Oil Biodegradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazen, Terry C.; Prince, Roger; Mahmoudi, Nagissa

Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to ‘bloom’ in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine watersmore » with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.« less

Marine Oil Biodegradation

DOE PAGES

Hazen, Terry C.; Prince, Roger; Mahmoudi, Nagissa

2015-12-23

Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to ‘bloom’ in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine watersmore » with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.« less

Discrimination in Degradability of Soil Pyrogenic Organic Matter Follows a Return-On-Energy-Investment Principle.

PubMed

Harvey, Omar R; Myers-Pigg, Allison N; Kuo, Li-Jung; Singh, Bhupinder Pal; Kuehn, Kevin A; Louchouarn, Patrick

2016-08-16

A fundamental understanding of biodegradability is central to elucidating the role(s) of pyrogenic organic matter (PyOM) in biogeochemical cycles. Since microbial community and ecosystem dynamics are driven by net energy flows, then a quantitative assessment of energy value versus energy requirement for oxidation of PyOM should yield important insights into their biodegradability. We used bomb calorimetry, stepwise isothermal thermogravimetric analysis (isoTGA), and 5-year in situ bidegradation data to develop energy-biodegradability relationships for a suite of plant- and manure-derived PyOM (n = 10). The net energy value (ΔE) for PyOM was between 4.0 and 175 kJ mol(-1); with manure-derived PyOM having the highest ΔE. Thermal-oxidation activation energy (Ea) requirements ranged from 51 to 125 kJ mol(-1), with wood-derived PyOM having the highest Ea requirements. We propose a return-on-investment (ROI) parameter (ΔE/Ea) for differentiating short-to-medium term biodegradability of PyOM and deciphering if biodegradation will most likely proceed via cometabolism (ROI < 1) or direct metabolism (ROI ≥ 1). The ROI-biodegradability relationship was sigmoidal with higher biodegradability associated with PyOM of higher ROI; indicating that microbes exhibit a higher preference for "high investment value" PyOM.

Application of micronucleus test and comet assay to evaluate BTEX biodegradation.

PubMed

Mazzeo, Dânia Elisa Christofoletti; Matsumoto, Silvia Tamie; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

2013-01-01

The BTEX (benzene, toluene, ethylbenzene and xylene) mixture is an environmental pollutant that has a high potential to contaminate water resources, especially groundwater. The bioremediation process by microorganisms has often been used as a tool for removing BTEX from contaminated sites. The application of biological assays is useful in evaluating the efficiency of bioremediation processes, besides identifying the toxicity of the original contaminants. It also allows identifying the effects of possible metabolites formed during the biodegradation process on test organisms. In this study, we evaluated the genotoxic and mutagenic potential of five different BTEX concentrations in rat hepatoma tissue culture (HTC) cells, using comet and micronucleus assays, before and after biodegradation. A mutagenic effect was observed for the highest concentration tested and for its respective non-biodegraded concentration. Genotoxicity was significant for all non-biodegraded concentrations and not significant for the biodegraded ones. According to our results, we can state that BTEX is mutagenic at concentrations close to its water solubility, and genotoxic even at lower concentrations, differing from some described results reported for the mixture components, when tested individually. Our results suggest a synergistic effect for the mixture and that the biodegradation process is a safe and efficient methodology to be applied at BTEX-contaminated sites. Copyright © 2012 Elsevier Ltd. All rights reserved.

Opportunities and challenges for the biodegradable magnesium alloys as next-generation biomaterials

PubMed Central

Ding, Wenjiang

2016-01-01

In recent years, biodegradable magnesium alloys emerge as a new class of biomaterials for tissue engineering and medical devices. Deploying biodegradable magnesium-based materials not only avoids a second surgical intervention for implant removal but also circumvents the long-term foreign body effect of permanent implants. However, these materials are often subjected to an uncontrolled and fast degradation, acute toxic responses and rapid structural failure presumably due to a localized, too rapid corrosion process. The patented Mg–Nd–Zn–based alloys (JiaoDa BioMg [JDBM]) have been developed in Shanghai Jiao Tong University in recent years. The alloy series exhibit lower biodegradation rate and homogeneous nanophasic degradation patterns as compared with other biodegradable Mg alloys. The in vitro cytotoxicity tests using various types of cells indicate excellent biocompatibility of JDBM. Finally, bone implants using JDBM-1 alloy and cardiovascular stents using JDBM-2 alloy have been successfully fabricated and in vivo long-term assessment via implantation in animal model have been performed. The results confirmed the reduced degradation rate in vivo, excellent tissue compatibility and long-term structural and mechanical durability. Thus, this novel Mg-alloy series with highly uniform nanophasic biodegradation represent a major breakthrough in the field and a promising candidate for manufacturing the next generation biodegradable implants. PMID:27047673

Robust and biodegradable elastomers based on corn starch and polydimethylsiloxane (PDMS).

PubMed

Ceseracciu, Luca; Heredia-Guerrero, José Alejandro; Dante, Silvia; Athanassiou, Athanassia; Bayer, Ilker S

2015-02-18

Designing starch-based biopolymers and biodegradable composites with durable mechanical properties and good resistance to water is still a challenging task. Although thermoplastic (destructured) starch has emerged as an alternative to petroleum-based polymers, its poor dimensional stability under humid and dry conditions extensively hinders its use as the biopolymer of choice in many applications. Unmodified starch granules, on the other hand, suffer from incompatibility, poor dispersion, and phase separation issues when compounded into other thermoplastics above a concentration level of 5%. Herein, we present a facile biodegradable elastomer preparation method by incorporating large amounts of unmodified corn starch, exceeding 80% by volume, in acetoxy-polyorganosiloxane thermosets to produce mechanically robust, hydrophobic bioelastomers. The naturally adsorbed moisture on the surface of starch enables autocatalytic rapid hydrolysis of polyorganosiloxane to form Si-O-Si networks. Depending on the amount of starch granules, the mechanical properties of the bioelastomers can be easily tuned with high elastic recovery rates. Moreover, starch granules considerably lowered the surface friction coefficient of the polyorganosiloxane network. Stress relaxation measurements indicated that the bioelastomers have strain energy dissipation factors that are lower than those of conventional rubbers, rendering them as promising green substitutes for plastic mechanical energy dampeners. Corn starch granules also have excellent compatibility with addition-cured polysiloxane chemistry that is used extensively in microfabrication. Regardless of the starch concentration, all of the developed bioelastomers have hydrophobic surfaces with lower friction coefficients and much less water uptake capacity than those of thermoplastic starch. The bioelastomers are biocompatible and are estimated to biodegrade in Mediterranean seawater within three to six years.

Identification of sources and seasonal variability of organic matter in Lake Sihwa and surrounding inland creeks, South Korea.

PubMed

Lee, Yeonjung; Hong, Seongjin; Kim, Min-Seob; Kim, Dahae; Choi, Bo-Hyung; Hur, Jin; Khim, Jong Seong; Shin, Kyung-Hoon

2017-06-01

Coastal areas are subjected to significant allochthonous organic matter deposits from surrounding areas; however, limited information is available on the source and delivery of this organic matter. In this study, to assess seasonal changes in the sources of organic matter in Lake Sihwa (Korea), biodegradability, fluorescence property, and stable isotopic compositions (carbon, nitrogen, and sulfur) of the organic matter were determined. Water samples were collected from the inner lake (n = 9) and inland creeks (n = 10) in five separate events, from November 2012 to October 2013. Organic matter originating from rural, urban, and industrial areas was examined as the potential sources. The organic matter contents and biodegradability in the industrial area were the highest, whereas low concentrations and poor biodegradability of organic matter were found in the rural area, and moderate properties were observed in the urban area. In Lake Sihwa, a large concentration of total organic matter and enhanced biodegradability were observed during March and August. However, main source of organic matter differed between the sampling events. The largest contribution of organic matter, deriving from marine phytoplankton, was found in March. On the other hand, in August, the organic matter originating from the industrial area, which is characterized by high levels of heavy metals and persistent organic pollutants, was significantly increased. Our results could be useful to enhance the management of water bodies aimed at reducing the organic matter concentrations and improving the water quality of Lake Sihwa, and even that of the Yellow Sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

The biodegradation of crude oil in the deep ocean.

PubMed

Prince, Roger C; Nash, Gordon W; Hill, Stephen J

2016-10-15

Oil biodegradation at a simulated depth of 1500m was studied in a high-pressure apparatus at 5°C, using natural seawater with its indigenous microbes, and 3ppm of an oil with dispersant added at a dispersant:oil ratio of 1:15. Biodegradation of the detectable hydrocarbons was prompt and extensive (>70% in 35days), although slower by about a third than under otherwise identical conditions equivalent to the surface. The apparent half-life of biodegradation of the total detectable hydrocarbons at 15MPa was 16days (compared to 13days at atmospheric pressure), although some compounds, such as the four-ring aromatic chrysene, were degraded rather more slowly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradability engineering of biodegradable Mg alloys: Tailoring the electrochemical properties and microstructure of constituent phases

PubMed Central

Cha, Pil-Ryung; Han, Hyung-Seop; Yang, Gui-Fu; Kim, Yu-Chan; Hong, Ki-Ha; Lee, Seung-Cheol; Jung, Jae-Young; Ahn, Jae-Pyeong; Kim, Young-Yul; Cho, Sung-Youn; Byun, Ji Young; Lee, Kang-Sik; Yang, Seok-Jo; Seok, Hyun-Kwang

2013-01-01

Crystalline Mg-based alloys with a distinct reduction in hydrogen evolution were prepared through both electrochemical and microstructural engineering of the constituent phases. The addition of Zn to Mg-Ca alloy modified the corrosion potentials of two constituent phases (Mg + Mg2Ca), which prevented the formation of a galvanic circuit and achieved a comparable corrosion rate to high purity Mg. Furthermore, effective grain refinement induced by the extrusion allowed the achievement of much lower corrosion rate than high purity Mg. Animal studies confirmed the large reduction in hydrogen evolution and revealed good tissue compatibility with increased bone deposition around the newly developed Mg alloy implants. Thus, high strength Mg-Ca-Zn alloys with medically acceptable corrosion rate were developed and showed great potential for use in a new generation of biodegradable implants. PMID:23917705

Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

PubMed

Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

2017-11-14

Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate.

PubMed

Kasanke, Christopher P; Leigh, Mary Beth

2017-01-01

Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the environment, especially in cold regions. We conducted aerobic and anaerobic microcosm studies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska. We also investigated the impacts of nutrient limitations and hydrocarbon co-contamination on sulfolane degradation. We found that sulfolane underwent biodegradation aerobically but not anaerobically under nitrate, sulfate, or iron-reducing conditions. No abiotic degradation activity was detectable under either oxic or anoxic conditions. Nutrient addition stimulated sulfolane biodegradation in sediment slurries at high sulfolane concentrations (100 mg L-1), but not at low sulfolane concentrations (500 μg L-1), and nutrient amendments were necessary to stimulate sulfolane biodegradation in incubations containing groundwater only. Hydrocarbon co-contamination retarded aerobic sulfolane biodegradation rates by ~30%. Our study is the first to investigate the sulfolane biodegradation potential of subarctic aquifer substrate and identifies several important factors limiting biodegradation rates. We concluded that oxygen is an important factor limiting natural attenuation of this sulfolane plume, and that nutrient amendments are unlikely to accelerate biodegradation within in the plume, although they may biostimulate degradation in ex situ groundwater treatment applications. Future work should be directed at elucidating the identity of indigenous sulfolane-degrading microorganisms and determining their distribution and potential activity in the environment.

Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate

PubMed Central

2017-01-01

Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the environment, especially in cold regions. We conducted aerobic and anaerobic microcosm studies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska. We also investigated the impacts of nutrient limitations and hydrocarbon co-contamination on sulfolane degradation. We found that sulfolane underwent biodegradation aerobically but not anaerobically under nitrate, sulfate, or iron-reducing conditions. No abiotic degradation activity was detectable under either oxic or anoxic conditions. Nutrient addition stimulated sulfolane biodegradation in sediment slurries at high sulfolane concentrations (100 mg L-1), but not at low sulfolane concentrations (500 μg L-1), and nutrient amendments were necessary to stimulate sulfolane biodegradation in incubations containing groundwater only. Hydrocarbon co-contamination retarded aerobic sulfolane biodegradation rates by ~30%. Our study is the first to investigate the sulfolane biodegradation potential of subarctic aquifer substrate and identifies several important factors limiting biodegradation rates. We concluded that oxygen is an important factor limiting natural attenuation of this sulfolane plume, and that nutrient amendments are unlikely to accelerate biodegradation within in the plume, although they may biostimulate degradation in ex situ groundwater treatment applications. Future work should be directed at elucidating the identity of indigenous sulfolane-degrading microorganisms and determining their distribution and potential activity in the environment. PMID:28727811

Biocorrosion properties and blood and cell compatibility of pure iron as a biodegradable biomaterial.

PubMed

Zhang, Erlin; Chen, Haiyan; Shen, Feng

2010-07-01

Biocorrosion properties and blood- and cell compatibility of pure iron were studied in comparison with 316L stainless steel and Mg-Mn-Zn magnesium alloy to reveal the possibility of pure iron as a biodegradable biomaterial. Both electrochemical and weight loss tests showed that pure iron showed a relatively high corrosion rate at the first several days and then decreased to a low level during the following immersion due to the formation of phosphates on the surface. However, the corrosion of pure iron did not cause significant increase in pH value to the solution. In comparison with 316L and Mg-Mn-Zn alloy, the pure iron exhibited biodegradable property in a moderate corrosion rate. Pure iron possessed similar dynamic blood clotting time, prothrombin time and plasma recalcification time to 316L and Mg-Mn-Zn alloy, but a lower hemolysis ratio and a significant lower number density of adhered platelets. MTT results revealed that the extract except the one with 25% 24 h extract actually displayed toxicity to cells and the toxicity increased with the increasing of the iron ion concentration and the incubation time. It was thought there should be an iron ion concentration threshold in the effect of iron ion on the cell toxicity.

Evaluation of toxicity and biodegradability of choline chloride based deep eutectic solvents.

PubMed

Radošević, Kristina; Bubalo, Marina Cvjetko; Srček, Višnje Gaurina; Grgas, Dijana; Dragičević, Tibela Landeka; Redovniković, Ivana Radojčić

2015-02-01

Deep eutectic solvents (DESs) have been dramatically expanding in popularity as a new generation of environmentally friendly solvents with possible applications in various industrial fields, but their ecological footprint has not yet been thoroughly investigated. In the present study, three choline chloride-based DESs with glucose, glycerol and oxalic acid as hydrogen bond donors were evaluated for in vitro toxicity using fish and human cell line, phytotoxicity using wheat and biodegradability using wastewater microorganisms through closed bottle test. Obtained in vitro toxicity data on cell lines indicate that choline chloride: glucose and choline chloride:glycerol possess low cytotoxicity (EC50>10 mM for both cell lines) while choline chloride:oxalic acid possess moderate cytotoxicity (EC50 value 1.64 mM and 4.19 mM for fish and human cell line, respectively). Results on phytotoxicity imply that tested DESs are non-toxic with seed germination EC50 values higher than 5000 mg L(-1). All tested DESs were classified as'readily biodegradable' based on their high levels of mineralization (68-96%). These findings indicate that DESs have a green profile and a good prospect for a wider use in the field of green technologies. Copyright © 2014 Elsevier Inc. All rights reserved.

4-Chlorophenol biodegradation facilitator composed of recombinant multi-biocatalysts immobilized onto montmorillonite.

PubMed

Kwean, Oh Sung; Cho, Su Yeon; Yang, Jun Won; Cho, Wooyoun; Park, Sungyoon; Lim, Yejee; Shin, Min Chul; Kim, Han-Suk; Park, Joonhong; Kim, Han S

2018-07-01

A biodegradation facilitator which catalyzes the initial steps of 4-chlorophenol (4-CP) oxidation was prepared by immobilizing multiple enzymes (monooxygenase, CphC-I and dioxygenase, CphA-I) onto a natural inorganic support. The enzymes were obtained via overexpression and purification after cloning the corresponding genes (cphC-I and cphA-I) from Arthrobacter chlorophenolicus A6. Then, the recombinant CphC-I was immobilized onto fulvic acid-activated montmorillonite. The immobilization yield was 60%, and the high enzyme activity (82.6%) was retained after immobilization. Kinetic analysis indicated that the Michaelis-Menten model parameters for the immobilized CphC-I were similar to those for the free enzyme. The enzyme stability was markedly enhanced after immobilization. The immobilized enzyme exhibited a high level of activity even after repetitive use (84.7%) and powdering (65.8%). 4-CP was sequentially oxidized by a multiple enzyme complex, comprising the immobilized CphC-I and CphA-I, via the hydroquinone pathway: oxidative transformation of 4-CP to hydroxyquinol followed by ring fission of hydroxyquinol. Copyright © 2018 Elsevier Ltd. All rights reserved.

Novel characteristics of sophorolipids, yeast glycolipid biosurfactants, as biodegradable low-foaming surfactants.

PubMed

Hirata, Yoshihiko; Ryu, Mizuyuki; Oda, Yuka; Igarashi, Keisuke; Nagatsuka, Asami; Furuta, Taro; Sugiura, Masaki

2009-08-01

Sophorolipids (SLs) are a family of glycolipid type biosurfactants, which are largely produced by the non-pathogenic yeast, Candida bombicola. In order to investigate the possibility of SLs for industrial use, here we examined the interfacial activities, cytotoxicity and biodegradability of SLs, and compared these properties with those of two lipopeptide type biosurfactants (surfactin and arthrofactin), sodium laurate (soap, SP) and four kinds of chemically synthesized surfactants including two block-copolymer nonionic surfactants (BPs), polyoxyethylene lauryl ether (AE) and sodium dodecyl sulfate (SDS). It was indicated that SLs had extremely low-foaming properties and high detergency comparable with commercially available low-foaming BPs. These interfacial activities of SLs were maintained under 100 ppm water hardness. Cytotoxicity of SLs on human keratinocytes was the same as surfactin, which has already been commercialized as cosmetic material, but higher than BPs. Moreover, biodegradability of SLs using the OECD Guidelines for Testing of Chemicals (301C, Modified MITI Test) displayed that SLs can be classified as "readily" biodegradable chemicals, which are defined as chemicals that are degraded 60% within 28 days under specified test methods. We observed 61% degradation of SLs on the eighth day of cultivation. Our results indicate that SLs are low-foaming surfactants with high detergency, which also exhibit both low cytotoxicity and readily biodegradable properties.

Biodegradation mechanism of 1H-1,2,4-triazole by a newly isolated strain Shinella sp. NJUST26

PubMed Central

Wu, Haobo; Shen, Jinyou; Wu, Ruiqin; Sun, Xiuyun; Li, Jiansheng; Han, Weiqing; Wang, Lianjun

2016-01-01

The highly recalcitrant 1H-1,2,4-triazole (TZ) is widely used in the synthesis of agricultural pesticide and considered to be an environmental pollutant. In this study, a novel strain NJUST26 capable of utilizing TZ as the sole carbon and nitrogen source, was isolated from TZ-contaminated soil, and identified as Shinella sp. The biodegradation assays suggested that optimal temperature and pH for TZ degradation by NJUST26 were 30 °C and 6–7, respectively. With the increase of initial TZ concentration from 100 to 320 mg L−1, the maximum volumetric degradation rate increased from 29.06 to 82.96 mg L−1 d−1, indicating high tolerance of NJUST26 towards TZ. TZ biodegradation could be accelerated through the addition of glucose, sucrose and yeast extract at relatively low dosage. The main metabolites, including 1,2-dihydro-3H-1,2,4-triazol-3-one (DHTO), semicarbazide and urea were identified. Based on these results, biodegradation pathway of TZ by NJUST26 was proposed, i.e., TZ was firstly oxidized to DHTO, and then the cleavage of DHTO ring occurred to generate N-hydrazonomethyl-formamide, which could be further degraded to biodegradable semicarbazide and urea. PMID:27436634

Laser transmission welding of poly(ethylene terephthalate) and biodegradable poly(ethylene terephthalate) - Based blends

NASA Astrophysics Data System (ADS)

Gisario, Annamaria; Veniali, Francesco; Barletta, Massimiliano; Tagliaferri, Vincenzo; Vesco, Silvia

2017-03-01

Joining of Poly(Ethylene Terephthalate) PET and its biodegradable derivatives is of high relevance to ensure good productive rate, low cost and operational safety for fabrication of medical and electronic devices, sport equipments as well as for manufacturing of food and drug packaging solutions. In the present investigation, granules of PET and PETs modified by organic additives, which promote biodegradation of the polymeric chains, were prepared by extrusion compounding. The achieved granules were subsequently re-extruded to shape thin (330 μm) flat sheets. Substrates cut from these sheets were joined by Laser Transmission Welding (LTW) with a continuous wave High Power Diode Laser (cw-HPDL). First, based on a qualitative evaluation of the welded joints, the most suitable operational windows for PETs laser joining were identified. Second, characterization of the mechanical properties of the welded joints was performed by tensile tests. Accordingly, Young's modulus of PET and biodegradable PET blends was studied by Takayanagi's model and, based on the experimental results, a novel predicting analytical model derived from the mixture rule was developed. Lastly, material degradation of the polymeric joints was evaluated by FT-IR analysis, thus allowing to identify the main routes to thermal degradation of PET and, especially, of biodegradable PET blends during laser processing.

Aerophytic Cyanobacteria as a Factor in the Biodegradation of Technical Materials on External Building Walls

NASA Astrophysics Data System (ADS)

Piontek, Marlena; Lechów, Hanna

2014-12-01

A study conducted at the Institute of Environmental Engineering, University of Zielona Góra showed the presence of 4 species of aerophytic cyanobacteria in the biological material sampled from the external building wall with visible biocorrosion: Gloeocapsa montana Kützing, Phormidium calcareum Kützing, Aphanothece saxicola Nägeli, Gloeothece caldariorum (P. Richter) Hollerbach. High levels of moisture were detected in the places of biofilm occurrence.

High-resolution nanopatterning of biodegradable polylactide by thermal nanoimprint lithography using gas permeable mold

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Hanabata, Makoto

2017-03-01

We report high-resolution (150 nm) nanopatterning of biodegradable polylactide by thermal nanoimprint lithography using dichloromethane as a volatile solvent for improving the liquidity and a porous cyclodextrin-based gas-permeable mold. This study demonstrates the high-resolution patterning of polylactic acid and other non-liquid functional materials with poor fluidity by thermal nanoimprinting. Such a patterning is expected to expand the utility of thermal nanoimprint lithography and fabricate non-liquid functional materials suitable for eco-friendly and biomedical applications.

Biodegradation of natural reinforcing fillers for polymer composites

NASA Astrophysics Data System (ADS)

Mastalygina, E. E.; Pantyukhov, P. V.; Popov, A. A.

2018-05-01

Twelve different natural raw materials were selected as possible fillers for eco-friendly biocomposites. The target was to find the most biodegradable ones. Two mycological tests were held: in the aqueous and agar media. It was found that two tests showed different results. In aqueous media, the fillers with a high content of water-soluble and easy-hydrolysed compounds demostrated the most intensive biofouling. In agar media, the entire filler was exposed to biodigestion by fungi. Therefore, multi-compound fillers with a set of different macro- and microelements were more biodegradable than others.

Advanced oxidation processes for treatment of effluents from a detergent industry.

PubMed

Martins, Rui C; Silva, Adrián M T; Castro-Silva, Sérgio; Garção-Nunes, Paulo; Quinta-Ferreira, Rosa M

2011-07-01

Ozonation, catalytic ozonation, Fenton's and heterogeneous Fenton-like processes were investigated as possible pretreatments of a low biodegradable and highly toxic wastewater produced by a detergent industry. The presence of a Mn-Ce-O catalyst in ozonation enhances the biodegradability and improves the degradation at low pH values. However, a high content of carbonyl compounds adsorbed on the recovered solid indicates some limitations for real-scale application. A commercial Fe2O3-MnOx catalyst shows higher activity as well as higher stability concerning carbon adsorption, but the leaching of metals is larger than for Mn-Ce-O. Regarding the heterogeneous Fenton-like route with an Fe-Ce-O catalyst, even though a high activity and stability are attained, the intermediates are less biodegradable than the original compounds, indicating that the resulting effluent cannot be conducted to an activated sludge post-treatment. The highest enhancement of effluent biodegradability is obtained with the classic homogeneous Fenton's process, with the BOD5/COD ratio increasing from 0.32 to 0.80. This process was scaled up and the treated effluent is now safely directed to a municipal wastewater treatment plant.

Bionanocomposites materials for food packaging applications: Concepts and future outlook.

PubMed

Youssef, Ahmed M; El-Sayed, Samah M

2018-08-01

Bionanocomposites materials open a chance for the usage of novel, high performance, lightweight, and ecofriendly composite materials making them take place the traditional non-biodegradable plastic packaging materials. Biopolymers like polysaccharides such as chitosan (CS), carboxymethyl cellulose (CMC), starch and cellophane could be used to resolve environmental hazards owing to their biodegradability and non-toxicity. In addition these advantages, polysaccharides have some disadvantages for example poor mechanical properties and low resistance to water. Therefore, nanomaterials are used to improve the thermal, mechanical and gas barrier properties without hindering their biodegradable and non-toxic characters. Furthermore, the most favorable nanomaterials are layered silicate nanoclays for example montmorillonite (MMT) and kaolinite, zinc oxide (ZnO-NPs), titanium dioxide (TiO 2 -NPs), and silver nanoparticles (Ag-NPs). In packaging application, the improvement of barrier properties of prepared films against oxygen, carbon dioxide, flavor compounds diffusion through the packaging films. Wide varieties of nanomaterials are suitable to offer smart and/or intelligent properties for food packaging materials, as demonstrated by oxygen scavenging capability, antimicrobial activity, and sign of the level of exposure to various harmful features for instance oxygen levels or insufficient temperatures. The compatibility between nanomaterials and polymers matrix consider the most challenge for the preparation of bionanocomposites as well as getting whole distribution of nanoparticles into the polymer matrix. We keen in this review the development of packaging materials performance and their mechanical, degradability and thermal stability as well as antibacterial activity for utilization of bionanocomposites in different packaging application is considered. Copyright © 2018 Elsevier Ltd. All rights reserved.

ANAEROBIC BIODEGRADATION OF VEGETABLE OIL AND ITS METABOLIC INTERMEDIATES IN OIL-ENRICHED FRESHWATER SEDIMENTS

EPA Science Inventory

Anaerobic biodegradation of vegetable oil in freshwater sediments is strongly inhibited by high concentrations of oil, but the presence of ferric hydroxide relieves the inhibition. The effect of ferric hydroxide is not due to physical or chemical interactions with long-chain fatt...

MTBE BIODEGRADATION IN A GRAVITY FLOW, HIGH-BIOMASS RETAINING BIOREACTOR

EPA Science Inventory

The aerobic biodegradation of methyl tert-butyl ether (MtBE), a widely used fuel oxygenate, was investigated using a pilot-scale biomass-retaining bioreactor called a Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d on Ci...

Discerning biodegradation and adsorption of microcystin-LR in a shallow semi-enclosed bay and bacterial community shifts in response to associated process.

PubMed

Li, Jieming; Li, Ji; Shi, Ge; Mei, Zulin; Wang, Ruiping; Li, Dianyue

2016-10-01

Hepatotoxic microcystins (MCs) produced by cyanobacteria pose serious risks to aquatic ecosystems and human health, to understand elimination pathways and mechanisms for MCs, especially in a shallow and semi-enclosed eutrophic area, is of great significance. This study succeed in discerning biodegradation and adsorption of microcystin-LR (MCLR) mediated by water and/or sediment in northern part of Meiliang Bay in Lake Taihu, China, and among the first to reveal the shifts of indigenous bacterial community composition in response to MCLR-biodegradation in sediment by Illumina high-throughput sequencing (HTS). Results confirmed that biodegradation predominantly governed MCLR elimination as compared to adsorption in study area. Through faster biodegradation with a rate of 49.21μgL(-1)d(-1), lake water contributed more to overall MCLR removal than sediment. Sediment also played indispensable role in MCLR removal via primarily biodegradation by indigenous community (a rate of 17.27μgL(-1)d(-1)) and secondarily adsorption (<20% of initial concentration). HTS analysis showed that indigenous community composition shifted with decreased phylogenetic diversity in response to sediment-mediated MCLR-biodegradation. Proteobacteria became predominant (39.34-86.78%) in overall composition after biodegradation, which was mostly contributed by sharp proliferation of β-proteobacteria (22.76-74.80%), and might closely link to MCLR-biodegradation in sediment. Moreover, the members of several genera belonging to α-proteobacteria, β-proteobacteria and γ-proteobacteria seemed to be key degraders because of their dominance or increasing population as MCLR degraded. This study expands understanding on natural elimination mechanism for MCs, and provides guidance to reduce MCs' biological risks and guarantee ecosystem safety in aquatic habitats. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of biological properties and fate in the environment of a new class of biosurfactants.

PubMed

Liwarska-Bizukojc, Ewa; Olejnik, Dorota; Delbeke, Elisabeth I P; Van Geem, Kevin M; Stevens, Christian V

2018-06-01

Selected sophorolipid quaternary ammonium salts (SQAS), being a new class of modified biosurfactants, were studied in this work for the first time with regard to their biodegradability and fate in the environment. It was made to find whether environment-friendly bioproducts like biosurfactants are still safe to the environment after their chemical modification. The susceptibility of these SQAS for biodegradation was estimated together with the evaluation of their influence on activated sludge microorganisms. Additionally, the mechanisms of removal of the SQAS from wastewater and from the aquatic environment, were analysed. The evaluated SQAS were potentially biodegradable, although none of them could be classified as readily biodegradable. The biodegradation degrees after 28 days ranged from 4 to 42%, dependent on the SQAS tested, i.e. below the required OECD 301D Closed Bottle Test level of 60%. Simultaneously, the analysis of the mass spectra revealed the presence of the breakdown products of each SQAS studied. Biodegradation was preceded by sorption of the SQAS on sludge particles, which occurred to be a main mechanism of the removal of these newly synthesized biosurfactants from wastewater. The mean degree of sorption calculated on the basis of SQAS determination was from 75 to 96%, dependent on the studied SQAS. The presence of SQAS in wastewater did not deteriorate the operation of the activated sludge system, although the products of the SQAS biodegradation remained in the liquid phase and might contribute to the increase of COD of the effluent to be introduced to the environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biodegradation kinetics of BTE-OX and MTBE by a diesel-grown biomass.

PubMed

Acuna-Askar, K; de la Torre-Torres, M A; Guerrero-Munoz, M J; Garza-Gonzalez, M T; Chavez-Gomez, B; Rodriguez-Sanchez, I P; Barrera-Saldana, H A

2006-01-01

The biodegradation kinetics of BTE-oX and MTBE, mixed all together in the presence of diesel-grown bioaugmented bacterial populations as high as 885 mg/L VSS, was evaluated. The effect of soil in aqueous samples and the effect of Tergitol NP-10 on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 54 h, every 6 h. All BTE-oX chemicals followed a first-order two-phase biodegradation kinetic model, whereas MTBE followed a zero-order removal kinetic model in all samples. BTE-oX removal rates were much higher than those of MTBE in all samples. The presence of soil in aqueous samples retarded BTE-oX and MTBE removal rates. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged between 64.8-98.9% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged between 18.7-40.8% and 7.2-10.3%, respectively.

Systemic approaches to biodegradation.

PubMed

Trigo, Almudena; Valencia, Alfonso; Cases, Ildefonso

2009-01-01

Biodegradation, the ability of microorganisms to remove complex chemicals from the environment, is a multifaceted process in which many biotic and abiotic factors are implicated. The recent accumulation of knowledge about the biochemistry and genetics of the biodegradation process, and its categorization and formalization in structured databases, has recently opened the door to systems biology approaches, where the interactions of the involved parts are the main subject of study, and the system is analysed as a whole. The global analysis of the biodegradation metabolic network is beginning to produce knowledge about its structure, behaviour and evolution, such as its free-scale structure or its intrinsic robustness. Moreover, these approaches are also developing into useful tools such as predictors for compounds' degradability or the assisted design of artificial pathways. However, it is the environmental application of high-throughput technologies from the genomics, metagenomics, proteomics and metabolomics that harbours the most promising opportunities to understand the biodegradation process, and at the same time poses tremendous challenges from the data management and data mining point of view.

Deciphering biodegradable chelant-enhanced phytoremediation through microbes and nitrogen transformation in contaminated soils.

PubMed

Fang, Linchuan; Wang, Mengke; Cai, Lin; Cang, Long

2017-06-01

Biodegradable chelant-enhanced phytoremediation offers an alternative treatment technique for metal contaminated soils, but most studies to date have addressed on phytoextraction efficiency rather than comprehensive understanding of the interactions among plant, soil microbes, and biodegradable chelants. In the present study, we investigated the impacts of biodegradable chelants, including nitrilotriacetate, S,S-ethylenediaminedisuccinic acid (EDDS), and citric acid on soil microbes, nitrogen transformation, and metal removal from contaminated soils. The EDDS addition to soil showed the strongest ability to promote the nitrogen cycling in soil, ryegrass tissue, and microbial metabolism in comparison with other chelants. Both bacterial community-level physiological profiles and soil mass specific heat rates demonstrated that soil microbial activity was inhibited after the EDDS application (between day 2 and 10), but this effect completely vanished on day 30, indicating the revitalization of microbial activity and community structure in the soil system. The results of quantitative real-time PCR revealed that the EDDS application stimulated denitrification in soil by increasing nitrite reductase genes, especially nirS. These new findings demonstrated that the nitrogen release capacity of biodegradable chelants plays an important role in accelerating nitrogen transformation, enhancing soil microbial structure and activity, and improving phytoextraction efficiency in contaminated soil.

Biodegradable poly-ε-caprolactone microcarriers for efficient production of human mesenchymal stromal cells and secreted cytokines in batch and fed-batch bioreactors.

PubMed

Lam, Alan Tin-Lun; Li, Jian; Toh, Jessica Pei-Wen; Sim, Eileen Jia-Hui; Chen, Allen Kuan-Liang; Chan, Jerry Kok-Yen; Choolani, Mahesh; Reuveny, Shaul; Birch, William R; Oh, Steve Kah-Weng

2017-03-01

Large numbers of human mesenchymal stromal cells (MSCs) used for a variety of applications in tissue engineering and cell therapy can be generated by scalable expansion in a bioreactor using microcarriers (MCs) systems. However, the enzymatic digestion process needed to detach cells from the growth surface can affect cell viability and potentially the potency and differentiation efficiency. Thus, the main aim of our study was to develop biocompatible and biodegradable MCs that can support high MSC yields while maintaining their differentiation capability and potency. After cell expansion, the cells that covered MCs can be directly implanted in vivo without the need for cell harvesting or use of scaffold. Poly-ε-caprolactone (PCL) is known as a biocompatible and biodegradable material. However, it cannot be used for generation of MCs because its high density (1.14 g/cm 3 ) would exclude its applicability for suspension MCs in stirred reactors. In this article, we describe expansion and potency of MSCs propagated on low-density (1.06 g/cm 3 ) porous PCL MCs coated with extracellular matrices (LPCLs) in suspended stirred reactors. Using these LPCLs, cell yields of about 4 × 10 4 cells/cm 2 and 7- to 10-fold increases were obtained using four different MSC lines (bone marrow, cord blood, fetal and Wharton's jelly). These yields were comparable with those obtained using non-degradable MCs (Cytodex 3) and higher than two-dimensional monolayer (MNL) cultures. A fed-batch process, which demonstrated faster cell expansion (4.5 × 10 4 cells/cm 2 in 5 days as compared with 7 days in batch culture) and about 70% reduction in growth media usage, was developed and scaled up from 100-mL spinner flask to 1-L controlled bioreactor. Surface marker expression, trilineage differentiation and clonogenic potential of the MSCs expanded on LPCL were not affected. Cytokine secretion kinetics, which occurred mostly during late logarithmic phase, was usually comparable with that obtained in Cytodex 3 cultures and higher than MNL cultures. In conclusion, biodegradable LPCL can be used to efficiently expand a variety of MSC lines in stirred scalable reactors in a cost-effective manner while maintaining surface markers expression, differentiation capability and high levels of cytokine secretion. This study is the first step in testing these cell-biodegradable porous MC aggregates for tissue engineering and cell therapy, such as bone and cartilage regeneration, or wound healing. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Biodegradable Polymers and Stem Cells for Bioprinting.

PubMed

Lei, Meijuan; Wang, Xiaohong

2016-04-29

It is imperative to develop organ manufacturing technologies based on the high organ failure mortality and serious donor shortage problems. As an emerging and promising technology, bioprinting has attracted more and more attention with its super precision, easy reproduction, fast manipulation and advantages in many hot research areas, such as tissue engineering, organ manufacturing, and drug screening. Basically, bioprinting technology consists of inkjet bioprinting, laser-based bioprinting and extrusion-based bioprinting techniques. Biodegradable polymers and stem cells are common printing inks. In the printed constructs, biodegradable polymers are usually used as support scaffolds, while stem cells can be engaged to differentiate into different cell/tissue types. The integration of biodegradable polymers and stem cells with the bioprinting techniques has provided huge opportunities for modern science and technologies, including tissue repair, organ transplantation and energy metabolism.

Subcutaneous implants for long-acting drug therapy in laboratory animals may generate unintended drug reservoirs.

PubMed

Guarnieri, Michael; Tyler, Betty M; Detolla, Louis; Zhao, Ming; Kobrin, Barry

2014-01-01

Long-acting therapy in laboratory animals offers advantages over the current practice of 2-3 daily drug injections. Yet little is known about the disintegration of biodegradable drug implants in rodents. Compare bioavailability of buprenorphine with the biodegradation of lipid-encapsulated subcutaneous drug pellets. Pharmacokinetic and histopathology studies were conducted in BALB/c female mice implanted with cholesterol-buprenorphine drug pellets. Drug levels are below the level of detection (0.5 ng/mL plasma) within 4-5 days of implant. However, necroscopy revealed that interstitial tissues begin to seal implants within a week. Visual inspection of the implant site revealed no evidence of inflammation or edema associated with the cholesterol-drug residue. Chemical analyses demonstrated that the residues contained 10-13% of the initial opiate dose for at least two weeks post implant. The results demonstrate that biodegradable scaffolds can become sequestered in the subcutaneous space. Drug implants can retain significant and unintended reservoirs of drugs.

Subcutaneous implants for long-acting drug therapy in laboratory animals may generate unintended drug reservoirs

PubMed Central

Guarnieri, Michael; Tyler, Betty M.; DeTolla, Louis; Zhao, Ming; Kobrin, Barry

2014-01-01

Background: Long-acting therapy in laboratory animals offers advantages over the current practice of 2-3 daily drug injections. Yet little is known about the disintegration of biodegradable drug implants in rodents. Objective: Compare bioavailability of buprenorphine with the biodegradation of lipid-encapsulated subcutaneous drug pellets. Methods: Pharmacokinetic and histopathology studies were conducted in BALB/c female mice implanted with cholesterol-buprenorphine drug pellets. Results: Drug levels are below the level of detection (0.5 ng/mL plasma) within 4-5 days of implant. However, necroscopy revealed that interstitial tissues begin to seal implants within a week. Visual inspection of the implant site revealed no evidence of inflammation or edema associated with the cholesterol-drug residue. Chemical analyses demonstrated that the residues contained 10-13% of the initial opiate dose for at least two weeks post implant. Discussion: The results demonstrate that biodegradable scaffolds can become sequestered in the subcutaneous space. Conclusion: Drug implants can retain significant and unintended reservoirs of drugs. PMID:24459402

Substrate inhibition kinetics of phenol biodegradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goudar, C.T.; Ganji, S.H.; Pujar, B.G.

Phenol biodegradation was studied in batch experiments using an acclimated inoculum and initial phenol concentrations ranging from 0.1 to 1.3 g/L. Phenol depletion an associated microbial growth were monitored over time to provide information that was used to estimate the kinetics of phenol biodegradation. Phenol inhibited biodegradation at high concentrations, and a generalized substrate inhibition model based on statistical thermodynamics was used to describe the dynamics of microbial growth in phenol. For experimental data obtained in this study, the generalized substrate inhibition model reduced to a form that is analogous to the Andrews equation, and the biokinetic parameters {micro}{sub max},more » maximum specific growth; K{sub s}, saturation constant; and K{sub i}, inhibition constant were estimated as 0.251 h{sup {minus}1}, 0.011 g/L, and 0.348 g/L, respectively, using a nonlinear least squares technique. Given the wide variability in substrate inhibition models used to describe phenol biodegradation, an attempt was made to justify selection of particular model based on theoretical considerations. Phenol biodegradation data from nine previously published studies were used in the generalized substrate inhibition model to determine the appropriate form of the substrate inhibition model. In all nine cases, the generalized substrate inhibition model reduced to a form analogous to the Andrews equation suggesting the suitability of the Andrews equation to describe phenol biodegradation data.« less

Discrimination in Degradability of Soil Pyrogenic Organic Matter Follows a Return-On-Energy-Investment Principle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Omar R.; Myers-Pigg, Allison N.; Kuo, Li-Jung

A fundamental understanding of biodegradability is central to elucidating the role(s) of pyrogenic organic matter (PyOM) in biogeochemical cycles. Since microbial community and ecosystem dynamics are driven by net energy flows, then a quantitative assessment of energy value versus energy requirement for oxidation of PyOM should yield important insights into their biodegradability. We used bomb calorimetry, step-wise isothermal thermogravimetric analysis (isoTGA) and 5-year in-situ bidegradation data, to develop energy-biodegradability relationships for a suite of plant- and manure-derived PyOM (n = 10). The net energy value (ΔE) for PyOM was between 4.0 and 175 kJ mol-1; with manure-derived PyOM having themore » highest ΔE. Thermal-oxidation activation energy (Ea) requirements ranged from 51 to 125 kJ mol-1, with wood-derived PyOM having the highest Ea requirements. We propose a return-on-investment (ROI) parameter (ΔE/Ea) for differentiating short-to-medium term biodegradability of PyOM and deciphering if biodegradation will most likely proceed via co-metabolism (ROI < 1) or direct metabolism (ROI ≥ 1). The ROI-biodegradability relationship was sigmoidal with higher biodegradability associated with PyOM of higher ROI; indicating that microbes exhibit a higher preference for “high investment value” PyOM.« less

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

PubMed Central

Lee, Jee-Wook; Han, Hyung-Seop; Han, Kyeong-Jin; Park, Jimin; Jeon, Hojeong; Ok, Myoung-Ryul; Seok, Hyun-Kwang; Ahn, Jae-Pyoung; Lee, Kyung Eun; Lee, Dong-Ho; Yang, Seok-Jo; Cho, Sung-Youn; Cha, Pil-Ryung; Kwon, Hoon; Nam, Tae-Hyun; Han, Jee Hye Lo; Rho, Hyoung-Jin; Lee, Kang-Sik; Kim, Yu-Chan; Mantovani, Diego

2016-01-01

There has been a tremendous amount of research in the past decade to optimize the mechanical properties and degradation behavior of the biodegradable Mg alloy for orthopedic implant. Despite the feasibility of degrading implant, the lack of fundamental understanding about biocompatibility and underlying bone formation mechanism is currently limiting the use in clinical applications. Herein, we report the result of long-term clinical study and systematic investigation of bone formation mechanism of the biodegradable Mg-5wt%Ca-1wt%Zn alloy implant through simultaneous observation of changes in element composition and crystallinity within degrading interface at hierarchical levels. Controlled degradation of Mg-5wt%Ca-1wt%Zn alloy results in the formation of biomimicking calcification matrix at the degrading interface to initiate the bone formation process. This process facilitates early bone healing and allows the complete replacement of biodegradable Mg implant by the new bone within 1 y of implantation, as demonstrated in 53 cases of successful long-term clinical study. PMID:26729859

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper

Treesearch

Yei Hwan Jung; Tzu-Hsuan Chang; Huilong Zhang; Chunhua Yao; Qifeng Zheng; Vina W. Yang; Hongyi Mi; Munho Kim; Sang June Cho; Dong-Wook Park; Hao Jiang; Juhwan Lee; Yijie Qiu; Weidong Zhou; Zhiyong Cai; Shaoqin Gong; Zhenqiang Ma

2015-01-01

Today’s consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems...

Biodegradable and Elastomeric Poly(glycerol sebacate) as a Coating Material for Nitinol Bare Stent

PubMed Central

Kim, Min Ji; Hwang, Moon Young; Kim, JiHeung; Chung, Dong June

2014-01-01

We synthesized and evaluated biodegradable and elastomeric polyesters (poly(glycerol sebacate) (PGS)) using polycondensation between glycerol and sebacic acid to form a cross-linked network structure without using exogenous catalysts. Synthesized materials possess good mechanical properties, elasticity, and surface erosion biodegradation behavior. The tensile strength of the PGS was as high as 0.28 ± 0.004 MPa, and Young's modulus was 0.122 ± 0.0003 MPa. Elongation was as high as 237.8 ± 0.64%, and repeated elongation behavior was also observed to at least three times the original length without rupture. The water-in-air contact angles of the PGS surfaces were about 60°. We also analyzed the properties of an electrospray coating of biodegradable PGS on a nitinol stent for the purpose of enhancing long-term patency for the therapeutic treatment of varicose veins disease. The surface morphology and thickness of coating layer could be controlled by adjusting the electrospraying conditions and solution parameters. PMID:24955369

Toxicity and biodegradability of high strength/toxic organic liquid industrial effluents and hazardous landfill leachates.

PubMed

Naidoo, V; du Preez, M; Rakgotho, T; Odhav, B; Buckley, C A

2002-01-01

Industrial effluents and leachates from hazardous landfill sites were tested for toxicity using the anaerobic toxicity assay. This test was done on several industrial effluents (brewery spent grain effluent, a chemical industry effluent, size effluent), and several hazardous landfill leachates giving vastly different toxicity results. The brewery effluent, spent grain effluent and size effluent were found to be less toxic than the chemical effluent and hazardous landfill leachate samples. The chemical industry effluent was found to be most toxic. Leachate samples from the H:h classified hazardous landfill site were found to be less toxic at high concentrations (40% (v/v)) while the H:H hazardous landfill leachate samples were found to be more toxic even at low concentrations of 4% (v/v). The 30 d biochemical methane potential tests revealed that the brewery effluent, organic spent grain effluent and size effluent were 89%, 63%, and 68% biodegradable, respectively. The leachate from Holfontein hazardous landfill site was least biodegradable (19%) while the chemical effluent and Aloes leachate were 29% and 32% biodegradable under anaerobic conditions.

Mössbauer and X-ray study of biodegradation of 57Fe3 O 4 magnetic nanoparticles in rat brain

NASA Astrophysics Data System (ADS)

Gabbasov, R. R.; Cherepanov, V. M.; Chuev, M. A.; Lomov, A. A.; Mischenko, I. N.; Nikitin, M. P.; Polikarpov, M. A.; Panchenko, V. Y.

2016-12-01

Biodegradation of a 57Fe3 O 4 - based dextran - stabilized ferrofluid in the ventricular cavities of the rat brain was studied by X-ray diffraction and Mössbauer spectroscopy. A two-step process of biodegradation, consisting of fast disintegration of the initial composite magnetic beads into separate superparamagnetic nanoparticles and subsequent slow dissolution of the nanoparticles has been found. Joint fitting of the couples of Mössbauer spectra measured at different temperatures in the formalism of multi-level relaxation model with one set of fitting parameters, allowed us to measure concentration of exogenous iron in the rat brain as a function of time after the injection of nanoparticles.

Biodegradability of PP/HMSPP and natural and synthetic polymers blends in function of gamma irradiation degradation

NASA Astrophysics Data System (ADS)

Cardoso, Elisabeth C. L.; Scagliusi, Sandra R.; Lima, Luis F. C. P.; Bueno, Nelson R.; Brant, Antonio J. C.; Parra, Duclerc F.; Lugão, Ademar B.

2014-01-01

Polymers are used for numerous applications in different industrial segments, generating enormous quantities of discarding in the environment. Polymeric materials composites account for an estimated from 20 to 30% total volume of solid waste. Polypropylene (PP) undergoes crosslinking and extensive main chain scissions when submitted to ionizing irradiation; as one of the most widely used linear hydrocarbon polymers, PP, made from cheap petrochemical feed stocks, shows easy processing leading it to a comprehensive list of finished products. Consequently, there is accumulation in the environment, at 25 million tons per year rate, since polymeric products are not easily consumed by microorganisms. PP polymers are very bio-resistant due to involvement of only carbon atoms in main chain with no hydrolysable functional group. Several possibilities have been considered to minimize the environmental impact caused by non-degradable plastics, subjecting them to: physical, chemical and biological degradation or combination of all these due to the presence of moisture, air, temperature, light, high energy radiation or microorganisms. There are three main classes of biodegradable polymers: synthetic polymers, natural polymers and blends of polymers in which one or more components are readily consumed by microorganisms. This work aims to biodegradability investigation of a PP/HMSPP (high melt strength polypropylene) blended with sugarcane bagasse, PHB (poly-hydroxy-butyrate) and PLA (poly-lactic acid), both synthetic polymers, at a 10% level, subjected to gamma radiation at 50, 100, 150 and 200 kGy doses. Characterization will comprise IR, DSC, TGA, OIT and Laboratory Soil Burial Test (LSBT).

Biodegradation of monoaromatic hydrocarbons by aquifer microorganisms using oxygen, nitrate, or nitrous oxide as the terminal electron acceptor.

PubMed Central

Hutchins, S R

1991-01-01

Microcosms were prepared from aquifer material, spiked with monoaromatic hydrocarbons, and amended with oxygen, nitrate, and nitrous oxide. Benzene and alkylbenzenes were degraded to concentrations below 5 micrograms/liter within 7 days under aerobic conditions, whereas only the alkylbenzenes were degraded when either nitrate or nitrous oxide was used. With limited oxygen, monoaromatic hydrocarbons were degraded but removal ceased once oxygen was consumed. However, when nitrate was also present, biodegradation of the alkylbenzenes continued with no apparent lag. Although benzene was still recalcitrant, levels were reduced compared with levels after treatment with nitrate or limited oxygen alone. PMID:1768110

An examination of the physical properties, fate, ecotoxicity and potential environmental risks for a series of propylene glycol ethers.

PubMed

Staples, Charles A; Davis, John W

2002-10-01

Propylene glycol ethers (PGEs) are comprised of mono-, di- and tri-PGEs and several of their acetate esters. The nature of the range of applications that use PGEs suggests that there is a potential for both intentional and unintentional entry of the materials into the environment. Selected physical/chemical properties, fate characteristics, aquatic toxicity data and calculated environmental concentrations were used to assess potential risks from the manufacture, handling, use, and disposal of PGEs. In general, the PGEs are low to moderately volatile, have high aqueous solubilities, low octanol-water partition coefficients (Kow), and bioconcentration factor values of <10, which indicate they are unlikely to accumulate in aquatic food chains. Both abiotic and biological degradation processes reduce environmental concentrations of PGEs. In air, vapor-phase PGEs react with photo-chemically produced hydroxyl radicals and have half-lives ranging from 5.5 to 34.4 h. A variety of ready and inherent biodegradation test methods, as well as tests that simulate biodegradation in wastewater treatment plants, surface water and soil have been conducted on PGEs. Significant aerobic biodegradation was generally observed, with a range of biodegradation half-lives on the order of 5-25 d. Acute aquatic toxicity studies with PGEs resulted in LC50 values ranging from approximately >100 to >20,000 mg/l for freshwater fish, the pelagic invertebrate Daphnia magna, green algae Selenastrum capricornutum (now called Pseudokirchneriella capricornutum) and bacteria. Level 3 multi-media modeling (EQC model of Mackay) was used to simulate regional-scale concentrations of PGEs in air, soil, water, and sediment. Toxicity thresholds were then compared with regional-scale water, soil and sediment concentrations to determine hazard quotients. Based upon this analysis, concentrations of PGEs are unlikely to pose adverse risks to the environment.

Effect of metal ions and petrochemicals on bioremediation of chlorpyrifos in aerobic sequencing batch bioreactor (ASBR).

PubMed

Khalid, Saira; Hashmi, Imran; Jamal Khan, Sher; Qazi, Ishtiaq A; Nasir, Habib

2016-10-01

Application of chlorpyrifos (CP) has increased its environmental concentration. Increasing CP concentration has increased chances of adverse health effects. Its removal from environment has attained researcher's attention. CP degrading bacterial strains were isolated from wastewater and agricultural soil. Finally, selected five bacterial strains were identified using 16S rRNA nucleotide sequence analysis as Pseudomonas kilonensis SRK1, Serratia marcescens SRK2, Bacillus pumilus SRK4, Achromobacter xylosoxidans SRK5, and Klebsiella sp. T13. Interaction studies among bacterial strains demonstrated possibility for development of five membered bacterial consortium. Biodegradation potential of bacterial consortium was investigated in the presence of petrochemicals and trace metals. About 98 % CP removal was observed in sequencing batch reactors at inoculum level, 10 %; pH, 7; CP concentration, 400 mgL -1 , and HRT, 48 h. Experimental data has shown an excellent fit to first order growth model. Among all petrochemicals only toluene (in low concentration) has stimulatory effect on biodegradation of CP. Addition of petrochemicals (benzene, toluene, and xylene) in high concentration (100 mg L -1 ) inhibited bacterial activity and decreased CP removal. At low concentration i.e., 1 mg L -1 of inorganic contaminants (Cu, Hg, and Zn) >96 % degradation was observed. Addition of Cu(II) in low concentration has stimulated CP removal efficiency. Hg(II) in all concentrations has strongly inhibited biodegradation rate except at 1 mgL -1 . In simulated pesticide, wastewater CP removal efficiency decreased to 77.5 %. Outcomes of study showed that both type and concentration of petrochemicals and trace metals influenced biodegradation of CP.

The use of biodegradable PLGA nanoparticles to mediate SOX9 gene delivery in human mesenchymal stem cells (hMSCs) and induce chondrogenesis.

PubMed

Kim, Jae-Hwan; Park, Ji Sun; Yang, Han Na; Woo, Dae Gyun; Jeon, Su Yeon; Do, Hyun-Jin; Lim, Hye-Young; Kim, Jung Mo; Park, Keun-Hong

2011-01-01

In stem cell therapy, transfection of specific genes into stem cells is an important technique to induce cell differentiation. To perform gene transfection in human mesenchymal stem cells (hMSCs), we designed and fabricated a non-viral vector system for specific stem cell differentiation. Several kinds of gene carriers were evaluated with regard to their transfection efficiency and their ability to enhance hMSCs differentiation. Of these delivery vehicles, biodegradable poly (DL-lactic-co-glycolic acid) (PLGA) nanoparticles yielded the best results, as they complexed with high levels of plasmid DNA (pDNA), allowed robust gene expression in hMSCs, and induced chondrogenesis. Polyplexing with polyethylenimine (PEI) enhanced the cellular uptake of SOX9 DNA complexed with PLGA nanoparticles both in vitro and in vivo. The expression of enhanced green fluorescent protein (EGFP) and SOX9 increased up to 75% in hMSCs transfected with PEI/SOX9 complexed PLGA nanoparticles 2 days after transfection. SOX9 gene expression was evaluated by RT-PCR, real time-qPCR, glycosaminoglycan (GAG)/DNA levels, immunoblotting, histology, and immunofluorescence. Copyright © 2010 Elsevier Ltd. All rights reserved.

Laccase Gene Expression and Vinasse Biodegradation by Trametes hirsuta Strain Bm-2.

PubMed

Tapia-Tussell, Raúl; Pérez-Brito, Daisy; Torres-Calzada, Claudia; Cortés-Velázquez, Alberto; Alzate-Gaviria, Liliana; Chablé-Villacís, Rubí; Solís-Pereira, Sara

2015-08-19

Vinasse is the dark-colored wastewater that is generated by bioethanol distilleries from feedstock molasses. The vinasse that is generated from molasses contains high amounts of pollutants, including phenolic compounds and melanoindin. The goal of this work was to study the expression of laccase genes in the Trametes hirsuta strain Bm-2, isolated in Yucatan, Mexico, in the presence of phenolic compounds, as well as its effectiveness in removing colorants from vinasse. In the presence of all phenolic compounds tested (guaiacol, ferulic acid, and vanillic acid), increased levels of laccase-encoding mRNA were observed. Transcript levels in the presence of guaiacol were 40 times higher than those in the control. The lcc1 and lcc2 genes of T. hirsuta were differentially expressed; guaiacol and vanillin induced the expression of both genes, whereas ferulic acid only induced the expression of lcc2. The discoloration of vinasse was concomitant with the increase in laccase activity. The highest value of enzyme activity (2543.7 U/mL) was obtained in 10% (v/v) vinasse, which corresponded to a 69.2% increase in discoloration. This study demonstrates the potential of the Bm-2 strain of T. hirsuta for the biodegradation of vinasse.

Bioaccessible Porosity in Soil Aggregates and Implications for Biodegradation of High Molecular Weight Petroleum Compounds.

PubMed

Akbari, Ali; Ghoshal, Subhasis

2015-12-15

We evaluated the role of soil aggregate pore size on biodegradation of essentially insoluble petroleum hydrocarbons that are biodegraded primarily at the oil-water interface. The size and spatial distribution of pores in aggregates sampled from biodegradation experiments of a clayey, aggregated, hydrocarbon-contaminated soil with relatively high bioremediation end point were characterized by image analyses of X-ray micro-CT scans and N2 adsorption. To determine the bioaccessible pore sizes, we performed separate experiments to assess the ability of hydrocarbon degrading bacteria isolated from the soil to pass through membranes with specific sized pores and to access hexadecane (model insoluble hydrocarbon). Hexadecane biodegradation occurred only when pores were 5 μm or larger, and did not occur when pores were 3 μm and smaller. In clayey aggregates, ∼ 25% of the aggregate volume was attributed to pores larger than 4 μm, which was comparable to that in aggregates from a sandy, hydrocarbon-contaminated soil (~23%) scanned for comparison. The ratio of volumes of inaccessible pores (<4 μm) to bioaccessible pores (>4 μm) in the clayey aggregates was 0.32, whereas in the sandy aggregates it was approximately 10 times lower. The role of soil microstructure on attainable bioremediation end points could be qualitatively assessed in various soils by the aggregate characterization approach outlined herein.

Using vibrational molecular spectroscopy to reveal association of steam-flaking induced carbohydrates molecular structural changes with grain fractionation, biodigestion and biodegradation

NASA Astrophysics Data System (ADS)

Xu, Ningning; Liu, Jianxin; Yu, Peiqiang

2018-04-01

Advanced vibrational molecular spectroscopy has been developed as a rapid and non-destructive tool to reveal intrinsic molecular structure conformation of biological tissues. However, this technique has not been used to systematically study flaking induced structure changes at a molecular level. The objective of this study was to use vibrational molecular spectroscopy to reveal association between steam flaking induced CHO molecular structural changes in relation to grain CHO fractionation, predicted CHO biodegradation and biodigestion in ruminant system. The Attenuate Total Reflectance Fourier-transform Vibrational Molecular Spectroscopy (ATR-Ft/VMS) at SRP Key Lab of Molecular Structure and Molecular Nutrition, Ministry of Agriculture Strategic Research Chair Program (SRP, University of Saskatchewan) was applied in this study. The fractionation, predicted biodegradation and biodigestion were evaluated using the Cornell Net Carbohydrate Protein System. The results show that: (1) The steam flaking induced significant changes in CHO subfractions, CHO biodegradation and biodigestion in ruminant system. There were significant differences between non-processed (raw) and steam flaked grain corn (P < .01); (2) The ATR-Ft/VMS molecular technique was able to detect the processing induced CHO molecular structure changes; (3) Induced CHO molecular structure spectral features are significantly correlated (P < .05) to CHO subfractions, CHO biodegradation and biodigestion and could be applied to potentially predict CHO biodegradation (R2 = 0.87, RSD = 0.74, P < .01) and intestinal digestible undegraded CHO (R2 = 0.87, RSD = 0.24, P < .01). In summary, the processing induced molecular CHO structure changes in grain corn could be revealed by the ATR-Ft/VMS vibrational molecular spectroscopy. These molecular structure changes in grain were potentially associated with CHO biodegradation and biodigestion.

A model framework to describe growth-linked biodegradation of trace-level pollutants in the presence of coincidental carbon substrates and microbes.

PubMed

Liu, Li; Helbling, Damian E; Kohler, Hans-Peter E; Smets, Barth F

2014-11-18

Pollutants such as pesticides and their degradation products occur ubiquitously in natural aquatic environments at trace concentrations (μg L(-1) and lower). Microbial biodegradation processes have long been known to contribute to the attenuation of pesticides in contaminated environments. However, challenges remain in developing engineered remediation strategies for pesticide-contaminated environments because the fundamental processes that regulate growth-linked biodegradation of pesticides in natural environments remain poorly understood. In this research, we developed a model framework to describe growth-linked biodegradation of pesticides at trace concentrations. We used experimental data reported in the literature or novel simulations to explore three fundamental kinetic processes in isolation. We then combine these kinetic processes into a unified model framework. The three kinetic processes described were: the growth-linked biodegradation of micropollutant at environmentally relevant concentrations; the effect of coincidental assimilable organic carbon substrates; and the effect of coincidental microbes that compete for assimilable organic carbon substrates. We used Monod kinetic models to describe substrate utilization and microbial growth rates for specific pesticide and degrader pairs. We then extended the model to include terms for utilization of assimilable organic carbon substrates by the specific degrader and coincidental microbes, growth on assimilable organic carbon substrates by the specific degrader and coincidental microbes, and endogenous metabolism. The proposed model framework enables interpretation and description of a range of experimental observations on micropollutant biodegradation. The model provides a useful tool to identify environmental conditions with respect to the occurrence of assimilable organic carbon and coincidental microbes that may result in enhanced or reduced micropollutant biodegradation.

Biodegradable plastic bags on the seafloor: A future threat for seagrass meadows?

PubMed

Balestri, Elena; Menicagli, Virginia; Vallerini, Flavia; Lardicci, Claudio

2017-12-15

Marine plastic litter is a global concern. Carrier bags manufactured from non-biodegradable polymers constitute a large component of this litter. Because of their adverse impact on marine life, non-biodegradable bags have recently been replaced by biodegradable ones. However, growing evidence shows that these latter are not readily degradable in marine sediments and can alter benthic assemblages. The potential impact of biodegradable bags on seagrasses inhabiting sandy bottoms, which are the most widespread and productive ecosystems of the coastal zones, has been ignored. Mesocosm experiments were conducted to assess the effect of a commercialized biodegradable bag on a common seagrass species of the Mediterranean, Cymodocea nodosa, both at the level of individual plant (clonal growth) and of plant community (plant-plant relationships), under three culture regimes (plant alone, in combination with a neighbour of the same species or of the co-existing seagrass Zostera noltei) simulating different natural conditions (bare substrate, monospecific meadows or mixed meadows). The bag behaviour in marine sediment and sediment physical/chemical variables were also examined. After six months of sediment exposure, the bag retained considerable mass (85% initial weight) and reduced sediment pore-water oxygen concentration and pH. In the presence of bag, C. nodosa root spread and vegetative recruitment increased compared to controls, both intra- and interspecific interactions shifted from neutral to competitive, and the growth form changed from guerrilla (loosely arranged group of widely spaced ramets) to phalanx form (compact structure of closed spaced ramets) but only with Z. noltei. These findings suggest that biodegradable bags altering sediment geochemistry could promote the spatial segregation of seagrass clones and influence species coexistence. Copyright © 2017 Elsevier B.V. All rights reserved.

Biodegradable Photonic Melanoidin for Theranostic Applications.

PubMed

Lee, Min-Young; Lee, Changho; Jung, Ho Sang; Jeon, Mansik; Kim, Ki Su; Yun, Seok Hyun; Kim, Chulhong; Hahn, Sei Kwang

2016-01-26

Light-absorbing nanoparticles for localized heat generation in tissues have various biomedical applications in diagnostic imaging, surgery, and therapies. Although numerous plasmonic and carbon-based nanoparticles with strong optical absorption have been developed, their clearance, potential cytotoxicity, and long-term safety issues remain unresolved. Here, we show that "generally regarded as safe (GRAS)" melanoidins prepared from glucose and amino acid offer a high light-to-heat conversion efficiency, biocompatibility, biodegradability, nonmutagenicity, and efficient renal clearance, as well as a low cost for synthesis. We exhibit a wide range of biomedical photonic applications of melanoidins, including in vivo photoacoustic mapping of sentinel lymph nodes, photoacoustic tracking of gastrointestinal tracts, photothermal cancer therapy, and photothermal lipolysis. The biodegradation rate and renal clearance of melanoidins are controllable by design. Our results confirm the feasibility of biodegradable melanoidins for various photonic applications to theranostic nanomedicines.

Synergistic effects of micropatterned biodegradable conduits and Schwann cells on sciatic nerve regeneration

NASA Astrophysics Data System (ADS)

Rutkowski, Gregory E.; Miller, Cheryl A.; Jeftinija, Srdija; Mallapragada, Surya K.

2004-09-01

This paper describes a novel biodegradable conduit that provides a combination of physical, chemical and biological cues at the cellular level to facilitate peripheral nerve regeneration. The conduit consists of a porous poly(D,L-lactic acid) (PDLLA) tubular support structure with a micropatterned inner lumen. Schwann cells were pre-seeded into the lumen to provide additional trophic support. Conduits with micropatterned inner lumens pre-seeded with Schwann cells (MS) were fabricated and compared with three types of conduits used as controls: M (conduits with micropatterned inner lumens without pre-seeded Schwann cells), NS (conduits without micropatterned inner lumens pre-seeded with Schwann cells) and N (conduits without micropatterned inner lumens, without pre-seeded Schwann cells). The conduits were implanted in rats with 1 cm sciatic nerve transections and the regeneration and functional recovery were compared in the four different cases. The number or size of regenerated axons did not vary significantly among the different conduits. The time of recovery, and the sciatic function index, however, were significantly enhanced using the MS conduits, based on qualitative observations as well as quantitative measurements using walking track analysis. This demonstrates that biodegradable micropatterned conduits pre-seeded with Schwann cells that provide a combination of physical, chemical and biological guidance cues for regenerating axons at the cellular level offer a better alternative for repairing sciatic nerve transactions than conventional biodegradable conduits.

Change of microbial community structure and functional gene abundance in nonylphenol-degrading sediment.

PubMed

Wang, Zhao; Yang, Yuyin; He, Tao; Xie, Shuguang

2015-04-01

Biodegradation by autochthonous microbial community is an important way to clean up nonylphenol (NP) from contaminated river sediment. Knowledge of sediment microbial community can aid in our understanding of biological processes related to NP degradation. However, the change in sediment microbial community associated with NP biodegradation remains unclear. The present study investigated the shift in bacterial community structure and NP-degrading gene abundance in response to NP attenuation in river sediment. Sediment microcosms with different levels of 4-NP (0, 100, or 300 μg/g) were constructed. A nearly complete attenuation of NP occurred in the microcosm with 100 μg/g NP after 9 days' incubation, while a residual NP rate of 8.1 % was observed in the microcosm with 300 μg/g NP after 22 days' incubation. Illumina MiSeq sequencing analysis indicated that Gammaproteobacteria, Alphaproteobacteria, and Bacteroidetes predominated in NP-degrading river sediment. Sediment bacterial community structure varied significantly during NP biodegradation and subsequent incubation, which was affected by the level of added NP. The n-alkane biodegradation (alkB) gene abundance showed a significant variation in each NP-amended microcosm (100 or 300 μg/g), while a significant increase in the single component monooxygenase (sMO) gene abundance only occurred in the microcosm spiked with 300 μg/g NP. This study can provide some new insights toward NP-degrading microbial ecology in the environment.

Degradation of seed mucilage by soil microflora promotes early seedling growth of a desert sand dune plant.

PubMed

Yang, Xuejun; Baskin, Carol C; Baskin, Jerry M; Zhang, Wenhao; Huang, Zhenying

2012-05-01

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High-performance anion-exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO(2) and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)-labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well-adapted. © 2011 Blackwell Publishing Ltd.

Integrated ozone and biotreatment of pulp mill effluent and changes in biodegradability and molecular weight distribution of organic compounds.

PubMed

Bijan, Leila; Mohseni, Madjid

2005-10-01

The overall effectiveness of integrating ozonation with biological treatment on the biodegradability enhancement and recalcitrant organic matter (ROM) removal from pulp mill alkaline bleach plant effluent was investigated. Ozonation was performed in a semi-batch bubble column reactor at pH of 11 and 4.5. Batch biological treatment was conducted in shake flasks. Samples obtained during the treatments were monitored for BOD5, COD, TOC, and molecular weight distribution. At an ozone dosage of 0.7-0.8 mg O3/mL wastewater, integrated treatment showed about 30% higher TOC mineralization compared to individual ozonation or biotreatment. Ozone treatment enhanced the biodegradability of the effluent (monitored as 21% COD reduction and 13% BOD5 enhancement), allowing for a higher removal of pollutants. The conversion of high molecular weight (HMW) to low molecular weight (LMW) compounds was an important factor in the overall biodegradability enhancement of the alkaline effluent. The overall biodegradability of the LMW compounds did not change over the course of ozonation, but it increased from 5% to 50% (measured as COD removal) for the HMW portion. Ozonation at pH of 11 was more effective than that at pH of 4.5 in terms of generating more biodegradable compounds.

Encapsulated Pseudomonas putida for phenol biodegradation: Use of a structural membrane for construction of a well-organized confined particle.

PubMed

Kurzbaum, Eyal; Raizner, Yasmin; Cohen, Oded; Suckeveriene, Ran Y; Kulikov, Anatoly; Hakimi, Ben; Iasur Kruh, Lilach; Armon, Robert; Farber, Yair; Menashe, Ofir

2017-09-15

Phenols are toxic byproducts from a wide range of industry sectors. If not treated, they form effluents that are very hazardous to the environment. This study presents the use of a Pseudomonas putida F1 culture encapsulated within a confined environment particle as an efficient technique for phenol biodegradation. The innovative encapsulation technique method, named the "Small Bioreactor Platform" (SBP) technology, enables the use of a microfiltration membrane constructed as a physical barrier for creating a confined environment for the encapsulated culture. The phenol biodegradation rate of the encapsulated culture was compared to its suspended state in order to evaluate the effectiveness of the encapsulation technique for phenol biodegradation. A maximal phenol biodegradation rate (q) of 2.12/d was exhibited by encapsulated P. putida at an initial phenol concentration of 100 mg/L. The biodegradation rate decreased significantly at lower and higher initial phenol concentrations of 50 and up to 3000 mg/L, reaching a rate of 0.1018/d. The results also indicate similar and up to double the degradation rate between the two bacterial states (encapsulated vs. suspended). High resolution scanning electron microscopy images of the SBP capsule's membrane morphology demonstrated a highly porous microfiltration membrane. These results, together with the long-term activity of the SBP capsules and verification that the culture remains pure after 60 days using 16S rRNA gene phylogenetic affiliation tests, provide evidence for a successful application of this new encapsulation technique for bioaugmentation of selected microbial cultures in water treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics and yields of pesticide biodegradation at low substrate concentrations and under conditions restricting assimilable organic carbon.

PubMed

Helbling, Damian E; Hammes, Frederik; Egli, Thomas; Kohler, Hans-Peter E

2014-02-01

The fundamentals of growth-linked biodegradation occurring at low substrate concentrations are poorly understood. Substrate utilization kinetics and microbial growth yields are two critically important process parameters that can be influenced by low substrate concentrations. Standard biodegradation tests aimed at measuring these parameters generally ignore the ubiquitous occurrence of assimilable organic carbon (AOC) in experimental systems which can be present at concentrations exceeding the concentration of the target substrate. The occurrence of AOC effectively makes biodegradation assays conducted at low substrate concentrations mixed-substrate assays, which can have profound effects on observed substrate utilization kinetics and microbial growth yields. In this work, we introduce a novel methodology for investigating biodegradation at low concentrations by restricting AOC in our experiments. We modified an existing method designed to measure trace concentrations of AOC in water samples and applied it to systems in which pure bacterial strains were growing on pesticide substrates between 0.01 and 50 mg liter(-1). We simultaneously measured substrate concentrations by means of high-performance liquid chromatography with UV detection (HPLC-UV) or mass spectrometry (MS) and cell densities by means of flow cytometry. Our data demonstrate that substrate utilization kinetic parameters estimated from high-concentration experiments can be used to predict substrate utilization at low concentrations under AOC-restricted conditions. Further, restricting AOC in our experiments enabled accurate and direct measurement of microbial growth yields at environmentally relevant concentrations for the first time. These are critical measurements for evaluating the degradation potential of natural or engineered remediation systems. Our work provides novel insights into the kinetics of biodegradation processes and growth yields at low substrate concentrations.

Biodegradability of immidazolium, pyridinium, piperidinium and pyrrolidinium based ionic liquid in different water source

NASA Astrophysics Data System (ADS)

Krishnan, S.; Quraishi, K. S.; Aminuddin, N. F.; Mazlan, F. A.; Leveque, J.-M.

2016-11-01

Ionic Liquid (IL), combination of an organic cation with an organic or inorganic cation, possess some remarkable physical chemical properties such as no virtual vapor pressure (allowing recyclability and reusability), wide liquid range, high thermal and chemical stability, ease to choose hydrophobic/hydrophilic character and wide electrochemical window. Owing to that, they have become increasingly popular as green solvents/additives/catalysts for organic synthetic chemistry, extraction, electrochemistry, catalysis, biomass conversion, biotechnologies and pharmaceutical applications. This is acknowledged by the exponential number of yearly published articles related to them. However, even if these are very widely studied in the international scientific community, they are not or very little used on an industrial scale, particularly because of the lack of data on their toxicity and biodegradability. Notably hydrophobic ILs seems to display higher toxicity towards microorganisms and lower biodegradability compared to their hydrophilic analogues since they are not readily disassociated in water. This present work aims to explore the biodegradability of 8 different insoluble ILs in different sources of water bearing varied amount of microorganisms to study the impact of the used water on the biodegradability assessment. The water sources used are Type III Water, Pond water and filtered Sewage Water. Based on the results obtained, it can be concluded that the type of water has a very minor influence on the biodegradability effect of insoluble ILs. However, there is still some degree of influence on the type of water with the biodegradability.

A case study on the method-induced difference in the chemical properties and biodegradability of soil water extractable organic carbon of a granitic forest soil.

PubMed

Wu, Yue; Jiang, Ying

2016-09-15

Water extractable organic carbon (WEOC) plays important roles in soil dissolved organic matter (DOM) research. In the present study, we have detected the chemical properties and biodegradability of WEOC obtained from one granitic forest soil with four commonly used or suggested extraction methods, to study the potential methodological influence in soil DOM research. Results showed great difference in both chemical properties and biodegradation of WEOC from various methods. For the chosen soil, compared to that from fresh soil, WEOC from dried soil contained large proportion of HIN, Base fractions and labile O-alkyl components which might be derived from microbial cell lysis, and showed low fluorescence characteristics, exhibiting great biodegradability. Similarly, WEOC extracted under low temperature and short time conditions showed low fluorescence characteristics and exhibited considerable biodegradability. Conversely, WEOC, which might be potentially subjected to decomposition and loss during extraction, contained higher percentages of HOA fractions and aromatic alkyl and aryl components, and showed high fluorescence characteristics, exhibiting low biodegradability. WEOC extracted in moderate time and temperature showed moderate biodegradability. These method-induced differences implied the direct comparison of the results from similar works is difficult, as we considered here a specific forest soil and other authors other soil types and uses. However, the complexity in comparison reminds that the methodological influence be paid more attention in future soil WEOC researches. Copyright © 2016 Elsevier B.V. All rights reserved.

Environmental fate and behavior of acesulfame in laboratory experiments.

PubMed

Storck, Florian R; Skark, Christian; Remmler, Frank; Brauch, Heinz-Jürgen

2016-12-01

Acesulfame is a widely used artificial sweetener. It can be discharged into surface water by domestic wastewater due to its incomplete retention during wastewater treatment. Concentrations may reach up to 10 μg/L for smaller rivers. State-of-the-art analysis allows the determination of acesulfame traces (0.01 μg/L) and thus a potential tracking of the presence of wastewater in riverbank filtrate. To evaluate the behavior of acesulfame in the aquatic environment, biodegradation and sorption of acesulfame were tested. Batch experiments yielded low sorption for several soils (estimated solid-water distribution coefficient of acesulfame <0.1 L/kg). Biodegradation in a fixed-bed reactor was not observed at environmental concentrations of 9 μg/L in aqueous compost and soil extract (observation period 56 days). Only in diluted effluent of a wastewater treatment plant did biodegradation start, after 17 days of operation, and acesulfame completely fade, within 28 days. Flow-through column experiments indicated conservative behavior of acesulfame (recovery >83%) and long-term observations at different concentration levels yielded no biodegradation. Overall, laboratory experiments demonstrated a conservative behavior of acesulfame under conditions typical for riverbank filtration. However, there are hints for certain settings which favor an adaptation of the microbial community and facilitate a rapid biodegradation of acesulfame.

Assessing weathered Endicott oil biodegradation in brackish water.

PubMed

Personna, Yves Robert; King, Thomas; Boufadel, Michel C; Zhang, Shuangyi; Kustka, Adam

2014-09-15

We evaluated the biodegradability of physically (WAF) and chemically (CEWAF) dispersed oil in brackish water (salinity ∼6.5 g/L), and the influence of nutrient availability (low nutrient-LN: background water vs. high nutrient-HN: addition of 100 mg NO3-N/L and 10mg PO4-P/L to background water) on oil biodegradation rates at 15±0.5 °C for 42 days. No oil removal occurred in WAF compared with CEWAF: 24% in HN and 14% in LN within two weeks. The oil biodegradation concerned mainly alkanes as confirmed by GC/MS analyses. Higher O2 consumption (10.30 mg L(-1) day(-1)) and CO2 production (3.89 mg CL(-1) day(-1)) were measured in HN compared with LN (O2: 2.79 mg L(-1) day(-1), CO2:0.18 mg CL(-1) day(-1)). Estimated biomass of hydrocarbon degraders and heterotrophic bacteria was at least an order of magnitude larger in HN than in LN. Combining dispersants with nutrients could enhance oil biodegradation and help improve oil spill mitigation responses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distribution of petroleum hydrocarbons and toluene biodegradation, Knox Street fire pits, Fort Bragg, North Carolina

USGS Publications Warehouse

Harden, S.L.; Landmeyer, J.E.

1996-01-01

An investigation was conducted at the Knox Street fire pits, Fort Bragg, North Carolina, to monitor the distribution of toluene, ethylbenzene, and xylene (TEX) in soil vapor, ground water, and ground-water/vapor to evaluate if total concentrations of TEX at the site are decreasing with time, and to quantify biodegradation rates of toluene in the unsaturated and saturated zones. Soil-vapor and ground-water samples were collected around the fire pits and ground-water/vapor samples were collected along the ground-water discharge zone, Beaver Creek, on a monthly basis from June 1994 through June 1995. Concentrations of TEX compounds in these samples were determined with a field gas chro- matograph. Laboratory experiments were performed on aquifer sediment samples to measure rates of toluene biodegradation by in situ micro- organisms. Based on field gas chromatographic analytical results, contamination levels of TEX compounds in both soil vapor and ground water appear to decrease downgradient of the fire-pit source area. During the 1-year study period, the observed temporal and spatial trends in soil vapor TEX concentrations appear to reflect differences in the distribution of TEX among solid, aqueous, and gaseous phases within fuel-contaminated soils in the unsaturated zone. Soil temperature and soil moisture are two important factors which influence the distribution of TEX com- pounds among the different phases. Because of the short period of data collection, it was not possible to distinguish between seasonal fluc- tuations in soil vapor TEX concentrations and an overall net decrease in TEX concentrations at the study site. No seasonal trend was observed in total TEX concentrations for ground- water samples collected at the study site. Although the analytical results could not be used to determine if ground-water TEX concen- trations decreased during the study at a specific location, the data were used to examine rate constants of toluene biodegradation. Based on ground-water toluene concentration data, a maximum rate constant for anaerobic biodegradation of toluene in the saturated zone was estimated to be as low as 0.002 d-1 or as high as 0.026 d-1. Based on analyses of ground-water/vapor samples, toluene was the prin- cipal TEX compound identified in ground water discharging to Beaver Creek. Observed decreases in ground-water/vapor toluene concentrations during the study period may reflect a decrease in source inputs, an increase in dilution caused by higher ground-water flow, and(or) removal by biological or other physical processes. Rate constants of toluene anaerobic biodegradation determined by laboratory measurements illustrate a typical acclimation response of micro-organisms to hydrocarbon contamination in sediments collected from the site. Toluene biodegradation rate constants derived from laboratory microcosm studies ranged from 0.001 to 0.027 d-1, which is similar to the range of 0.002 to 0.026 d-1 for toluene biodegradation rate constants derived from ground-water analytical data. The close agreement of toluene biodegradation rate constants reported using both approaches offer strong evidence that toluene can be degraded at environmentally significant rates at the study site.

Comparison between the evaluation of bacterial regrowth capability in a turbidimeter and biodegradable dissolved organic carbon bioreactor measurements in water.

PubMed

Kott, Y; Ribas, F; Frías, J; Lucena, F

1997-09-01

In recent years, two different approaches to the study of biodegradable organic matter in distribution systems have been followed. The assimilable organic carbon (AOC) indicates the portion of the dissolved organic matter used by bacteria and converted to biomass, which is directly measured as total bacteria, active bacteria or colony-forming units and indirectly as ATP or increase in turbidity. In contrast, the biodegradable dissolved organic carbon (BDOC) is the portion of the dissolved organic carbon that can be mineralized by heterotrophic microorganisms, and it is measured as the difference between the inflow and the outflow of a bioreactor. In this study, at different steps in a water treatment plant, the bacterial regrowth capability was determined by the AOC method that measures the maximum growth rate by using a computerized Monitek turbidimeter. The BDOC was determined using a plug flow bioreactor. Measurements of colony-forming units and total organic carbon (TOC) evolution in a turbidimeter and of colony-forming units at the inflow/outflow of the bioreactor were also performed, calculating at all sampling points the coefficient yield (Y = cfu/delta TOC) in both systems. The correlations between the results from the bioreactor and turbidimeter have been calculated; a high correlation level was observed between BDOC values and all the other parameters, except for Y calculated from bacterial suspension measured in the turbidimeter.

Nonthrombogenic, biodegradable elastomeric polyurethanes with variable sulfobetaine content.

PubMed

Ye, Sang-Ho; Hong, Yi; Sakaguchi, Hirokazu; Shankarraman, Venkat; Luketich, Samuel K; D'Amore, Antonio; Wagner, William R

2014-12-24

For applications where degradable polymers are likely to have extended blood contact, it is often important for these materials to exhibit high levels of thromboresistance. This can be achieved with surface modification approaches, but such modifications may be transient with degradation. Alternatively, polymer design can be altered such that the bulk polymer is thromboresistant and this is maintained with degradation. Toward this end a series of biodegradable, elastic polyurethanes (PESBUUs) containing different zwitterionic sulfobetaine (SB) content were synthesized from a polycaprolactone-diol (PCL-diol):SB-diol mixture (100:0, 75:25, 50:50, 25:75 and 0:100) reacted with diisocyanatobutane and chain extended with putrescine. The chemical structure, tensile mechanical properties, thermal properties, hydrophilicity, biodegradability, fibrinogen adsorption and thrombogenicity of the resulting polymers was characterized. With increased SB content some weakening in tensile properties occurred in wet conditions and enzymatic degradation also decreased. However, at higher zwitterionic molar ratios (50% and 75%) wet tensile strength exceeded 15 MPa and breaking strain was >500%. Markedly reduced thrombotic deposition was observed both before and after substantial degradation for both of these PESBUUs and they could be processed by electrospinning into a vascular conduit format with appropriate compliance properties. The mechanical and degradation properties as well as the acute in vitro thrombogenicity assessment suggest that these tunable polyurethanes could provide options appropriate for use in blood contacting applications where a degradable, elastomeric component with enduring thromboresistance is desired.

Feasibility of the UV/AA process as a pretreatment approach for bioremediation of dye-laden wastewater.

PubMed

Yang, Minghui; Wu, Bingdang; Li, Qiuhao; Xiong, Xiaofeng; Zhang, Haoran; Tian, Yu; Xie, Jiawen; Huang, Ping; Tan, Suo; Wang, Guodong; Zhang, Li; Zhang, Shujuan

2018-03-01

Biodegradability and toxicity are two important indexes in considering the feasibility of a chemical process for environmental remediation. The acetylacetone (AA) mediated photochemical process has been proven as an efficient approach for dye decolorization. Both AA and its photochemical degradation products had a high bioavailability. However, the biocompatibility and ecotoxicology of the UV/AA treated solutions are unclear yet. In the present work, we evaluated the biocompatibility and toxicity of the UV/AA treated solutions at both biochemical and organismal levels. The biodegradability of the treated solution was evaluated with the ratio of 5-d biological oxygen demand (BOD 5 ) to chemical oxygen demand (COD) and a 28-d activated sludge assay (Zahn-Wellens tests). The UV/AA process significantly improved the biodegradability of the tested dye solutions. Toxicity was assessed with responses of microorganisms (microbes in activated sludge and Daphnia magna) and plants (bok choy, rice seed, and Arabidopsis thaliana) to the treated solutions, which showed that the toxicity of the UV/AA treated solutions was lower or comparable to that of the UV/H 2 O 2 counterparts. The results are helpful for us to determine whether the UV/AA process is applicable to certain wastewaters and how the UV/AA process could be effectively combined into a sequential chemical-biological water treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams

PubMed Central

Álvarez-Barragán, Joyce; Domínguez-Malfavón, Lilianha; Vargas-Suárez, Martín; González-Hernández, Ricardo; Aguilar-Osorio, Guillermo

2016-01-01

ABSTRACT Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum. The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm−1) and N—H bonds (1,540 and 1,261 cm−1), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. IMPORTANCE Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling. PMID:27316963

Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams.

PubMed

Álvarez-Barragán, Joyce; Domínguez-Malfavón, Lilianha; Vargas-Suárez, Martín; González-Hernández, Ricardo; Aguilar-Osorio, Guillermo; Loza-Tavera, Herminia

2016-09-01

Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Microencapsulation of hydrophilic drug substances using biodegradable polyesters. Part II: Implants allowing controlled drug release--a feasibility study using bisphosphonates.

PubMed

Weidenauer, U; Bodmer, D; Kissel, T

2004-03-01

The prolonged delivery of hydrophilic drug salts from hydrophobic polymer carriers at high drug loading is an ambitious goal. Pamidronate disodium salt (APD) containing implants prepared from spray-dried microparticles were investigated using a laboratory ram extruder. An APD-containing polymer matrix consisting of an APD-chitosan implant embedded in the biodegradable polymer D,L-poly(lactide-co-glycolide acid-glucose) (PLG-GLU) was compared with a matrix system with the micronized drug distributed in the PLG-GLU. The APD-chitosan matrix system showed a triphasic release behaviour at loading levels of 6.86 and 15.54% (w/w) over 36 days under in-vitro conditions. At higher loading (31.92%), a drug burst was observed within 6 days due to the formation of pores and channels in the polymeric matrix. In contrast, implants containing the micronized drug showed a more continuous release profile over 48 days up to a loading of 31.78% (w/w). At a drug loading of 46.17% (w/w), a drug burst was observed. Using micronized drug salts and reducing the surface area available for diffusion, parenteral delivery systems for highly water-soluble drug candidates were shown to be technically feasible at high drug loadings.

The Treatment of PPCP-Containing Sewage in an Anoxic/Aerobic Reactor Coupled with a Novel Design of Solid Plain Graphite-Plates Microbial Fuel Cell

PubMed Central

Chang, Yi-Tang; Yang, Chu-Wen; Chang, Yu-Jie; Chang, Ting-Chieh; Wei, Da-Jiun

2014-01-01

Synthetic sewage containing high concentrations of pharmaceuticals and personal care products (PPCPs, mg/L level) was treated using an anoxic/aerobic (A/O) reactor coupled with a microbial fuel cell (MFC) at hydraulic retention time (HRT) of 8 h. A novel design of solid plain graphite plates (SPGRPs) was used for the high surface area biodegradation of the PPCP-containing sewage and for the generation of electricity. The average CODCr and total nitrogen removal efficiencies achieved were 97.20% and 83.75%, respectively. High removal efficiencies of pharmaceuticals, including acetaminophen, ibuprofen, and sulfamethoxazole, were also obtained and ranged from 98.21% to 99.89%. A maximum power density of 532.61 mW/cm2 and a maximum coulombic efficiency of 25.20% were measured for the SPGRP MFC at the anode. Distinct differences in the bacterial community were presented at various locations including the mixed liquor suspended solids and biofilms. The bacterial groups involved in PPCP biodegradation were identified as Dechloromonas spp., Sphingomonas sp., and Pseudomonas aeruginosa. This design, which couples an A/O reactor with a novel design of SPGRP MFC, allows the simultaneous removal of PPCPs and successful electricity production. PMID:25197659

Biodegradable Hybrid Stomatocyte Nanomotors for Drug Delivery

PubMed Central

2017-01-01

We report the self-assembly of a biodegradable platinum nanoparticle-loaded stomatocyte nanomotor containing both PEG-b-PCL and PEG-b-PS as a potential candidate for anticancer drug delivery. Well-defined stomatocyte structures could be formed even after incorporation of 50% PEG-b-PCL polymer. Demixing of the two polymers was expected at high percentage of semicrystalline poly(ε-caprolactone) (PCL), resulting in PCL domain formation onto the membrane due to different properties of two polymers. The biodegradable motor system was further shown to move directionally with speeds up to 39 μm/s by converting chemical fuel, hydrogen peroxide, into mechanical motion as well as rapidly delivering the drug to the targeted cancer cell. Uptake by cancer cells and fast doxorubicin drug release was demonstrated during the degradation of the motor system. Such biodegradable nanomotors provide a convenient and efficient platform for the delivery and controlled release of therapeutic drugs. PMID:28187254

Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

NASA Astrophysics Data System (ADS)

Apri, M.; Silmi, M.; Heryanto, T. E.; Moeis, M. R.

2016-04-01

PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LC Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).

Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apri, M., E-mail: m.apri@math.itb.ac.id; Silmi, M.; Heryanto, T. E.

PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LCmore » Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).« less

Biological removal of phenol from wastewaters: a mini review

NASA Astrophysics Data System (ADS)

Pradeep, N. V.; Anupama, S.; Navya, K.; Shalini, H. N.; Idris, M.; Hampannavar, U. S.

2015-06-01

Phenol and its derivatives are common water pollutants and include wide variety of organic chemicals. Phenol poisoning can occur by skin absorption, inhalation, ingestion and various other methods which can result in health effects. High exposures to phenol may be fatal to human beings. Accumulation of phenol creates toxicity both for flora and fauna. Therefore, removal of phenol is crucial to perpetuate the environment and individual. Among various treatment methods available for removal of phenols, biodegradation is environmental friendly. Biological methods are gaining importance as they convert the wastes into harmless end products. The present work focuses on assessment of biological removal (biodegradation) of phenol. Various factors influence the efficiency of biodegradation of phenol such as ability of the microorganism, enzymes involved, the mechanism of degradation and influencing factors. This study describes about the sources of phenol, adverse effects on the environment, microorganisms involved in the biodegradation (aerobic and anaerobic) and enzymes that polymerize phenol.

Biotechnological potential for degradation of isoprene: a review.

PubMed

Srivastva, Navnita; Singh, Abhishek; Bhardwaj, Yashpal; Dubey, Suresh Kumar

2018-06-01

Isoprene, the ubiquitous, highly emitted non-methane volatile hydrocarbon, affects atmospheric chemistry and human health, and this makes its removal from the contaminated environment imperative. Physicochemical degradation of isoprene is inefficient and generates secondary pollutants. Therefore, biodegradation can be considered as the safer approach for its efficient abatement. This review summarizes efforts in this regard that led to tracking the diverse groups of isoprene degrading bacteria such as Methanotrophs, Xanthobacter, Nocardia, Alcaligenes, Rhodococcus, Actinobacteria, Alphaproteobacteria, Bacteriodetes, Pseudomonas, and Alcanivorax. Biodegradation of isoprene by such bacteria in batch and continuous modes has been elaborated. The products, pathways and the key enzymes associated with isoprene biodegradation have also been presented.

Infrared spectra and physochemical properties of oils

NASA Astrophysics Data System (ADS)

Strelets, L. A.; Svarovskaya, L. I.; Manakov, A. Yu.

2017-12-01

The paper reports on a multiparametric study of West Siberian crude oils using Fourier transform infrared (FTIR) spectroscopy to establish a relationship between the physicochemical properties of the oils, their spectral coefficients, and biodegradation levels. It is found that the test oils are slightly biodegraded, feature a roughly linear dependence between the freezing temperature and the content of resin and asphaltene, and display a relation of their emulsifying ability and spectral coefficient C2, being the ratio of alkanes and substituted alkylbenzene compounds.

An injection molding process for manufacturing highly porous and interconnected biodegradable polymer matrices for use as tissue engineering scaffolds.

PubMed

Kramschuster, Adam; Turng, Lih-Sheng

2010-02-01

In this research, injection molding was combined with a novel material combination, supercritical fluid processing, and particulate leaching techniques to produce highly porous and interconnected structures that have the potential to act as scaffolds for tissue engineering applications. The foamed structures, molded with polylactide (PLA) and polyvinyl alcohol (PVOH) with salt as the particulate, were processed without the aid of organic solvents, which can be detrimental to tissue growth. The pore size in the scaffolds is controlled by salt particulates and interconnectivity is achieved by the co-continuous blending morphology of biodegradable PLA matrix with water-soluble PVOH. Carbon dioxide (CO(2)) at the supercritical state is used to serve as a plasticizer, thereby imparting moldability of blends even with an ultra high salt particulate content, and allows the use of low processing temperatures, which are desirable for temperature-sensitive biodegradable polymers. Interconnected pores of approximately 200 microm in diameter and porosities of approximately 75% are reported and discussed.

Biodegradation of high concentrations of hexadecane by Aspergillus niger in a solid-state system: kinetic analysis.

PubMed

Volke-Sepúlveda, Tania; Gutiérrez-Rojas, Mariano; Favela-Torres, Ernesto

2006-09-01

Solid-state microcosms were used to assess the influence of constant and variable C/N ratios on the biodegradation efficiency by Aspergillus niger at high hexadecane (HXD) concentrations (180-717 mg g-1). With a constant C/N ratio, 100% biodegradation (33-44% mineralization) was achieved after 15 days, at rates increasing as the HXD concentration increased. Biomass yields (YX/S) remained almost independent (approximately 0.77) of the carbon-source amount, while the specific growth rates (mu) decreased with increasing concentrations of HXD. With C/N ratios ranging from 29 to 115, complete degradation was only attained at 180 mg g-1, corresponding to 46% mineralization. YX/S diminished (approximately 0.50 units) as the C/N ratio increased. The highest values of mu (1.08 day-1) were obtained at low C/N values. Our results demonstrate that, under balanced nutritional conditions, high HXD concentrations can be completely degraded in solid-state microcosms, with a negligible (<10%) formation of by-products.

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

PubMed

Leiknes, T; Lazarova, M; Odegaard, H

2005-01-01

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

Local sustained delivery of acetylsalicylic acid via hybrid stent with biodegradable nanofibers reduces adhesion of blood cells and promotes reendothelialization of the denuded artery

PubMed Central

Lee, Cheng-Hung; Lin, Yu-Huang; Chang, Shang-Hung; Tai, Chun-Der; Liu, Shih-Jung; Chu, Yen; Wang, Chao-Jan; Hsu, Ming-Yi; Chang, Hung; Chang, Gwo-Jyh; Hung, Kuo-Chun; Hsieh, Ming-Jer; Lin, Fen-Chiung; Hsieh, I-Chang; Wen, Ming-Shien; Huang, Yenlin

2014-01-01

Incomplete endothelialization, blood cell adhesion to vascular stents, and inflammation of arteries can result in acute stent thromboses. The systemic administration of acetylsalicylic acid decreases endothelial dysfunction, potentially reducing thrombus, enhancing vasodilatation, and inhibiting the progression of atherosclerosis; but, this is weakened by upper gastrointestinal bleeding. This study proposes a hybrid stent with biodegradable nanofibers, for the local, sustained delivery of acetylsalicylic acid to injured artery walls. Biodegradable nanofibers are prepared by first dissolving poly(D,L)-lactide-co-glycolide and acetylsalicylic acid in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution is then electrospun into nanofibrous tubes, which are then mounted onto commercially available bare-metal stents. In vitro release rates of pharmaceuticals from nanofibers are characterized using an elution method, and a highperformance liquid chromatography assay. The experimental results suggest that biodegradable nanofibers release high concentrations of acetylsalicylic acid for three weeks. The in vivo efficacy of local delivery of acetylsalicylic acid in reducing platelet and monocyte adhesion, and the minimum tissue inflammatory reaction caused by the hybrid stents in treating denuded rabbit arteries, are documented. The proposed hybrid stent, with biodegradable acetylsalicylic acid-loaded nanofibers, substantially contributed to local, sustained delivery of drugs to promote re-endothelialization and reduce thrombogenicity in the injured artery. The stents may have potential applications in the local delivery of cardiovascular drugs. Furthermore, the use of hybrid stents with acetylsalicylic acid-loaded nanofibers that have high drug loadings may provide insight into the treatment of patients with high risk of acute stent thromboses. PMID:24421640

Revealing potential functions of VBNC bacteria in polycyclic aromatic hydrocarbons biodegradation.

PubMed

Su, X M; Bamba, A M; Zhang, S; Zhang, Y G; Hashmi, M Z; Lin, H J; Ding, L X

2018-04-01

The bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated sites is not running smoothly, because of the lower activity of PAH-degrading bacteria in actual bioremediation applications. The phenomenon of "viable but nonculturable" (VBNC) state may be a main limiting factor for their poor biodegradation capabilities of PAHs. Due to their abilities of entering into the VBNC state, most of bacterial populations with PAH-degradation potential remain unculturable. Resuscitation of VBNC bacteria will enhance the degradation capability of indigenous bacteria which will eventually obtain their better capabilities in environmental bioremediation. Although evidences have been presented indicating that resuscitation of VBNC bacteria in polychlorinated biphenyl (PCB)-contaminated environments not only significantly enhanced PCB degradation, but also obtained novel highly efficient PCB-degrading bacteria, scanty information is available on the VBNC bacteria in PAH-contaminated sites. VBNC bacteria, as a vast majority of potential microbial resource could be the repository of novel highly efficient PAH-biodegraders. Therefore, studies need to be done on resuscitation of VBNC bacteria to overcome key bottlenecks in bioremediation of PAH-contaminated sites. This mini-review provides a new insight into the potential functions of VBNC bacteria in PAHs biodegradation. As the vast majority microbial resource, viable but nonculturable (VBNC) bacteria, which showed their potential functions in polycyclic aromatic hydrocarbons (PAHs) biodegradation, can be of great significance in environmental bioremediation. It is therefore important to resuscitate VBNC bacteria for their better capabilities. Meanwhile, preventing the indigenous functional community from entering into the VBNC state will also maintain the high activity of PAH-degrading bacteria in actual bioremediation applications. Undoubtedly, much more work needs to be done to reveal indigenous micro-organisms in the VBNC state from the perspective of environmental functions. © 2018 The Society for Applied Microbiology.

Bioremediation assessment of diesel-biodiesel-contaminated soil using an alternative bioaugmentation strategy.

PubMed

Colla, Tatiana Simonetto; Andreazza, Robson; Bücker, Francielle; de Souza, Marcela Moreira; Tramontini, Letícia; Prado, Gerônimo Rodrigues; Frazzon, Ana Paula Guedes; Camargo, Flávio Anastácio de Oliveira; Bento, Fátima Menezes

2014-02-01

This study investigated the effectiveness of successive bioaugmentation, conventional bioaugmentation, and biostimulation of biodegradation of B10 in soil. In addition, the structure of the soil microbial community was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis. The consortium was inoculated on the initial and the 11th day of incubation for successive bioaugmentation and only on the initial day for bioaugmentation and conventional bioaugmentation. The experiment was conducted for 32 days. The microbial consortium was identified based on sequencing of 16S rRNA gene and consisted as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Ochrobactrum intermedium. Nutrient introduction (biostimulation) promoted a positive effect on microbial populations. The results indicate that the edaphic community structure and dynamics were different according to the treatments employed. CO2 evolution demonstrated no significant difference in soil microbial activity between biostimulation and bioaugmentation treatments. The total petroleum hydrocarbon (TPH) analysis indicated a biodegradation level of 35.7 and 32.2 % for the biostimulation and successive bioaugmentation treatments, respectively. Successive bioaugmentation displayed positive effects on biodegradation, with a substantial reduction in TPH levels.

Settlement behavior of municipal solid waste due to internal and external environmental factors in a lysimeter.

PubMed

Melo, Márcio C; Caribé, Rômulo M; Ribeiro, Libânia S; Sousa, Raul B A; Monteiro, Veruschka E D; de Paiva, William

2016-12-05

Long-term settlement magnitude is influenced by changes in external and internal factors that control the microbiological activity in the landfill waste body. To improve the understanding of settlement phenomena, it is instructive to study lysimeters filled with MSW. This paper aims to understand the settlement behavior of MSW by correlating internal and external factors that influence waste biodegradation in a lysimeter. Thus, a lysimeter was built, instrumented and filled with MSW from the city of Campina Grande, the state of Paraíba, Brazil. Physicochemical analysis of the waste (from three levels of depth of the lysimeter) was carried out along with MSW settlement measurements. Statistical tools such as descriptive analysis and principal component analysis (PCA) were also performed. The settlement/compression, coefficient of variation and PCA results indicated the most intense rate of biodegradation in the top layer. The PCA results of intermediate and bottom levels presented fewer physicochemical and meteorological variables correlated with compression data in contrast with the top layer. It is possible to conclude that environmental conditions may influence internal indicators of MSW biodegradation, such as the settlement.

Characterizations of biodegradable epoxy-coated cellulose nanofibrils (CNF) thin film for flexible microwave applications

Treesearch

Hongyi Mi; Chien-Hao Liu; Tzu-Husan Chang; Jung-Hun Seo; Huilong Zhang; Sang June Cho; Nader Behdad; Zhenqiang Ma; Chunhua Yao; Zhiyong Cai; Shaoqin Gong

2016-01-01

Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric...

Remediation of phenol-contaminated soil by a bacterial consortium and Acinetobacter calcoaceticus isolated from an industrial wastewater treatment plant.

PubMed

Cordova-Rosa, S M; Dams, R I; Cordova-Rosa, E V; Radetski, M R; Corrêa, A X R; Radetski, C M

2009-05-15

Time-course performance of a phenol-degrading indigenous bacterial consortium, and of Acinetobacter calcoaceticus var. anitratus, isolated from an industrial coal wastewater treatment plant was evaluated. This bacterial consortium was able to survive in the presence of phenol concentrations as high as 1200mgL(-1) and the consortium was more fast in degrading phenol than a pure culture of the A. calcoaceticus strain. In a batch system, 86% of phenol biodegradation occurred in around 30h at pH 6.0, while at pH 3.0, 95.2% of phenol biodegradation occurred in 8h. A high phenol biodegradation (above 95%) by the mixed culture in a bioreactor was obtained in both continuous and batch systems, but when test was carried out in coke gasification wastewater, no biodegradation was observed after 10 days at pH 9-11 for both pure strain or the isolated consortium. An activated sludge with the same bacterial consortium characterized above was mixed with a textile sludge-contaminated soil with a phenol concentration of 19.48mgkg(-1). After 20 days of bioaugmentation, the remanescent phenol concentration of the sludge-soil matrix was 1.13mgkg(-1).

Pyrene biodegradation with layer-by-layer assembly bio-microcapsules.

PubMed

Deng, Fucai; Zhang, Zhengfang; Yang, Chen; Guo, Chuling; Lu, Guining; Dang, Zhi

2017-04-01

Biotechnology is considered as a promising technology for the removal of polycyclic aromatic hydrocarbons from the environment. Free bacteria are often sensitive to some biotic and abiotic factors in the environment to the extent that their ability to effect biodegradation of organic pollutants, such as polycyclic aromatic hydrocarbons, is hampered. Consequently, it is imperative to carry out investigations into biological systems that will obviate or aid tolerance of bacteria to harsh environmental conditions. Chitosan/alginate bio-microcapsules produced using layer-by-layer (LBL) assembly method were tested for pyrene (PYR) biodegradation under harsh environmental conditions. Morphology observation indicated that the flake bio-microcapsules could be successfully prepared through LBL assembly method. Surface analysis showed that the bio-microcapsules had large fractions of mesopores. The results of the biodegradation experiments revealed that the 95% of 10mgL -1 PYR could be removed by the bacteria encapsulated chitosan/alginate bio-microcapsules in 3 days, which was higher than that of the free bacteria (59%). Compared to the free cells, the bacteria encapsulated chitosan/alginate bio-microcapsules produced 1-6 times higher PYR biodegradation rates at a high initial PYR concentration (50mgL -1 ) and extremely low pH values (pH =3) or temperatures (10°C or 40°C), as well as high salt stress. The results indicated that bacteria in microcapsules treatment gained a much higher tolerance to environmental stress and LBL bio-microcapsule could be promising candidate for remediating the organic pollutants. Copyright © 2016 Elsevier Inc. All rights reserved.

Dissolved organic nitrogen in urban streams: Biodegradability and molecular composition studies.

PubMed

Lusk, Mary G; Toor, Gurpal S

2016-06-01

A portion of the dissolved organic nitrogen (DON) is biodegradable in water bodies, yet our knowledge of the molecular composition and controls on biological reactivity of DON is limited. Our objective was to investigate the biodegradability and molecular composition of DON in streams that drain a gradient of 19-83% urban land use. Weekly sampling over 21 weeks suggested no significant relationship between urban land use and DON concentration. We then selected two streams that drain 28% and 83% urban land use to determine the biodegradability and molecular composition of the DON by coupling 5-day bioassay experiments with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Both urban streams contained a wide range of N-bearing biomolecular formulas and had >80% DON in lignin-like compounds, with only 5-7% labile DON. The labile DON consisted mostly of lipid-and protein-like structures with high H/C and low O/C values. Comparison of reactive formulas and formed counterparts during the bioassay experiments indicated a shift toward more oxygenated and less saturated N-bearing DON formulas due to the microbial degradation. Although there was a little net removal (5-7%) of organic-bound N over the 5-day bioassay, there was some change to the carbon skeleton of DON compounds. These results suggest that DON in urban streams contains a complex mixture of compounds such as lipids, proteins, and lignins of variable chemical structures and biodegradability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Insight into unresolved complex mixtures of aromatic hydrocarbons in heavy oil via two-dimensional gas chromatography coupled with time-of-flight mass spectrometry analysis.

PubMed

Weng, Na; Wan, Shan; Wang, Huitong; Zhang, Shuichang; Zhu, Guangyou; Liu, Jingfu; Cai, Di; Yang, Yunxu

2015-06-12

The aromatic hydrocarbon fractions of five crude oils representing a natural sequence of increasing degree of biodegradation from the Liaohe Basin, NE, China, were analyzed using conventional gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography (GC×GC). Because of the limited peak capability and low resolution, compounds in the aromatic fraction of a heavily biodegraded crude oil that were analyzed by GC-MS appeared as unresolved complex mixtures (UCMs) or GC "humps". They could be separated based on their polarity by GC×GC. UCMs are composed mainly of aromatic biomarkers and aromatic hydrocarbons with branched alkanes or cycloalkanes substituents. The quantitative results achieved by GC×GC-FID were shown that monoaromatic hydrocarbons account for the largest number and mass of UCMs in the aromatic hydrocarbon fraction of heavily biodegraded crude oil, at 45% by mass. The number and mass of diaromatic hydrocarbons ranks second at 33% by mass, followed by the aromatic biomarker compounds, triaromatic, tetraaromatic, and pentaaromatic hydrocarbons, that account for 10%, 6%, 1.5%, and 0.01% of all aromatic compounds by mass, respectively. In the heavily biodegraded oil, compounds with monocyclic cycloalkane substituents account for the largest proportion of mono- and diaromatic hydrocarbons, respectively. The C4-substituted compounds account for the largest proportion of naphthalenes and the C3-substituted compounds account for the largest proportion of phenanthrenes, which is very different from non-biodegraded, slightly biodegraded, and moderately biodegraded crude oil. It is inferred that compounds of monoaromatic, diaromatic and triaromatic hydrocarbons are affected by biodegradation, that compounds with C1-, C2-substituents are affected by the increase in degree of biodegradation, and that their relative content decreased, whereas compounds with C3-substituents or more were affected slightly or unaffected, and their relative content also increased. The varying regularity of relative content of substituted compounds may be used to reflect the degree of degradation of heavy oil. Moreover, biomarkers for the aromatic hydrocarbons of heavily biodegraded crude oil are mainly aromatic steranes, aromatic secohopanes, aromatic pentacyclotriterpanes, and benzohopanes. According to resultant data, aromatic secohopanes could be used as a specific marker because of their relatively high concentration. This aromatic compound analysis of a series of biodegraded crude oil is useful for future research on the quantitative characterization of the degree of biodegradation of heavy oil, unconventional oil maturity evaluation, oil source correlation, depositional environment, and any other geochemical problems. Copyright © 2015 Elsevier B.V. All rights reserved.

Occurrence and Biodegradation of Nonylphenol in the Environment

PubMed Central

Mao, Zhen; Zheng, Xiao-Fei; Zhang, Yan-Qiu; Tao, Xiu-Xiang; Li, Yan; Wang, Wei

2012-01-01

Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors. PMID:22312266

Analysis, toxicity, occurrence and biodegradation of nonylphenol isomers: a review.

PubMed

Lu, Zhijiang; Gan, Jay

2014-12-01

Over the last two decades, nonylphenols (NPs) have become to be known as a priority hazardous substance due primarily to its estrogenicity and ubiquitous occurrence in the environment. Nonylphenols are commonly treated as a single compound in the evaluation of their environmental occurrence, fate and transport, treatment or toxicity. However, technical nonylphenols (tNPs) are in fact a mixture of more than 100 isomers and congeners. Recent studies showed that some of these isomers behaved significantly differently in occurrence, estrogenicity and biodegradability. The most estrogenic isomer was about 2 to 4 times more active than tNP. Moreover, the half lives of the most recalcitrant isomers were about 3 to 4 times as long as those of readily-biodegradable isomers. Negligence of NP's isomer specificity may result in inaccurate assessment of its ecological and health effects. In this review, we summarized the recent publications on the analysis, occurrence, toxicity and biodegradation of NP at the isomer level and highlighted future research needs to improve our understanding of isomer-specificity of NP. Copyright © 2014. Published by Elsevier Ltd.

Towards excimer-laser-based stereolithography: a rapid process to fabricate rigid biodegradable photopolymer scaffolds

PubMed Central

Beke, S.; Anjum, F.; Tsushima, H.; Ceseracciu, L.; Chieregatti, E.; Diaspro, A.; Athanassiou, A.; Brandi, F.

2012-01-01

We demonstrate high-resolution photocross-linking of biodegradable poly(propylene fumarate) (PPF) and diethyl fumarate (DEF) using UV excimer laser photocuring at 308 nm. The curing depth can be tuned in a micrometre range by adjusting the total energy dose (total fluence). Young's moduli of the scaffolds are found to be a few gigapascal, high enough to support bone formation. The results presented here demonstrate that the proposed technique is an excellent tool for the fabrication of stiff and biocompatible structures on a micrometre scale with defined patterns of high resolution in all three spatial dimensions. Using UV laser photocuring at 308 nm will significantly improve the speed of rapid prototyping of biocompatible and biodegradable polymer scaffolds and enables its production in a few seconds, providing high lateral and horizontal resolution. This short timescale is indeed a tremendous asset that will enable a more efficient translation of technology to clinical applications. Preliminary cell tests proved that PPF : DEF scaffolds produced by excimer laser photocuring are biocompatible and, therefore, are promising candidates to be applied in tissue engineering and regenerative medicine. PMID:22696484

Novel synthetic selectively degradable vascular prostheses: a preliminary implantation study.

PubMed

Izhar, U; Schwalb, H; Borman, J B; Hellener, G R; Hotoveli-Salomon, A; Marom, G; Stern, T; Cohn, D

2001-02-01

Vascular grafts perform less well than autologous arterial or vein grafts. The purpose of this study was to evaluate the short-term performance of selectively biodegradable filament-wound vascular prostheses, comprising elastomeric poly(ether urethane) (Lycra) scaffolds and flexible, hydrophilic biodegradable coatings. Two types of selectively biodegradable vascular grafts were manufactured, comprising a filament-wound Lycra scaffold, subsequently coated with a biodegradable poly(ethylene glycol)/poly(lactic acid) (PELA) block copolymer. The two types of grafts differed in both the overall porosity of the scaffold and the hydrophilicity of the biodegradable constituent. A 60-mm-long and 6-mm-diameter filament-wound and polytetrafluoroethylene (ePTFE) grafts were implanted as interposition prostheses, randomly, at the right- and left-side carotid arteries. Implantation studies proved the grafts to be patent and pulsatile for periods of up to 3 months. Increasing the scaffold porosity and enhancing the hydrophilicity of the biodegradable component improved both the transmural tissue ingrowth process and the vascularization of the prosthesis wall. Also, a well-adhered peripheral tissue and a thin, uniform intima and endothelial lining were obtained. All ePTFE graft controls, although patent, were rather stiff and nonpulsatile. A thick pseudointima, poorly attached to the prosthesis inner surface, was observed. The compliance of the wet grafts was significantly higher than in the dry state, stemming mainly from the water-plasticizing effect on the biodegradable component. The grafts explanted after a period of 6 weeks exhibited compliance only slightly lower than that of the wet grafts. After 12 weeks, however, the hoop compliance was 20% lower than that prior to implantation. At 100 mm Hg, for example, the original compliance of the wet graft was 2.5%/100 mm Hg decreasing to 2.0%/100 mm Hg after a 3-month implantation. The compliance reduction with implantation is attributed to the ingrowth of the perigraft tissue as revealed by the histological study. A compliance of 2.0%/100 mm Hg is slightly better than that of a standard PTFE graft with an original compliance of 1.6%/100 mm Hg. Yet it is still an order of magnitude smaller than that of a canine carotid artery. The improved mechanical properties and enhanced healing of the highly porous filament-wound Lycra scaffold graft coated with hydrophilic biodegradable PELA has the potential of being a highly effective small caliber prosthetic graft. Copyright 2000 Academic Press.

Biodegradation of Poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) Plastic under Anaerobic Sludge and Aerobic Seawater Conditions: Gas Evolution and Microbial Diversity.

PubMed

Wang, Shunli; Lydon, Keri A; White, Evan M; Grubbs, Joe B; Lipp, Erin K; Locklin, Jason; Jambeck, Jenna R

2018-05-15

Poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) (poly(3HB- co-3HHx)) thermoplastics are a promising biodegradable alternative to traditional plastics for many consumer applications. Biodegradation measured by gaseous carbon loss of several types of poly(3HB- co-3HHx) plastic was investigated under anaerobic conditions and aerobic seawater environments. Under anaerobic conditions, the biodegradation levels of a manufactured sheet of poly(3HB- co-3HHx) and cellulose powder were not significantly different from one another over 85 days with 77.1 ± 6.1 and 62.9 ± 19.7% of the carbon converted to gas, respectively. However, the sheet of poly(3HB- co-3HHx) had significantly higher methane yield ( p ≤ 0.05), 483.8 ± 35.2 mL·g -1 volatile solid (VS), compared to cellulose controls, 290.1 ± 92.7 mL·g -1 VS, which is attributed to a greater total carbon content. Under aerobic seawater conditions (148-195 days at room temperature), poly(3HB- co-3HHx) sheets were statistically similar to cellulose for biodegradation as gaseous carbon loss (up to 83% loss in about 6 months), although the degradation rate was lower than that for cellulose. The microbial diversity was investigated in both experiments to explore the dominant bacteria associated with biodegradation of poly(3HB- co-3HHx) plastic. For poly(3HB- co-3HHx) treatments, Cloacamonales and Thermotogales were enriched under anaerobic sludge conditions, while Clostridiales, Gemmatales, Phycisphaerales, and Chlamydiales were the most enriched under aerobic seawater conditions.

Pollution profile and biodegradation characteristics of fur-suede processing effluents.

PubMed

Yildiz Töre, G; Insel, G; Ubay Cokgör, E; Ferlier, E; Kabdaşli, I; Orhon, D

2011-07-01

This study investigated the effect of stream segregation on the biodegradation characteristics of wastewaters generated by fur-suede processing. It was conducted on a plant located in an organized industrial district in Turkey. A detailed in-plant analysis of the process profile and the resulting pollution profile in terms of significant parameters indicated the characteristics of a strong wastewater with a maximum total COD of 4285 mg L(-1), despite the excessive wastewater generation of 205 m3 (ton skin)(-1). Respirometric analysis by model calibration yielded slow biodegradation kinetics and showed that around 50% of the particulate organics were utilized at a rate similar to that of endogenous respiration. A similar analysis on the segregated wastewater streams suggested that biodegradation of the plant effluent is controlled largely by the initial washing/pickling operations. The effect of other effluent streams was not significant due to their relatively low contribution to the overall organic load. The respirometric tests showed that the biodegradation kinetics of the joint treatment plant influent of the district were substantially improved and exhibited typical levels reported for tannery wastewater, so that the inhibitory impact was suppressed to a great extent by dilution and mixing with effluents of the other plants. The chemical treatment step in the joint treatment plant removed the majority of the particulate organics so that 80% of the available COD was utilized in the oxygen uptake rate (OUR) test, a ratio quite compatible with the biodegradable COD fractions of tannery wastewater. Consequently, process kinetics and especially the hydrolysis rate appeared to be significantly improved.

Perspectives of using fungi as bioresource for bioremediation of pesticides in the environment: a critical review.

PubMed

Maqbool, Zahid; Hussain, Sabir; Imran, Muhammad; Mahmood, Faisal; Shahzad, Tanvir; Ahmed, Zulfiqar; Azeem, Farrukh; Muzammil, Saima

2016-09-01

Pesticides are used for controlling the development of various pests in agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistent nature and the anomalies they create. Hence removal of such pesticides from the environment is a topic of interest for the researchers nowadays. During the recent years, use of biological resources to degrade or remove pesticides has emerged as a powerful tool for their in situ degradation and remediation. Fungi are among such bioresources that have been widely characterized and applied for biodegradation and bioremediation of pesticides. This review article presents the perspectives of using fungi for biodegradation and bioremediation of pesticides in liquid and soil media. This review clearly indicates that fungal isolates are an effective bioresource to degrade different pesticides including lindane, methamidophos, endosulfan, chlorpyrifos, atrazine, cypermethrin, dieldrin, methyl parathion, heptachlor, etc. However, rate of fungal degradation of pesticides depends on soil moisture content, nutrient availability, pH, temperature, oxygen level, etc. Fungal strains were found to harbor different processes including hydroxylation, demethylation, dechlorination, dioxygenation, esterification, dehydrochlorination, oxidation, etc during the biodegradation of different pesticides having varying functional groups. Moreover, the biodegradation of different pesticides was found to be mediated by involvement of different enzymes including laccase, hydrolase, peroxidase, esterase, dehydrogenase, manganese peroxidase, lignin peroxidase, etc. The recent advances in understanding the fungal biodegradation of pesticides focusing on the processes, pathways, genes/enzymes and factors affecting the biodegradation have also been presented in this review article.

Assessment of sanitary landfill leachate characterizations and its impacts on groundwater at Alexandria.

PubMed

Hassan, Ahmed Hossam; Ramadan, Mohamed Hassan

2005-01-01

The total amount of solid waste generated in Alexandria is 2820 tons/d which increases to 3425 tons/day during summer. In the past, 77% of the collected solid wastes was open dumped. The open dumping sites did not have the minimum requirements for pollution control. Following the exacerbation of the problem, the Alexandria Governorate contracted a company to carry out the solid waste management. The contracted company transferred 75% of the daily generated solid wastes to a new constructed sanitary lanfill. The site receives a daily average of 1910 tons. The landfilling is performed by trench method in the form of cells. The produced leachate is discharged into two lined aerated lagoons. The biogas formed from biodegradation of landfilled solid wastes is burned and the produced heat is used for drying the lagoons leachate. The remaining residues are relandfilled. The study aims at assessment of the solid waste sanitary landfill leachate characterization and its impacts on the groundwater. The analysis of the collected data confirms that leachates from the landfill are severely contaminated with organics, salts, and heavy metals. The fluctuations in concentration levels of the different parameters were attributed to aging and thickness of waste layers, stage of decomposition, and re-landfilling of the concentrated residues from the drying lagoons. The concentrations of NH4-N (600 mg/l) indicated that the process of stabilization was still in the initial stages and attributed to the compaction process. The high BOD5 results (28,833 mg/l) indicated that the process of stabilization was in the initial stages which were very slow. The high COD results (45,240 mg/l) can be attributed to the compaction of the wastes which also retards the degradation of the solid wastes. The BOD and COD values indicated clearly severe contamination. The BOD5/COD ratio measured in the current study (0.64) indicated that the leachate of the present study was biodegradable and unstabilized, and required time and favourable conditions for anaerobic biodegradation. Heavy metals were lower compared with what have been observed in other countries. Re-landfilling of the residue after drying the leachate in lagoons and the short time of biodegradation in the landfill site were factors which effected the high strength of most of the parameters concentrations of the leachate. Assessment of groundwater contamination through piezometer wells around the active cells indicated that there was no contamination from the leachate to the groundwater surrounding the site. The study recommended emphasizing the importance of adjusting the biodegradation factors, the monitoring program, the prohibition of disposing heavy metals, determination of the leachate generation rate, and treatment of leachate.

Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon

PubMed Central

Bagby, Sarah C.; Reddy, Christopher M.; Aeppli, Christoph; Fisher, G. Burch; Valentine, David L.

2017-01-01

The 2010 Deepwater Horizon disaster introduced an unprecedented discharge of oil into the deep Gulf of Mexico. Considerable uncertainty has persisted regarding the oil’s fate and effects in the deep ocean. In this work we assess the compound-specific rates of biodegradation for 125 aliphatic, aromatic, and biomarker petroleum hydrocarbons that settled to the deep ocean floor following release from the damaged Macondo Well. Based on a dataset comprising measurements of up to 168 distinct hydrocarbon analytes in 2,980 sediment samples collected within 4 y of the spill, we develop a Macondo oil “fingerprint” and conservatively identify a subset of 312 surficial samples consistent with contamination by Macondo oil. Three trends emerge from analysis of the biodegradation rates of 125 individual hydrocarbons in these samples. First, molecular structure served to modulate biodegradation in a predictable fashion, with the simplest structures subject to fastest loss, indicating that biodegradation in the deep ocean progresses similarly to other environments. Second, for many alkanes and polycyclic aromatic hydrocarbons biodegradation occurred in two distinct phases, consistent with rapid loss while oil particles remained suspended followed by slow loss after deposition to the seafloor. Third, the extent of biodegradation for any given sample was influenced by the hydrocarbon content, leading to substantially greater hydrocarbon persistence among the more highly contaminated samples. In addition, under some conditions we find strong evidence for extensive degradation of numerous petroleum biomarkers, notably including the native internal standard 17α(H),21β(H)-hopane, commonly used to calculate the extent of oil weathering. PMID:27994146

Enantioselective reductive transformation of climbazole: A concept towards quantitative biodegradation assessment in anaerobic biological treatment processes.

PubMed

Brienza, Monica; Chiron, Serge

2017-06-01

An efficient chiral method-based using liquid chromatography-high resolution-mass spectrometry analytical method has been validated for the determination of climbazole (CBZ) enantiomers in wastewater and sludge with quantification limits below the 1 ng/L and 2 ng/g range, respectively. On the basis of this newly developed analytical method, the stereochemistry of CBZ was investigated over time in sludge biotic and sterile batch experiments under anoxic dark and light conditions and during wastewater biological treatment by subsurface flow constructed wetlands. CBZ stereoselective degradation was exclusively observed under biotic conditions, confirming the specificity of enantiomeric fraction variations to biodegradation processes. Abiotic CBZ enantiomerization was insignificant at circumneutral pH and CBZ was always biotransformed into CBZ-alcohol due to the specific and enantioselective reduction of the ketone function of CBZ into a secondary alcohol function. This transformation was almost quantitative and biodegradation gave good first order kinetic fit for both enantiomers. The possibility to apply the Rayleigh equation to enantioselective CBZ biodegradation processes was investigated. The results of enantiomeric enrichment allowed for a quantitative assessment of in situ biodegradation processes due to a good fit (R 2  > 0.96) of the anoxic/anaerobic CBZ biodegradation to the Rayleigh dependency in all the biotic microcosms and was also applied in subsurface flow constructed wetlands. This work extended the concept of applying the Rayleigh equation towards quantitative biodegradation assessment of organic contaminants to enantioselective processes operating under anoxic/anaerobic conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon.

PubMed

Bagby, Sarah C; Reddy, Christopher M; Aeppli, Christoph; Fisher, G Burch; Valentine, David L

2017-01-03

The 2010 Deepwater Horizon disaster introduced an unprecedented discharge of oil into the deep Gulf of Mexico. Considerable uncertainty has persisted regarding the oil's fate and effects in the deep ocean. In this work we assess the compound-specific rates of biodegradation for 125 aliphatic, aromatic, and biomarker petroleum hydrocarbons that settled to the deep ocean floor following release from the damaged Macondo Well. Based on a dataset comprising measurements of up to 168 distinct hydrocarbon analytes in 2,980 sediment samples collected within 4 y of the spill, we develop a Macondo oil "fingerprint" and conservatively identify a subset of 312 surficial samples consistent with contamination by Macondo oil. Three trends emerge from analysis of the biodegradation rates of 125 individual hydrocarbons in these samples. First, molecular structure served to modulate biodegradation in a predictable fashion, with the simplest structures subject to fastest loss, indicating that biodegradation in the deep ocean progresses similarly to other environments. Second, for many alkanes and polycyclic aromatic hydrocarbons biodegradation occurred in two distinct phases, consistent with rapid loss while oil particles remained suspended followed by slow loss after deposition to the seafloor. Third, the extent of biodegradation for any given sample was influenced by the hydrocarbon content, leading to substantially greater hydrocarbon persistence among the more highly contaminated samples. In addition, under some conditions we find strong evidence for extensive degradation of numerous petroleum biomarkers, notably including the native internal standard 17α(H),21β(H)-hopane, commonly used to calculate the extent of oil weathering.

Biogas production from Pongamia biomass wastes and a model to estimate biodegradability from their composition.

PubMed

Gunaseelan, Victor Nallathambi

2014-02-01

In this study, I investigated the chemical characteristics, biochemical methane potential, conversion kinetics and biodegradability of untreated and NaOH-treated Pongamia plant parts, and pod husk and press cake from the biodiesel industry to evaluate their suitability as an alternative feedstock for biogas production. The untreated Pongamia seeds exhibited the maximum CH4 yield of 473 ml g (-1) volatile solid (VS) added. Yellow, withered leaves gave a yield as low as 122 ml CH4 g (-1) VS added. There were significant variations in the CH4 production rate constants, which ranged from 0.02 to 0.15 d (-1), and biodegradability, which ranged from 0.25 to 0.98. NaOH treatment of leaf and pod husk, which were highly rich in fibers, increased the yields by 15-22% and CH4 production rate constants by 20-75%. Utilization of Pongamia wastes in biogas digesters not only influences the economics of biodiesel production but also yields CH4 fuel and protects the environment. The experimental data from this study were used to develop a multiple regression model, which could estimate biodegradability based on biochemical characteristics. The model predicted the biodegradability of previously published biomass wastes (r(2) = 0.88) from their biochemical composition. The theoretical CH4 yields estimated as 350 ml g(-1) chemical oxygen demand destroyed are much higher than the experimental yields as 100% biodegradability is assumed for each substrate. Upon correcting the theoretical CH4 yields with biodegradability data obtained from chemical analyses of substrates, their ultimate CH4 yields could be predicted rapidly.

Potential for biodegradation and sorption of acetaminophen, caffeine, propranolol and acebutolol in lab-scale aqueous environments.

PubMed

Lin, Angela Yu-Chen; Lin, Chih-Ann; Tung, Hsin-Hsin; Chary, N Sridhara

2010-11-15

Sorption and combined sorption-biodegradation experiments were conducted in laboratory batch studies with 100 g soil/sediments and 500 mL water to investigate the fates in aqueous environments of acetaminophen, caffeine, propranolol, and acebutolol, four frequently used and often-detected pharmaceuticals. All four compounds have demonstrated significant potential for degradation and sorption in natural aqueous systems. For acetaminophen, biodegradation was found to be a primary mechanism for degradation, with a half-life (t(1/2)) for combined sorption-biodegradation of 2.1 days; in contrast, sorption alone was responsible only for a 30% loss of aqueous-phase acetaminophen after 15 days. For caffeine, both biodegradation and sorption were important (t(1/2) for combined sorption-biodegradation was 1.5 days). However, for propranolol and acebutolol, sorption was found to be the most significant removal mechanism and was not affected by biodegradation. Desorption experiments revealed that the sorption process was mostly irreversible. High values were found for K(d) for caffeine, propranolol, and acebutolol, ranging from 250 to 1900 L kg(-1), which explained their greater tendency for sorption onto sediments, compared to the more hydrophilic acetaminophen. Experimentally derived values for logK(oc) differed markedly from values calculated from correlation equations. This discrepancy was attributed to the fact that these equations are well suited for hydrophobic interactions but may fail to predict the sorption of polar and ionic compounds. These results suggest that mechanisms other than hydrophobic interactions played an important role in the sorption process. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater.

PubMed

Greses, S; Zamorano-López, N; Borrás, L; Ferrer, J; Seco, A; Aguado, D

2018-07-15

Anaerobic digestion of indigenous Scenedesmus spp. microalgae was studied in continuous lab-scale anaerobic reactors at different temperatures (35 °C and 55 °C), and sludge retention time - SRT (50 and 70 days). Mesophilic digestion was performed in a continuous stirred-tank reactor (CSTR) and in an anaerobic membrane bioreactor (AnMBR). Mesophilic CSTR operated at 50 days SRT only achieved 11.9% of anaerobic biodegradability whereas in the AnMBR at 70 days SRT and 50 days HRT reached 39.5%, which is even higher than the biodegradability achieved in the thermophilic CSTR at 50 days SRT (30.4%). Microbial analysis revealed a high abundance of cellulose-degraders in both reactors, AnMBR (mainly composed of 9.4% Bacteroidetes, 10.1% Chloroflexi, 8.0% Firmicutes and 13.2% Thermotogae) and thermophilic CSTR (dominated by 23.8% Chloroflexi and 12.9% Firmicutes). However, higher microbial diversity was found in the AnMBR compared to the thermophilic CSTR which is related to the SRT. since high SRT promoted low growth-rate microorganisms, increasing the hydrolytic potential of the system. These results present the membrane technology as a promising approach to revalue microalgal biomass, suggesting that microalgae biodegradability and consequently the methane production could be improved operating at higher SRT. Copyright © 2018 Elsevier Ltd. All rights reserved.

A sustainable slashing industry using biodegradable sizes from modified soy protein to replace petro-based poly(vinyl alcohol).

PubMed

Zhao, Yi; Zhao, Yuzhu; Xu, Helan; Yang, Yiqi

2015-02-17

Biodegradable sizing agents from triethanolamine (TEA) modified soy protein could substitute poly(vinyl alcohol)(PVA) sizes for high-speed weaving of polyester and polyester/cotton yarns to substantially decrease environmental pollution and impel sustainability of textile industry. Nonbiodegradable PVA sizes are widely used and mainly contribute to high chemical oxygen demand (COD) in textile effluents. It has not been possible to effectively degrade, reuse or replace PVA sizes so far. Soy protein with good biodegradability showed potential as warp sizes in our previous studies. However, soy protein sizes lacked film flexibility and adhesion for required high-speed weaving. Additives with multiple hydroxyl groups, nonlinear molecule, and electric charge could physically modify secondary structure of soy protein and lead to about 23.6% and 43.3% improvement in size adhesion and ability of hair coverage comparing to unmodified soy protein. Industrial weaving results showed TEA-soy protein had relative weaving efficiency 3% and 10% higher than PVA and chemically modified starch sizes on polyester/cotton fabrics, and had relative weaving efficiency similar to PVA on polyester fabrics, although with 3- 6% lower add-on. In addition, TEA-soy sizes had a BOD5/COD ratio of 0.44, much higher than 0.03 for PVA, indicating that TEA-soy sizes were easily biodegradable in activated sludge.

Excessive Labeling Technique Provides a Highly Sensitive Fluorescent Probe for Real-time Monitoring of Biodegradation of Biopolymer Pharmaceuticals in vivo.

PubMed

Terekhov, S S; Smirnov, I V; Shamborant, O G; Zenkova, M A; Chernolovskaya, E L; Gladkikh, D V; Murashev, A N; Dyachenko, I A; Knorre, V D; Belogurov, A A; Ponomarenko, N A; Deyev, S M; Vlasov, V V; Gabibov, A G

2014-10-01

Recombinant proteins represent a large sector of the biopharma market. Determination of the main elimination pathways raises the opportunities to significantly increase their half-lives in vivo. However, evaluation of biodegradation of pharmaceutical biopolymers performed in the course of pre-clinical studies is frequently complicated. Noninvasive pharmacokinetic and biodistribution studies in living organism are possible using proteins conjugated with near-infrared dyes. In the present study we designed a highly efficient probe based on fluorescent dye self-quenching for monitoring of in vivo biodegradation of recombinant human butyrylcholinesterase. The maximum enhancement of integral fluorescence in response to degradation of an intravenously administered enzyme was observed 6 h after injection. Importantly, excessive butyrylcholinesterase labeling with fluorescent dye results in significant changes in the pharmacokinetic properties of the obtained conjugate. This fact must be taken into consideration during future pharmacokinetic studies using in vivo bioimaging.

Kinetics of degradation of surfactant-solubilized fluoranthene by a Sphingomonas paucimobilis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willumsen, P.A.; Arvin, E.

To achieve a better quantitative understanding of the stimulating or inhibiting effect of surfactants on the metabolism of polycyclic aromatic hydrocarbons (PAHs), a biodegradation model describing solubilization, bioavailability, and biodegradation of crystalline fluoranthene is proposed and used to model experimental data. The degradation was investigated in batch systems containing the PAH-degrading bacterium Sphingomonas paucimobilis strain EPA505, the nonionic surfactant Triton X-100, and a fluoranthene-amended liquid mineral salts medium. Surfactant-enhanced biodegradation is complex; however, the biodegradation model predicted fluoranthene disappearance and the initial mineralization well. Surfactant-amendment did increase fluoranthene mineralization rates by strain EPA505; however, the increases were not proportional tomore » the rates of fluoranthene solubilization. The surfactant clearly influenced the microbial PAH metabolism as indicated by a rapid accumulation of colored products and by a surfactant -related decreased in the overall extent of fluoranthene mineralization. Model estimations of the bioavailability of micelle-solubilized fluoranthene, the relatively fast fluoranthene disappearance, and the accumulation of extracellular compounds in the degradation system suggest that low availability of micellar fluoranthene is not the only factor controlling surfactant-enhanced biodegradation. Also factors such as the extent of accumulation and bioavailability of the PAH metabolites and the crystalline solubilization rate in the presence of surfactants may determine the overall effect of surfactant-enhanced biodegradation of high molecular weight PAHs.« less

Effect of Commercial SiO2 and SiO2 from rice husk ash loading on biodegradation of Poly (lactic acid) and crosslinked Poly (lactic acid)

NASA Astrophysics Data System (ADS)

Prapruddivongs, C.; Apichartsitporn, M.; Wongpreedee, T.

2017-09-01

In this work, biodegradation behavior of poly (lactic acid) (PLA) and crosslinked PLA filled with two types of SiO2, precipitated SiO2 (commercial SiO2) and SiO2 from rice husk ash, were studied. Rice husks were first treated with 2 molar hydrochloric acid (HCl) to produce high purity SiO2, before burnt in a furnace at 800°C for 6 hours. All components were melted bending by an internal mixer then hot pressed using compression molder to form tested specimens. FTIR spectra of SiO2 and PLA samples were investigated. The results showed the lack of silanol group (Si-OH) of rice husk ash after steric acid surface modification, while the addition of particles can affect the crosslinking of the PLA. For biodegradation test by evaluating total amount of carbon dioxide (CO2) evolved during 60 days incubation at a controlled temperature of 58±2°C, the results showed that the biodegradation of crosslinked PLA occurred slower than the neat PLA. However, SiO2 incorporation enhanced the degree of biodegradation In particular, introducing commercial SiO2 in PLA and crosslinked PLA tended to clearly increase the degree of biodegradation as a consequence of the more accelerated hydrolysis degradation.

Efficient biodegradation of phenanthrene by a novel strain Massilia sp. WF1 isolated from a PAH-contaminated soil.

PubMed

Wang, Haizhen; Lou, Jun; Gu, Haiping; Luo, Xiaoyan; Yang, Li; Wu, Laosheng; Liu, Yong; Wu, Jianjun; Xu, Jianming

2016-07-01

A novel phenanthrene (PHE)-degrading strain Massilia sp. WF1, isolated from PAH-contaminated soil, was capable of degrading PHE by using it as the sole carbon source and energy in a range of pH (5.0-8.0), temperatures (20-35 °C), and PHE concentrations (25-400 mg L(-1)). Massilia sp. WF1 exhibited highly effective PHE-degrading ability that completely degraded 100 mg L(-1) of PHE over 2 days at optimal conditions (pH 6.0, 28 °C). The kinetics of PHE biodegradation by Massilia sp. WF1 was well represented by the Gompertz model. Results indicated that PHE biodegradation was inhibited by the supplied lactic acid but was promoted by the supplied carbon sources of glucose, citric acid, and succinic acid. Salicylic acid (SALA) and phthalic acid (PHTA) were not utilized by Massilia sp. WF1 and had no obvious effect on PHE biodegradation. Only two metabolites, 1-hydroxy-2-naphthoic acid (1H2N) and PHTA, were identified in PHE biodegradation process. Quantitatively, nearly 27.7 % of PHE was converted to 1H2N and 30.3 % of 1H2N was further metabolized to PHTA. However, the PHTA pathway was broken and the SALA pathway was ruled out in PHE biodegradation process by Massilia sp. WF1.

Biodegradation testing of chemicals with high Henry's constants - Separating mass and effective concentration reveals higher rate constants.

PubMed

Birch, Heidi; Andersen, Henrik R; Comber, Mike; Mayer, Philipp

2017-05-01

During simulation-type biodegradation tests, volatile chemicals will continuously partition between water phase and headspace. This study addressed how (1) this partitioning affects test results and (2) can be accounted for by combining equilibrium partition and dynamic biodegradation models. An aqueous mixture of 9 (semi)volatile chemicals was first generated using passive dosing and then diluted with environmental surface water producing concentrations in the ng/L to μg/L range. After incubation for 2 h to 4 weeks, automated Headspace Solid Phase Microextraction (HS-SPME) was applied directly on the test systems to measure substrate depletion by biodegradation relatively to abiotic controls. HS-SPME was also applied to determine air to water partitioning ratios. Biodegradation rate constants relating to the chemical in the water phase, k water , were generally a factor 1 to 11 times higher than biodegradation rate constants relating to the total mass of chemical in the test system, k system , with one exceptional factor of 72 times for a long chain alkane. True water phase degradation rate constants were found (i) more appropriate for risk assessment than test system rate constants, (ii) to facilitate extrapolation to other air-water systems and (iii) to be better defined input parameters for aquatic exposure and fate models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradation kinetics of dissolved organic matter chromatographic fractions in an intermittent river

NASA Astrophysics Data System (ADS)

Catalán, N.; Casas-Ruiz, J. P.; von Schiller, D.; Proia, L.; Obrador, B.; Zwirnmann, E.; Marcé, R.

2017-01-01

Controls on the degradation of dissolved organic matter (DOM) are complex but key to understand the role of freshwaters in the carbon cycle. Both the origin and previous degradation history have been suggested to determine DOM reactivity, but it is still a major challenge to understand the links between DOM composition and biodegradation kinetics. An appropriate context to study these links are intermittent rivers, as summer drought naturally diversifies DOM sources and sinks. Here we investigated the biodegradation kinetics of DOM in the main aquatic environments present in a temporary river. During dark incubations we traced the dynamics of bulk DOM and its main chromatographic fractions defined using LC-OCD: high molecular weight substances (HMWS), low molecular weight substances (LMWS), and humic substances and building blocks. Bulk DOM decay patterns were successfully fitted to the reactivity continuum (RC) biodegradation model. The RC parameters depicted running waters as the sites presenting a more reactive DOM, and temporary pools, enriched in leaf litter, as the ones with slowest DOM decay. The decay patterns of each DOM fraction were consistent throughout sites. LMWS and HMWS decayed in all cases and could be modeled using the RC model. Notably, the dynamics of LMWS controlled the bulk DOM kinetics. We discuss the mechanistic basis for the chromatographic fractions' kinetics during biodegradation and the implications that preconditioning and summer drought can have for DOM biodegradation in intermittent rivers.

Concentration of ofloxacin in canine prostate tissue and prostate fluid after intraprostatic injection of biodegradable sustained-releasing microspheres containing ofloxacin.

PubMed

Bahk, J Y; Hyun, J S; Lee, J Y; Kim, J; Cho, Y H; Lee, J H; Park, J S; Kim, M O

2000-05-01

Excellent treatment results in chronic prostatitis by direct intra-prostatic injection of antibiotic were reported several decades ago with only minimal scientific background. We examined the distribution, in prostatic tissue and fluid, of the antibiotic in canines after intra-prostatic injection of biodegradable sustained-releasing microspheres containing 12 mg. of ofloxacin. A total of 36 male dogs, 12 controls and 24 experimental, older than 2 years, were used. Experimental dogs were given biodegradable sustained releasing microspheres containing ofloxacin 12 mg. and poly(D,L-lactic) acid 28 mg., designed to release over more than a 4 week period. The 12 control animals were divided into 2 groups, and oral ofloxacin 100 mg. was given twice a day for 2 and 4 weeks. The 24 experimental animals were divided into 4 subgroups of 6 dogs each, 4 for prostatic tissue and 2 for prostatic fluid level of ofloxacin determination. Anesthesia was initiated with ketamine HCl and xylazine, and maintained with intermittent ketamine HCl. In the experimental groups, 1 ml. of resolved formula was injected into one lobe of surgically exposed prostates. The concentration of ofloxacin was measured by high performance liquid chromatography (HPLC) of blood, prostatic tissue and prostatic fluid. Pilocarpine 0.5 mg./kg. was used for the collection of the prostatic fluid. The total ofloxacin of controls were 2,800 (2 weeks) and 5,600 (4 weeks) mg. In control groups, tissue concentrations of ofloxacin were relatively even at all segments of prostate, 7.4 +/- 0.8 (2 weeks) and 9.2 +/- 1.1 microg./ml. (4 weeks). The blood level ranged between 3.6 to 5.1 microg./ml. The prostatic fluid level ranged from 3.1 to 5.7 microg. /ml. In the experimental groups, the tissue levels of ofloxacin were 10.5 +/- 3.0 (1 week), 13.8 +/- 4.5 (2 weeks), 7.1 +/- 0.9 (3 weeks) and 7.7 +/- 3.0 microg./ml. (4 weeks) in the injected lobe. The opposite lobes were 8.0 +/- 1.1 (1 week), 10.2 +/- 4.2 (2 weeks), 5. 1 +/- 1.4 (3 weeks) and 7.6 +/- 0.8 (4 weeks) microg./ml. The blood level in the experimental groups ranged between 0.16 to 0.59 microg./ml. The prostate fluid level ranged from 2.9 to 6.1 microg./ml. in 8 dogs. Upon pathologic examination, the microspheres were interposed between prostate stroma and their size was reduced over time. Our study indicates that there is communication between the right and left prostate lobes. Direct injection of biodegradable sustained releasing ofloxacin formula into the prostate may be a substitute for long term antibiotic medication in humans for chronic prostatitis in the future without hurting the minimal inhibitory concentration(MIC)90.

Biodegradation of kerosene by Aspergillus ochraceus NCIM-1146.

PubMed

Saratale, Ganesh; Kalme, Satish; Bhosale, Sanjyot; Govindwar, Sanjay

2007-10-01

The filamentous fungus Aspergillus ochraceus NCIM-1146 was found to degrade kerosene, when previously grown mycelium (96 h) was incubated in the broth containing kerosene. Higher levels of NADPH-DCIP reductase, aminopyrine N-demethylase and kerosene biodegradation activities were found to be present after the growth in potato dextrose broth for 96 h, when compared with the activities at different time intervals during the growth phase. NADPH was the preferred cofactor for enzyme activity, which was inhibited by CO, indicating cytochrome P450 mediated reactions. A significant increase in all the enzyme activities was observed when mycelium incubated for 18 h in mineral salts medium, containing cholesterol, camphor, naphthalene, 1,2-dimethoxybenzene, phenobarbital, n-hexane, kerosene or saffola oil as inducers. Acetaldehyde produced by alcohol dehydrogenase could be used as an indicator for the kerosene biodegradation.

Fate of the antibiotic sulfadiazine in natural soils: Experimental and numerical investigations.

PubMed

Engelhardt, Irina; Sittig, Stephan; Šimůnek, Jirka; Groeneweg, Joost; Pütz, Thomas; Vereecken, Harry

2015-01-01

Based on small-scale laboratory and field-scale lysimeter experiments, the sorption and biodegradation of sulfonamide sulfadiazine (SDZ) were investigated in unsaturated sandy and silty-clay soils. Sorption and biodegradation were low in the laboratory, while the highest leaching rates were observed when SDZ was mixed with manure. The leaching rate decreased when SDZ was mixed with pure water, and was smallest with the highest SDZ concentrations. In the laboratory, three transformation products (TPs) developed after an initial lag phase. However, the amount of TPs was different for different mixing-scenarios. The TP 2-aminopyrimidine was not observed in the laboratory, but was the most prevalent TP at the field scale. Sorption was within the same range at the laboratory and field scales. However, distinctive differences occurred with respect to biodegradation, which was higher in the field lysimeters than at the laboratory scale. While the silty-clay soil favored sorption of SDZ, the sandy, and thus highly permeable, soil was characterized by short half-lives and thus a quick biodegradation of SDZ. For 2-aminopyrimidine, half-lives of only a few days were observed. Increased field-scale biodegradation in the sandy soil resulted from a higher water and air permeability that enhanced oxygen transport and limited oxygen depletion. Furthermore, low pH was more important than the organic matter and clay content for increasing the biodegradation of SDZ. A numerical analysis of breakthrough curves of bromide, SDZ, and its TPs showed that preferential flow pathways strongly affected the solute transport within shallow parts of the soil profile at the field scale. However, this effect was reduced in deeper parts of the soil profile. Due to high field-scale biodegradation in several layers of both soils, neither SDZ nor 2-aminopyrimidine was detected in the discharge of the lysimeter at a depth of 1m. Synthetic 50 year long simulations, which considered the application of manure with SDZ for general agricultural practices in Germany and humid climate conditions, showed that the concentration of SDZ decreased below 0.1 μg/L in both soils below the depth of 50 cm. Copyright © 2015 Elsevier B.V. All rights reserved.

Fate of the antibiotic sulfadiazine in natural soils: Experimental and numerical investigations

NASA Astrophysics Data System (ADS)

Engelhardt, Irina; Sittig, Stephan; Šimůnek, Jirka; Groeneweg, Joost; Pütz, Thomas; Vereecken, Harry

2015-06-01

Based on small-scale laboratory and field-scale lysimeter experiments, the sorption and biodegradation of sulfonamide sulfadiazine (SDZ) were investigated in unsaturated sandy and silty-clay soils. Sorption and biodegradation were low in the laboratory, while the highest leaching rates were observed when SDZ was mixed with manure. The leaching rate decreased when SDZ was mixed with pure water, and was smallest with the highest SDZ concentrations. In the laboratory, three transformation products (TPs) developed after an initial lag phase. However, the amount of TPs was different for different mixing-scenarios. The TP 2-aminopyrimidine was not observed in the laboratory, but was the most prevalent TP at the field scale. Sorption was within the same range at the laboratory and field scales. However, distinctive differences occurred with respect to biodegradation, which was higher in the field lysimeters than at the laboratory scale. While the silty-clay soil favored sorption of SDZ, the sandy, and thus highly permeable, soil was characterized by short half-lives and thus a quick biodegradation of SDZ. For 2-aminopyrimidine, half-lives of only a few days were observed. Increased field-scale biodegradation in the sandy soil resulted from a higher water and air permeability that enhanced oxygen transport and limited oxygen depletion. Furthermore, low pH was more important than the organic matter and clay content for increasing the biodegradation of SDZ. A numerical analysis of breakthrough curves of bromide, SDZ, and its TPs showed that preferential flow pathways strongly affected the solute transport within shallow parts of the soil profile at the field scale. However, this effect was reduced in deeper parts of the soil profile. Due to high field-scale biodegradation in several layers of both soils, neither SDZ nor 2-aminopyrimidine was detected in the discharge of the lysimeter at a depth of 1 m. Synthetic 50 year long simulations, which considered the application of manure with SDZ for general agricultural practices in Germany and humid climate conditions, showed that the concentration of SDZ decreased below 0.1 μg/L in both soils below the depth of 50 cm.

Recent advances in high performance poly(lactide): from "green" plasticization to super-tough materials via (reactive) compounding.

PubMed

Kfoury, Georgio; Raquez, Jean-Marie; Hassouna, Fatima; Odent, Jérémy; Toniazzo, Valérie; Ruch, David; Dubois, Philippe

2013-01-01

Due to its origin from renewable resources, its biodegradability, and recently, its industrial implementation at low costs, poly(lactide) (PLA) is considered as one of the most promising ecological, bio-sourced and biodegradable plastic materials to potentially and increasingly replace traditional petroleum derived polymers in many commodity and engineering applications. Beside its relatively high rigidity [high tensile strength and modulus compared with many common thermoplastics such as poly(ethylene terephthalate) (PET), high impact poly(styrene) (HIPS) and poly(propylene) (PP)], PLA suffers from an inherent brittleness, which can limit its applications especially where mechanical toughness such as plastic deformation at high impact rates or elongation is required. Therefore, the curve plotting stiffness vs. impact resistance and ductility must be shifted to higher values for PLA-based materials, while being preferably fully bio-based and biodegradable upon the application. This review aims to establish a state of the art focused on the recent progresses and preferably economically viable strategies developed in the literature for significantly improve the mechanical performances of PLA. A particular attention is given to plasticization as well as to impact resistance modification of PLA in the case of (reactive) blending PLA-based systems.

Recent advances in high performance poly(lactide): from “green” plasticization to super-tough materials via (reactive) compounding

PubMed Central

Kfoury, Georgio; Raquez, Jean-Marie; Hassouna, Fatima; Odent, Jérémy; Toniazzo, Valérie; Ruch, David; Dubois, Philippe

2013-01-01

Due to its origin from renewable resources, its biodegradability, and recently, its industrial implementation at low costs, poly(lactide) (PLA) is considered as one of the most promising ecological, bio-sourced and biodegradable plastic materials to potentially and increasingly replace traditional petroleum derived polymers in many commodity and engineering applications. Beside its relatively high rigidity [high tensile strength and modulus compared with many common thermoplastics such as poly(ethylene terephthalate) (PET), high impact poly(styrene) (HIPS) and poly(propylene) (PP)], PLA suffers from an inherent brittleness, which can limit its applications especially where mechanical toughness such as plastic deformation at high impact rates or elongation is required. Therefore, the curve plotting stiffness vs. impact resistance and ductility must be shifted to higher values for PLA-based materials, while being preferably fully bio-based and biodegradable upon the application. This review aims to establish a state of the art focused on the recent progresses and preferably economically viable strategies developed in the literature for significantly improve the mechanical performances of PLA. A particular attention is given to plasticization as well as to impact resistance modification of PLA in the case of (reactive) blending PLA-based systems. PMID:24790960

Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

PubMed Central

Masaki, Kazuo; Kamini, Numbi Ramudu; Ikeda, Hiroko; Iefuji, Haruyuki

2005-01-01

A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ɛ-caprolactone), and poly(3-hydroxybutyrate). PMID:16269800

A protocol for assessing the effectiveness of oil spill dispersants in stimulating the biodegradation of oil.

PubMed

Prince, Roger C; Butler, Josh D

2014-01-01

Dispersants are important tools in oil spill response. Taking advantage of the energy in even small waves, they disperse floating oil slicks into tiny droplets (<70 μm) that entrain in the water column and drift apart so that they do not re-agglomerate to re-form a floating slick. The dramatically increased surface area allows microbial access to much more of the oil, and diffusion and dilution lead to oil concentrations where natural background levels of biologically available oxygen, nitrogen, and phosphorus are sufficient for microbial growth and oil consumption. Dispersants are only used on substantial spills in relatively deep water (usually >10 m), conditions that are impossible to replicate in the laboratory. To date, laboratory experiments aimed at following the biodegradation of dispersed oil usually show only minimal stimulation of the rate of biodegradation, but principally because the oil in these experiments disperses fairly effectively without dispersant. What is needed is a test protocol that allows comparison between an untreated slick that remains on the water surface during the entire biodegradation study and dispersant-treated oil that remains in the water column as small dispersed oil droplets. We show here that when this is accomplished, the rate of biodegradation is dramatically stimulated by an effective dispersant, Corexit 9500. Further development of this approach might result in a useful tool for comparing the full benefits of different dispersants.

Trimeprazine is enantioselectively degraded by an activated sludge in ready biodegradability test conditions.

PubMed

Escuder-Gilabert, Laura; Martín-Biosca, Yolanda; Perez-Baeza, Mireia; Sagrado, Salvador; Medina-Hernández, María José

2018-05-09

A great number of available pharmaceuticals are chiral compounds. Although they are usually manufactured as racemic mixtures, they can be enantioselectively biodegraded as a result of microbial processes. In this paper, a biodegradability assay in similar conditions to those recommended in OECD tests of enantiomers of trimeprazine (a phenothiazine employed as a racemate) is carried out. Experiments were performed in batch mode using a minimal salts medium inoculated with an activated sludge (collected from a Valencian Waste Water Treatment Plant, WWTP) and supplemented with the racemate. The concentration of the enantiomers of trimeprazine were monitored by means of a chiral HPLC method using a cellulose-based chiral stationary phase and 0.5 M NaClO 4 /acetonitrile (60:40, v/v) mobile phases. Experiments were performed at three concentration levels of the racemate. In parallel, the optical density at 600 nm (OD600) was measured to control the biomass growth and to connect it with enantioselectivity. The calculated enantiomeric fractions (EF) offer the first evidence of enantioselective biodegradation of trimeprazine. A simplified Monod equation was used as a curve fitting approach for concentration (S), biodegradation (BD), and for the first time, EF experimental data in order to expand the usefulness of the results. Precision studies on S (repeatability conditions) and, for the first time, EF (intermediate precision conditions) were also performed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aerobic biodegradation of a nonylphenol polyethoxylate and toxicity of the biodegradation metabolites.

PubMed

Jurado, Encarnación; Fernández-Serrano, Mercedes; Núñez-Olea, Josefa; Lechuga, Manuela

2009-09-01

In this paper a study was made of the biodegradation of a non-ionic surfactant, a nonylphenol polyethoxylate, in biodegradability tests by monitoring the residual surfactant matter. The influence of the concentration on the extent of primary biodegradation, the toxicity of biodegradation metabolites, and the kinetics of degradation were also determined. The primary biodegradation was studied at different initial concentrations: 5, 25 and 50 mg/L, (at sub-and supra-critical micelle concentration). The NPEO used in this study can be considered biodegradable since the primary biodegradation had already taken place (a biodegradation greater than 80% was found for the different initial concentration tested). The initial concentration affected the shape of the resulting curve, the mean biodegradation rate and the percentage of biodegradation reached (99% in less than 8 days at 5 mg/L, 98% in less than 13 days at 25 mg/L and 95% in 14 days at 50 mg/L). The kinetic model of Quiroga and Sales (1991) was applied to predict the biodegradation of the NPEO. The toxicity value was measured as EC(20) and EC(50). In addition, during the biodegradation process of the surfactant a toxicity analysis was made of the evolution of metabolites generated, confirming that the subproducts of the biodegradation process were more toxic than the original.

Concurrent microbial reduction of high concentrations of nitrate and perchlorate in an ion exchange membrane bioreactor.

PubMed

Fox, Shalom; Bruner, Tali; Oren, Yoram; Gilron, Jack; Ronen, Zeev

2016-09-01

We investigated effective simultaneous removal of high loads of nitrate and perchlorate from synthetic groundwater using an ion exchange membrane bioreactor (IEMB). The aim of this research was to characterize both transport aspects and biodegradation mechanisms involved in the treatment process of high loads of the two anions. Biodegradation process was proven to be efficient with over 99% efficiency of both perchlorate and nitrate, regardless of their load. The maximum biodegradation rates were 18.3 (mmol m(-2)  h(-1) ) and 5.5 (mmol m(-2)  h(-1) ) for nitrate and perchlorate, respectively. The presence of a biofilm on the bio-side of the membrane only slightly increased the nitrate and perchlorate transmembrane flux as compared to the measured flux during a Donnan dialysis experiment where there is no biodegradation of perchlorate and nitrate in the bio-compartment. The nitrate flux in presence of a biofilm was 18.3 (±1.9) (mmole m(-2)  h(-1) ), while without the biofilm, the flux was 16.9 (±1.5) (mmole m(-2)  h(-1) ) for the same feed inlet nitrate concentration of 4 mM. The perchlorate transmembrane flux increased similarly by an average of 5%. Samples of membrane biofilm and suspended bacteria from the bio-reactor were analyzed for diversity and abundance of the perchlorate and nitrate reducing bacteria. Klebsiella oxytoca, known as a glycerol fermenter, accounted for 70% of the suspended bacteria. In contrast, perchlorate and nitrate reducing bacteria predominated in the biofilm present on the membrane. These results are consistent with our proposed two stage biodegradation mechanism where glycerol is first fermented in the suspended phase of the bio-reactor and the fermentation products drive perchlorate and nitrate bio-reduction in the biofilm attached to the membrane. These results suggest that the niche exclusion of microbial populations in between the reactor and membrane is controlled by the fluxes of the electron donors and acceptors. Such a mechanism has important implications for controlling the bio-reduction reaction in the IEMB when using glycerol as a carbon source and allowing treating a complex contamination of high concentrations of perchlorate and nitrating in groundwater and successfully biodegrading them to non-hazardous components. Biotechnol. Bioeng. 2016;113: 1881-1891. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Biodegradation of engine oil by fungi from mangrove habitat.

PubMed

Ameen, Fuad; Hadi, Sarfaraz; Moslem, Mohamed; Al-Sabri, Ahmed; Yassin, Mohamed A

2015-01-01

The pollution of land and water by petroleum compounds is a matter of growing concern necessitating the development of methodologies, including microbial biodegradation, to minimize the impending impacts. It has been extensively reported that fungi from polluted habitats have the potential to degrade pollutants, including petroleum compounds. The Red Sea is used extensively for the transport of oil and is substantially polluted, due to leaks, spills, and occasional accidents. Tidal water, floating debris, and soil sediment were collected from mangrove stands on three polluted sites along the Red Sea coast of Saudi Arabia and forty-five fungal isolates belonging to 13 genera were recovered from these samples. The isolates were identified on the basis of a sequence analysis of the 18S rRNA gene fragment. Nine of these isolates were found to be able to grow in association with engine oil, as the sole carbon source, under in vitro conditions. These selected isolates and their consortium accumulated greater biomass, liberated more CO2, and produced higher levels of extracellular enzymes, during cultivation with engine oil as compared with the controls. These observations were authenticated by gas chromatography-mass spectrophotometry (GC-MS) analysis, which indicated that many high mass compounds present in the oil before treatment either disappeared or showed diminished levels.

Molecular-Level Transformations of Lignin During Photo-Oxidation and Biodegradation

NASA Astrophysics Data System (ADS)

Feng, X.; Hills, K.; Simpson, A. J.; Simpson, M. J.

2009-05-01

As the second most abundant component of terrestrial plant residues, lignin plays a key role in regulating plant litter decomposition, humic substance formation, and dissolved organic matter (OM) production from terrestrial sources. Biodegradation is the primary decomposition process of lignin on land. However, photo- oxidation of lignin-derived compounds has been reported in aquatic systems and is considered to play a vital role in arid and semiarid regions. With increasing ultraviolet (UV) radiation due to ozone depletion, it is important to understand the biogeochemical fate of lignin exposed to photo-oxidation in terrestrial environments. This study examines and compares the transformation of lignin in a three-month laboratory simulation of biodegradation and photo-oxidation using molecular-level techniques. Lignin-derived monomers extracted by copper oxidation were analyzed by gas chromatography/mass spectrometry (GC/MS) from the water-soluble and insoluble OM of 13C-labeled corn leaves. Biodegradation increased the solubility of lignin monomers in comparison to the control samples, and the acid-to-aldehyde (Ad/Al) ratios increased in both the water-soluble and insoluble OM, indicating a higher degree of side-chain lignin oxidation. Photo-oxidation did not produce a significant change on the solubility or Ad/Al ratios of lignin from corn leaves. However, the ratios of trans-to-cis isomers of both cinnamyl units (p-coumaric acid and ferulic acid) increased with photo-oxidation and decreased with biodegradation in the insoluble OM. We also investigated the role of photo-oxidation in lignin transformation in soils cropped with 13C-labeled corn. Interestingly, the organic carbon content increased significantly with time in the water-soluble OM from soil/corn residues under UV radiation. An increase in the concentration of lignin monomers and dimers and the Ad/Al ratios was also observed with photo-oxidation. Iso-branched fatty acids of microbial origin remained in a similar concentration in the water-soluble OM from the UV-radiated and control soils, indicating little microbial contribution to the observed increase in water-soluble carbon. These observations suggest that photo-oxidation may increase the solubility of soil organic matter (SOM) through the oxidation of lignin-derived compounds. Mechanisms of lignin oxidation (demethylation or side-chain oxidation) and molecular size distribution changes of the water-soluble and NaOH-soluble OM during photo-oxidation and biodegradation will also be examined using solution-state nuclear magnetic resonance (NMR) spectroscopy. Collectively, our experiment demonstrates that while biodegradation predominates in the decomposition of lignin in plant litter, photo- oxidation may play an important part in destabilizing lignin-derived compounds in the soil.

Molecular-level transformations of lignin during photo-oxidation and biodegradation

NASA Astrophysics Data System (ADS)

Feng, X.; Hills, K.; Simpson, A. J.; Simpson, M. J.

2009-04-01

As the second most abundant component of terrestrial plant residues, lignin plays a key role in regulating plant litter decomposition, humic substance formation, and dissolved organic matter (OM) production from terrestrial sources. Biodegradation is the primary decomposition process of lignin on land. However, photo-oxidation of lignin-derived compounds has been reported in aquatic systems and is considered to play a vital role in arid and semiarid regions. With increasing ultraviolet (UV) radiation due to ozone depletion, it is important to understand the biogeochemical fate of lignin exposed to photo-oxidation in terrestrial environments. This study examines and compares the transformation of lignin in a three-month laboratory simulation of biodegradation and photo-oxidation using molecular-level techniques. Lignin-derived monomers extracted by copper oxidation were analyzed by gas chromatography/mass spectrometry (GC/MS) from the water-soluble and insoluble OM of 13C-labeled corn leaves. Biodegradation increased the solubility of lignin monomers in comparison to the control samples, and the acid-to-aldehyde (Ad/Al) ratios increased in both the water-soluble and insoluble OM, indicating a higher degree of side-chain lignin oxidation. Photo-oxidation did not produce a significant change on the solubility or Ad/Al ratios of lignin from corn leaves. However, the ratios of trans-to-cis isomers of both cinnamyl units (p-coumaric acid and ferulic acid) increased with photo-oxidation and decreased with biodegradation in the insoluble OM. We also investigated the role of photo-oxidation in lignin transformation in soils cropped with 13C-labeled corn. Interestingly, the organic carbon content increased significantly with time in the water-soluble OM from soil/corn residues under UV radiation. An increase in the concentration of lignin monomers and dimers and the Ad/Al ratios was also observed with photo-oxidation. Iso-branched fatty acids of microbial origin remained in a similar concentration in the water-soluble OM from the UV-radiated and control soils, indicating little microbial contribution to the observed increase in water-soluble carbon. These observations suggest that photo-oxidation may increase the solubility of soil organic matter (SOM) through the oxidation of lignin-derived compounds. Mechanisms of lignin oxidation (demethylation or side-chain oxidation) and molecular size distribution changes of the water-soluble and NaOH-soluble OM during photo-oxidation and biodegradation will also be examined using solution-state nuclear magnetic resonance (NMR) spectroscopy. Collectively, our experiment demonstrates that while biodegradation predominates in the decomposition of lignin in plant litter, photo-oxidation may play an important part in destabilizing lignin-derived compounds in the soil.

Determination of optimal conditions for 5-methyl-benzotriazole biodegradation with activated sludge communities by dilution of the inoculum.

PubMed

Yuan, Heyang; Herzog, Bastian; Helmreich, Brigitte; Lemmer, Hilde; Müller, Elisabeth

2014-07-15

The aerobic biodegradation of 5-methyl-benzotriazole (5-TTri) was optimized using lab-scale setups and activated sludge communities (ASC) collected from three wastewater treatment plants (WWTP) MBR-MH, CAS-E and CAS-M being different in their treatment technologies. ASC inocula were diluted to rule out non-biodegrading species and incubated under two nutrient conditions: A) mineral salt media (MSM) and B) carbon and nitrogen supplied MSM giving MSM-CN. 5-TTri removal with the ASC ranged from 60% to 100% in only 10 days. 100 μL suspended biomass from the biodegrading setups was subsequently plated on solid media to eliminate possible activated sludge remnants. After growth occurred, mixed colonies were harvested and inoculated in fresh liquid MSM containing 20 mg L(-1) 5-TTri. These bacterial consortia showed good 5-TTri removal in MSM-CN rather than in MSM, indicating nutrient supply being required for efficient biodegradation. In addition, experiments with high 5-TTri concentrations ranging from 20 to 1,000 mg L(-1) were conducted in both, MSM and MSM-CN and the maximal 5-TTri removal capacity of the ASC evaluated. 50 mg L(-1) 5-TTri was still removed in both media whereas 100 mg L(-1) was solely removed in MSM-CN. 5-TTri biodegradation patterns also indicated that 5-TTri might be co-metabolized by microbial consortia. Furthermore, experiments with gradient-solid-media-plates showed 5-TTri to be inhibitory for the ASC in concentrations above 50 mg L(-1) and revealed the optimal conditions regarding carbon and nitrogen concentration and pH value for effective 5-TTri biodegradation by ASC. Nitrogen proved a crucial factor for enhancing organisms' biodegradation capacity with an optimal pH around 7 while carbon showed no such effect. Copyright © 2013 Elsevier B.V. All rights reserved.

Dissolved organic carbon in Alaskan boreal forest: Sources, chemical characteristics, and biodegradability

USGS Publications Warehouse

Wickland, K.P.; Neff, J.C.; Aiken, G.R.

2007-01-01

The fate of terrestrially-derived dissolved organic carbon (DOC) is important to carbon (C) cycling in both terrestrial and aquatic environments, and recent evidence suggests that climate warming is influencing DOC dynamics in northern ecosystems. To understand what determines the fate of terrestrial DOC, it is essential to quantify the chemical nature and potential biodegradability of this DOC. We examined DOC chemical characteristics and biodegradability collected from soil pore waters and dominant vegetation species in four boreal black spruce forest sites in Alaska spanning a range of hydrologic regimes and permafrost extents (Well Drained, Moderately Well Drained, Poorly Drained, and Thermokarst Wetlands). DOC chemistry was characterized using fractionation, UV-Vis absorbance, and fluorescence measurements. Potential biodegradability was assessed by incubating the samples and measuring CO2 production over 1 month. Soil pore water DOC from all sites was dominated by hydrophobic acids and was highly aromatic, whereas the chemical composition of vegetation leachate DOC varied significantly with species. There was no seasonal variability in soil pore water DOC chemical characteristics or biodegradability; however, DOC collected from the Poorly Drained site was significantly less biodegradable than DOC from the other three sites (6% loss vs. 13-15% loss). The biodegradability of vegetation-derived DOC ranged from 10 to 90% loss, and was strongly correlated with hydrophilic DOC content. Vegetation such as Sphagnum moss and feathermosses yielded DOC that was quickly metabolized and respired. In contrast, the DOC leached from vegetation such as black spruce was moderately recalcitrant. Changes in DOC chemical characteristics that occurred during microbial metabolism of DOC were quantified using fractionation and fluorescence. The chemical characteristics and biodegradability of DOC in soil pore waters were most similar to the moderately recalcitrant vegetation leachates, and to the microbially altered DOC from all vegetation leachates. ?? 2007 Springer Science+Business Media, LLC.

Cloning and expression of vgb gene in Bacillus cereus, improve phenol and p-nitrophenol biodegradation

NASA Astrophysics Data System (ADS)

Vélez-Lee, Angel Eduardo; Cordova-Lozano, Felipe; Bandala, Erick R.; Sanchez-Salas, Jose Luis

2016-02-01

In this work, the vgb gene from Vitrocilla stercoraria was used to genetically modify a Bacillus cereus strain isolated from pulp and paper wastewater effluent. The gene was cloned in a multicopy plasmid (pUB110) or uni-copy gene using a chromosome integrative vector (pTrpBG1). B. cereus and its recombinant strains were used for phenol and p-nitrophenol biodegradation using aerobic or micro-aerobic conditions and two different temperatures (i.e. 37 and 25 °C). Complete (100%) phenol degradation was obtained for the strain where the multicopy of vgb gene was present, 98% for the strain where uni-copy gene was present and 45% for wild type strain for the same experimental conditions (i.e. 37 °C and aerobic condition). For p-nitrophenol degradation at the same conditions, the strain with the multi-copy vgb gene was capable to achieve 50% of biodegradation, ˜100% biodegradation was obtained using the uni-copy strain and ˜24% for wild type strain. When the micro-aerobic condition was tested, the biodegradation yield showed a significant decreased. The biodegradation trend observed for aerobic was similar for micro-aerobic assessments: the modified strains showed higher degradation rates when compared with wild type strain. For all experimental conditions, the highest p-nitrophenol degradation was observed using the strain with uni-copy of vgb gene. Besides the increase of biodegradative capability of the strain, insertion of the vgb gene was observed able to modify other morphological characteristics such as avoiding the typical flake formation in the B. cereus culture. In both cases, the modification seems to be related with the enhancement of oxygen supply to the cells generated by the vgb gene insertion. The application of the genetically modified microorganism (GMM) to the biodegradation of pollutants in contaminated water possesses high potential as an environmentally friendly technology to facing this emergent problem.

Biodegradability and biodegradation rate of poly(caprolactone)-starch blend and poly(butylene succinate) biodegradable polymer under aerobic and anaerobic environment.

PubMed

Cho, H S; Moon, H S; Kim, M; Nam, K; Kim, J Y

2011-03-01

The biodegradability and the biodegradation rate of two kinds biodegradable polymers; poly(caprolactone) (PCL)-starch blend and poly(butylene succinate) (PBS), were investigated under both aerobic and anaerobic conditions. PCL-starch blend was easily degraded, with 88% biodegradability in 44 days under aerobic conditions, and showed a biodegradation rate of 0.07 day(-1), whereas the biodegradability of PBS was only 31% in 80 days under the same conditions, with a biodegradation rate of 0.01 day(-1). Anaerobic bacteria degraded well PCL-starch blend (i.e., 83% biodegradability for 139 days); however, its biodegradation rate was relatively slow (6.1 mL CH(4)/g-VS day) compared to that of cellulose (13.5 mL CH(4)/g-VS day), which was used as a reference material. The PBS was barely degraded under anaerobic conditions, with only 2% biodegradability in 100 days. These results were consistent with the visual changes and FE-SEM images of the two biodegradable polymers after the landfill burial test, showing that only PCL-starch blend had various sized pinholes on the surface due to attack by microorganisms. This result may be use in deciding suitable final disposal approaches of different types of biodegradable polymers in the future. Copyright © 2010 Elsevier Ltd. All rights reserved.

Rhamnolipid-enhanced aerobic biodegradation of triclosan (TCS) by indigenous microorganisms in water-sediment systems.

PubMed

Guo, Qian; Yan, Jia; Wen, Junjie; Hu, Yongyou; Chen, Yuanbo; Wu, Wenjin

2016-11-15

Bioremediation of triclosan (TCS) is a challenge because of its low bioavailability, persistence in the environment and recalcitrance to remediation efforts. Rhamnolipid (RL) was used to enhance TCS biodegradation by indigenous microbes in an aerobic water-sediment system. However, knowledge of the effects of TCS on the bacterial community and environmental factors in an RL-enhanced, TCS-degrading system are lacking. Therefore, in this study, the influence of environmental factors on RL-enhanced biodegradation of TCS was investigated by single factor experiments, and shifts in aerobic TCS-degrading bacterial populations, with and without RL, were analyzed by high-throughput sequencing technology. The results showed that aerobic biodegradation of TCS was significantly promoted by the addition of RL. Environmental conditions, which included RL addition (0.125-0.5g/L), medium concentrations of TCS (<90μg/g), water disturbance, elevated temperature, ionic strength (0.001-0.1mol/L NaCl) and weak alkaline environments (pH8-9), were monitored. High concentrations of TCS had a remarkable influence on the bacterial community structure, and this influence on the distribution proportion of the main microorganisms was strengthened by RL addition. Alpha-proteobacteria (e.g., Sphingomonadaceae and Caulobacteraceae) might be resistant to TCS or even capable of TCS biodegradation, while Sphingobacteria, Beta- and Delta-proteobacteria were sensitive to TCS toxicity. This research provides ecological information on the degradation efficiency and bacterial community stability in RL-enhanced bioremediation of TCS-polluted aquatic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Arabidopsis Glutathione Transferases U24 and U25 Exhibit a Range of Detoxification Activities with the Environmental Pollutant and Explosive, 2,4,6-Trinitrotoluene1[C][W][OPEN

PubMed Central

Gunning, Vanda; Tzafestas, Kyriakos; Sparrow, Helen; Johnston, Emily J.; Brentnall, Andrew S.; Potts, Jennifer R.; Rylott, Elizabeth L.; Bruce, Neil C.

2014-01-01

The explosive 2,4,6-trinitrotoluene (TNT) is a major worldwide military pollutant. The presence of this toxic and highly persistent pollutant, particularly at military sites and former manufacturing facilities, presents various health and environmental concerns. Due to the chemically resistant structure of TNT, it has proven to be highly recalcitrant to biodegradation in the environment. Here, we demonstrate the importance of two glutathione transferases (GSTs), GST-U24 and GST-U25, from Arabidopsis (Arabidopsis thaliana) that are specifically up-regulated in response to TNT exposure. To assess the role of GST-U24 and GST-U25, we purified and characterized recombinant forms of both enzymes and demonstrated the formation of three TNT glutathionyl products. Importantly, GST-U25 catalyzed the denitration of TNT to form 2-glutathionyl-4,6-dinitrotoluene, a product that is likely to be more amenable to subsequent biodegradation in the environment. Despite the presence of this biochemical detoxification pathway in plants, physiological concentrations of GST-U24 and GST-U25 result in only a limited innate ability to cope with the levels of TNT found at contaminated sites. We demonstrate that Arabidopsis plants overexpressing GST-U24 and GST-U25 exhibit significantly enhanced ability to withstand and detoxify TNT, properties that could be applied for in planta detoxification of TNT in the field. The overexpressing lines removed significantly more TNT from soil and exhibited a corresponding reduction in glutathione levels when compared with wild-type plants. However, in the absence of TNT, overexpression of these GSTs reduces root and shoot biomass, and although glutathione levels are not affected, this effect has implications for xenobiotic detoxification. PMID:24733884

Application of plastic polymers in remediating wine with elevated alkyl-methoxypyrazine levels.

PubMed

Botezatu, Andreea; Pickering, Gary J

2015-01-01

3-Alkyl-2-methoxypyrazines (MPs) are odour-active compounds that elicit atypical green aromas and flavours in some wines, and are resilient to removal using traditional wine-making approaches. They originate either as contaminants from Coccinellidae beetles inadvertently introduced during wine processing ("ladybug taint") or as grape-derived constituents that are undesirable at elevated levels. In this study we investigated the capacity of a selection of plastic polymers to reduce concentrations of three MPs: isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP). In Trial 1, red wine was spiked with IPMP (20 ng/l), SBMP (20 ng/l) and IBMP (20 ng/l), then separately treated with 13 plastic polymers (surface area 350 cm(2)/l). Three polymers were then identified for further testing based on the results from Trial 1: silicone, ethylene and vinyl acetate (EVA) and a poly-lactic acid-based biodegradable polymer. In Trial 2, the efficacy of these selected polymers to reduce MP levels in red wine was tested as a function of contact time. Solid-phase micro-extraction multi-dimensional GC-MS was used to measure MP levels before and after treatment with the polymers. Results showed significant reductions in all target odorants after 24 h treatment: silicone reduced IPMP and IBMP by 96% and 100%, respectively, while the biodegradable polymer decreased IPMP and IBMP concentrations by 52% and 36%, respectively. EVA was less effective in lowering MP levels (7% IPMP and 23% IBMP after 24 h). Taken overall, the data suggest the potential for the use of poly-lactic acid and silicone in treating wines contaminated by ladybug taint, as well as in reducing high levels of grape-derived MPs.

Slowly biodegradable organic compounds impact the biostability of non-chlorinated drinking water produced from surface water.

PubMed

Hijnen, W A M; Schurer, R; Bahlman, J A; Ketelaars, H A M; Italiaander, R; van der Wal, A; van der Wielen, P W J J

2018-02-01

It is possible to distribute drinking water without a disinfectant residual when the treated water is biologically stable. The objective of this study was to determine the impact of easily and slowly biodegradable compounds on the biostability of the drinking water at three full-scale production plants which use the same surface water, and on the regrowth conditions in the related distribution systems. Easily biodegradable compounds in the drinking water were determined with AOC-P17/Nox during 2012-2015. Slowly biodegradable organic compounds measured as particulate and/or high-molecular organic carbon (PHMOC), were monitored at the inlet and after the different treatment stages of the three treatments during the same period. The results show that PHMOC (300-470 μg C L -1 ) was approximately 10% of the TOC in the surface water and was removed to 50-100 μg C L -1 . The PHMOC in the water consisted of 40-60% of carbohydrates and 10% of proteins. A significant and strong positive correlation was observed for PHMOC concentrations and two recently introduced bioassay methods for slowly biodegradable compounds (AOC-A3 and biomass production potential, BPC 14 ). Moreover, these three parameters in the biological active carbon effluent (BACF) of the three plants showed a positive correlation with regrowth in the drinking water distribution system, which was assessed with Aeromonas, heterotrophic plate counts, coliforms and large invertebrates. In contrast, the AOC-P17/Nox concentrations did not correlate with these regrowth parameters. We therefore conclude that slowly biodegradable compounds in the treated water from these treatment plants seem to have a greater impact on regrowth in the distribution system than easily biodegradable compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradation of free cyanide and subsequent utilisation of biodegradation by-products by Bacillus consortia: optimisation using response surface methodology.

PubMed

Mekuto, Lukhanyo; Ntwampe, Seteno Karabo Obed; Jackson, Vanessa Angela

2015-07-01

A mesophilic alkali-tolerant bacterial consortium belonging to the Bacillus genus was evaluated for its ability to biodegrade high free cyanide (CN(-)) concentration (up to 500 mg CN(-)/L), subsequent to the oxidation of the formed ammonium and nitrates in a continuous bioreactor system solely supplemented with whey waste. Furthermore, an optimisation study for successful cyanide biodegradation by this consortium was evaluated in batch bioreactors (BBs) using response surface methodology (RSM). The input variables, that is, pH, temperature and whey-waste concentration, were optimised using a numerical optimisation technique where the optimum conditions were found to be as follows: pH 9.88, temperature 33.60 °C and whey-waste concentration of 14.27 g/L, under which 206.53 mg CN(-)/L in 96 h can be biodegraded by the microbial species from an initial cyanide concentration of 500 mg CN(-)/L. Furthermore, using the optimised data, cyanide biodegradation in a continuous mode was evaluated in a dual-stage packed-bed bioreactor (PBB) connected in series to a pneumatic bioreactor system (PBS) used for simultaneous nitrification, including aerobic denitrification. The whey-supported Bacillus sp. culture was not inhibited by the free cyanide concentration of up to 500 mg CN(-)/L, with an overall degradation efficiency of ≥ 99 % with subsequent nitrification and aerobic denitrification of the formed ammonium and nitrates over a period of 80 days. This is the first study to report free cyanide biodegradation at concentrations of up to 500 mg CN(-)/L in a continuous system using whey waste as a microbial feedstock. The results showed that the process has the potential for the bioremediation of cyanide-containing wastewaters.

Long-term monitoring and prediction for settlement and composition of refuse in Shanghai Laogang Municipal Landfill.

PubMed

Jiangying, Liu; Dimin, Xu; Youcai, Zhao; Shaowei, Chen; Guojian, Li; Qi, Zhou

2004-09-01

Parameters about composition of refuse such as mass percentage of biodegradable matter, volatile solid, organic carbon, cellulose, total sugar, and settlement were monitored and analyzed in a large-scale experimental unit. The empirical formulas between composition and refuse age were established in terms of the data obtained from the experimental unit and verified by comparing with the corresponding parameters of refuse in the closed landfill units from 1991 until 1994 in the Shanghai Laogang Municipal Landfill. Furthermore, the long-term prediction for the composition of refuse was made, and it was predicted that the half-life is 7 to 11 years for biodegradable matter, 9 to 12 years for organic carbon or volatile solid, 7 to 16 years for cellulose, and 4 to 6 years for total sugar. In addition, a mathematical model, based on the mechanism of refuse biodegradation in the landfill, was developed to simulate the relationship between the settlement and the refuse age and manifests the secondary settlement potential. The mathematical model was proved not only to be reliable but also should be accurate for predicting the settlement of the landfill. The secondary settlement, which mainly results from the slow and gradual biodegradation of refuse, is linear with respect to the exponent of refuse age. Finally, according to the settlement model and empirical biodegradation formulas, it may be predicted that, 79.4% of biodegradable matter, 92.9% of total sugar, 72.7% of volatile solid and organic carbon, and 73.1% of cellulose will be biodegraded and that 79% of the maximum secondary settlement potential will occur before the Shanghai Laogang Municipal Landfill is in a high stabilization situation, i.e., approximately 21 years after final closure.

A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

PubMed Central

Cheng, Kuo-Wei; Hsu, Shan-hui

2017-01-01

Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50–60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers. PMID:28280341

A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles.

PubMed

Cheng, Kuo-Wei; Hsu, Shan-Hui

2017-01-01

Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50-60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers.

Sorption and biodegradation of sulfonamide antibiotics by activated sludge: experimental assessment using batch data obtained under aerobic conditions.

PubMed

Yang, Sheng-Fu; Lin, Cheng-Fang; Lin, Angela Yu-Chen; Hong, Pui-Kwan Andy

2011-05-01

This study investigated the adsorption, desorption, and biodegradation characteristics of sulfonamide antibiotics in the presence of activated sludge with and without being subjected to NaN(3) biocide. Batch experiments were conducted and the relative contributions of adsorption and biodegradation to the observed removal of sulfonamide antibiotics were determined. Three sulfonamide antibiotics including sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), which had been detected in the influent and the activated sludge of wastewater treatment plants (WWTP) in Taiwan, were selected for this study. Experimental results showed that the antibiotic compounds were removed via sorption and biodegradation by the activated sludge, though biodegradation was inhibited in the first 12 h possibly due to competitive inhibition of xenobiotic oxidation by readily biodegradable substances. The affinity of sulfonamides to sterilized sludge was in the order of SDM > SMM > SMX. The sulfonamides existed predominantly as anions at the study pH of 6.8, which resulted in a low level of adsorption to the activated sludge. The adsorption/desorption isotherms were of a linear form, as well described by the Freundlich isotherm with the n value approximating unity. The linear distribution coefficients (K(d)) were determined from batch equilibrium experiments with values of 28.6 ± 1.9, 55.7 ± 2.2, and 110.0 ± 4.6 mL/g for SMX, SMM, and SDM, respectively. SMX, SMM, and SDM desorb reversibly from the activated sludge leaving behind on the solids 0.9%, 1.6%, and 5.2% of the original sorption dose of 100 μg/L. The sorbed antibiotics can be introduced into the environment if no further treatments were employed to remove them from the biomass. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluating degradation of hexachlorcyclohexane (HCH) isomers within a contaminated aquifer using compound-specific stable carbon isotope analysis (CSIA).

PubMed

Bashir, Safdar; Hitzfeld, Kristina L; Gehre, Matthias; Richnow, Hans H; Fischer, Anko

2015-03-15

The applicability of compound-specific stable carbon isotope analysis (CSIA) for assessing biodegradation of hexachlorocyclohexane (HCH) isomers was investigated in a contaminated aquifer at a former pesticide processing facility. A CSIA method was developed and tested for efficacy in determining carbon isotope ratios of HCH isomers in groundwater samples using gas chromatography - isotope ratio mass spectrometry (GC-IRMS). The carbon isotope ratios of HCHs measured for samples taken from the field site confirmed contaminant source zones at former processing facilities, a storage depot and a waste dump site. The (13)C-enrichment in HCHs provided evidence for biodegradation of HCHs especially downstream of the contaminant source zones. CSIA from monitoring campaigns in 2008, 2009 and 2010 revealed temporal trends in HCH biodegradation. Thus, the impact and progress of natural attenuation processes could be evaluated within the investigated aquifer. Calculations based on the Rayleigh-equation approach yielded levels of HCH biodegradation ranging from 30 to 86 %. Moreover, time- and distance-dependent in situ first-order biodegradation rate constants were estimated with maximal values of 3 × 10(-3) d(-1) and 10 × 10(-3) m(-1) for α-HCH, 11 × 10(-3) d(-1) and 37 × 10(-3) m(-1) for β-HCH, and 6 × 10(-3) d(-1) and 19 × 10(-3) m(-1) for δ-HCH, respectively. This study highlights the applicability of CSIA for the assessment of HCH biodegradation within contaminated aquifers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays

PubMed Central

Alfonso-Gordillo, Guadalupe; Flores-Ortiz, César Mateo; Morales-Barrera, Liliana

2016-01-01

This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater. PMID:27907122

Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays.

PubMed

Alfonso-Gordillo, Guadalupe; Flores-Ortiz, César Mateo; Morales-Barrera, Liliana; Cristiani-Urbina, Eliseo

2016-01-01

This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater.

Biodegradable Nanoparticles of mPEG-PLGA-PLL Triblock Copolymers as Novel Non-Viral Vectors for Improving siRNA Delivery and Gene Silencing

PubMed Central

Du, Jing; Sun, Ying; Shi, Qiu-Sheng; Liu, Pei-Feng; Zhu, Ming-Jie; Wang, Chun-Hui; Du, Lian-Fang; Duan, You-Rong

2012-01-01

Degradation of mRNA by RNA interference is one of the most powerful and specific mechanisms for gene silencing. However, insufficient cellular uptake and poor stability have limited its usefulness. Here, we report efficient delivery of siRNA via the use of biodegradable nanoparticles (NPs) made from monomethoxypoly(ethylene glycol)-poly(lactic-co-glycolic acid)-poly-l-lysine (mPEG-PLGA-PLL) triblock copolymers. Various physicochemical properties of mPEG-PLGA-PLL NPs, including morphology, size, surface charge, siRNA encapsulation efficiency, and in vitro release profile of siRNA from NPs, were characterized by scanning electron microscope, particle size and zeta potential analyzer, and high performance liquid chromatography. The levels of siRNA uptake and targeted gene inhibition were detected in human lung cancer SPC-A1-GFP cells stably expressing green fluorescent protein. Examination of the cultured SPC-A1-GFP cells with fluorescent microscope and flow cytometry showed NPs loading Cy3-labeled siRNA had much higher intracellular siRNA delivery efficiencies than siRNA alone and Lipofectamine-siRNA complexes. The gene silencing efficiency of mPEG-PLGA-PLL NPs was higher than that of commercially available transfecting agent Lipofectamine while showing no cytotoxicity. Thus, the current study demonstrates that biodegradable NPs of mPEG-PLGA-PLL triblock copolymers can be potentially applied as novel non-viral vectors for improving siRNA delivery and gene silencing. PMID:22312268

Evaluating the impact of water supply strategies on p-xylene biodegradation performance in an organic media-based biofilter.

PubMed

Gallastegui, G; Muñoz, R; Barona, A; Ibarra-Berastegi, G; Rojo, N; Elías, A

2011-01-30

The influence of water irrigation on both the long-term and short-term performance of p-xylene biodegradation under several organic loading scenarios was investigated using an organic packing material composed of pelletised sawdust and pig manure. Process operation in a modular biofilter, using no external water supply other than the moisture from the saturated inlet air stream, showed poor p-xylene abatement efficiencies (≈33 ± 7%), while sustained irrigation every 25 days rendered a high removal efficiency (RE) for a critical loading rate of 120 g m(-3)h(-1). Periodic profiles of removal efficiency, temperature and moisture content were recorded throughout the biofilter column subsequent to each biofilter irrigation. Hence, higher p-xylene biodegradation rates were always initially recorded in the upper module, which resulted in a subsequent increase in temperature and a decrease in moisture content. This decrease in the moisture content in the upper module resulted in a higher removal rate in the middle module, while the moisture level in the lower module steadily increased as a result of water condensation. Based on these results, mass balance calculations performed using measured bed temperatures and relatively humidity values were successfully used to account for water balances in the biofilter over time. Finally, the absence of bed compaction after 550 days of continuous operation confirmed the suitability of this organic material for biofiltration processes. Copyright © 2010 Elsevier B.V. All rights reserved.

Biodegradable stents for the treatment of benign stenoses of the small and large intestines.

PubMed

Rejchrt, S; Kopacova, M; Brozik, J; Bures, J

2011-10-01

Biodegradable stents, which are made of various synthetic polymers, such as polylactide or polyglycolide, or co-polymers, such as polydioxanone, can be used for the treatment of benign refractory stenoses of the gastrointestinal tract. Here we report 11 patients (median age 41) with stenosing Crohn's disease of the small and/or large intestine. Endoscopic insertion of a biodegradable stent was successful at the first attempt in all patients except one. Subsequent follow-up was for a mean of 16 months, median 17 months, range 12-29 months. Early stent migration (between 2 days and 8 weeks) was seen in three patients. Mucosal overgrowth (epithelial hyperplasia) was not observed in any of the patients during the follow-up period. The high rate of early stent migration might be solved by appropriate tailoring and further improvements in the design of the biodegradable stents. Proof of long-term efficacy and safety requires further studies. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Substitutions on the Biodegradation Potential of Benzotriazole Derivatives

NASA Astrophysics Data System (ADS)

Abu-Dalo, M. A.; O'Brien, I.; Hernandez, M. T.

2018-02-01

Fourteen benzotriazole derivatives were subjected to microcosm tests to study the influence of substitutions on their biodegradation potential. Methylated, nitrated, carboxylated, and propionated bezotriazoles, a heterocyclic triazole, as well as methylated benzimidazoles, were introduced to activated sludge and soil enrichment cultures as the only carbon source. Some of the enrichment cultures were derived from airport soils that had been previously contaminated with aircraft deicing fluids and subsequently enriched with the commercially significant corrosion inhibitor methylbenzotriazole. The 5-methylbenzotriazole and only the carboxylated derivatives were degraded by soil or activated sludge biomass regardless of acclimation conditions. Radiotracer studies of [U-14C] 5-methylbenzotriazole, and [U-14C] 5-carboxybenzotriazole confirmed that relatively high concentrations (25mg L-1) of these derivatives can be completely mineralized in relatively short time frames by microbial consortia regardless of prior exposure. Observations suggested that the growth yield on these compounds is likely low. Biodegradation patterns suggested that carboxylated benzotriazole derivatives are more readily biodegradable than their more popular methylated counterparts.

Efficient removal of malachite green dye using biodegradable graft copolymer derived from amylopectin and poly(acrylic acid).

PubMed

Sarkar, Amit Kumar; Pal, Aniruddha; Ghorai, Soumitra; Mandre, N R; Pal, Sagar

2014-10-13

This article reports on the application of a high performance biodegradable adsorbent based on amylopectin and poly(acrylic acid) (AP-g-PAA) for removal of toxic malachite green dye (MG) from aqueous solution. The graft copolymer has been synthesized and characterized using various techniques including FTIR, GPC, SEM and XRD analyses. Biodegradation study suggests that the co-polymer is biodegradable in nature. The adsorbent shows excellent potential (Qmax, 352.11 mg g(-1); 99.05% of MG has been removed within 30 min) for removal of MG from aqueous solution. It has been observed that point to zero charge (pzc) of graft copolymer plays significant role in adsorption efficacy. The adsorption kinetics and isotherm follow pseudo-second order and Langmuir isotherm models, respectively. Thermodynamics parameters suggest that the process of dye uptake is spontaneous. Finally desorption study shows excellent regeneration efficiency of adsorbent. Copyright © 2014 Elsevier Ltd. All rights reserved.

The nonylphenol biodegradation study by estuary sediment-derived fungus Penicillium simplicissimum.

PubMed

Zhang, Yan; Liu, Ying; Dong, Han; Li, Xianguo; Zhang, Dahai

2016-08-01

Nonylphenols (NPs) are persistent organic pollutants (POPs) with estrogenic properties that can perform endocrine-disrupting activities. By using high-concentration NP as environmental selection pressure, one NP biodegradation strain named NPF-4 was isolated and purified from estuary sediment of the Moshui River. It was identified as Penicillium simplicissimum (PS1) by appearance and 18S rDNA analysis. In different culture situations, the strain mass growth and biodegradation ability were evaluated. Within 4-n-nonylphenol (4-n-NP) initial concentration of 20 mg L(-1), it could be degraded 53.76, 90.08, and 100.00 % at 3, 7, and 14 days, respectively. In feeding experiments, it showed that NPF-4 could use 4-n-NP as a sole carbon source. Based on seven products/intermediates detected with GC and LC-MS, a novel biopathway for 4-n-NP biodegradation was proposed, in which sequential hydroxylation, oxidation, and decarboxylation at terminal β-C atom may occur for 4-n-NP detoxification, even complete mineralization in the end.

Enhanced biodegradation of cyclotetramethylenetetranitramine (HMX) under mixed electron-acceptor condition.

PubMed

Boopathy, R

2001-02-01

The biodegradation of cyclotetramethylenetetranitramine, commonly known as 'high melting explosive' (HMX), under various electron-acceptor conditions was investigated using enrichment cultures developed from the anaerobic digester sludge of Thibodaux sewage treatment plant. The results indicated that the HMX was biodegraded under sulfate reducing, nitrate reducing, fermenting, methanogenic, and mixed electron accepting conditions. However, the rates of degradation varied among the various conditions studied. The fastest removal of HMX (from 22 ppm on day 0 to < 0.05 ppm on day 11) was observed under mixed electron-acceptor conditions, followed in order by sulfate reducing, fermenting, methanogenic, and nitrate reducing conditions. Under aerobic conditions, HMX was not biodegraded, which indicated that HMX degradation takes place under anaerobic conditions via reduction. HMX was converted to methanol and chloroform under mixed electron-acceptor conditions. This study showed evidence for HMX degradation under anaerobic conditions in a mixed microbial population system similar to any contaminated field sites, where a heterogeneous population exists.

Wood-plastic composites as promising green-composites for automotive industries!

PubMed

Ashori, Alireza

2008-07-01

Wood-plastic composite (WPC) is a very promising and sustainable green material to achieve durability without using toxic chemicals. The term WPCs refers to any composites that contain plant fiber and thermosets or thermoplastics. In comparison to other fibrous materials, plant fibers are in general suitable to reinforce plastics due to relative high strength and stiffness, low cost, low density, low CO2 emission, biodegradability and annually renewable. Plant fibers as fillers and reinforcements for polymers are currently the fastest-growing type of polymer additives. Since automakers are aiming to make every part either recyclable or biodegradable, there still seems to be some scope for green-composites based on biodegradable polymers and plant fibers. From a technical point of view, these bio-based composites will enhance mechanical strength and acoustic performance, reduce material weight and fuel consumption, lower production cost, improve passenger safety and shatterproof performance under extreme temperature changes, and improve biodegradability for the auto interior parts.

Use of Organic Substrates as a Best Management Practice for Active Ranges

DTIC Science & Technology

2011-11-30

is much more limited in high organic carbon soils due to a combination of enhanced sorption and degradation . Organic materials can enhance explosive... degradation by stimulating anaerobic biodegradation of the target contaminants and reducing naturally occurring Fe(III) to Fe(II), providing a reservoir...of reducing power to maintain anoxic conditions in the soil and enhance abiotic degradation . Humic materials slowly biodegrade, consuming oxygen

Solvent-free biodegradable scleral plugs providing sustained release of vancomycin, amikacin, and dexamethasone--an in vivo study.

PubMed

Peng, Yi-Jie; Kau, Yi-Chuan; Wen, Chin-Wei; Liu, Kuo-Sheng; Liu, Shih-Jung

2010-08-01

Delivering effective drugs at sufficiently high concentrations to the area of infection is a standard treatment for infectious disease, such as endophthalmitis. This is currently done by empirical trans pars plana intravitreal injection of both antibiotics directed against gram-positive and gram-negative microorganisms and steroids. However, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage, as well as retinal detachment. This article explores the alternative of using biodegradable polymers as scleral plugs for a long-term drug release in vivo. To manufacture plugs, poly(lactide-glycolide) copolymers were first mixed with vancomycin, amikacin, and dexamethasone. The mixture was compressed and sintered at 55 degrees C to form scleral plugs 1.4 mm in diameter. Biodegradable scleral plugs released high concentrations of antibiotics (well above the minimum inhibitory concentrations, MIC) and steroids in vivo for the period of time needed to treat intraocular infection. In addition, no major complications such as infectious or sterile endophthalmitis, retinal detachment, ocular phthisis, or uvea protrusion at sclerotomy site were observed throughout the experiment. The sclerotomy wound healed after total degradation of the scleral implants without leakage or local necrosis. Antibiotic/steroid-impregnated biodegradable scleral plugs may have a potential role in the treatment of various intraocular infections. (c) 2010 Wiley Periodicals, Inc.

Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Putri, Zufira; Arcana, I. Made

2014-03-01

Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO2 are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO2 compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO2 blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM).

Fabrication of balloon-expandable self-lock drug-eluting polycaprolactone stents using micro-injection molding and spray coating techniques.

PubMed

Liu, Shih-Jung; Chiang, Fu-Jun; Hsiao, Chao-Ying; Kau, Yi-Chuan; Liu, Kuo-Sheng

2010-10-01

The purpose of this report was to develop novel balloon-expandable self-lock drug-eluting poly(ε-caprolactone) stents. To fabricate the biodegradable stents, polycaprolactone (PCL) components were first fabricated by a lab-scale micro-injection molded machine. They were then assembled and hot-spot welded into mesh-like stents of 3 and 5 mm in diameters. A special geometry of the components was designed to self-lock the assembled stents and to resist the external pressure of the blood vessels after being expanded by balloons. Characterization of the biodegradable PCL stents was carried out. PCL stents exhibited comparable mechanical property to that of metallic stents. No significant collapse pressure reduction and weight loss of the stents were observed after being submerged in PBS for 12 weeks. In addition, the developed stent was coated with paclitaxel by a spray coating technique and the release characteristic of the drug was determined by an in vitro elution method. The high-performance liquid chromatography analysis showed that the biodegradable stents could release a high concentration of paclitaxel for more than 60 days. By adopting the novel techniques, we will be able to fabricate biodegradable drug-eluting PCL stents of different sizes for various cardiovascular applications.

Mineralization of high concentrations of the endocrine disruptor dibutyl phthalate by Fusarium culmorum.

PubMed

Ahuactzin-Pérez, Miriam; Tlecuitl-Beristain, Saúl; García-Dávila, Jorge; Santacruz-Juárez, Ericka; González-Pérez, Manuel; Gutiérrez-Ruíz, María Concepción; Sánchez, Carmen

2018-01-01

Dibutyl phthalate (DBP) is a widely used plasticizer, whose presence in the environment as a pollutant raises concern because of its endocrine-disrupting toxicity. Growth kinetics, glucose uptake, biodegradation constant of DBP ( k ), half-life of DBP biodegradation ( t 1/2 ) and percentage of removal efficiency (% E ) were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DBP (500 and 1000 mg/l). Intermediate compounds of biodegraded DBP were identified by GC-MS and a novel DBP biodegradation pathway was proposed on the basis of the intermolecular flow of electrons of the intermediates identified using quantum chemical modeling. F. culmorum degraded 99% of both 1000 and 500 mg of DBP/l after an incubation period of 168 and 228 h, respectively. % E was 99.5 and 99.3 for 1000 and 500 mg of DBP/l, respectively. The k was 0.0164 and 0.0231 h -1 for 500 and 1000 mg of DBP/l, respectively. DBP was fully metabolized to fumaric and malic acids, which are compounds that enter into the Krebs cycle. F. culmorum has a promising ability for bioremediation of environments polluted with DBP because it efficiently degrades DBP and uses high concentrations of this compound as carbon and energy source.

Ciprofloxacin degradation in anaerobic sulfate-reducing bacteria (SRB) sludge system: Mechanism and pathways.

PubMed

Jia, Yanyan; Khanal, Samir Kumar; Shu, Haoyue; Zhang, Huiqun; Chen, Guang-Hao; Lu, Hui

2018-06-01

Ciprofloxacin (CIP), a fluoroquinolone antibiotic, removal was examined for the first time, in an anaerobic sulfate-reducing bacteria (SRB) sludge system. About 28.0% of CIP was biodegraded by SRB sludge when the influent CIP concentration was 5000 μg/L. Some SRB genera with high tolerance to CIP (i.e. Desulfobacter), were enriched at CIP concentration of 5000 μg/L. The changes in antibiotic resistance genes (ARGs) of SRB sludge coupled with CIP biodegradation intermediates were used to understand the mechanism of CIP biodegradation for the first time. The percentage of efflux pump genes associated with ARGs increased, while the percentage of fluoroquinolone resistance genes that inhibit the DNA copy of bacteria decreased during prolonged exposure to CIP. It implies that some intracellular CIP was extruded into extracellular environment of microbial cells via efflux pump genes to reduce fluoroquinolone resistance genes accumulation caused by exposure to CIP. Additionally, the degradation products and the possible pathways of CIP biodegradation were also examined using the new method developed in this study. The results suggest that CIP was biodegraded intracellularly via desethylation reaction in piperazinyl ring and hydroxylation reaction catalyzed by cytochrome P450 enzymes. This study provides an insight into the mechanism and pathways of CIP biodegradation by SRB sludge, and opens-up a new opportunity for the treatment of CIP-containing wastewater using sulfur-mediated biological process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbial degradation on glacier surface is the missing piece of environmental fate of pesticides in cold areas

NASA Astrophysics Data System (ADS)

Ambrosini, Roberto; Ferrario, Claudia; Pittino, Francesca; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Azzoni, Roberto S.; Diolaiuti, Guglielmina A.; Smiraglia, Claudio; Franzetti, Andrea; Villa, Sara

2017-04-01

Organic contaminants deposited on glacier surfaces undergo different partition and degradation processes which determine their environmental fate and accumulation into the trophic chains. Among these processes, biodegradation by supraglacial bacteria has been neglected so far. To assess the relevance of biodegradative processes, in situ microcosm experiments were conducted simulating cryoconite hole systems on an Alpine glacier exposed to the organophosphorus insecticide chlorpyrifos (CPF) as model of xenobiotic molecule which accumulate on glaciers after medium range transports. Results showed that biodegradation is the most efficient process contributing to the removal of CPF on the glacier surface. The high concentrations of CPF in cryoconite and its half-life in the range of 35 - 69 days indicated that biodegradation process can significantly contrast the release of CPF transported on glaciers. Moreover, the metabolic versatility of cryoconite bacteria suggest that these habitats might contribute to the degradation of a wide class of pollutants with different physical-chemical properties. Metagenomics data indicated that photoheterotrophic bacteria might be involved in the biodegradation of CPF by using light to supplement their metabolic demands, thus contributing to the biological removal of CPF without the constrain of using this pesticide as sole energy source. In conclusion. cryoconite might act as a "biofilter" for organic pollutants on glaciers by accumulating them and promoting their biodegradation. Owing to its relevance, the contribution of cryoconite to the removal of organic pollutants should be included in the models predicting the environmental fate of these compounds in cold areas.

Influence of ozonation and biodegradation on toxicity of industrial textile wastewater.

PubMed

Paździor, Katarzyna; Wrębiak, Julita; Klepacz-Smółka, Anna; Gmurek, Marta; Bilińska, Lucyna; Kos, Lech; Sójka-Ledakowicz, Jadwiga; Ledakowicz, Stanisław

2017-06-15

The textile industry demands huge volumes of high quality water which converts into wastewater contaminated by wide spectrum of chemicals. Estimation of textile wastewater influence on the aquatic systems is a very important issue. Therefore, closing of the water cycle within the factories is a promising method of decreasing its environmental impact as well as operational costs. Taking both reasons into account, the aim of this work was to establish the acute toxicity of the textile wastewater before and after separate chemical, biological as well as combined chemical-biological treatment. For the first time the effects of three different combinations of chemical and biological methods were investigated. The acute toxicity analysis were evaluated using the Microtox ® toxicity test. Ozonation in two reactors of working volume 1 dm 3 (stirred cell) and 20 dm 3 (bubble column) were tested as chemical process, while biodegradation was conducted in two, different systems - Sequence Batch Reactors (SBR; working volume 1.5 dm 3 ) and Horizontal Continuous Flow Bioreactor (HCFB; working volume 12 dm 3 ). The untreated wastewater had the highest toxicity (EC50 value in range: 3-6%). Ozonation caused lower reduction of the toxicity than biodegradation. In the system with SBR the best results were obtained for the biodegradation followed by the ozonation and additional biodegradation - 96% of the toxicity removal. In the second system (with HCFB) two-stage treatment (biodegradation followed by the ozonation) led to the highest toxicity reduction (98%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradable packaging materials conception based on starch and polylactic acid (PLA) reinforced with cellulose.

PubMed

Masmoudi, Fatma; Bessadok, Atef; Dammak, Mohamed; Jaziri, Mohamed; Ammar, Emna

2016-10-01

The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.

Biodegradation of trichloroethylene and involvement of an aromatic biodegradative pathway.

PubMed Central

Nelson, M J; Montgomery, S O; Mahaffey, W R; Pritchard, P H

1987-01-01

Biodegradation of trichloroethylene (TCE) by bacterial strain G4 resulted in complete dechlorination of the compound, as indicated by the production of inorganic chloride. A component of the water from which strain G4 was isolated that was required for TCE degradation was identified as phenol. Strain G4 degraded TCE in the presence of chloramphenicol only when preinduced with phenol. Toluene, o-cresol. and m-cresol could replace the phenol requirement. Two of the inducers of TCE metabolism, phenol and toluene, apparently induced the same aromatic degradative pathway that cleaved the aromatic ring by meta fission. Cells induced with either phenol or toluene had similar oxidation rates for several aromatic compounds and had similar levels of catechol-2,3-dioxygenase. The results indicate that one or more enzymes of an inducible pathway for aromatic degradation in strain G4 are responsible for the degradation of TCE. PMID:3606099

A "room-temperature" injection molding/particulate leaching approach for fabrication of biodegradable three-dimensional porous scaffolds.

PubMed

Wu, Linbo; Jing, Dianying; Ding, Jiandong

2006-01-01

A "room-temperature" injection molding approach combined with particulate leaching (RTIM/PL) has been, for the first time, developed in this work to fabricate three-dimensional porous scaffolds composed of biodegradable polyesters for tissue engineering. In this approach, a "wet" composite of particulate/polymer/solvent was used in processing, and thus the injection was not performed at melting state. Appropriate viscosity and flowability were facilely obtained at a certain solvent content so that the composite was able to be injected into a mould under low pressure at room temperature, which was very beneficial for avoiding thermal degradation of polyesters. As a demonstration, tubular and ear-shaped porous scaffolds were fabricated from biodegradable poly(D,L-lactide-co-glycolide) (PLGA) by this technology. Porosities of the resulting scaffolds were as high as 94%. The pores were well interconnected. Besides the well-known characteristics of injection molding to be suitable for automatization of a fabrication process with high repeatability and precision, this RTIM/PL approach is much suitable for tailoring highly porous foams with its advantages flexible for shaping complicated scaffolds, free of thermal degradation and high-pressure machine, etc.

Bioremediation of coal contaminated soil under sulfate-reducing condition.

PubMed

Kuwano, Y; Shimizu, Y

2006-01-01

The objective of this study was to investigate the biodegradation of coal-derived hydrocarbons, especially high molecular weight (HMW) components, under anaerobic conditions. For this purpose biodegradation experiments were performed, using specifically designed soil column bioreactors. For the experiment, coal-contaminated soil was prepared, which contains high molecular weight hydrocarbons at high concentration (approx. 55.5 mgC g-drysoil(-1)). The experiment was carried out in two different conditions: sulfate reducing (SR) condition (SO4(2-) = 10 mmol l(-1) in the liquid medium) and control condition (SO4(2-)<0.5 mmol l(-1)). Although no degradation was observed under the control condition, the resin fraction decreased to half (from 6,541 to 3,386 mgC g-soil(-1)) under SR condition, with the concomitant increase of two PAHs (phenanthrene and fluoranthene, 9 and 2.5 times, respectively). From these results, we could conclude that high molecular hydrocarbons were biodegradable and transformed to low molecular weight PAHs under the sulfate-reducing condition. Since these PAHs are known to be biologically degraded under aerobic condition, a serial combination of anaerobic (sulfate reducing) and then aerobic bioremediations could be effective and useful for the soil pollution by petroleum and/or coal derived hydrocarbons.

Biodegradation of carbamazepine and clarithromycin by Trichoderma harzianum and Pleurotus ostreatus investigated by liquid chromatography - high-resolution tandem mass spectrometry (FTICR MS-IRMPD).

PubMed

Buchicchio, Alessandro; Bianco, Giuliana; Sofo, Adriano; Masi, Salvatore; Caniani, Donatella

2016-07-01

In this study, the capability of pharmaceutical biodegradation of fungus Trichoderma harzianum was evaluated through the comparison with the well-known biodegradation capability of white-rot fungus Pleurotus ostreatus. The study was performed in aqueous phase under aerobic conditions, using two of the most frequently detected drugs in water bodies: carbamazepine and clarithromycin, with concentrations commonly found in treated wastewater (4μg/l and 0.03μg/l respectively). For the first time, we demonstrated that T. harzianum is able to remove carbamazepine and clarithromycin. The analyses were performed by reversed-phase liquid chromatography/mass spectrometry, using high-resolution Fourier-transform ion cyclotron resonance mass spectrometry upon electrospray ionization in positive ion mode. The high selectivity and mass accuracy provided by high-resolution mass spectrometry, allowed us to identify some unknown metabolites. On the basis of our study, the major metabolites detected in liquid culture treated by T. harzianum were: 14-hydroxy-descladinosyl- and descladinosyl-clarithromycin, which are pharmacologically inactive products not dangerous for the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary Ecotoxicity and Biodegradability Assessment of Metalworking Fluids

NASA Astrophysics Data System (ADS)

Gerulová, Kristína; Amcha, Peter; Filická, Slávka

2010-01-01

The main aim of this study was to evaluate the potential of activated sludge from sewage treatment plant to degrade selected MWFs (ecotoxicity to bacterial consortium) and to evaluate the ecotoxicity by Lemna minor-higher plant. After evaluating the ecotoxicity, biodegradations rate with activated sludge was assessed on the basis of COD measurement. Preliminary study of measuring the ecotoxicity according to OECD 221 by Lemna minor shows effective concentration of Emulzin H at the rate of 81.6 mg l-1, for Ecocool 82.9 mg l-1, for BC 25 about 99.3 mg l-1, and for Dasnobor about 97.3 mg l-1. Preliminary study of measuring the ecotoxicity by bacterial consortium according to OECD 209 (STN EN ISO 8192) shows effective concentration of Blasocut BC 25 at the rate 227.4 mg l-1. According to OECD 302B, the biodegradations level of Emulzin H, Ecocool and BC 25 achieved 80% in 10 days. It can be stated that these MWFs have potential to ultimate degradation, but the statement has to be confirmed by a biodegradability test with other parameters than COD, which exhibits some disadvantages in testing O/W emulsions.

Biodegradation of poly(hydroxy butanoic acid) copolymer mulch films in soil

NASA Astrophysics Data System (ADS)

Kukade, Pranav

Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene (PE) mulch films; however, these are not environment friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, film retrieval and disposal costs. In this study, an in-house laboratory scale test method was developed in which the rate of disintegration, as a result of biodegradation of films based on polyhydroxybutanoic acid (PHB) copolymers was investigated in a soil environment using the residual weight loss method. The influence of soil composition, moisture levels in the soil, and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films was investigated. The soil composition has significant effect on the disintegration kinetics of PHB copolymer films, since the increasing compost levels in the soil lowered the rate of disintegration of the film. Also, with the increase in moisture level up to a threshold limit, the microbial activity and, hence, the rate of disintegration increased. Lastly, the developed lab-scale test protocol was found to be sensitive to even small concentrations of industry-standard antimicrobial additive in the film composition.

Potential of Biological Agents in Decontamination of Agricultural Soil

PubMed Central

Javaid, Muhammad Kashif; Ashiq, Mehrban; Tahir, Muhammad

2016-01-01

Pesticides are widely used for the control of weeds, diseases, and pests of cultivated plants all over the world, mainly since the period after the Second World War. The use of pesticides is very extensive to control harm of pests all over the globe. Persistent nature of most of the synthetic pesticides causes serious environmental concerns. Decontamination of these hazardous chemicals is very essential. This review paper elaborates the potential of various biological agents in decontamination of agricultural soils. The agricultural crop fields are contaminated by the periodic applications of pesticides. Biodegradation is an ecofriendly, cost-effective, highly efficient approach compared to the physical and chemical methods which are expensive as well as unfriendly towards environment. Biodegradation is sensitive to the concentration levels of hydrogen peroxide and nitrogen along with microbial community, temperature, and pH changes. Experimental work for optimum conditions at lab scale can provide very fruitful results about specific bacterial, fungal strains. This study revealed an upper hand of bioremediation over physicochemical approaches. Further studies should be carried out to understand mechanisms of biotransformation. PMID:27293964

Biosynthesis, purification and characterization of polyhydroxybutyrate from Botryococcus braunii kütz.

PubMed

Kavitha, Ganapathy; Kurinjimalar, Chidambaram; Sivakumar, Krishnan; Palani, Perumal; Rengasamy, Ramasamy

2016-08-01

Polyhydroxybutyrate (PHB) is completely biodegradable which is metabolised by microorganisms in the soil as their sole food source in few years. The level of PHB up to 10.6% of algal dry weight is of great potential of the eco-friendly nature. Botryococcus braunii is mainly used for the production of biodiesel and is also capable of producing biopolymer polyhydroxy butyrate (PHB). In this study, Botryococcus braunii is used which generally produce PHB to around 20% of the dry weight. Three different microalgae were isolated from the fresh water of Kolavoi lake of Tamil Nadu. They were identified by their morphological features under the light microscope. The primary screening of PHB intracellular granules was made by using Nile red dye under a fluorescent microscope. Among them, Botryococcus braunii showed high accumulation of PHB granules. For authentic confirmation, the chloroform extracted PHB was analysed by FTIR, XRD and DSC-TGA analyses to characterize PHB with commercial biodegradable thermoplastic. This is the first report in B. braunii for its PHB production. Copyright © 2016 Elsevier B.V. All rights reserved.

Potential of Biological Agents in Decontamination of Agricultural Soil.

PubMed

Javaid, Muhammad Kashif; Ashiq, Mehrban; Tahir, Muhammad

2016-01-01

Pesticides are widely used for the control of weeds, diseases, and pests of cultivated plants all over the world, mainly since the period after the Second World War. The use of pesticides is very extensive to control harm of pests all over the globe. Persistent nature of most of the synthetic pesticides causes serious environmental concerns. Decontamination of these hazardous chemicals is very essential. This review paper elaborates the potential of various biological agents in decontamination of agricultural soils. The agricultural crop fields are contaminated by the periodic applications of pesticides. Biodegradation is an ecofriendly, cost-effective, highly efficient approach compared to the physical and chemical methods which are expensive as well as unfriendly towards environment. Biodegradation is sensitive to the concentration levels of hydrogen peroxide and nitrogen along with microbial community, temperature, and pH changes. Experimental work for optimum conditions at lab scale can provide very fruitful results about specific bacterial, fungal strains. This study revealed an upper hand of bioremediation over physicochemical approaches. Further studies should be carried out to understand mechanisms of biotransformation.

Molecular evidence for biodegradation of geomacromolecules

NASA Astrophysics Data System (ADS)

Jenisch-Anton, A.; Adam, P.; Michaelis, W.; Connan, J.; Herrmann, D.; Rohmer, M.; Albrecht, P.

2000-10-01

The biodegradability of macromolecular organic structures of geological origin was investigated by performing in vitro studies. Cultures of the common Nocardioides simplex were grown, first, on a high molecular weight, asymmetric thioether (1-(phytanylsulfanyl)-octadecane 1) and then on macromolecular fractions isolated from a sulfur-rich oil. Gross data indicate that bacteria convert macromolecular substances to material of higher polarity by oxidizing the abundant thioethers to sulfones and sulfoxides and by introducing new functionalities, such as carboxylic acid, keto or hydroxyl groups. Furthermore, bacteria remineralize the macromolecular structures. Bacterially induced alterations were also studied on a molecular level after chemical desulfurization of the macromolecular structure. Thus, it could be established that the amounts of linear hydrocarbons in the macromolecular structure are decreased relative to branched and cyclic structures due to a preferential bacterial attack of the linear moieties bound to the macromolecules. This is further supported by the detection of S-bound fatty acids resulting from the bacterial oxidation of S-bound n-alkanes. Moreover, N. simplex also degraded sulfur-bound steranes by oxidation of the steroid side-chain leading to S-bound steroid acids.

Electroactive biodegradable polyurethane significantly enhanced Schwann cells myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering.

PubMed

Wu, Yaobin; Wang, Ling; Guo, Baolin; Shao, Yongpin; Ma, Peter X

2016-05-01

Myelination of Schwann cells (SCs) is critical for the success of peripheral nerve regeneration, and biomaterials that can promote SCs' neurotrophin secretion as scaffolds are beneficial for nerve repair. Here we present a biomaterials-approach, specifically, a highly tunable conductive biodegradable flexible polyurethane by polycondensation of poly(glycerol sebacate) and aniline pentamer, to significantly enhance SCs' myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering. SCs are cultured on these conductive polymer films, and the biocompatibility of these films and their ability to enhance myelin gene expressions and sustained neurotrophin secretion are successfully demonstrated. The mechanism of SCs' neurotrophin secretion on conductive films is demonstrated by investigating the relationship between intracellular Ca(2+) level and SCs' myelination. Furthermore, the neurite growth and elongation of PC12 cells are induced by adding the neurotrophin medium suspension produced from SCs-laden conductive films. These data suggest that these conductive degradable polyurethanes that enhance SCs' myelin gene expressions and sustained neurotrophin secretion perform great potential for nerve regeneration applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

A laboratory study of the biodegradation of an alcohol ethoxylate surfactant by native soil microbes

NASA Astrophysics Data System (ADS)

Ang, Carolina C.; Abdul, Abdul S.

1992-09-01

Laboratory experiments were conducted to study the biodegradation of a nonionic alcohol ethoxylate surfactant by native microbes from a contaminated site. Three sets of experiments consisting of 13 microcosms were carried out to evaluate the rate of biodegradation and the effect of nutrients and supplementary oxygen on the degradation process. The results from these active microcosms were compared with those for controlled microcosms in which a biocide was added to inhibit biological activities. In the presence of ground water and sterilized soil, surfactant solutions with initial concentrations of 1000, 650, 250, and 180 mgl -1 were reduced to less than 5 mgl -1 in 36 days, 20 days, 17 days, and 17 days, respectively. The biodegradation rate in microcosms with added nutrients was more than twice the rate in the reactor without nutrients. The results from experiments in which various nitrogen and phosphorus nutrients were added showed that a ratio of 10 carbon:2 nitrogen:1 phosphorus was the optimum for the biodegradation of surfactant under the microcosm conditions. The addition of 5 mgl -1 of oxygen in the form of hydrogen peroxide increased the degradation rate of surfactant by 30%. The study showed that microbes indigenous to the soil and ground water at a contaminated site rapidly degrade the low levels of the surfactant that may remain at the site after soil washing, and that the degradation rate can be increased by the addition of nutrients and oxygen.

Biodegradation screening of chemicals in an artificial matrix simulating the water-sediment interface.

PubMed

Baginska, Ewelina; Haiß, Annette; Kümmerer, Klaus

2015-01-01

Biodegradation is the most important attenuation process for most of organic chemicals in the environment. This process decides whether the organic substance itself or its degradation products rests in the environment and should be considered for a further risk assessment. This work presents the development of a water sediment screening test, based on OECD guideline 308, with a high significance to environmental conditions and with a good reproducibility and consistency of results. The increased reproducibility was achieved by creating an artificial and standardized medium, based on the existing OECD guidelines OECD 302C, 301D and 218. Each test consisted of five different series: blank, quality control, test, toxicity control and abiotic control. Biodegradation was assessed by measurement of pressure difference in closed vessels using the OxiTop(®) system. Aniline, diethylene glycol and sodium acetate were used to optimize and validate test conditions. Additionally, two pharmaceuticals: Acetaminophen and ciprofloxacin (CIP) were tested as an example of possible test application. Acetaminophen was mainly removed from the system by biodegradation whereas CIP was removed from water phase by sorption onto sediment. Water sediment test proved to be a promising tool for the biodegradation investigation of chemicals in the water-sediment interface. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Elmitwalli, Tarek A; Otterpohl, Ralf

2007-03-01

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).

Biocorrosion behavior of biodegradable nanocomposite fibers coated layer-by-layer on AM50 magnesium implant.

PubMed

Abdal-Hay, Abdalla; Hasan, Anwarul; Kim, Yu-Kyoung; Yu-Kyoung; Lee, Min-Ho; Hamdy, Abdel Salam; Khalil, Khalil Abdelrazek

2016-01-01

This article demonstrates the use of hybrid nanofibers to improve the biodegradation rate and biocompatibility of AM50 magnesium alloy. Biodegradable hybrid membrane fiber layers containing nano-hydroxyapatite (nHA) particles and poly(lactide)(PLA) nanofibers were coated layer-by-layer (LbL) on AM50 coupons using a facile single-step air jet spinning (AJS) approach. The corrosion performance of coated and uncoated coupon samples was investigated by means of electrochemical measurements. The results showed that the AJS 3D membrane fiber layers, particularly the hybrid membrane layers containing a small amount of nHA (3 wt.%), induce a higher biocorrosion resistance and effectively decrease the initial degradation rate compared with the neat AM50 coupon samples. The adhesion strength improved highly due to the presence of nHA particles in the AJS layer. Furthermore, the long biodegradation rates of AM50 alloy in Hank's balanced salt solution (HBSS) were significantly controlled by the AJS-coatings. The results showed a higher cytocompatibility for AJS-coatings compared to that for neat Mg alloys. The nanostructured nHA embedded hybrid PLA nanofiber coating can therefore be a suitable coating material for Mg alloy as a potential material for biodegradable metallic orthopedic implants. Copyright © 2015 Elsevier B.V. All rights reserved.

Functional Resistance to Recurrent Spatially Heterogeneous Disturbances Is Facilitated by Increased Activity of Surviving Bacteria in a Virtual Ecosystem

PubMed Central

König, Sara; Worrich, Anja; Banitz, Thomas; Harms, Hauke; Kästner, Matthias; Miltner, Anja; Wick, Lukas Y.; Frank, Karin; Thullner, Martin; Centler, Florian

2018-01-01

Bacterial degradation of organic compounds is an important ecosystem function with relevance to, e.g., the cycling of elements or the degradation of organic contaminants. It remains an open question, however, to which extent ecosystems are able to maintain such biodegradation function under recurrent disturbances (functional resistance) and how this is related to the bacterial biomass abundance. In this paper, we use a numerical simulation approach to systematically analyze the dynamic response of a microbial population to recurrent disturbances of different spatial distribution. The spatially explicit model considers microbial degradation, growth, dispersal, and spatial networks that facilitate bacterial dispersal mimicking effects of mycelial networks in nature. We find: (i) There is a certain capacity for high resistance of biodegradation performance to recurrent disturbances. (ii) If this resistance capacity is exceeded, spatial zones of different biodegradation performance develop, ranging from no or reduced to even increased performance. (iii) Bacterial biomass and biodegradation dynamics respond inversely to the spatial fragmentation of disturbances: overall biodegradation performance improves with increasing fragmentation, but bacterial biomass declines. (iv) Bacterial dispersal networks can enhance functional resistance against recurrent disturbances, mainly by reactivating zones in the core of disturbed areas, even though this leads to an overall reduction of bacterial biomass. PMID:29696013

Removal and Biodegradation of Nonylphenol by Four Freshwater Microalgae

PubMed Central

He, Ning; Sun, Xian; Zhong, Yu; Sun, Kaifeng; Liu, Weijie; Duan, Shunshan

2016-01-01

The removal and biodegradation of nonylphenol (NP) by four freshwater microalgae, including three green algae (Scendesmus quadriauda, Chlorella vulgaris, and Ankistrodesmus acicularis) and one cyanobacterium (Chroococcus minutus) were studied in bacteria-free cultures exposed to different concentrations of NP for 5 days. All four algal species showed a rapid and high ability to remove NP (including bioaccumulation and biodegradation). Among these species, A. acicularis (Ankistrodesmus acicularis) had the highest NP removal rate (83.77%) at 120 h when exposed to different NP treatments (0.5–2.5 mg·L−1), followed by C. vulgaris (Chlorella vulgaris) (80.80%), S. quadriauda (Scendesmus quadriauda) (70.96%) and C. minutus (Chroococcus minutus) (64.26%). C. vulgaris had the highest NP biodegradation percentage (68.80%) at 120 h, followed by A. acicularis (65.63%), S. quadriauda (63.10%); and C. minutus (34.91%). The extracellular NP contents were lower than the intracellular NP contents in all tested algae. The ratio of the extracellular NP content and the intracellular NP content ranged from 0.04 to 0.85. Therefore, the removal of NP from the medium was mainly due to the algal degradation. These results indicate that A. acicularis and C. vulgaris are more tolerant to NP and could be used for treatment of NP contaminated aqueous systems effectively by bioremoval and biodegradation. PMID:27983663

Concomitant aerobic biodegradation of benzene and thiophene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dyreborg, S.; Arvin, E.; Broholm, K.

The concomitant aerobic biodegradation of benzene and thiophene was investigated in microcosm experiments using a groundwater enrichment culture. Benzene was biodegraded within 1 d, whereas thiophene could not be biodegraded as the sole source of carbon and energy. Some interesting phenomena were observed when both benzene and thiophene were present. In most cases, removal of thiophene was observed, and the removal occurred concomitantly with the biodegradation of benzene, suggesting that benzene was used as a primary substrate in the cometabolic biodegradation of thiophene. No biodegradation of the two compounds was observed for some combinations of concentrations, suggesting that thiophene couldmore » act as an inhibitor to benzene biodegradation. However, this effect could be overcome if more benzene was added to the microcosm. Residual concentrations of benzene and thiophene were observed in some microcosms and the data indicated that the biodegradation of the two compounds stopped when a critical threshold ratio between the concentrations of thiophene and benzene was reached. This ratio varied between 10 and 20. Results from modeling the biodegradation data suggested that thiophene was cometabolized concomitantly with the biodegradation of benzene and that the biodegradation may be described by a modified model based on a traditional model with an inhibition term incorporated.« less

Concanavalin A conjugated biodegradable nanoparticles for oral insulin delivery

NASA Astrophysics Data System (ADS)

Hurkat, Pooja; Jain, Aviral; Jain, Ashish; Shilpi, Satish; Gulbake, Arvind; Jain, Sanjay K.

2012-11-01

Major research issues in oral protein delivery include the stabilization of protein in delivery devices which could increase its oral bioavailability. The study deals with development of oral insulin delivery system utilizing biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and modifying its surface with Concanavalin A to increase lymphatic uptake. Surface-modified PLGA nanoparticles were characterized for conjugation efficiency of ligand, shape and surface morphology, particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro drug release. Stability of insulin in the developed formulation was confirmed by SDS-PAGE, and integrity of entrapped insulin was assessed using circular dichroism spectrum. Ex vivo study was performed on Wistar rats, which exhibited the higher intestinal uptake of Con A conjugated nanoparticles. In vivo study performed on streptozotocin-induced diabetic rats which indicate that a surface-modified nanoparticle reduces blood glucose level effectively within 4 h of its oral administration. In conclusion, the present work resulted in successful production of Con A NPs bearing insulin with sustained release profile, and better absorption and stability. The Con A NPs showed high insulin uptake, due to its relative high affinity for non-reducing carbohydrate residues i.e., fucose present on M cells and have the potential for oral insulin delivery in effective management of Type 1 diabetes condition.

Microbial degradation of high impact polystyrene (HIPS), an e-plastic with decabromodiphenyl oxide and antimony trioxide.

PubMed

Sekhar, Vini C; Nampoothiri, K Madhavan; Mohan, Arya J; Nair, Nimisha R; Bhaskar, Thallada; Pandey, Ashok

2016-11-15

Accumulation of electronic waste has increased catastrophically and out of that various plastic resins constitute one of the leading thrown out materials in the electronic machinery. Enrichment medium, containing high impact polystyrene (HIPS) with decabromodiphenyl oxide and antimony trioxide as sole carbon source, was used to isolate microbial cultures. The viability of these cultures in the e-plastic containing mineral medium was further confirmed by triphenyl tetrazolium chloride (TTC) reduction test. Four cultures were identified by 16S rRNA sequencing as Enterobacter sp., Citrobacter sedlakii, Alcaligenes sp. and Brevundimonas diminuta. Biodegradation experiments were carried out in flask level and gelatin supplementation (0.1% w/v) along with HIPS had increased the degradation rate to a maximum of 12.4% (w/w) within 30days. This is the first report for this kind of material. The comparison of FTIR, NMR, and TGA analysis of original and degraded e-plastic films revealed structural changes under microbial treatment. Polystyrene degradation intermediates in the culture supernatant were also detected using HPLC analysis. The gravity of biodegradation was validated by morphological changes under scanning electron microscope. All isolates displayed depolymerase activity to substantiate enzymatic degradation of e-plastic. Copyright © 2016 Elsevier B.V. All rights reserved.

High Yields of Hydrogen Production Induced by Meta-Substituted Dichlorophenols Biodegradation from the Green Alga Scenedesmus obliquus

PubMed Central

Papazi, Aikaterini; Andronis, Efthimios; Ioannidis, Nikolaos E.; Chaniotakis, Nikolaos; Kotzabasis, Kiriakos

2012-01-01

Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H2-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H2-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O2 production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements. PMID:23145057

Model of heterogeneous material dissolution in simulated biological fluid

NASA Astrophysics Data System (ADS)

Knyazeva, A. G.; Gutmanas, E. Y.

2015-11-01

In orthopedic research, increasing attention is being paid to bioresorbable/biodegradable implants as an alternative to permanent metallic bone healing devices. Biodegradable metal based implants possessing high strength and ductility potentially can be used in load bearing sites. Biodegradable Mg and Fe are ductile and Fe possess high strength, but Mg degrades too fast and Fe degrades too slow, Ag is a noble metal and should cause galvanic corrosion of the more active metallic iron - thus, corrosion of Fe can be increased. Nanostructuring should results in higher strength and can result in higher rate of dissolution/degradation from grain boundaries. In this work, a simple dissolution model of heterogeneous three phase nanocomposite material is considered - two phases being metal Fe and Ag and the third - nanopores. Analytical solution for the model is presented. Calculations demonstrate that the changes in the relative amount of each phase depend on mass exchange and diffusion coefficients. Theoretical results agree with preliminary experimental results.

Biodegradation of high molecular weight lignin under sulfate reducing conditions: lignin degradability and degradation by-products.

PubMed

Ko, Jae-Jung; Shimizu, Yoshihisa; Ikeda, Kazuhiro; Kim, Seog-Ku; Park, Chul-Hwi; Matsui, Saburo

2009-02-01

This study is designed to investigate the biodegradation of high molecular weight (HMW) lignin under sulfate reducing conditions. With a continuously mesophilic operated reactor in the presence of co-substrates of cellulose, the changes in HMW lignin concentration and chemical structure were analyzed. The acid precipitable polymeric lignin (APPL) and lignin monomers, which are known as degradation by-products, were isolated and detected. The results showed that HMW lignin decreased and showed a maximum degradation capacity of 3.49 mg/l/day. APPL was confirmed as a polymeric degradation by-product and was accumulated in accordance with HMW lignin reduction. We also observed non-linear accumulation of aromatic lignin monomers such as hydrocinnamic acid. Through our experimental results, it was determined that HMW lignin, when provided with a co-substrate of cellulose, is biodegraded through production of APPL and aromatic monomers under anaerobic sulfate reducing conditions with a co-substrate of cellulose.

Impact of substrates acclimation strategy on simultaneous biodegradation of hydrogen sulfide and ammonia.

PubMed

Jiang, Xia; Luo, Yiqun; Yan, Rong; Tay, Joo Hwa

2009-12-01

Three columns were differentiated with feeding mixture of H(2)S and NH(3) (MFC), feeding NH(3) followed by H(2)S (NFC), and feeding H(2)S followed by NH(3) (SFC). Removal performance, biodegradation capacity and microbial community structures in the three columns were compared. The results show that NFC has a shorter acclimation period for the removal of NH(3) gas and nitrification than MFC. Under the high loading of H(2)S and NH(3) at 164 and 82 gm(-3) h(-1), respectively, NFC exhibited high removal efficiency of NH(3) (>95%) while the removal efficiencies were obtained at 63 and 75% in MFC and SFC, respectively. The removal of NH(3) gas in NFC was significantly attributed to nitrification (over 50%), while adsorption and chemical reaction contributed to the removal of NH(3) in MFC and SFC. The different biodegradation capacities of NH(3) could be due to the dissimilarity in the microbial population presented in each column.

Anaerobic biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by a facultative anaerobe Pseudomonas sp. JP1.

PubMed

Liang, Lei; Song, Xiaohui; Kong, Jing; Shen, Chenghui; Huang, Tongwang; Hu, Zhong

2014-11-01

Polycyclic aromatic hydrocarbons (PAHs) are harmful persistent organic pollutants, while the high-molecular-weight (HMW) PAHs are even more detrimental to the environment and human health. However, microbial anaerobic degradation of HMW PAHs has rarely been reported. One facultative anaerobe Pseudomonas sp. JP1 was isolated from Shantou Bay, Shantou, China, which could degrade a variety of HMW PAHs. After 40 days cultivation with strain JP1, anaerobic biodegradation rate of benzo[a]pyrene (BaP), fluoranthene, and phenanthrene was 30, 47, and 5 %, respectively. Consumption of nitrate as the electron acceptor was confirmed by N-(1-naphthyl) ethylenediamine spectrophotometry. Supplementation of sodium sulfite, maltose, or glycine, and in a salinity of 0-20 ‰ significantly stimulated anaerobic degradation of BaP. Lastly, the anaerobic degradation metabolites of BaP by strain JP1 were investigated using GC/MS, and the degradation pathway was proposed. This study is helpful for further studies on the mechanism of anaerobic biodegradation of PAHs.

A Diverse Soil Microbiome Degrades More Crude Oil than Specialized Bacterial Assemblages Obtained in Culture.

PubMed

Bell, Terrence H; Stefani, Franck O P; Abram, Katrina; Champagne, Julie; Yergeau, Etienne; Hijri, Mohamed; St-Arnaud, Marc

2016-09-15

Soil microbiome modification may alter system function, which may enhance processes like bioremediation. In this study, we filled microcosms with gamma-irradiated soil that was reinoculated with the initial soil or cultivated bacterial subsets obtained on regular media (REG-M) or media containing crude oil (CO-M). We allowed 8 weeks for microbiome stabilization, added crude oil and monoammonium phosphate, incubated the microcosms for another 6 weeks, and then measured the biodegradation of crude oil components, bacterial taxonomy, and functional gene composition. We hypothesized that the biodegradation of targeted crude oil components would be enhanced by limiting the microbial taxa competing for resources and by specifically selecting bacteria involved in crude oil biodegradation (i.e., CO-M). Postincubation, large differences in taxonomy and functional gene composition between the three microbiome types remained, indicating that purposeful soil microbiome structuring is feasible. Although phylum-level bacterial taxonomy was constrained, operational taxonomic unit composition varied between microbiome types. Contrary to our hypothesis, the biodegradation of C10 to C50 hydrocarbons was highest when the original microbiome was reinoculated, despite a higher relative abundance of alkane hydroxylase genes in the CO-M microbiomes and of carbon-processing genes in the REG-M microbiomes. Despite increases in the relative abundances of genes potentially linked to hydrocarbon processing in cultivated subsets of the microbiome, reinoculation of the initial microbiome led to maximum biodegradation. In this study, we show that it is possible to sustainably modify microbial assemblages in soil. This has implications for biotechnology, as modification of gut microbial assemblages has led to improved treatments for diseases like Clostridium difficile infection. Although the soil environment determined which major phylogenetic groups of bacteria would dominate the assemblage, we saw differences at lower levels of taxonomy and in functional gene composition (e.g., genes related to hydrocarbon degradation). Further studies are needed to determine the success of such an approach in nonsterile environments. Although the biodegradation of certain crude oil fractions was still the highest when we inoculated with the diverse initial microbiome, the possibility of discovering and establishing microbiomes that are more efficient in crude oil degradation is not precluded. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be usedmore » for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of three to five times, leading to a more rapid clean-up of the DNAPL zone. The most favored electron donor to add is one which partitions well with the chlorinated solvent or can be concentrated near it. Unfortunately, an ideal electron donor, such as vegetable oil, is difficult to introduce and mix with DNAPL in the ground, doing this properly remains an engineering challenge. Numerical model studies have indicated that several factors may significantly influence the rate and extent of enhancement, including the inhibitory effects of PCE and cDCE, the level of ED concentration, DNAPL configuration, and competition for ED. Such factors need to be considered when contemplating engineered DNAPL bioremediation. Pseudomonas stuzeri KC is an organism that transforms CT to carbon dioxide and chloride without the formation of the hazardous intermediate, chloroform. This is accomplished by production and secretion of a molecule called PDTC. This study was direct ed towards determining how PDTC works. Cu (II) at a ratio of 1:1 Cu to PDTC was found to result in the most rapid CT transformation, confirming that the PDTC-Cu complex is both a reactant and a catalyst in CT transformation. CT degradation requires that the PDTC be in a reduced form, which is generated by contact with cell components. Fe(II) inhibits CT transformation by PDTC. Studies indicated that this inhibition is enhanced by some compound or factor in the supernatant with molecular weight greater than 10,000 Da. We have made progress in determining what this factor might be, but have not yet been able to identify it. In related studies, we found that CT transformation by another organism, Shewanella oneidensis MR1, also involves an excreted factor, but this factor is different from PDTC and results in chloroform transformation as an intermediate. Our studies have indicated that this factor is similar to vitamin K2, and we have also confirmed that vitamin K2 does transform C T into chloroform.« less

Production of mono- and di-carboxylated polyethylene glycols as a factor obstacle to the successful ozonation-assisted biodegradation of ethoxylated compounds.

PubMed

Nakai, Satoshi; Okuda, Tetsuji; Nishijima, Wataru; Okada, Mitsumasa

2015-10-01

Ozonation is believed to improve the biodegradability of organic compounds. In the present study, degradation of nonylphenol ethoxylates (NPEOs) was monitored in hybrid treatment systems consisting of ozonation and microbial degradation processes. We found that ozonation of NPEOs decreased, rather than increased, the biodegradability under certain conditions. The timing of ozonation was a definitive factor in determining whether ozonation increased or decreased the biodegradation rates of NPEOs. Initial ozonation of NPEOs prior to biodegradation reduced the rate of dissolved organic carbon (DOC) removal during the subsequent 14 d of biodegradation, whereas intermediate ozonation at the 9th day of biodegradation improved subsequent DOC removal during 14 d of NPEO biodegradation. Furthermore, reduction of DOC removal was also observed, when initial ozonation prior to biodegradation was subjected to cetyl alcohol ethoxylates. The production of less biodegradable intermediates, such as mono- and dicarboxylated polyethylene glycols (MCPEGs and DCPEGs), was responsible for the negative effect of ozonation on biodegradability of NPEOs. DCPEGs and MCPEGs were produced by biodegradation of polyethylene glycols (PEGs) that were ozonolysis products of the NPEOs, and the biodegradability of DCPEGs and MCPEGs was less than that of the precursor PEGs. The results indicate that, if the target chemicals contain ethoxy chains, production of PEGs may be one of the important factors when ozonation is considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

PubMed

Rožman, Marko; Acuña, Vicenç; Petrović, Mira

2018-02-01

A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimating the in situ biodegradation of naphthenic acids in oil sands process waters by HPLC/HRMS.

PubMed

Han, Xiumei; MacKinnon, Michael D; Martin, Jonathan W

2009-06-01

The oil sands industry in Northern Alberta produces large volumes of oil sands process water (OSPW) containing high concentrations of persistent naphthenic acids (NAs; C(n)H(2n+Z)O(2)). Due to the growing volumes of OSPW that need to be reclaimed, it is important to understand the fate of NAs in aquatic systems. A recent laboratory study revealed several potential markers of microbial biodegradation for NAs; thus here we examined for these signatures in field-aged OSPW on the site of Syncrude Canada Ltd. (Fort McMurray, AB). NA concentrations were lower in older OSPW; however parent NA signatures were remarkably similar among all OSPW samples examined, with no discernible enrichment of the highly cyclic fraction as was observed in the laboratory. Comparison of NA signatures in fresh oil sands ore extracts to OSPW in active settling basins, however, suggested that the least cyclic fraction (i.e. Z=0 and Z=-2 homologues) may undergo relatively rapid biodegradation in active settling basins. Further evidence for biodegradation of NAs came from a significantly higher proportion of oxidized NAs (i.e. C(n)H(2n+Z)O(3)+C(n)H(2n+Z)O(4)) in the oldest OSPW from experimental reclamation ponds. Taken together, there is indirect evidence for rapid biodegradation of relatively labile Z=0 and Z=-2 NAs in active settling basins, but the remaining steady-state fraction of NAs in OSPW appear to be very recalcitrant, with half-lives on the order of 12.8-13.6 years. Alternative fate mechanisms to explain the slow disappearance of parent NAs from OSPW are discussed, including adsorption and atmospheric partitioning.

Biodegradation of hexachlorocyclohexane (HCH) by microorganisms.

PubMed

Phillips, Theresa M; Seech, Alan G; Lee, Hung; Trevors, Jack T

2005-08-01

The organochlorine pesticide Lindane is the gamma-isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only gamma-HCH, but also large amounts of predominantly alpha-, beta- and delta-HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low (< 500 mg/kg) concentrations of HCH in soil. Information on the effects of inorganic nutrients, organic carbon sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed.

Resistance to moist conditions of whey protein isolate and pea starch biodegradable films and low density polyethylene nondegradable films: a comparative study

NASA Astrophysics Data System (ADS)

Mehyar, G. F.; Bawab, A. Al

2015-10-01

Biodegradable packaging materials are degraded under the natural environmental conditions. Therefore using them could alleviate the problem of plastics accumulation in nature. For effective replacement of plastics, with biodegradable materials, biodegradable packages should keep their properties under the high relative humidity (RH) conditions. Therefore the objectives of the study were to develop biodegradable packaging material based on whey protein isolate (WPI) and pea starch (PS). To study their mechanical, oxygen barrier and solubility properties under different RHs compared with those of low density polyethylene (LDPE), the most used plastic in packaging. Films of WPI and PS were prepared separately and conditioned at different RH (30-90%) then their properties were studied. At low RHs (<50%), WPI films had 2-3 times lower elongation at break (E or stretchability) than PS and LDPE. Increasing RH to 90% significantly (P<0.01) increased the elongation of PS but not WPI and LDPE films. LDPE and WPI films kept significantly (P<0.01) higher tensile strength (TS) than PS films at high RH (90%). Oxygen permeability (OP) of all films was very low (<0.5 cm3 μm m-2 d-1 kPa-1) below 40% RH but increased for PS films and became significantly (P<0.01) different than that of LDPE and WPI at > 40% RH. Oxygen permeability of WPI and LDPE did not adversely affected by increasing RH to 65%. Furthermore, WPI and LDPE films had lower degree of hydration at 50% and 90% RH and total soluble matter than PS films. These results suggest that WPI could be successfully replacing LDPE in packaging of moist products.

Understanding the anaerobic biodegradability of food waste: Relationship between the typological, biochemical and microbial characteristics.

PubMed

Fisgativa, Henry; Tremier, Anne; Le Roux, Sophie; Bureau, Chrystelle; Dabert, Patrick

2017-03-01

In this study, an extensive characterisation of food waste (FW) was performed with the aim of studying the relation between FW characteristics and FW treatability through an anaerobic digestion process. In addition to the typological composition (paper, meat, fruits, vegetables contents, etc) and the physicochemical characteristics, this study provides an original characterisation of microbial populations present in FW. These intrinsic populations can actively participate to aerobic and anaerobic degradation with the presence of Proteobacteria and Firmicutes species for the bacteria and of Ascomycota phylum for the fungi. However, the characterisation of FW bacterial and fungi community shows to be a challenge because of the biases generated by the non-microbial DNA coming from plant and by the presence of mushrooms in the food. In terms of relations, it was demonstrated that some FW characteristics as the density, the volatile solids and the fibres content vary as a function of the typological composition. No direct relationship was demonstrated between the typological composition and the anaerobic biodegradability. However, the Pearson's matrix results reveal that the anaerobic biodegradation potential of FW was highly related to the total chemical oxygen demand (tCOD), the total solid content (TS), the high weight organic matter molecules soluble in water (SOL W >1.5 kDa) and the C/N ratio content. These relations may help predicting FW behaviour through anaerobic digestion process. Finally, this study also showed that the storage of FW before collection, that could induce pre-biodegradation, seems to impact several biochemical characteristics and could improve the biodegradability of FW. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradation of 17alpha-methyltestosterone and isolation of MT-degrading bacterium from sediment of Nile tilapia masculinization pond.

PubMed

Homklin, Supreeda; Wattanodorn, Theerachit; Ong, Say Kee; Limpiyakorn, Tawan

2009-01-01

The fast growing and highly tolerant fish Nile tilapia is one of the most commonly raised fish in the aquaculture industry. To produce an all-male population, a common practice is to feed the Nile tilapia fry with 17alpha-methyltestosterone (MT)-impregnated food. Uneaten fish food with MT may accumulate in the masculinization ponds and be released into the receiving waters. Not much is known about the fate of MT in the fish farms and in the receiving streams. The objective of this study is to investigate the biodegradation of MT under aerobic condition and to isolate responsible microorganisms. Aerobic biodegradation tests were conducted with MT concentrations of 0.3, 1.0, 5.0, 7.0, and 10.0 mg/L using sediment from the masculinization pond as microbial seed. The results suggested that MT is biodegradable. Lag phase was not observed in all cases. With initial concentrations of 0.3, 1.0, 5.0, 7.0, and 10.0 mg/l, the first-order degradation rates were 0.52, 0.23, 0.17, 0.13 and 0.10 day(-1), respectively. Degradation rates were found to decrease with an increase in the initial MT concentration. Analysis of 16S rRNA gene sequences of a strain isolated from the sediment indicated that the strain was highly similar to Pimelobacter simplex strain S151 (100%) which is in the genus Nocardioidaceae. Using this strain, MT is degraded with a first-order degradation rate of 0.044 h(-1) excluding the lag phase. This is the first work reporting biodegradation of MT and isolation of MT-degrading bacterium from environment.

Gallic acid grafting effect on delivery performance and antiglaucoma efficacy of antioxidant-functionalized intracameral pilocarpine carriers.

PubMed

Chou, Shih-Feng; Luo, Li-Jyuan; Lai, Jui-Yang

2016-07-01

Functionalization of therapeutic carrier biomaterials can potentially provide additional benefits in drug delivery for disease treatment. Given that this modification determines final therapeutic efficacy of drug carriers, here, we investigate systematically the role of grafting amount of antioxidant gallic acid (GA) onto GN in situ gelling copolymers made of biodegradable gelatin and thermo-responsive poly(N-isopropylacrylamide) for intracameral delivery of pilocarpine in antiglaucoma treatment. As expected, increasing redox reaction time increased total antioxidant activities and free radical scavenging abilities of synthesized carrier biomaterials. The hydrophilic nature of antioxidant molecules strongly affected physicochemical properties of carrier materials with varying GA grafting amounts, thereby dictating in vitro release behaviors and mechanisms of pilocarpine. In vitro oxidative stress challenges revealed that biocompatible carriers with high GA content alleviated lens epithelial cell damage and reduced reactive oxygen species. Intraocular pressure and pupil diameter in glaucomatous rabbits showed correlations with GA-mediated release of pilocarpine. Additionally, enhanced pharmacological treatment effects prevented corneal endothelial cell loss during disease progression. Increasing GA content increased total antioxidant level and decreased nitrite level in the aqueous humor, suggesting a much improved antioxidant status in glaucomatous eyes. This work significantly highlights the dependence of physicochemical properties, drug release behaviors, and bioactivities on intrinsic antioxidant capacities of therapeutic carrier biomaterials for glaucoma treatment. Development of injectable biodegradable polymer depots and functionalization of carrier biomaterials with antioxidant can potentially provide benefits such as improved bioavailability, controlled release pattern, and increased therapeutic effect in intracameral pilocarpine administration for glaucoma treatment. For the first time, this study demonstrated that the biodegradable in situ gelling copolymers can incorporate different levels of antioxidant gallic acid to tailor the structure-property-function relationship of the intracameral drug delivery system. The systematic evaluation fully verified the dependence of phase transition, degradation behavior, drug release mechanism, and antiglaucoma efficacy on intrinsic antioxidant capacities of carrier biomaterials. The report highlights the significant role of grafting amount of gallic acid in optimizing performance of antioxidant-functionalized polymer therapeutics as new drug delivery platforms in disease treatment. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Evaluating the primary and ready biodegradability of dianilinodithiophosphoric acid.

PubMed

Lin, Weixiong; Sun, Shuiyu; Xu, Pingting; Dai, Yongkang; Ren, Jie

2016-04-01

Dianilinodithiophosphoric acid (DDA) is widely used as sulfide mineral flotation collector in China. It is necessary to investigate the biodegradability of DDA to provide the fundamental knowledge to assess the environmental fate in the risk assessment of DDA and to design and operate the DDA flotation wastewater biological treatment plant. In the present study, the primary and ready aerobic biodegradations of DDA were studied and the primary biodegradation kinetic model of DDA was developed. The results show that DDA displays a good primary biodegradability and its biodegradation ratio reaches 99.8 % in 7 days. In contrast, DDA is not easily ready biodegradable; hence, it is a partially biodegradable organic compound. The primary aerobic biodegradation kinetics can be described using the first-order reaction kinetics equation: C = 19.72191e(-0.01513t).

Assessment of penetration potential of pH responsive double walled biodegradable nanogels coated with eucalyptus oil for the controlled delivery of 5-fluorouracil: In vitro and ex vivo studies.

PubMed

Sahu, Prashant; Kashaw, Sushil K; Jain, Sanyog; Sau, Samaresh; Iyer, Arun K

2017-05-10

Penetration enhancers coated biodegradable polymeric nanogels loaded with cytotoxic drugs applied via the topical route, can be a promising strategy for improving the chemotherapeutic efficiency of skin cancers. The major objective of proposed research was to investigate the in vitro and ex vivo chemotherapeutic potential of double walled PLGA-chitosan biodegradable nanogel entrapped with 5-fluororuacil (5-FU) coated with eucalyptus oil, topically applied onto the skin. 5-FU was first entrapped in PLGA core by solvent evaporation technique followed by coating with cationic chitosan for ionic interaction with anionic skin cancer cell membrane. A surface coating of eucalyptus oil (1%) was employed to improve the penetration efficacy of the nanogel into stratum corneum. The surface modified biodegradable double walled nanogel was characterized for particle size, charge and thermal properties followed by pH dependent in vitro analysis. Human keratinocyte (HaCaT) cell line was employed for the bio- and cyto-compatibility testing prior to the hemolysis assay and coagulation assessment. A porcine skin ex vivo screening was performed for assessing the penetration potential of the nanogels. DLS and TEM revealed a particle size about 170nm for the double walled nanogels. The nanogels also exhibited high thermal stability as analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). The drug entrapment efficacy was about ~40%. The drug release showed sustained release pattern noted up to 24h. The low hemolysis of 2.39% with short prothrombin time (PT) and activated partial thromboplastin time (APTT) of 14.2 and 35.5s respectively, revealed high biocompatibility of the nanogels. The cellular uptake and localization was assessed by confocal microscopy. The cytotoxicity (MTT assay) on HaCaT cell line demonstrated high cytocompatibilty of the nanogels. An ex vivo evaluation using porcine skin displayed efficient and steady state flux of 5-FU from the biodegradable nanogles into the skin, while the histology of the porcine skin revealed enhanced penetration potential of eucalyptus oil coated PLGA-chitosan double walled nanogels. Taken together the in vivo and ex vivo results portend promising potential for the utility of the biodegradable nanogels for treating skin cancers. Copyright © 2017. Published by Elsevier B.V.

Cadmium-induced stress response of Phanerochaete chrysosporium during the biodegradation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47).

PubMed

Feng, Mi; Yin, Hua; Cao, Yajuan; Peng, Hui; Lu, Guining; Liu, Zehua; Dang, Zhi

2018-06-15

Cd-induced stress response of Phanerochaete chrysosporium during the biodegradation of BDE-47 was investigated in this study, with the goal of elucidating the tolerance behavior and the detoxification mechanisms of P. chrysosporium to resist the Cd stress in the course of BDE-47 biodegradation, which has implications for expanding the application of P. chrysosporium in the bioremediation of Cd and BDE-47 combined pollution. The results suggested that single BDE-47 exposure did not induce obvious oxidative stress in P. chrysosporium, but coexistent Cd significantly triggered ROS generation, both intracellular ROS level and H 2 O 2 content showed positive correlation with Cd concentration. The activities of SOD and CAT were enhanced by low level of Cd (≤ 1 mg/L), but Cd of higher doses (＞1 mg/L) depressed the expression of these two antioxidant enzymes at the later exposure period (3-5 days). The intracellular content of GSH along with GSH/GSSG ratio also exhibited a bell-shaped response with a maximum value at Cd of 1 mg/L. Furthermore, Cd-induced ROS generation resulted in the lipid peroxidation, as indicated by a noticeable increment of MDA content found after 3 days. Moreover, the study also indicated that Cd less than 1 mg/L promoted the production of extracellular protein and quickened the decrease of pH value in the medium, while excessive Cd (＞1 mg/L) would lead to inhibition. These findings obtained demonstrated that P. chrysosporium had a certain degree of tolerance to Cd within a specific concentration range via regulating the antioxidant levels, inducing the synthesis of extracellular protein as well as stimulating the production of organic acids, and 1 mg/L is suggested to be the tolerance threshold of this strains under Cd stress during BDE-47 biodegradation. Copyright © 2018 Elsevier Inc. All rights reserved.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

NASA Astrophysics Data System (ADS)

Asriza, Ristika O.; Arcana, I. Made

2015-09-01

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Bioremediation of RDX in the vadose zone beneath the Pantex Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shull, T.L.; Speitel, G.E. Jr.; McKinney, D.C.

1999-01-01

The presence of dissolved high explosives (HE), in particular RDX and HMX, is well documented in the perched aquifer beneath the Pantex Plant, but the distribution of HE in the vadose zone has not yet been well defined. Although current remediation activities focus on the contamination in the perched aquifer, eventually regulatory concern is likely to turn to the residual contamination in the vadose zone. Sources of HE include the infiltration of past wastewater discharges from several HE-processing facilities through the ditch drainage system and leachate from former Landfill 3. With limited existing data on the HE distribution in themore » vadose zone and without preventive action, it must be assumed that residual HE could be leached into infiltrating water, providing a continuing supply of contamination to the perched aquifer. The purpose of this project was to more closely examine the fate and transport of HE in the vadose zone through mathematical modeling and laboratory experimentation. In particular, this report focuses on biodegradation as one possible fate of HE. Biodegradation of RDX in the vadose zone was studied because it is both present in highest concentration and is likely to be of the greatest regulatory concern. This study had several objectives: determine if indigenous soil organisms are capable of RDX biodegradation; determine the impact of electron acceptor availability and nutrient addition on RDX biodegradation; determine the extent of RDX mineralization (i.e., conversion to inorganic carbon) during biodegradation; and estimate the kinetics of RDX biodegradation to provide information for mathematical modeling of fate and transport.« less

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of themore » absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.« less

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The fraction of organics biodegraded (Fbio... biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as determined in accordance with the... biodegradation rate (MRbio) for a treated hazardous waste. (i) The MRbio shall be determined based on results for...

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The fraction of organics biodegraded (Fbio... biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as determined in accordance with the... biodegradation rate (MRbio) for a treated hazardous waste. (i) The MRbio shall be determined based on results for...

40 CFR 158.2280 - Environmental fate.

Code of Federal Regulations, 2013 CFR

2013-07-01

... biodegradability, porous pot, the biodegradation in activated sludge study as described in the “Simulation Tests to... applicant must choose either to: A. Conduct the biodegradation in activated sludge study as described in the... ready biodegradability study; or B. Conduct one of the following studies: The biodegradation in...

40 CFR 158.2280 - Environmental fate.

Code of Federal Regulations, 2014 CFR

2014-07-01

... biodegradability, porous pot, the biodegradation in activated sludge study as described in the “Simulation Tests to... applicant must choose either to: A. Conduct the biodegradation in activated sludge study as described in the... ready biodegradability study; or B. Conduct one of the following studies: The biodegradation in...

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The fraction of organics biodegraded (Fbio... biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as determined in accordance with the... biodegradation rate (MRbio) for a treated hazardous waste. (i) The MRbio shall be determined based on results for...

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The fraction of organics biodegraded (Fbio... biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as determined in accordance with the... biodegradation rate (MRbio) for a treated hazardous waste. (i) The MRbio shall be determined based on results for...

Biocompatible, Biodegradable Polymers for Use in Bone Repair,

DTIC Science & Technology

1987-01-01

as intact polymers and because their degradation products are carbon dioxide and water. 7 B. Microstructure, Morphology, Synthesis The microstructure...Hydrophilic flIe x iblIe 0 6. Carbonate R-O-C-O-R Hydrophilic r ig id Hollinger Ibav %lark page 15 D. Potential Biodegradable Polymers For producing high...diacids or hydroxvacids. Lactone rings with three to six carbons within the ring can be used as monomers. This limits the ratio ot sp4 to sp2 carbons

Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Putri, Zufira, E-mail: zufira.putri@gmail.com, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: zufira.putri@gmail.com, E-mail: arcana@chem.itb.ac.id

Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO{sub 2} are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes tomore » be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO{sub 2} compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO{sub 2} blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM)« less

The potential of autochthonous microbial culture encapsulation in a confined environment for phenol biodegradation.

PubMed

Azaizeh, Hassan; Kurzbaum, Eyal; Said, Ons; Jaradat, Husain; Menashe, Ofir

2015-10-01

Olive mill wastewater (OMWW) is claimed to be one of the most polluting effluents produced by agro-food industries, providing high contaminants load that encase cytotoxic agents such as phenolic and polyphenolic compounds. Therefore, a significant and continuous stress episode is induced once the mixed liquor of the wastewater treatment plants (WWTP's) is being exposed to OMWW. The use of bio-augmentation treatment procedures can be useful to eliminate or reduce such stress episodes. In this study, we have estimated the use of autochthonous biomass implementation within small bioreactor platform (SBP) particles as a bio-augmentation method to challenge against WWTPs stress episodes. Our results showed that SBP particles significantly reduced the presence of various phenolics: tannic, gallic and caffeic acid in a synthetic medium and in crude OMWW matrix. Moreover, the SBP particles succeeded to biodegrade a very high concentration of phenol blend (3000 mg L(-1)). Our findings indicated that the presence of the SBP microfiltration membrane has reduced the phenol biodegradation rate by 50 % compared to the same suspended culture. Despite the observed reduction in biodegradation rate, encapsulation in a confined environment can offer significant values such as overcoming the grazing forcers and dilution, thus achieving a long-term sufficient biomass. The potential for reducing stress episodes caused by cytotoxic agents through bio-augmentation treatment procedure using the SBP technology is discussed.

Biodegradation of PAHs in Soil: Influence of Initial PAHs Concentration

NASA Astrophysics Data System (ADS)

Kamil, N. A. F. M.; Talib, S. A.

2016-07-01

Most studies on biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) evaluate the effect of initial PAHs concentration in liquid medium. There are limited studies on evaluation in solid medium such as contaminated soil. This study investigated the potential of the bacteria, Corynebacterium urealyticum isolated from municipal sludge in degrading phenanthrene contaminated soil in different phenanthrene concentration. Batch experiments were conducted over 20 days in reactors containing artificially contaminated phenanthrene soil at different concentration inoculated with a bacterial culture. This study established the optimum condition for phenanthrene degradation by the bacteria under nonindigenous condition at 500 mg/kg of initial phenanthrene concentration. High initial concentration required longer duration for biodegradation process compared to low initial concentration. The bacteria can survive for three days for all initial phenanthrene concentrations.

Structure-biodegradability study and computer-automated prediction of aerobic biodegradation of chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klopman, G.; Tu, M.

1997-09-01

It is shown that a combination of two programs, MultiCASE and META, can help assess the biodegradability of industrial organic materials in the ecosystem. MultiCASE is an artificial intelligence computer program that had been trained to identify molecular substructures believed to cause or inhibit biodegradation and META is an expert system trained to predict the aerobic biodegradation products of organic molecules. These two programs can be used to help evaluate the fate of disposed chemicals by estimating their biodegradability and the nature of their biodegradation products under conditions that may model the environment.

How UV photolysis accelerates the biodegradation and mineralization of sulfadiazine (SD).

PubMed

Pan, Shihui; Yan, Ning; Liu, Xinyue; Wang, Wenbing; Zhang, Yongming; Liu, Rui; Rittmann, Bruce E

2014-11-01

Sulfadiazine (SD), one of broad-spectrum antibiotics, exhibits limited biodegradation in wastewater treatment due to its chemical structure, which requires initial mono-oxygenation reactions to initiate its biodegradation. Intimately coupling UV photolysis with biodegradation, realized with the internal loop photobiodegradation reactor, accelerated SD biodegradation and mineralization by 35 and 71 %, respectively. The main organic products from photolysis were 2-aminopyrimidine (2-AP), p-aminobenzenesulfonic acid (ABS), and aniline (An), and an SD-photolysis pathway could be identified using C, N, and S balances. Adding An or ABS (but not 2-AP) into the SD solution during biodegradation experiments (no UV photolysis) gave SD removal and mineralization rates similar to intimately coupled photolysis and biodegradation. An SD biodegradation pathway, based on a diverse set of the experimental results, explains how the mineralization of ABS and An (but not 2-AP) provided internal electron carriers that accelerated the initial mono-oxygenation reactions of SD biodegradation. Thus, multiple lines of evidence support that the mechanism by which intimately coupled photolysis and biodegradation accelerated SD removal and mineralization was through producing co-substrates whose oxidation produced electron equivalents that stimulated the initial mono-oxygenation reactions for SD biodegradation.

Improving ready biodegradability testing of fatty amine derivatives.

PubMed

van Ginkel, C G; Gancet, C; Hirschen, M; Galobardes, M; Lemaire, Ph; Rosenblom, J

2008-09-01

This study assesses the biodegradation potential of a number of fatty amine derivatives in tests following the OECD guidelines for ready biodegradability. A number of methods are used to reduce toxicity and improve the bioavailability of the fatty amine derivatives in these tests. Alkyl-1,3-diaminopropanes and octadecyltrimethylammonium chloride are toxic to microorganisms at concentrations used in OECD ready biodegradability tests. The concentration of these fatty amine derivatives in the aqueous phase can be reduced by reacting humic, or lignosulphonic acids with the derivatives or through the addition of silica gel to the test bottles. Using these non-biodegradable substances, ready biodegradability test results were obtained with tallow-1,3-diaminopropane and octadecyltrimethylammonium chloride. Demonstration of the ready biodegradability of the water-insoluble dioctadecylamine under the prescribed standard conditions is almost impossible due to the limited bioavailability of this compound. However, ready biodegradability results were achieved by using very low initial test substance concentrations and by introducing an organic phase. The contents of the bottles used to assess the biodegradability of dioctadecylamine were always mixed. False negative biodegradability results obtained with the fatty amine derivatives studied are the result of toxic effects and/or limited bioavailability. The aids investigated therefore improve ready biodegradability testing.

Controlled release of modified insulin glargine from novel biodegradable injectable gels.

PubMed

Anand, Om; Almoazen, Hassan; Mehrotra, Nitin; Johnson, James; Shukla, Atul

2012-03-01

The objective of this study was to investigate the duration of biological effects of modified insulin glargine released from a novel biodegradable injectable gel in type II diabetic Zucker diabetic fatty (ZDF) rats. Modified insulin glargine was purified from the marketed formulation by process of dialysis followed by freeze-drying, and the purity was confirmed by the single peak, corresponding to insulin glargine in the HPLC chromatogram. To determine and to compare the biological activity of purified insulin glargine with marketed formulation, it was suspended in isotonic saline solutions and administered subcutaneously to ZDF rats at a dose of 10 IU/kg of insulin and the blood glucose levels were measured. The blood glucose levels of ZDF rats after a subcutaneous injection of a suspension of purified insulin glargine decreased below 200 mg/dL within 2 h and remained at this level up to 6 h, then steadily raised above 400 mg/dL in 12 h. Insulin glargine particles were loaded into a novel biodegradable injectable gel formulation prepared from a blend of polylactic-co-glycolic acid (PLGA) and biocompatible plasticizers. Approximately 0.1 mL of insulin glargine-loaded gel prepared with PLGA was administered subcutaneously to the ZDF rats, and blood glucose levels were measured. The PLGA gel formulations prepared with insulin glargine particles had duration of action of 10 days following a single subcutaneous injection. The addition of zinc sulfate to the formulations prepared with purified insulin glargine particles further slowed down the drop in blood glucose concentrations.

Paracetamol in the environment and its degradation by microorganisms.

PubMed

Wu, Shijin; Zhang, Lili; Chen, Jianmeng

2012-11-01

Paracetamol (4'-hydroxyacetanilide, N-acetyl-p-aminophenol, acetaminophen, and paracetamol) is a widely used over-the-counter analgesic and antipyretic drug. Paracetamol and structural analogs are ubiquitous in the natural environment and easily accumulate in aquatic environment, which have been detected in surface waters, wastewater, and drinking water throughout the world. Paracetamol wastewater is mainly treated by chemical oxidation processes. Although these chemical methods may be available for treating these pollutants, the harsh reaction conditions, the generation of secondary pollutants, and the high operational cost associated with these methods have often made them not a desirable choice. Biodegradation of paracetamol is being considered as an environmentally friendly and low-cost option. The goal of this review is to provide an outline of the current knowledge of biodegradation of paracetamol in the occurrence, degrading bacteria, and proposed metabolic/biodegrading pathways, enzymes and possible intermediates. The comprehensive understanding of the metabolic pathways and enzyme systems involved in the utilization of paracetamol means will be helpful for optimizing and allowing rational design of biodegradation systems for paracetamol-contaminated wastewater.

Uptake and biodegradation of the antimicrobial sulfadimidine by the species Tripolium pannonicum acting as biofilter and its further biodegradation by anaerobic digestion and concomitant biogas production.

PubMed

Turcios, Ariel E; Weichgrebe, Dirk; Papenbrock, Jutta

2016-11-01

This project analyses the uptake and biodegradation of the antimicrobial sulfadimidine (SDI) from the culture medium and up to the anaerobic digestion. Tripolium pannonicum was grown under hydroponic conditions with different concentrations of SDI (0, 5 and 10mg·L(-1)) and the fresh biomass, containing different amounts of SDI taken up, was used as substrate for biogas production. SDI was analyzed by liquid chromatography coupled to positive ion electrospray mass spectrometry (ESI LC-MS). Based on the findings, T. pannonicum is able to uptake SDI. The more SDI is in the culture medium, the higher the SDI content in the plant tissue. According to this study, it is possible to produce high yields of biogas using biomass of T. pannonicum containing SDI and at the same time biodegradation of SDI is carried out. The highest specific biogas yield is obtained using shoots as substrate of the plants cultivated at 5mg·L(-1) SDI. Copyright © 2016 Elsevier Ltd. All rights reserved.

Activated sludge is a potential source for production of biodegradable plastics from wastewater.

PubMed

Khardenavis, A; Guha, P K; Kumar, M S; Mudliar, S N; Chakrabarti, T

2005-05-01

Increased utilization of synthetic plastics caused severe environmental pollution due to their non-biodegradable nature. In the search for environmentally friendly materials to substitute for conventional plastics, different biodegradable plastics have been developed by microbial fermentations. However, limitations of these materials still exist due to high cost. This study aims at minimization of cost for the production of biodegradable plastics P(3HB) and minimization of environmental pollution. The waste biological sludge generated at wastewater treatment plants is used for the production of P(3HB) and wastewater is used as carbon source. Activated sludge was induced by controlling the carbon: nitrogen ratio to accumulate storage polymer. Initially polymer accumulation was studied by using different carbon and nitrogen sources. Maximum accumulation of polymer was observed with carbon source acetic acid and diammonium hydrogen phosphate (DAHP) as nitrogen source. Further studies were carried out to optimize the carbon: nitrogen ratios using acetic acid and DAHP. A maximum of 65.84% (w/w) P(3HB) production was obtained at C/N ratio of 50 within 96 hours of incubation.

Development of high-performance biodegradable rigid polyurethane foams using all bioresource-based polyols: Lignin and soy oil-derived polyols.

PubMed

Luo, Xiaogang; Xiao, Yuqin; Wu, Qiangxian; Zeng, Jian

2018-04-25

Development of biodegradable polyurethane materials is the most promising in the wider context of the "greening" of industrial chemistry. To tackle this challenge, a novel biodegradable polyurethane foam from all bioresource-based polyols (lignin and soy oil-derived polyols) and polymeric methyldiphenyl diisocyanate (pMDI) have been synthesized via a one-pot and self-rising process. All these foam samples have the internal cellular morphology and microstructure. FTIR result exhibits characteristic peaks of polyurethane, and indicates covalent bonds between soy-based polyurethane and lignin, and the lignin powders can react with pMDI via active -H and -CNO. In addition, hydrogen bonding also plays an important role in forming the 3D structures. These interactions and chemical bonds made the prepared foam samples form the 3D macromolecular structure with improved mechanical, thermal, and biodegradable properties. The reaction process is time-saving and cost-effective as it requires no blowing agent and minimum processing steps, while exploring the potential of using the higher content of nature bioresource constituents. Copyright © 2018 Elsevier B.V. All rights reserved.

Biotransformation of potentially persistent alkylphenols in natural seawater.

PubMed

Lofthus, Synnøve; Almås, Inger K; Evans, Peter; Pelz, Oliver; Brakstad, Odd Gunnar

2016-08-01

Produced water (PW) discharged to the marine environment may contain both natural substances and industrial chemicals that are potentially persistent, bioaccumulating and toxic (PBT). Identification of substances as PBT is dependent upon accurate assessment of biodegradation rates, but these measurements can be impeded where substances exhibit inherently low solubility in water. Examples of substances of this kind include some alkylated phenols (APs). Biotransformation of three APs, suspected to be PBT compounds in PW, was investigated by adopting a new methodology in which they were immobilized to hydrophobic adsorbents submerged in natural seawater. These compounds were not ready biodegradable by conventional screening biochemical oxygen demand (BOD) methods at high concentrations (2 mg/L). However, potential biodegradability for two of the three APs were demonstrated by the immobilization method at low concentrations (appr. 100 μg/L), with biotransformation half-lives <50 days. Thus, standard screening tests should be supplemented by biodegradation methods suited for testing of poorly soluble substances before the persistence of potential PBT substances are defined. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study of microbes having potentiality for biodegradation of plastics.

PubMed

Ghosh, Swapan Kumar; Pal, Sujoy; Ray, Sumanta

2013-07-01

Plastic is a broad name given to the different types of organic polymers having high molecular weight and is commonly derived from different petrochemicals. Plastics are generally not biodegradable or few are degradable but in a very slow rate. Day by day, the global demand of these polymers is sharply increasing; however, considering their abundance and potentiality in causing different environmental hazards, there is a great concern in the possible methods of degradation of plastics. Recently, there have been some debates at the world stage about the potential degradation procedures of these synthetic polymers and microbial degradation has emerged as one of the potential alternative ways of degradation of plastics. Alternatively, some scientists have also reported many adverse effects of these polymers in human health, and thus, there is an immediate need of a potential screening of some potential microbes to degrade these synthetic polymers. In this review, we have taken an attempt to accumulate all information regarding the chemical nature along with some potential microbes and their enzymatic nature of biodegradation of plastics along with some key factors that affect their biodegradability.

Biodegradation of carbamazepine using freshwater microalgae Chlamydomonas mexicana and Scenedesmus obliquus and the determination of its metabolic fate.

PubMed

Xiong, Jiu-Qiang; Kurade, Mayur B; Abou-Shanab, Reda A I; Ji, Min-Kyu; Choi, Jaeyoung; Kim, Jong Oh; Jeon, Byong-Hun

2016-04-01

This study evaluated the toxicity and cellular stresses of carbamazepine (CBZ) on Chlamydomonas mexicana and Scenedesmus obliquus, and its biodegradation by both microalgal species. The growth of both microalgal species decreased with increase of CBZ concentration. The growth of S. obliquus was significantly inhibited (97%) at 200 mg CBZ L(-1), as compared to the control after 10days; whereas, C. mexicana showed 30% inhibition at the same experimental conditions. Biochemical characteristics including total chlorophyll, carotenoid contents and enzyme activities (SOD and CAT) for both species were affected by CBZ at relatively high concentration. C. mexicana and S. obliquus could achieve a maximum of 35% and 28% biodegradation of CBZ, respectively. Two metabolites (10,11-dihydro-10,11-expoxycarbamazepine and n-hydroxy-CBZ) were identified by UPLC-MS, as a result of CBZ biodegradation by C. mexicana. This study demonstrated that C. mexicana was more tolerant to CBZ and could be used for treatment of CBZ contaminated wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Research regarding biodegradable properties of food polymeric products under microorganism activity

NASA Astrophysics Data System (ADS)

Opran, Constantin; Lazar, Veronica; Fierascu, Radu Claudiu; Ditu, Lia Mara

2018-02-01

Aim of this research is the structural analysis by comparison of the biodegradable properties of two polymeric products made by non-biodegradable polymeric material (polypropylene TIPPLEN H949 A) and biodegradable polymeric material (ECOVIO IS 1335), under microorganism activity in order to give the best solution for the manufacture of food packaging biodegradable products. It presents the results of experimental determinations on comparative analysis of tensile strength for the two types of polymers. The sample weight variations after fungal biodegradation activity revealed that, after 3 months, there are no significant changes in polymeric substratum for non-biodegradable polymeric. The microscopically analysis showed that the fungal filaments did not strongly adhered on the non-biodegradable polymeric material, instead, both filamentous fungi strains adhered and covered the surface of the biodegradable sample with germinated filamentous conidia. The spectral analysis of polymer composition revealed that non-biodegradable polymer polypropylene spectra are identical for control and for samples that were exposed to fungal activity, suggesting that this type of sample was not degraded by the fungi strains. Instead, for biodegradable polymer sample, it was observed significant structural changes across multiple absorption bands, suggesting enzyme activity manifested mainly by Aspergillus niger strain. Structural analysis of interdisciplinary research results, lead, to achieving optimal injection molded technology emphasizing technological parameters, in order to obtain food packaging biodegradable products.

A new bioseed for determination of wastewater biodegradability: analysis of the experimental procedure.

PubMed

Ballesteros Martín, M M; Esteban García, B; Ortega-Gómez, E; Sánchez Pérez, J A

2014-01-01

A new bioassay proposed in the patent P201300029 was applied to a pre-treated wastewater containing a mixture of commercial pesticides to simulate a recalcitrant industrial wastewater in order to determine its biodegradability. The test uses a mixture of standardized inoculum of the lyophilized bacteria Pseudomonas putida with the proper proportion of salts and minerals. The results highlight that biodegradation efficiency can be calculated using a gross parameter (chemical oxygen demand (COD)) which facilitates the biodegradability determination for routine water biodegradability analysis. The same trend was observed throughout the assay with the dehydrated and fresh inoculums, and only a difference of 5% in biodegradation efficiency (E f) was observed. The obtained results showed that the P. putida biodegradability assay can be used as a commercial test with a lyophilized inoculum in order to monitor the ready biodegradability of an organic pollutant or a WWTP influent. Moreover, a combination of the BOD5/COD ratio and the P. putida biodegradability test is an attractive alternative in order to evaluate the biodegradability enhancement in water pre-treated with advanced oxidation processes (AOPs).

Biodegradation of organic sulfur compounds in crude oils from Oman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopmans, M.P.; Sinninghe Damste, J.S.; Leeuw, J.W. de

1996-10-01

Five closely related crude oils from Oman, showing various degrees of biodegradation ranging from non-biodegraded to severely biodegraded, were quantitatively investigated for free and sulfur-bound hydrocarbons. Hydrocarbons sequestered in the alkylsulfide fraction and the polar fraction were analysed after Raney Ni desulfurisation and subsequent hydrogenation. With increasing degree of biodegradation, pristane (Pr), phytane (Ph) and a series of mid-chain methyl alkanes are enriched relative to the n-alkanes, as evidenced by increased Pr/n-C{sub 17} and Ph/n-C{sub 18} ratios. In the severely biodegraded oil no free n-alkanes, mid-chain alkanes or isoprenoid alkanes could be detected. Sterane and hopane distributions, however, remain unchangedmore » throughout the biodegradation series. Hydrocarbons sequestered in the alkylsulfide fraction (i.e. n-alkanes, mid-chain methyl alkanes, Pr and Ph) are biodegraded at lower rates than the corresponding hydrocarbons in the saturated hydrocarbon fraction. Similar hydrocarbons sequestered in the polar fraction are biodegraded at even lower rates. These results suggest that hydrocarbons bound by a higher amount of sulfur links are biodegraded at a lower rate.« less

Biodegradable tocopherol acetate as a drug carrier to prevent ureteral stent-associated infection.

PubMed

Elayarajah; Rajendran, R; Venkatrajah; Sreekumar, Sweda; Sudhakar, Asa; Janiga; Sreekumar, Soumya

2011-03-01

Biomaterial-centred bacterial infections present common and challenging complications with medical implants like ureteral stent which provide substratum for the biofilm formation. Hence the purpose of this study is to make antibacterial stent surface with biodegradable polymer (tocopherol acetate) and anti-infective agents (norfloxacin and metronidazole) using a modified dip-coating procedure. This is done by impregnating the stent pieces in the anti-infective solution (a mixture of norfloxacin-metronidazole and polymer) for uniform surface coating (drug-carrier-coated stents). After coating, agar diffusion test was performed as qualitative test to find out the sensitivity of coated stents against the clinical isolates, Staphylococcus epidermidis and Escherichia coli. Quantitative test was measured by calculating the numbers of adhered bacteria on coated and uncoated stents by incubating the stent pieces in artificial urine. Difference in the number of viable bacteria adhered on the surface of coated and uncoated stents were statistically calculated using chi square test with p < 0.05 considered significant. The stent colonising ability of Staphylococcus epidermidis and Escherichia coli in a controlled environment chamber was determined using two-challenge dose of the isolates by in vitro challenge test. In qualitative test, the zone of inhibition around the coated stents showed sensitivity against the clinical isolates. In quantitative test, the number of adhered bacteria on the surface of coated stents was reduced to a significant level (p < 0.05). The polymer, tocopherol acetate is highly biodegradable in nature. Due to its degrading ability in body tissues, it releases the anti-infective drugs at a constant and sustained rate.

Fabrication, characterization, and modeling of a biodegradable battery for transient electronics

NASA Astrophysics Data System (ADS)

Edupuganti, Vineet; Solanki, Raj

2016-12-01

Traditionally, emphasis has been placed on durable, long-lasting electronics. However, electronics that are meant to intentionally degrade over time can actually have significant practical applications. Biodegradable, or transient, electronics would open up opportunities in the field of medical implants, where the need for surgical removal of devices could be eliminated. Environmental sensors and, eventually, consumer electronics would also greatly benefit from this technology. An essential component of transient electronics is the battery, which serves as a biodegradable power source. This work involves the fabrication, characterization, and modeling of a magnesium-based biodegradable battery. Galvanostatic discharge tests show that an anode material of magnesium alloy AZ31 extends battery lifetime by over six times, as compared to pure magnesium. With AZ31, the maximum power and capacity of the fabricated device are 67 μW and 5.2 mAh, respectively, though the anode area is just 0.8 cm2. The development of an equivalent circuit model provided insight into the battery's behavior by extracting fitting parameters from experimental data. The model can accurately simulate device behavior, taking into account its intentional degradation. The size of the device and the power it produces are in accordance with typical levels for low-power transient systems.

Corexit 9500 Enhances Oil Biodegradation and Changes ...

EPA Pesticide Factsheets

While COREXIT 9500 is widely applied after oil spills for its reported dispersing activity, there is still a debate on the effectiveness on enhancing oil biodegradation and its potential toxic effect on microbial communities. To better understand the impact of COREXIT 9500 on the structure and activity levels of hydrocarbon degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at cryophilic and mesophilic conditions and using both DNA and RNA extracts as sequencing templates. Oil biodegradation patterns in both cryophilic and mesophilic enrichments were consistent with those reported in the literature (i.e., aliphatics were degraded faster than aromatics). A slight increase in biodegradation was observed in the presence of COREXIT at both 25°C and 5°C experiments. Differences in community structure were observed between treatment conditions in the DNA-based libraries. The 25°C consortia was dominated by unclassified members of the Vibrio, Pseudoidiomarina, Marinobacter, Alcanivorax, and Thallassospira species, while the 5°C consortia were dominated by several genera of Flavobacteria, Alcanivorax and Oleispira. With the exception of Vibrio-like species, members of these genera have been linked to hydrocarbon degradation and have been observed after oil spills. Colwellia and Cycloclasticus, known aromatic degraders, was also found in these enrichments. RNA-based sequencing of 25°C

Quantifying structural modifications of gills of two fish species Astyanax altiparanae (Lambari) and Prochilodus lineatus (Curimbatá) after exposure to biodegradable detergents in urban lake water.

PubMed

Fiorelini Pereira, Bruno; Alves, Anderson Luis; Senhorini, José Augusto; Hakime Scalize, Priscilla; Tocchini De Figueiredo, Fellipe Augusto; Pitol, Dimítrius Leonardo; Caetano, Flávio Henrique

2017-01-01

Anthropic actions in rivers and urban lakes are a cause for concern to our ecosystem. The effects on fauna and flora of substances discharged into waterways have become a focus for investigations globally. Biodegradable detergents are widely used in residences and small industries, but little is known regarding the consequences on fish fauna. The objective of the present study was to identify modifications in gill structure in two fish species, Astyanax altiparanae and Prochilodus lineatus, after treatment with water obtained from an urban lake and an exposure to 1 ppm diluted biodegradable detergents (linear alkylbenzene sulfonate). Data demonstrated exposure to urban lake produced various alterations in gill functions such as lamellar fusions, aneurysms, mucous, and chlorine cell proliferation, which may be attributed to the presence of detergents in the water but may also be a consequence of synergetic actions of detergents with other pollutants. Results showed that the levels of NO - 2 , Na, F - , Cl - , and Fe were significantly higher in urban lake water but in the presence of detergents Ni was also detected. Evidence indicates that biodegradable detergents produce damage to gill functions, which subsequently alters the fish physiology and reduces the ability to cope with stress and survival.

Effect of Biodegradable Scleral Plugs Containing Curcumin on Proliferative Vitreoretinopathy.

PubMed

Zhang, Jun; Zhou, Nalei; Zhang, Bin; Ma, Jingxue

2018-01-01

This study aimed to explore the inhibitory effect of biodegradable scleral plugs containing curcumin on rabbits with proliferative vitreoretinopathy (PVR). The biodegradable scleral plugs containing curcumin were prepared by dissolving PLGA [poly(lactide-co-glycolide)] and curcumin. In total, 30 rabbits were divided into 2 groups: the model group received a vitreous injection of self-blood, and the treatment group received a vitreous injection of self-blood plus biodegradable scleral implants containing 1.5 mg of curcumin. On days 1, 3, 7, 14, 21, and 28 after the operation, clinical observations and PVR classifications were performed. Then, after vitreous samples were collected, different cytokines were detected using antibody chip technology. The scleral plug was 5 mm in length and 1 mm in diameter. Clinical observation showed marked inflammation in the model group. The development grade of PVR in the treatment group was lower than that in the model group (p < 0.05). The outcome of antibody chip technology showed that the expression levels of IL-1α, IL-1β, IL-8, leptin, MMP-9, NCAM, and TNF-α in the treatment group at different time points were significantly lower than those in the model group (p < 0.05). Curcumin might have great potential as a therapeutic agent for PVR by inhibiting various inflammatory factors. © 2017 S. Karger AG, Basel.

Biodegradation of subsurface oil in a tidally influenced sand beach: Impact of hydraulics and interaction with pore water chemistry

NASA Astrophysics Data System (ADS)

Geng, Xiaolong; Boufadel, Michel C.; Lee, Kenneth; Abrams, Stewart; Suidan, Makram

2015-05-01

The aerobic biodegradation of oil in tidally influenced beaches was investigated numerically in this work using realistic beach and tide conditions. A numerical model BIOMARUN, coupling a multiple-Monod kinetic model BIOB to a density-dependent variably saturated groundwater flow model 2-D MARUN, was used to simulate the biodegradation of low-solubility hydrocarbon and transport processes of associated solute species (i.e., oxygen and nitrogen) in a tidally influenced beach environment. It was found that different limiting factors affect different portions of the beach. In the upper intertidal zone, where the inland incoming nutrient concentration was large (1.2 mg N/L), oil biodegradation occurred deeper in the beach (i.e., 0.3 m below the surface). In the midintertidal zone, a reversal was noted where the biodegradation was fast at shallow locations (i.e., 0.1 m below the surface), and it was due to the decrease of oxygen with depth due to consumption, which made oxygen the limiting factor for biodegradation. Oxygen concentration in the midintertidal zone exhibited two peaks as a function of time. One peak was associated with the high tide, when dissolved oxygen laden seawater filled the beach and a second oxygen peak was observed during low tides, and it was due to pore oxygen replenishment from the atmosphere. The effect of the capillary fringe (CF) height was investigated, and it was found that there is an optimal CF for the maximum biodegradation of oil in the beach. Too large a CF (i.e., very fine material) would attenuate oxygen replenishment (either from seawater or the atmosphere), while too small a CF (i.e., very coarse material) would reduce the interaction between microorganisms and oil in the upper intertidal zone due to rapid reduction in the soil moisture at low tide. This article was corrected on 22 JUN 2015. See the end of the full text for details.

BTEX biodegradation by bacteria from effluents of petroleum refinery.

PubMed

Mazzeo, Dânia Elisa Christofoletti; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

2010-09-15

Groundwater contamination with benzene, toluene, ethylbenzene and xylene (BTEX) has been increasing, thus requiring an urgent development of methodologies that are able to remove or minimize the damages these compounds can cause to the environment. The biodegradation process using microorganisms has been regarded as an efficient technology to treat places contaminated with hydrocarbons, since they are able to biotransform and/or biodegrade target pollutants. To prove the efficiency of this process, besides chemical analysis, the use of biological assessments has been indicated. This work identified and selected BTEX-biodegrading microorganisms present in effluents from petroleum refinery, and evaluated the efficiency of microorganism biodegradation process for reducing genotoxic and mutagenic BTEX damage through two test-systems: Allium cepa and hepatoma tissue culture (HTC) cells. Five different non-biodegraded BTEX concentrations were evaluated in relation to biodegraded concentrations. The biodegradation process was performed in a BOD Trak Apparatus (HACH) for 20 days, using microorganisms pre-selected through enrichment. Although the biodegradation usually occurs by a consortium of different microorganisms, the consortium in this study was composed exclusively of five bacteria species and the bacteria Pseudomonas putida was held responsible for the BTEX biodegradation. The chemical analyses showed that BTEX was reduced in the biodegraded concentrations. The results obtained with genotoxicity assays, carried out with both A. cepa and HTC cells, showed that the biodegradation process was able to decrease the genotoxic damages of BTEX. By mutagenic tests, we observed a decrease in damage only to the A. cepa organism. Although no decrease in mutagenicity was observed for HTC cells, no increase of this effect after the biodegradation process was observed either. The application of pre-selected bacteria in biodegradation processes can represent a reliable and effective tool in the treatment of water contaminated with BTEX mixture. Therefore, the raw petroleum refinery effluent might be a source of hydrocarbon-biodegrading microorganisms. Copyright 2010 Elsevier B.V. All rights reserved.

Accelerated Biodegradation of Cement by Sulfur-Oxidizing Bacteria as a Bioassay for Evaluating Immobilization of Low-Level Radioactive Waste

PubMed Central

Aviam, Orli; Bar-Nes, Gabi; Zeiri, Yehuda; Sivan, Alex

2004-01-01

Disposal of low-level radioactive waste by immobilization in cement is being evaluated worldwide. The stability of cement in the environment may be impaired by sulfur-oxidizing bacteria that corrode the cement by producing sulfuric acid. Since this process is so slow that it is not possible to perform studies of the degradation kinetics and to test cement mixtures with increased durability, procedures that accelerate the biodegradation are required. Semicontinuous cultures of Halothiobacillus neapolitanus and Thiomonas intermedia containing thiosulfate as the sole energy source were employed to accelerate the biodegradation of cement samples. This resulted in a weight loss of up to 16% after 39 days, compared with a weight loss of 0.8% in noninoculated controls. Scanning electron microscopy of the degraded cement samples revealed deep cracks, which could be associated with the formation of low-density corrosion products in the interior of the cement. Accelerated biodegradation was also evident from the leaching rates of Ca2+ and Si2+, the major constituents of the cement matrix, and Ca exhibited the highest rate (up to 20 times greater than the control rate) due to the reaction between free lime and the biogenic sulfuric acid. Leaching of Sr2+ and Cs+, which were added to the cement to simulate immobilization of the corresponding radioisotopes, was also monitored. In contrast to the linear leaching kinetics of calcium, silicon, and strontium, the leaching pattern of cesium produced a saturation curve similar to the control curve. Presumably, the leaching of cesium is governed by the diffusion process, whereas the leaching kinetics of the other three ions seems to governed by dissolution of the cement. PMID:15466547

Biodegradation: Updating the concepts of control for microbial cleanup in contaminated aquifers.

PubMed

Meckenstock, Rainer U; Elsner, Martin; Griebler, Christian; Lueders, Tillmann; Stumpp, Christine; Aamand, Jens; Agathos, Spiros N; Albrechtsen, Hans-Jørgen; Bastiaens, Leen; Bjerg, Poul L; Boon, Nico; Dejonghe, Winnie; Huang, Wei E; Schmidt, Susanne I; Smolders, Erik; Sørensen, Sebastian R; Springael, Dirk; van Breukelen, Boris M

2015-06-16

Biodegradation is one of the most favored and sustainable means of removing organic pollutants from contaminated aquifers but the major steering factors are still surprisingly poorly understood. Growing evidence questions some of the established concepts for control of biodegradation. Here, we critically discuss classical concepts such as the thermodynamic redox zonation, or the use of steady state transport scenarios for assessing biodegradation rates. Furthermore, we discuss if the absence of specific degrader populations can explain poor biodegradation. We propose updated perspectives on the controls of biodegradation in contaminant plumes. These include the plume fringe concept, transport limitations, and transient conditions as currently underestimated processes affecting biodegradation.

Biodegradability Evaluation of Polymers by ISO 14855-2

PubMed Central

Funabashi, Masahiro; Ninomiya, Fumi; Kunioka, Masao

2009-01-01

Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed. PMID:20111676

Influence of low oxygen tensions and sorption to sediment black carbon on biodegradation of pyrene.

PubMed

Ortega-Calvo, José-Julio; Gschwend, Philip M

2010-07-01

Sorption to sediment black carbon (BC) may limit the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) in resuspension events and intact sediment beds. We examined this hypothesis experimentally under conditions that were realistic in terms of oxygen concentrations and BC content. A new method, based on synchronous fluorescence observations of (14)C-pyrene, was developed for continuously measuring the uptake of dissolved pyrene by Mycobacterium gilvum VM552, a representative degrader of PAHs. The effect of oxygen and pyrene concentrations on pyrene uptake followed Michaelis-Menten kinetics, resulting in a dissolved oxygen half-saturation constant (K(om)) of 14.1 microM and a dissolved pyrene half-saturation constant (K(pm)) of 6 nM. The fluorescence of (14)C-pyrene in air-saturated suspensions of sediments and induced cells followed time courses that reflected simultaneous desorption and biodegradation of pyrene, ultimately causing a quasi-steady-state concentration of dissolved pyrene balancing desorptive inputs and biodegradation removals. The increasing concentrations of (14)CO(2) in these suspensions, as determined with liquid scintillation, evidenced the strong impact of sorption to BC-rich sediments on the biodegradation rate. Using the best-fit parameter values, we integrated oxygen and sorption effects and showed that oxygen tensions far below saturation levels in water are sufficient to enable significant decreases in the steady-state concentrations of aqueous-phase pyrene. These findings may be relevant for bioaccumulation scenarios that consider the effect of sediment resuspension events on exposure to water column and sediment pore water, as well as the direct uptake of PAHs from sediments.

The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation.

PubMed

Campeão, Mariana E; Reis, Luciana; Leomil, Luciana; de Oliveira, Louisi; Otsuki, Koko; Gardinali, Piero; Pelz, Oliver; Valle, Rogerio; Thompson, Fabiano L; Thompson, Cristiane C

2017-01-01

One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical-chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae , and Alcanivoracaceae ), archaea (e.g., Halobacteriaceae, Desulfurococcaceae , and Methanobacteriaceae ), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web.

The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation

PubMed Central

Campeão, Mariana E.; Reis, Luciana; Leomil, Luciana; de Oliveira, Louisi; Otsuki, Koko; Gardinali, Piero; Pelz, Oliver; Valle, Rogerio; Thompson, Fabiano L.; Thompson, Cristiane C.

2017-01-01

One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical–chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae, and Alcanivoracaceae), archaea (e.g., Halobacteriaceae, Desulfurococcaceae, and Methanobacteriaceae), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web. PMID:28659874

Comparison of 3 biodegradable polymer and durable polymer-based drug-eluting stents in all-comers (BIO-RESORT): rationale and study design of the randomized TWENTE III multicenter trial.

PubMed

Lam, Ming Kai; Sen, Hanim; Tandjung, Kenneth; van Houwelingen, K Gert; de Vries, Arie G; Danse, Peter W; Schotborgh, Carl E; Scholte, Martijn; Löwik, Marije M; Linssen, Gerard C M; Ijzerman, Maarten J; van der Palen, Job; Doggen, Carine J M; von Birgelen, Clemens

2014-04-01

To evaluate the safety and efficacy of 2 novel drug-eluting stents (DES) with biodegradable polymer-based coatings versus a durable coating DES. BIO-RESORT is an investigator-initiated, prospective, patient-blinded, randomized multicenter trial in 3540 Dutch all-comers with various clinical syndromes, requiring percutaneous coronary interventions (PCI) with DES implantation. Randomization (stratified for diabetes mellitus) is being performed in a 1:1:1 ratio between ORSIRO sirolimus-eluting stent with circumferential biodegradable coating, SYNERGY everolimus-eluting stent with abluminal biodegradable coating, and RESOLUTE INTEGRITY zotarolimus-eluting stent with durable coating. The primary endpoint is the incidence of the composite endpoint target vessel failure at 1 year, consisting of cardiac death, target vessel-related myocardial infarction, or clinically driven target vessel revascularization. Power calculation assumes a target vessel failure rate of 8.5% with a 3.5% non-inferiority margin, giving the study a power of 85% (α level .025 adjusted for multiple testing). The impact of diabetes mellitus on post-PCI outcome will be evaluated. The first patient was enrolled on December 21, 2012. BIO-RESORT is a large, prospective, randomized, multicenter trial with three arms, comparing two DES with biodegradable coatings versus a reference DES with a durable coating in 3540 all-comers. The trial will provide novel insights into the clinical outcome of modern DES and will address the impact of known and so far undetected diabetes mellitus on post-PCI outcome. Copyright © 2014 The Authors. Published by Mosby, Inc. All rights reserved.

Use of dynamic simulation to assess the behaviour of linear alkyl benzene sulfonates and their biodegradation intermediates (sulfophenylcarboxylic acids) in estuaries

NASA Astrophysics Data System (ADS)

García-Luque, E.; González-Mazo, E.; Forja, J. M.; Gómez-Parra, A.

2009-02-01

Dynamic laboratory simulation of processes affecting chemical species in their transit through estuaries is a very useful tool to characterize these littoral systems. To date, laboratory studies concerning biodegradation and sorption (onto suspended particulate matter) of LAS in an estuary are scarce. For this reason, a dynamic automated estuarine simulator has been employed to carry out different experiments in order to assess the biodegradability of linear alkyl benzene sulfonates (LAS) and their biodegradation intermediates (sulfophenylcarboxylic acids, SPCs) using environmentally representative LAS concentrations in estuaries by a continuous injection of LAS into the system. During the experiments, a great affinity of LAS for the solid phase has been found, as well as an increased adsorption in line with increased chain length. On the other hand, the presence of SPCs with chain length between 6 and 13 carbon atoms was detected. Accumulation and persistence of medium chain length SPCs (C 6-C 8) along the experiments show that their degradation constitutes the limiting step for the process of LAS mineralization. In the final zone of the simulated estuarine system, the levels of SPCs were below the limits of detection. Thus, the disappearance of SPCs indicated that LAS biodegradation had been completed along the estuary. Similar results have been described for different Iberian littoral ecosystems. Therefore, the simulator employed in this research appears to be a useful tool to anticipate the behaviour of a xenobiotic chemical in its transit through littoral systems with different salinity gradients.

Potential of vetiver (vetiveria zizanioides (L.) Nash) for phytoremediation of petroleum hydrocarbon-contaminated soils in Venezuela.

PubMed

Brandt, Regine; Merkl, Nicole; Schultze-Kraft, Rainer; Infante, Carmen; Broll, Gabriele

2006-01-01

Venezuela is one of the largest oil producers in the world. For the rehabilitation of oil-contaminated sites, phytoremediation represents a promising technology whereby plants are used to enhance biodegradation processes in soil. A greenhouse study was conducted to determine the tolerance of vetiver (Vetiveria zizanioides (L.) Nash) to a Venezuelan heavy crude oil in soil. Additionally, the plant's potential for stimulating the biodegradation processes of petroleum hydrocarbons was tested under the application of two fertilizer levels. In the presence of contaminants, biomass and plant height were significantly reduced. As for fertilization, the lower fertilizer level led to higher biomass production. The specific root surface area was reduced under the effects of petroleum. However, vetiver was found to tolerate crude-oil contamination in a concentration of 5% (w/w). Concerning total oil and grease content in soil, no significant decrease under the influence of vetiver was detected when compared to the unplanted control. Thus, there was no evidence of vetiver enhancing the biodegradation of crude oil in soil under the conditions of this trial. However, uses of vetiver grass in relation to petroleum-contaminated soils are promising for amelioration of slightly polluted sites, to allow other species to get established and for erosion control.

Biodegradation of sorbed chemicals in soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scow, K.M.; Fan, S.; Johnson, C.

Rates of biodegradation of sorbed chemicals are usually lower in soil than in aqueous systems, in part because sorption reduces the availability of the chemical to microorganisms. Biodegradation, sorption, and diffusion occur simultaneously and are tightly coupled. In soil, the rate of biodegradation is a function of a chemical`s diffusion coefficient, sorption partition coefficient, the distance it must diffuse from the site of sorption to microbial populations that can degrade it, and its biodegradation rate constant. A model (DSB model) was developed that describes biodegradation of chemicals limited in the availability by sorption and diffusion. Different kinetics expressions describe biodegradationmore » depending on whether the reaction is controlled by mass transfer (diffusion and sorption) or the intrinsic biodegradation rate, and whether biodegradation begins during or after the majority of sorption has occurred. We tested the hypothesis that there is a direct relationship between how strongly a chemical is sorbed and the chemical`s biodegradation rate. In six soils with different organic carbon contents, there was no relationship between the extent or rate of biodegradation and the sorption partition coefficient for phenanthrene. Aging of phenanthrene residues in soil led to a substantial reduction in the rate of biodegradation compared to biodegradation rates of recently added phenanthrene. Considerable research has focused on identification and development of techniques for enhancing in situ biodegradation of sorbed chemicals. Development of such techniques, especially those involving inoculation with microbial strains, should consider physical mass transfer limitations and potential decreases in bioavailability over time. 4 refs., 3 figs., 1 tab.« less

Study of the Bioremediation of Atrazine under Variable Carbon and Nitrogen Sources by Mixed Bacterial Consortium Isolated from Corn Field Soil in Fars Province of Iran

PubMed Central

Nasseri, Simin; Hashemi, Hassan

2013-01-01

Atrazine herbicide that is widely used in corn production is frequently detected in water resources. The main objectives of this research were focused on assessing the effects of carbon and nitrogen sources on atrazine biodegradation by mixed bacterial consortium and by evaluating the feasibility of using mixed bacterial consortium in soil culture. Shiraz corn field soil with a long history of atrazine application has been explored for their potential of atrazine biodegradation. The influence of different carbon compounds and the effect of nitrogen sources and a different pH (5.5–8.5) on atrazine removal efficiency by mixed bacterial consortium in liquid culture were investigated. Sodium citrate and sucrose had the highest atrazine biodegradation rate (87.22%) among different carbon sources. Atrazine biodegradation rate decreased more quickly by the addition of urea (26.76%) compared to ammonium nitrate. Based on the data obtained in this study, pH of 7.0 is optimum for atrazine biodegradation. After 30 days of incubation, the percent of atrazine reduction rates were significantly enhanced in the inoculated soils (60.5%) as compared to uninoculated control soils (12%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with mixed bacterial consortium may enhance the rate of atrazine degradation in a highly polluted soil. PMID:23533452

In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime.

PubMed

la Cecilia, Daniele; Maggi, Federico

2017-08-01

A comprehensive biodegradation reaction network of atrazine (ATZ) and its 18 byproducts was coupled to the nitrogen cycle and integrated in a computational solver to assess the in-situ biodegradation effectiveness and leaching along a 5m deep soil cultivated with wheat in West Wyalong, New South Wales, Australia. Biodegradation removed 97.7% of 2kg/ha ATZ yearly applications in the root zone, but removal substantially decreased at increasing depths; dechlorination removed 79% of ATZ in aerobic conditions and 18% in anaerobic conditions, whereas deethylation and oxidation removed only 0.11% and 0.15% of ATZ, respectively. The residual Cl mass fraction in ATZ and 4 byproducts was 2.4% of the applied mass. ATZ half-life ranged from 150 to 247days in the soil surface. ATZ reached 5m soil depth within 200years and its concentration increased from 1×10 -6 to 4×10 -6 mg/kg dry-soil over time. The correlation between ATZ specific biomass degradation affinity Φ 0 and half-life t 1/2 , although relatively uncertain for both hydrolyzing and oxidizing bacteria, suggested that microorganisms with high Φ 0 led to low ATZ t 1/2 . Greater ATZ applications were balanced by small nonlinear increments of ATZ biodegraded fraction within the root zone and therefore less ATZ leached into the shallow aquifer. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of methane biodegradation kinetics in two-phase partitioning bioreactors by pulse respirometry.

PubMed

Ordaz, Alberto; López, Juan C; Figueroa-González, Ivonne; Muñoz, Raúl; Quijano, Guillermo

2014-12-15

Biological methane biodegradation is a promising treatment alternative when the methane produced in waste management facilities cannot be used for energy generation. Two-phase partitioning bioreactors (TPPBs), provided with a non-aqueous phase (NAP) with high affinity for the target pollutant, are particularly suitable for the treatment of poorly water-soluble compounds such as methane. Nevertheless, little is known about the influence of the presence of the NAP on the resulting biodegradation kinetics in TPPBs. In this study, an experimental framework based on the in situ pulse respirometry technique was developed to assess the impact of NAP addition on the methane biodegradation kinetics using Methylosinus sporium as a model methane-degrading microorganism. A comprehensive mass transfer characterization was performed in order to avoid mass transfer limiting scenarios and ensure a correct kinetic parameter characterization. The presence of the NAP mediated significant changes in the apparent kinetic parameters of M. sporium during methane biodegradation, with variations of 60, 120, and 150% in the maximum oxygen uptake rate, half-saturation constant and maximum specific growth rate, respectively, compared with the intrinsic kinetic parameters retrieved from a control without NAP. These significant changes in the kinetic parameters mediated by the NAP must be considered for the design, operation and modeling of TPPBs devoted to air pollution control. Copyright © 2014 Elsevier Ltd. All rights reserved.

In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime

NASA Astrophysics Data System (ADS)

la Cecilia, Daniele; Maggi, Federico

2017-08-01

A comprehensive biodegradation reaction network of atrazine (ATZ) and its 18 byproducts was coupled to the nitrogen cycle and integrated in a computational solver to assess the in-situ biodegradation effectiveness and leaching along a 5 m deep soil cultivated with wheat in West Wyalong, New South Wales, Australia. Biodegradation removed 97.7% of 2 kg/ha ATZ yearly applications in the root zone, but removal substantially decreased at increasing depths; dechlorination removed 79% of ATZ in aerobic conditions and 18% in anaerobic conditions, whereas deethylation and oxidation removed only 0.11% and 0.15% of ATZ, respectively. The residual Cl mass fraction in ATZ and 4 byproducts was 2.4% of the applied mass. ATZ half-life ranged from 150 to 247 days in the soil surface. ATZ reached 5 m soil depth within 200 years and its concentration increased from 1 ×10-6 to 4 ×10-6 mg/kgdry-soil over time. The correlation between ATZ specific biomass degradation affinity Φ0 and half-life t1/2, although relatively uncertain for both hydrolyzing and oxidizing bacteria, suggested that microorganisms with high Φ0 led to low ATZ t1/2. Greater ATZ applications were balanced by small nonlinear increments of ATZ biodegraded fraction within the root zone and therefore less ATZ leached into the shallow aquifer.

New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process.

PubMed

Cregut, Mickael; Bedas, M; Durand, M-J; Thouand, G

2013-12-01

Polyurethanes are polymeric plastics that were first used as substitutes for traditional polymers suspected to release volatile organic hazardous substances. The limitless conformations and formulations of polyurethanes enabled their use in a wide variety of applications. Because approximately 10 Mt of polyurethanes is produced each year, environmental concern over their considerable contribution to landfill waste accumulation appeared in the 1990s. To date, no recycling processes allow for the efficient reuse of polyurethane waste due to their high resistance to (a)biotic disturbances. To find alternatives to systematic accumulation or incineration of polyurethanes, a bibliographic analysis was performed on major scientific advances in the polyurethane (bio)degradation field to identify opportunities for the development of new technologies to recondition this material. Until polymers exhibiting oxo- or hydro-biodegradative traits are generated, conventional polyurethanes that are known to be only slightly biodegradable are of great concern. The research focused on polyurethane biodegradation highlights recent attempts to reprocess conventional industrial polyurethanes via microbial or enzymatic degradation. This review describes several wonderful opportunities for the establishment of new processes for polyurethane recycling. Meeting these new challenges could lead to the development of sustainable management processes involving polymer recycling or reuse as environmentally safe options for industries. The ability to upgrade polyurethane wastes to chemical compounds with a higher added value would be especially attractive. © 2013.

Atomic elucidation of the cyclodextrin effects on DDT solubility and biodegradation.

PubMed

Ren, Baiping; Zhang, Mingzhen; Gao, Huipeng; Zheng, Jie; Jia, Lingyun

2016-07-14

DDT (1,1,1-trichloro-2.2-bis(p-chlorophenyl)ethane), one of the most abused insecticides, is a highly hazardous component for both human health and environmental applications. The biodegradation of DDT into non-toxic, environmentally benign components is strongly limited by the poor bioavailability of DDT. In this work, we combined experiments and molecular simulations to examine the effect of three cyclodextrins (α-, β-, and γ-CD) on their structure-specific interactions with DDT, specifically in relation to DDT solubility and biodegradability. It was found that all three CDs were able to bind to DDT with their inner hydrophobic cavity and different binding affinities and orientations, demonstrating their ability to improve DDT solubility. Different from the strong binding between DDT and β-/γ-CDs via a fully DDT bury mode, α-CD had a relatively weak binding with DDT via a partial DDT bury mode, which allowed DDT to be readily disassociated from α-CD at the lipid membrane interface, followed by DDT permeation into and across the cell membrane. The different binding modes between DDT and CDs explain why only α-CD can promote the bioavailability and biodegradation of DDT by simultaneously increasing its aqueous solubility and membrane interaction. This work provides structural-based binding information for the further modification and optimization of these three CDs to enhance their solubility and biodegradability of DDT.

Biodegradable polymer nanoparticles that rapidly penetrate the human mucus barrier

PubMed Central

Tang, Benjamin C.; Dawson, Michelle; Lai, Samuel K.; Wang, Ying-Ying; Suk, Jung Soo; Yang, Ming; Zeitlin, Pamela; Boyle, Michael P.; Fu, Jie; Hanes, Justin

2009-01-01

Protective mucus coatings typically trap and rapidly remove foreign particles from the eyes, gastrointestinal tract, airways, nasopharynx, and female reproductive tract, thereby strongly limiting opportunities for controlled drug delivery at mucosal surfaces. No synthetic drug delivery system composed of biodegradable polymers has been shown to penetrate highly viscoelastic human mucus, such as non-ovulatory cervicovaginal mucus, at a significant rate. We prepared nanoparticles composed of a biodegradable diblock copolymer of poly(sebacic acid) and poly(ethylene glycol) (PSA-PEG), both of which are routinely used in humans. In fresh undiluted human cervicovaginal mucus (CVM), which has a bulk viscosity approximately 1,800-fold higher than water at low shear, PSA-PEG nanoparticles diffused at an average speed only 12-fold lower than the same particles in pure water. In contrast, similarly sized biodegradable nanoparticles composed of PSA or poly(lactic-co-glycolic acid) (PLGA) diffused at least 3,300-fold slower in CVM than in water. PSA-PEG particles also rapidly penetrated sputum expectorated from the lungs of patients with cystic fibrosis, a disease characterized by hyperviscoelastic mucus secretions. Rapid nanoparticle transport in mucus is made possible by the efficient partitioning of PEG to the particle surface during formulation. Biodegradable polymeric nanoparticles capable of overcoming human mucus barriers and providing sustained drug release open significant opportunities for improved drug and gene delivery at mucosal surfaces. PMID:19901335

Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium.

PubMed

Nievas, M L; Commendatore, M G; Esteves, J L; Bucalá, V

2008-06-15

The biodegradation of a hazardous waste (bilge waste), a fuel oil-type complex residue from normal ship operations, was studied in a batch bioreactor using a microbial consortium in seawater medium. Experiments with initial concentrations of 0.18 and 0.53% (v/v) of bilge waste were carried out. In order to study the biodegradation kinetics, the mass of n-alkanes, resolved hydrocarbons and unresolved complex mixture (UCM) hydrocarbons were assessed by gas chromatography (GC). Emulsification was detected in both experiments, possibly linked to the n-alkanes depletion, with differences in emulsification start times and extents according to the initial hydrocarbon concentration. Both facts influenced the hydrocarbon biodegradation kinetics. A sequential biodegradation of n-alkanes and UMC was found for the higher hydrocarbon content. Being the former growth associated, while UCM biodegradation was a non-growing process showing enzymatic-type biodegradation kinetics. For the lower hydrocarbon concentration, simultaneous biodegradation of n-alkanes and UMC were found before emulsification. Nevertheless, certain UCM biodegradation was observed after the medium emulsification. According to the observed kinetics, three main types of hydrocarbons (n-alkanes, biodegradable UCM and recalcitrant UCM) were found adequate to represent the multicomponent substrate (bilge waste) for future modelling of the biodegradation process.

Residual toxicity after biodegradation: interactions among benzene, toluene, and chloroform.

PubMed

da Silva Nunes-Halldorson, Vânia; Steiner, Robert L; Smith, Geoffrey B

2004-02-01

A microbial enrichment originating from a pristine aquifer was found to aerobically biodegrade benzene and toluene, but not chloroform. This enrichment culture was used to study changes in pollutant toxicity as affected by biodegradative activity. Two assays for toxicity were used: (1) a 48-h acute toxicity test using the freshwater invertebrate Ceriodaphnia dubia and (2) microbial biodegradation activity as affected by the presence of mixed pollutants. At 20-ppm concentrations, toluene was significantly more toxic (99% mortality) to C. dubia than benzene (48% mortality) or chloroform (40% mortality). Also at 20-ppm concentrations, but before biodegradation, toluene was significantly more toxic (88% mortality) to C. dubia than benzene (33% mortality). After biodegradation of 98% of toluene and benzene, significant residual toxicity still remained in the bacterial supernatant: toluene-degraded supernatant caused 33% mortality in C. dubia and benzene-degraded supernatant caused 24% mortality. In the second toxicity assay, examining the effect of mixed pollutants on biodegradation activity, the presence of benzene slowed the biodegradation of toluene, but chloroform had no effect on either benzene or toluene biodegradation. Results indicate that significant toxicity remain after biodegradation and that halogenated aliphatic hydrocarbons may have little or no effect on aromatic hydrocarbon biodegradation at sites impacted by mixed pollutants.

Biochemical interpretation of quantitative structure-activity relationships (QSAR) for biodegradation of N-heterocycles: a complementary approach to predict biodegradability.

PubMed

Philipp, Bodo; Hoff, Malte; Germa, Florence; Schink, Bernhard; Beimborn, Dieter; Mersch-Sundermann, Volker

2007-02-15

Prediction of the biodegradability of organic compounds is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. We combined quantitative structure-activity relationships (QSAR) with the systematic collection of biochemical knowledge to establish rules for the prediction of aerobic biodegradation of N-heterocycles. Validated biodegradation data of 194 N-heterocyclic compounds were analyzed using the MULTICASE-method which delivered two QSAR models based on 17 activating (OSAR 1) and on 16 inactivating molecular fragments (GSAR 2), which were statistically significantly linked to efficient or poor biodegradability, respectively. The percentages of correct classifications were over 99% for both models, and cross-validation resulted in 67.9% (GSAR 1) and 70.4% (OSAR 2) correct predictions. Biochemical interpretation of the activating and inactivating characteristics of the molecular fragments delivered plausible mechanistic interpretations and enabled us to establish the following biodegradation rules: (1) Target sites for amidohydrolases and for cytochrome P450 monooxygenases enhance biodegradation of nonaromatic N-heterocycles. (2) Target sites for molybdenum hydroxylases enhance biodegradation of aromatic N-heterocycles. (3) Target sites for hydratation by an urocanase-like mechanism enhance biodegradation of imidazoles. Our complementary approach represents a feasible strategy for generating concrete rules for the prediction of biodegradability of organic compounds.

Evaluation of the effects of nanoscale zero-valent iron (nZVI) dispersants on intrinsic biodegradation of trichloroethylene (TCE).

PubMed

Chang, Y C; Huang, S C; Chen, K F

2014-01-01

In this study, the biodegradability of nanoscale zero-valent iron (nZVI) dispersants and their effects on the intrinsic biodegradation of trichloroethylene (TCE) were evaluated. Results of a microcosm study show that the biodegradability of three dispersants followed the sequence of: polyvinyl alcohol-co-vinyl acetate-co-itaconic acid (PV3A) > polyoxyethylene (20) sorbitan monolaurate (Tween 20) > polyacrylic acid (PAA) under aerobic conditions, and PV3A > Tween 20 > PAA under anaerobic conditions. Natural biodegradation of TCE was observed under both aerobic and anaerobic conditions. No significant effects were observed on the intrinsic biodegradation of TCE under aerobic conditions with the presence of the dispersants. The addition of PAA seemed to have a slightly adverse impact on anaerobic TCE biodegradation. Higher accumulation of the byproducts of anaerobic TCE biodegradation was detected with the addition of PV3A and Tween 20. The diversity of the microbial community was enhanced under aerobic conditions with the presence of more biodegradable PV3A and Tween 20. The results of this study indicate that it is necessary to select an appropriate dispersant for nZVI to prevent a residual of the dispersant in the subsurface. Additionally, the effects of the dispersant on TCE biodegradation and the accumulation of TCE biodegrading byproducts should also be considered.

Coupling UV-H2O2 to accelerate dimethyl phthalate (DMP) biodegradation and oxidation.

PubMed

Chen, Bin; Song, Jiaxiu; Yang, Lihui; Bai, Qi; Li, Rongjie; Zhang, Yongming; Rittmann, Bruce E

2015-11-01

Dimethyl phthalate (DMP), an important industrial raw material, is an endocrine disruptor of concern for human and environmental health. DMP exhibits slow biodegradation, and its coupled treatment by means of advanced oxidation may enhance its biotransformation and mineralization. We evaluated two ways of coupling UV-H2O2 advanced oxidation to biodegradation: sequential coupling and intimate coupling in an internal circulation baffled biofilm reactor (ICBBR). During sequential coupling, UV-H2O2 pretreatment generated carboxylic acids that depressed the pH, and subsequent biodegradation generated phthalic acid; both factors inhibited DMP biodegradation. During intimately coupled UV-H2O2 with biodegradation, carboxylic acids and phthalic acid (PA) did not accumulate, and the biodegradation rate was 13 % faster than with biodegradation alone and 78 % faster than with biodegradation after UV-H2O2 pretreatment. Similarly, DMP oxidation with intimate coupling increased by 5 and 39 %, respectively, compared with biodegradation alone and sequential coupling. The enhancement effects during intimate coupling can be attributed to the rapid catabolism of carboxylic acids, which generated intracellular electron carriers that directly accelerated di-oxygenation of PA and relieved the inhibition effect of PA and low pH. Thus, intimate coupling optimized the impacts of energy input from UV irradiation used together with biodegradation.

Microbial synthesis of poly(epsilon-lysine) and its various applications.

PubMed

Shih, Ing-Lung; Shen, Ming-Haw; Van, Yi-Tsong

2006-06-01

This review article deals with the microbial synthesis, physiochemical properties, and potential applications of poly-epsilon-lysine (epsilon-PL), which is a naturally occurring biomaterial that is water soluble, biodegradable, edible and non-toxic toward humans and the environment. The potential applications of epsilon-PL as food preservatives, emulsifying agent, dietary agent, biodegradable fibers, highly water absorbable hydrogels, drug carriers, anticancer agent enhancer, biochip coatings in the fields of food, medicine, agriculture and electronics are also discussed in this review.

Barrier layers against oxygen transmission on the basis of electron beam cured methacrylated gelatin

NASA Astrophysics Data System (ADS)

Scherzer, Tom

1997-08-01

The development of barrier layers against oxygen transmission on the basis of radiation-curable methacrylated gelatin will be reported. The electron beam cured gelatin coatings show an extremely low oxygen permeability and a high resistance against boiling water. Moreover, the methacrylated gelatins possess good adhesion characteristics. Therefore, they are suited as barrier adhesives in laminates for food packaging applications. If substrate foils from biodegradable polymers are used, the development of completely biodegradable packaging materials seems to be possible.

Biodegradation of Trichloroethylene by an Endophyte of Hybrid Poplar

PubMed Central

Kang, Jun Won; Khan, Zareen

2012-01-01

We isolated and characterized a novel endophyte from hybrid poplar. This unique endophyte, identified as Enterobacter sp. strain PDN3, showed high tolerance to trichloroethylene (TCE). Without the addition of inducers, such as toluene or phenol, PDN3 rapidly reduced TCE levels in medium from 72.4 μM to 30.1 μM in 24 h with a concurrent release of 127 μM chloride ion, and nearly 80% of TCE (55.3 μM) was dechlorinated by PDN3 in 5 days with 166 μM chloride ion production, suggesting TCE degradation. PMID:22367087

Investigating the importance of flow when utilizing hyaluronan scaffolds for tissue engineering.

PubMed

Donegan, Gail C; Hunt, John A; Rhodes, Nicholas

2010-02-01

Esterified hyaluronan scaffolds offer significant advantages for tissue engineering. They are recognized by cellular receptors, interact with many other extracellular matrix proteins and their metabolism is mediated by intrinsic cellular pathways. In this study differences in the viability and structural integrity of vascular tissue models cultured on hyaluronan scaffolds under laminar flow conditions highlighted potential differences in the biodegradation kinetics, processes and end-products, depending on the culture environment. Critical factors are likely to include seeding densities and the duration and magnitude of applied biomechanical stress. Proteomic evaluation of the timing and amount of remodelling protein expression, the resulting biomechanical changes arising from this response and metabolic cell viability assay, together with examination of tissue morphology, were conducted in vascular tissue models cultured on esterified hyaluronan felt and PTFE mesh scaffolds. The vascular tissue models were derived using complete cell sheets derived from harvested and expanded umbilical cord vein cells. This seeding method utilizes high-density cell populations from the outset, while the cells are already supported by their own abundant extracellular matrix. Type I and type IV collagen expression in parallel with MMP-1 and MMP-2 expression were monitored in the tissue models over a 10 day culture period under laminar flow regimes using protein immobilization technologies. Uniaxial tensile testing and scanning electron microscopy were used to compare the resulting effects of hydrodynamic stimulation upon structural integrity, while viability assays were conducted to evaluate the effects of shear on metabolic function. The proteomic results showed that the hyaluronan felt-supported tissues expressed higher levels of all remodelling proteins than those cultured on PTFE mesh. Overall, a 21% greater expression of type I collagen, 24% higher levels of type IV collagen, 24% higher levels of MMP-1 and 34% more MMP-2 were observed during hydrodynamic stress. This was coupled with a loss of structural integrity in these models after the introduction of laminar flow, as compared to the increases in all mechanical properties observed in the PTFE mesh-supported tissues. However, under flow conditions, the hyaluronan-supported tissues showed some recovery of the viability originally lost during static culture conditions, in contrast to PTFE mesh-based models, where initial gains were followed by a decline in metabolic viability after applied shear stress. Proteomic, cell viability and mechanical testing data emphasized the need for extended in vitro evaluations to enable better understanding of multi-stage remodelling and reparative processes in tissues cultured on biodegradable scaffolds. This study also highlighted the possibility that in high-density tissue culture with a biodegradable component, dynamic conditions may be more conducive to optimal tissue development than the static environment because they facilitate the efficient removal of high concentrations of degradation end-products accumulating in the pericellular space.

Effects of triethyl phosphate and nitrate on electrokinetically enhanced biodegradation of diesel in low permeability soils.

PubMed

Lee, G T; Ro, H M; Lee, S M

2007-08-01

Bench-scale experiments for electrokinetically enhanced bioremediation of diesel in low permeability soils were conducted. An electrokinetic reactor (ER) was filled with kaolin that was artificially contaminated with diesel at a level of 2500 mg kg(-1). A constant voltage gradient of 1.0 V cm(-1) was applied. In phosphorus transport experiments, KH2PO4 was not distributed homogeneously along the ER, and most of the transported phosphorus was converted to water-insoluble aluminum phosphate after 12 days of electrokinetic (EK) operation. However, the advancing P front of triethyl phosphate (TEP) progressed with time and resulted in uniform P distribution. The treatments employed in the electrokinetically enhanced bioremediation of diesel were control (no addition of nitrogen and phosphorus), NP (KNO3+ KH2PO4), NT (KNO3+ TEP), UP (urea+ KH2PO4), and UT (urea+TEP). Analysis of effluent collected during the first 12 days of EK operation showed that diesel was not removed from the kaolin. After nutrient delivery, using the EK operation, the ER was transferred into an incubator for the biodegradation process. After 60 days of biodegradation, the concentrations of diesel in the kaolin for the NP, NT, UP, UT, and control treatments were 1356, 1002, 1658, 1612, and 2003 mg kg(-1), respectively. The ratio of biodegraded diesel concentration to initial concentration (2465 mg kg(-1)) in NP, NT, UP, UT, and control were 45.0%, 59.4%, 32.7%, 34.6%, and 18.7%, respectively. This result showed that TEP, treated along with NO3-, was most effective for the biodegradation of diesel. TEP was delivered more efficiently to the target zones and with less phosphorus loss than KH2PO4. However, this facilitated phosphorus delivery was effective in biodegrading diesel under anaerobic conditions only when electron acceptors, such as NO3-, were present.

Effects of biochars and MWNTs on biodegradation behavior of atrazine by Acinetobacter lwoffii DNS32.

PubMed

Yang, Fan; Jiang, Qun; Zhu, Moran; Zhao, Lulu; Zhang, Ying

2017-01-15

Whether the biodegradation of atrazine by Acinetobacter lwoffii DNS32 can have a difference in the presence of two representative carbon materials (CMs), namely, biochars (BCs) and carbon nanotubes (CNTs) is explored, through investigating the influence of CMs on the biodegradation rate, the viability of bacteria and the expression of atrazine genes in aqueous medium. Multi-walled carbon nanotubes (MWNTs), biochars resulted from corn straws (C-BCs) and that made from banana peels (B-BCs) were chosen as the examples. Compared to the control in the absence of C-BCs, B-BCs and MWNTs, the biodegradation efficiencies decrease from 95.3%, 101.8% and 94.8% to 82.6%, 41.8% and 31.1% as the concentrations of these materials increase from 10 to 100mg/L, indicating that BCs have relatively lower toxicity on the biodegradation of atrazine than CNTs, which are agreement with the results of bacterial viability. Transmission electron microscope (TEM) images of Acinetobacter lwoffii DNS32 cells exposure to CMs at 50mg/L show that the cell membrane can be destroyed at different levels after being exposed to various CMs, suggesting that the damage to the cell membrane induced by CMs is a substantial factor leading to the inactivation of bacteria, further decreasing the degradation rate and efficiency of bacteria. The enhanced bacterial growth and the up-regulation of degradation genes can stimulate the degradation rate to pre-adsorbed atrazine on the CMs. This study suggests that biodegradation of atrazine associated with CMs may depend on the carbon composition, structure and CM concentrations. The innovation point of this report is to compare the effects of biochars and CNTs on the degradation rate and activity of Acinetobacter lwoffii DNS32 and may help to further understand the environment effects of CMs. Copyright © 2016 Elsevier B.V. All rights reserved.

Biodegradable composite scaffolds: a strategy to modulate stem cell behaviour.

PubMed

Armentano, Ilaria; Fortunati, Elena; Mattioli, Samantha; Rescignano, Nicolatta; Kenny, José M

2013-04-01

The application of new biomaterial technologies offers the potential to direct the stem cell fate, targeting the delivery of cells and reducing immune rejection, thereby supporting the development of regenerative medicine. Cells respond to their surrounding structure and with nanostructures exhibit unique proliferative and differentiation properties. This review presents the relevance, the promising perspectives and challenges of current biodegradable composite scaffolds in terms of material properties, processing technology and surface modification, focusing on significant recent patents in these fields. It has been reported how biodegradable porous composite scaffolds can be engineered with initial properties that reproduce the anisotropy, viscoelasticity, tension-compression non-linearity of different tissues by introducing specific nanostructures. Moreover the modulation of electrical, morphological, surface and topographic scaffold properties enables specific stem cell response. Recent advances in nanotechnology have allowed to engineer novel biomaterials with these complexity levels. Understanding the specific biological response triggered by various aspects of the fibrous environment is important in guiding the design and engineering of novel substrates that mimic the native cell matrix interactions in vivo.

Biodegradation of effluent contaminated with diesel fuel and gasoline.

PubMed

Vieira, P A; Vieira, R B; de França, F P; Cardoso, V L

2007-02-09

We studied the effects of fuel concentration (diesel and gasoline), nitrogen concentration and culture type on the biodegradation of synthetic effluent similar to what was found at inland fuel distribution terminals. An experimental design with two levels and three variables (2(3)) was used. The mixed cultures used in this study were obtained from lake with a history of petroleum contamination and were named culture C(1) (collected from surface sediment) and C(2) (collected from a depth of approximately 30cm). Of the parameters studied, the ones that had the greatest influence on the removal of total petroleum hydrocarbons (TPH) were a nitrogen concentration of 550mg/L and a fuel concentration of 4% (v/v) in the presence of culture C(1). The biodegradability study showed a TPH removal of 90+/-2% over a process period of 49 days. Analysis using gas chromatography identified 16 hydrocarbons. The aromatic compounds did not degrade as readily as the other hydrocarbons that were identified.

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils.

PubMed

Ylivainio, Kari

2010-10-01

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg(-1)). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Model coupling intraparticle diffusion/sorption, nonlinear sorption, and biodegradation processes

USGS Publications Warehouse

Karapanagioti, Hrissi K.; Gossard, Chris M.; Strevett, Keith A.; Kolar, Randall L.; Sabatini, David A.

2001-01-01

Diffusion, sorption and biodegradation are key processes impacting the efficiency of natural attenuation. While each process has been studied individually, limited information exists on the kinetic coupling of these processes. In this paper, a model is presented that couples nonlinear and nonequilibrium sorption (intraparticle diffusion) with biodegradation kinetics. Initially, these processes are studied independently (i.e., intraparticle diffusion, nonlinear sorption and biodegradation), with appropriate parameters determined from these independent studies. Then, the coupled processes are studied, with an initial data set used to determine biodegradation constants that were subsequently used to successfully predict the behavior of a second data set. The validated model is then used to conduct a sensitivity analysis, which reveals conditions where biodegradation becomes desorption rate-limited. If the chemical is not pre-equilibrated with the soil prior to the onset of biodegradation, then fast sorption will reduce aqueous concentrations and thus biodegradation rates. Another sensitivity analysis demonstrates the importance of including nonlinear sorption in a coupled diffusion/sorption and biodegradation model. While predictions based on linear sorption isotherms agree well with solution concentrations, for the conditions evaluated this approach overestimates the percentage of contaminant biodegraded by as much as 50%. This research demonstrates that nonlinear sorption should be coupled with diffusion/sorption and biodegradation models in order to accurately predict bioremediation and natural attenuation processes. To our knowledge this study is unique in studying nonlinear sorption coupled with intraparticle diffusion and biodegradation kinetics with natural media.

Intravascular imaging comparison of two metallic limus-eluting stents abluminally coated with biodegradable polymers: IVUS and OCT results of the DESTINY trial.

PubMed

Costa, J Ribamar; Chamié, Daniel; Abizaid, Alexandre A C; Ribeiro, Expedito; Meireles, George C; Prudente, Maurício; Campos, Carlos A; Castro, Juliana P; Costa, Ricardo; Lemos, Pedro A

2017-02-01

We sought to compare, by means of IVUS and OCT imaging, the performance of a novel sirolimus-eluting drug-eluting stent (DES) with biodegradable polymer (Inspiron™) to the Biomatrix™ DES. From the DESTINY trial, a total of 70 randomized patients (2:1) were enrolled in the IVUS substudy (Inspiron™, n = 46; Biomatrix™: n = 20) while 25 patients were evaluated with OCT (Inspiron™, n = 19; Biomatrix™: n = 06) at 9-month follow-up. The main endpoints were % of neointimal tissue obstruction (IVUS) and neointimal stut coverage (OCT) at 9 months. Patients treated with both DES had very little NIH formation at 9 months either by IVUS (% of NIH obstruction of 4.9 ± 4.1 % with Inspiron™ vs. 2.7 ± 2.9 % with Biomatrix™, p = 0.03) or by OCT (neointimal thickness of 144.2 ± 72.5 µm Inspiron™ vs. 115.0 ± 53.9 µm with Biomatrix™, p = 0.45). Regarding OCT strut-level assessment, again both devices showed excellent 9-month performance, with high rates of strut coverage (99.49 ± 1.01 % with Inspiron™ vs. 97.62 ± 2.21 % with Biomatrix™, p < 0.001) and very rare malapposition (0.29 ± 1.06 % with Inspiron™ vs. 0.53 ± 0.82 % with Biomatrix™, p = 0.44). Patients with any uncovered struts were more frequently identified in the Biomatrix™ group (9.78 ± 7.13 vs. 2.29 ± 3.91 %, p < 0.001). In the present study, midterm IVUS and OCT evaluations showed that both new generation DES with biodegradable polymer were effective in terms of suppressing excessive neointimal response, with very high rates of apposed and covered struts, suggesting a consistent and benign healing pattern.

A review of plastic waste biodegradation.

PubMed

Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

2005-01-01

With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

Additional Equipment for Soil Biodegradation

NASA Astrophysics Data System (ADS)

Vondráčková, Terezie; Kraus, Michal; Šál, Jiří

2017-12-01

Intensification of industrial production, increasing citizens’ living standards, expanding the consumer assortment mean in the production - consumption cycle a constantly increasing occurrence of waste material, which by its very nature must be considered as a source of useful raw materials in all branches of human activity. In addition to strict legislative requirements, a number of circumstances characterize waste management. It is mainly extensive transport associated with the handling and storage of large volumes of substances with a large assortment of materials (substances of all possible physical and chemical properties) and high demands on reliability and time coordination of follow-up processes. Considerable differences in transport distances, a large number of sources, processors and customers, and not least seasonal fluctuations in waste and strong price pressures cannot be overlooked. This highlights the importance of logistics in waste management. Soils that are contaminated with oil and petroleum products are hazardous industrial waste. Methods of industrial waste disposal are landfilling, biological processes, thermal processes and physical and chemical methods. The paper focuses on the possibilities of degradation of oil pollution, in particular biodegradation by bacteria, which is relatively low-cost among technologies. It is necessary to win the fight with time so that no ground water is contaminated. We have developed two additional devices to help reduce oil accident of smaller ranges. In the case of such an oil accident, it is necessary to carry out the permeability test of contaminated soil in time and, on this basis, to choose the technology appropriate to the accident - either in-sit biodegradation - at the site of the accident, or on-sit - to remove the soil and biodegrade it on the designated deposits. A special injection drill was developed for in-sit biodegradation, tossing and aeration equipment of the extracted soil was developed for on-sit biodegradation.

Influence of copper composition on mechanical properties of biodegradable material Mg-Zn-Cu for orthopedic application

NASA Astrophysics Data System (ADS)

Purniawan, A.; Maulidiah, H. M.; Purwaningsih, H.

2018-04-01

Implant is usually used as a treatment of bone fracture. At the moment, non-biodegradable implants is still widely employed in this application. Non-biodegradable implant requires re-surgery to retrieve implants that are installed in the body. It increase the cost and it is painful for the patient itself. In order to solve the problem, Mg-based biodegradable metals is developing so that the material will be compatible with body and gradually degrade in patient's body. However, magnesium has several disadvantages such as high degradation rates and low mechanical properties when compared to the mechanical properties of natural bone. Therefore, it is necessary to add elements into the magnesium alloy. In this research, copper (Cu) was alloyed in Mg alloy based biodegradable material. In addition, Cu is not only strengthening the structure but also for supporting element for the immune system, antibacterial and antifungal. The purpose of this research is to improve mechanical properties of Mg-based biodegradable material using Cu alloying. Powder metallurgy method was used to fabricate the device. The variation used in this research is the composition of Cu (0.5, 1, and 1.5% Cu). The porosity test was performed using apparent porosity test, compressive test and hardness test to know the mechanical properties of the alloy, and the weightless test to find out the material degradation rate. Based on the results can be conclude that Mg-Zn-Cu alloy material with 1% Cu composition is the most suitable specimen to be applied as a candidate for orthopedic devices material with hardness value is 393.6 MPa. Also obtained the value of the compressive test is 153 MPa.

Behaviour of five pharmaceuticals with high baseline toxicity in wastewater treatment

NASA Astrophysics Data System (ADS)

van Driezum, Inge; McArdell, Christa; Fenner, Kathrin; Helbling, Damian; van Breukelen, Boris

2013-04-01

Many pharmaceuticals enter the aquatic environment through sewer systems and are partially removed in wastewater treatment plants (WWTP) by sorption to sludge biomass or biodegradation. Biodegradation often does not lead to complete mineralization but to the formation of stable transformation products (TPs), which might still be harmful to the environment. Recently, a study was undertaken to assess the risk of the top 100 pharmaceuticals from wastewater of a hospital in Switzerland. The predicted toxicity was linked to the predicted environmental concentration in order to assess overall risk potential. In this study, biodegradation and sorption studies were carried out on the top five selected pharmaceuticals (amiodarone, atorvastatin, clotrimazole, meclozine and ritonavir). Potential TPs that are formed during activated sludge treatment were identified and concentrations of both the parent compounds and TPs were measured in the WWTP. With this data, the fate of these compounds was modeled in a WWTP system using a multi-reactor steady-state WWTP model. This study showed that sorption was the most important loss process for amiodarone and meclozine. They had an elimination of more than 99%. Sorption was also the main loss process for clotrimazole, but it was combined with some biodegradation. For ritonavir, both biodegradation and sorption played a role in the loss of this compound. The most important removal process for atorvastatin was biodegradation. Four TPs, formed through β-oxidation and monohydroxilation, were identified in both the activated sludge batch reactors and the WWTP effluent. In the WWTP effluent, only atorvastatin, clotrimazole and ritonavir were found. All identified TPs of atorvastatin were detected in the effluent. Risk quotients (RQ) of all five pharmaceuticals were estimated based on effluent concentration and baseline toxicity and ranged from zero to 2.14. Only ritonavir potentially poses an ecotoxicological risk for the aquatic environment.

Influence of Mechanical Properties of Aerial Shells made from Biodegradable Plastics on Smaller Fragmentation

NASA Astrophysics Data System (ADS)

Kudo, Makoto; Murata, Kenji; Kamata, Satoru; Hamada, Fumio

In this paper, a new aerial shell made of biodegradable plastics was developed and explosion tests were carried out using 2.5-10 gou-size firework aerial shells at a ground test site in order to observe the fragmentation. The dispersed fragments were then collected and their size and distribution measured. In order to monitor the fragmentation visually, a high-speed camera was used to film the ignition of the bursting charge and the scattering of the shell fragments. The shell fragments became much smaller, because mechanical properties of biodegradable plastics that were added improved polyvinyl alcohol (PVA) and chaff powder (CP). Fibrillation was seen in PBS/PVA/CP, and it seemed effective for mechanical properties. As a result, safer aerial shells which disperse into smaller fragments on explosion were successfully developed.

Multi-element isotope fractionation concepts to characterize the biodegradation of hydrocarbons - from enzymes to the environment.

PubMed

Vogt, Carsten; Dorer, Conrad; Musat, Florin; Richnow, Hans-Hermann

2016-10-01

Multi-element compound-specific isotope fractionation (ME-CSIA) has become a state-of-the-art approach for identifying biotransformation reactions. In the last decade, several studies focused on the combined analysis of carbon and hydrogen stable isotopes upon biodegradation of hydrocarbons due to its widespread environmental occurrence as contaminants, often in high concentrations. Most known initial transformation reactions of hydrocarbons have been isotopically characterized in laboratory experiments using model cultures. The data suggest that several of these reactions - especially those occurring under anoxic conditions - can be identified by ME-CSIA, although a number of constraints have been realized which may lead to wrong ME-CSIA data interpretations in field studies. Generally, the applicability of ME-CSIA regarding hydrocarbon biodegradation needs to be corroborated in future field studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cell encapsulation in biodegradable hydrogels for tissue engineering applications.

PubMed

Nicodemus, Garret D; Bryant, Stephanie J

2008-06-01

Encapsulating cells in biodegradable hydrogels offers numerous attractive features for tissue engineering, including ease of handling, a highly hydrated tissue-like environment for cell and tissue growth, and the ability to form in vivo. Many properties important to the design of a hydrogel scaffold, such as swelling, mechanical properties, degradation, and diffusion, are closely linked to the crosslinked structure of the hydrogel, which is controlled through a variety of different processing conditions. Degradation may be tuned by incorporating hydrolytically or enzymatically labile segments into the hydrogel or by using natural biopolymers that are susceptible to enzymatic degradation. Because cells are present during the gelation process, the number of suitable chemistries and formulations are limited. In this review, we describe important considerations for designing biodegradable hydrogels for cell encapsulation and highlight recent advances in material design and their applications in tissue engineering.

Biodegradation of Benzene, Toluene, Ethylbenzene, and o-, m-, and p-Xylenes by the Newly Isolated Bacterium Comamonas sp. JB.

PubMed

Jiang, Bei; Zhou, Zunchun; Dong, Ying; Tao, Wei; Wang, Bai; Jiang, Jingwei; Guan, Xiaoyan

2015-07-01

A bacterium designated strain JB, able to degrade six benzene, toluene, ethylbenzene, and o-, m-, and p-xylene (BTEX) compounds, was isolated from petroleum-contaminated soil. Taxonomic analyses showed that the isolate belonged to Comamonas, and until now, the genus Comamonas has not included any known BTEX degraders. The BTEX biodegradation rate was slightly low on the mineral salt medium (MSM), but adding a small amount of yeast extract greatly enhanced the biodegradation. The relationship between specific degradation rate and individual BTEX was described well by Michaelis-Menten kinetics. The treatment of petrochemical wastewater containing BTEX mixture and phenol was shown to be highly efficient by BTEX-grown JB. In addition, toxicity assessment indicated the treatment of the petrochemical wastewater by BTEX-grown JB led to less toxicity than untreated wastewater.

Production of biodegradable plastics from activated sludge generated from a food processing industrial wastewater treatment plant.

PubMed

Suresh Kumar, M; Mudliar, S N; Reddy, K M K; Chakrabarti, T

2004-12-01

Most of the excess sludge from a wastewater treatment plant (60%) is disposed by landfill. As a resource utilization of excess sludge, the production of biodegradable plastics using the sludge has been proposed. Storage polymers in bacterial cells can be extracted and used as biodegradable plastics. However, widespread applications have been limited by high production cost. In the present study, activated sludge bacteria in a conventional wastewater treatment system were induced, by controlling the carbon: nitrogen ratio to accumulate storage polymers. Polymer yield increased to a maximum 33% of biomass (w/w) when the C/N ratio was increased from 24 to 144, where as specific growth yield decreased with increasing C/N ratio. The conditions which are required for the maximum polymer accumulation were optimized and are discussed.

Long-term results of a sirolimus-eluting stent with biodegradable polymer (RAPSTROM™) in de novo coronary stenoses.

PubMed

Figini, Filippo; Manjunath, Chaman Nadish; Srinivas, Balaji Chandra; Sadananda, Kanvar Sarat; Sreedharan, Madhu; Fischer, Louie; Pillai, Ramakrishna; Varghese, Kiron; Gopal, Ajay K; Nagesh, Chamarajnagar Mahadevappa; Sheiban, Imad

2017-10-07

To report long-term results of a novel sirolimus-eluting stent with biodegradable polymer BACKGROUND: Newer generation drug-eluting stents are characterized by thin struts, improved platform design and highly biocompatible polymer carrying the antiproliferative drug. The RapstromTM stent, sharing these features, showed promising outcomes in preclinical models and in a first-in-man trial. The present study is a multicenter, non-randomized post-market registry, including patients with de novo coronary artery disease treated with implantation of one or more Rapstrom stents. Primary endpoint of the study was the rate of major adverse cardiac events (MACE) at three-year follow-up. 1073 patients were enrolled, with a high prevalence of diabetes (35%) and acute coronary syndrome at presentation (82%); at three-year follow up, MACE rate was 14.8%, with a low incidence of definite or probable stent thrombosis (0.75%). These data confirm the good clinical performance of the Rapstrom stent, supporting the concept that the combination of thin struts and biodegradable polymer is associated with positive clinical outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Diversity of Cellulolytic Microbes and the Biodegradation of Municipal Solid Waste by a Potential Strain

PubMed Central

Gautam, S. P.; Bundela, P. S.; Pandey, A. K.; Jamaluddin; Awasthi, M. K.; Sarsaiya, S.

2012-01-01

Municipal solid waste contains high amounts of cellulose, which is an ideal organic waste for the growth of most of microorganism as well as composting by potential microbes. In the present study, Congo red test was performed for screening of microorganism, and, after selecting a potential strains, it was further used for biodegradation of organic municipal solid waste. Forty nine out of the 250 different microbes tested (165 belong to fungi and 85 to bacteria) produced cellulase enzyme and among these Trichoderma viride was found to be a potential strain in the secondary screening. During the biodegradation of organic waste, after 60 days, the average weight losses were 20.10% in the plates and 33.35% in the piles. There was an increase in pH until 20 days. pH however, stabilized after 30 days in the piles. Temperature also stabilized as the composting process progressed in the piles. The high temperature continued until 30 days of decomposition, after which the temperature dropped to 40°C and below during the maturation. Good quality compost was obtained in 60 days. PMID:22518141

Screening of surfactants for harmful algal blooms mitigation.

PubMed

Sun, Xiao-Xia; Han, Kyung-Nam; Choi, Joong-Ki; Kim, Eun-Ki

2004-05-01

Screening experiments were conducted in order to find promising synthetic surfactants for harmful algal blooms (HABs) mitigation. The chemically synthesized surfactant cocamidopropyl betaine (CAPB) showed characteristics of relatively high inhibition efficiency, high biodegradability and low cost. The motility inhibition ratios of 10 mg/L CAPB on Cochlodinium polykrikoides and Alexandrium tamarense were about 60% after 5 min. The biodegradation test indicated that the half-life of CAPB in seawater was shorter than one day and 90% was biodegraded after five days under the initial concentration of 100 mg/L at 25 degrees C. Further cell lysis experiments revealed the selective lysis effect of CAPB on different HAB organisms. More than 90% of C. polykrikoides lysed at the concentration of 10 mg/L CAPB after 24 h and at 15 mg/L CAPB after 4 h, whereas the lysis effect of CAPB on A. tamarense was slight, no more than 10% after 2 h interaction with 50 mg/L CAPB. This research provided preliminary data for CAPB as a candidate in harmful algal blooms mitigation and pointed out unresolved problems for its practical application in the meantime.

Development of biodegradable materials; balancing degradability and performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, J.M.; Allen, A.L.; Dell, P.A.

1993-12-31

The development of biodegradable materials suitable for packaging must take into consideration various performance criteria such as mechanical and barrier properties, as well as rate of biodegradability in given environments. Individual or blended biopolymer films were obtained commercially or blown into film in the laboratory and tested for tensile strength, ultimate elongation and oxygen barrier. These films were then subjected to accelerated marine biodegradation tests as well as simulated marine respirometry. Starch/ethylene vinyl alcohol films exhibited good mechanical and excellent oxygen barrier properties, but were very slow to biodegrade in the simulated and excellent oxygen barrier properties, but were verymore » slow to biodegrade in the simulated marine environment. Polyhydroxyalkanoates had good mechanical properties, average oxygen barrier and good biodegradability. Data indicate that performance and biodegradability of packaging can be tailored to needs by combining individual biopolymers in different proportions in blends and laminates.« less

Rate and extent NOM removal during oxidation and biofiltration.

PubMed

Black, Kerry E; Bérubé, Pierre R

2014-04-01

The presence of natural organic matter (NOM) in drinking water treatment presents many challenges. Integrated treatment processes combining oxidation and biofiltration have been demonstrated to be very effective at reducing NOM, specifically biodegradable organics. Laboratory bench-scale experiments were carried out to investigate the effect of oxidation by ozonation or UV/H2O2 on NOM. Specifically the rate of biodegradation was studied by performing bench-scale biodegradation experiments using acclimatized biological activated carbon (BAC). For the source water investigated, oxidation did not preferentially react with the biodegradable or non-biodegradable NOM. In addition, the type or dose of oxidation applied did not affect the observed rate of biodegradation. The rate kinetics for biodegradation were constant for all oxidation conditions investigated. Oxidation prior to biofiltration increased the overall removal of organic matter, but did not affect the rate of biodegradation of NOM. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of biodegradation of poly(ethylene glycol)s and poly(propylene glycol)s.

PubMed

Zgoła-Grześkowiak, Agnieszka; Grześkowiak, Tomasz; Zembrzuska, Joanna; Łukaszewski, Zenon

2006-07-01

The biodegradation of poly(ethylene glycol)s (PEGs) and poly(propylene glycol)s (PPGs), both being major by-products of non-ionic surfactants biodegradation, was studied under the conditions of the River Water Die-Away Test. PEGs were isolated from a water matrix using solid-phase extraction with graphitized carbon black sorbent, then derivatized with phenyl isocyanate and determined by HPLC with UV detection. PPGs were isolated from a water matrix by liquid-liquid extraction with chloroform, then derivatized with naphthyl isocyanate and determined by HPLC with fluorescence detection. The primary biodegradation of both PEGs and PPGs reached approximately 99% during the test. The tests show different biodegradation pathways of PEG and PPG. During PEG biodegradation, their chains are shortened leading to the formation of ethylene glycol and diethylene glycol. During PPG biodegradation, no short-chained biodegradation products were found.

Enhanced Biodegradability of Pharmaceuticals and Personal Care Products by Ionizing Radiation.

PubMed

Kim, Hyun Young; Lee, O-Mi; Kim, Tae-Hun; Yu, Seungho

2015-04-01

The radiolytic degradation of antibiotic compounds, including lincomycin (LMC), sulfamethoxazole (SMX), and tetracycline (TCN), and the change of biodegradability of the radiation-treated target compounds were evaluated. As a result, the degradation of target antibiotics by hydrolysis, biodegradation, and gamma irradiation showed a compound-dependent manner. However, the biodegradability of all target compounds was enhanced by the gamma irradiation. The enhanced biodegradability after gamma irradiation (2 kGy) followed the trend of LMC (18.89%)

Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

PubMed

Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

2002-10-01

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

Biological Production of Methane from Lunar Mission Solid Waste: An Initial Feasibility Assessment

NASA Astrophysics Data System (ADS)

Strayer, Richard; Garland, Jay; Janine, Captain

A preliminary assessment was made of the potential for biological production of methane from solid waste generated during an early planetary base mission to the moon. This analysis includes: 1) estimation of the amount of biodegradable solid waste generated, 2) background on the potential biodegradability of plastics given their significance in solid wastes, and 3) calculation of potential methane production from the estimate of biodegradable waste. The completed analysis will also include the feasibility of biological methane production costs associated with the biological processing of the solid waste. NASA workshops and Advanced Life Support documentation have estimated the projected amount of solid wastes generated for specific space missions. From one workshop, waste estimates were made for a 180 day transit mission to Mars. The amount of plastic packaging material was not specified, but our visual examination of trash returned from stocktickerSTS missions indicated a large percentage would be plastic film. This plastic, which is not biodegradable, would amount to 1.526 kgdw crew-1 d-1 or 6.10 kgdw d-1 for a crew of 4. Over a mission of 10 days this would amount to 61 kgdw of plastics and for an 180 day lunar surface habitation it would be nearly 1100 kgdw . Approx. 24 % of this waste estimate would be biodegradable (human fecal waste, food waste, and paper), but if plastic packaging was replaced with biodegradable plastic, then 91% would be biodegradable. Plastics are man-made long chain polymeric molecules, and can be divided into two main groups; thermoplastics and thermoset plastics. Thermoplastics comprise over 90% of total plastic use in the placecountry-regionUnited States and are derived from polymerization of olefins via breakage of the double bond and subsequent formation of additional carbon to carbon bonds. The resulting sole-carbon chain polymers are highly resistant to biodegradation and hydrolytic cleavage. Common thermoplastics include low density polyethylene (packaging, bags), high density polyethylene (bottles, containers, pipes), polystyrene (tanks, containers), polypropylene (tanks, containers), and polyvinylchloride (pipes, containers). Thermoset plastics are formed by the condensation of alcohols or amines to form polyesters or polyamides, and are typically solidified after heating. As opposed to the linear structure of thermoplastic, thermoset plastics have a cross-linked structure which results in higher strength. The most common thermoset plastic is polyurethane which is used for coatings, insulation, paints, and packing. Given both the concerns over pollution reduction and energy conservation, significant efforts are underway on Earth to evaluate biodegradable plastics made from renewable feedstocks; the following summarizes the current state of these efforts. Production of biodegradable plastics involves either the introduction of biodegradable or photo-oxidizable components into the polymer chain or the use of biodegradable polymers themselves. The first approach is based on the observation that polyolefins of low molecular weight (<500 Da) are biodegradable. Insertion of structures susceptible to either photoor chemical degradation within the overall polyolefins chain (which are of 4 - 28 kDa molecular weight), can produce segments sufficiently small to be assimilated and degraded by microorganisms. Biodegradable polymers based strictly on nonpetroleum, biologically-based material have been developed, including some which are used to make currently marketed products. Polyhydroxyalkanoates (PHAs) are polyesters which are accumulated as carbon storage materials by microorganisms under nutrient limiting conditions. MirelTM , a "bioplastic" based on stocktickerPHA produced from microbial fermentation of sugars or oils from vegetables crops, is being produced by TellesTM . The company markets MirelTM bioplastics for use in molding, coatings, films, adhesives, and fibers. Another type of bioplastic is based on polylactic acid, or stocktickerPLA. Starch, typically from corn, is fermented by bacteria to yield lactic acid which is then used to synthesize the stocktickerPLA polymer. stocktickerPLA can be degraded via a combination of abiotic hydrolysis and microbial degradation. NatureWorks LLC markets stocktickerPLA-based plastics (NatureWorks R , IngeoTM ) for a variety of applications, including high-value films, rigid thermoformed food and beverage containers, coated papers and boards and other packaging applications. This review suggests that biodegradable plastics may be feasible for use on near-term lunar missions. Biodegradable plastics products are commercially available, and cost, the main limitation to terrestrial use, is not an issue for the small-scale, specialty use by NASA. If the plastic content of the lunar mission solid waste stream is biodegradable, then a potential yield of methane from the waste can be estimated. Investigators at the placePlaceTypeUniversity of PlaceNameFlorida have reported on a three-stage anaerobic composting system for treatment of solid wastes expected in an Advanced Life Support System for space surface habitation. Their system, a sequential batch anaerobic composter (SEBAC) has been demonstrated for a variety of terrestrial solid wastes. Results for methane production rate from a simulated stocktickerALS solid waste of inedible rice crop debris, paper, and simulated feces averaged 0.30 L CH4 per gdw volatile solids (VS, i.e., organic matter) added. If we extrapolate from their results and assume that the VS in space mission solid waste is 100% biodegradable, then a potential for 620 LCH4 crew-1 d-1 might be obtained with a comparable SEBAC. For a crew of four, 2480 LCH4 d-1 (or 110.7 molesCH4 d-1 , 1772 gCH4 d-1 , or 3.90 lbCH4 d-1 )., would be produced. Over a 180 day surface habitation, this generation rate would yield a total of 446,000 LCH4 (319 kgCH4 , 702 lbCH4 ). The next step in this effort is to estimate the costs of biological processing system required to convert the solid waste steam to methane. We will employ equivalent system mass (ESM) analysis to define the costs of the system in terms of energy, mass, and manpower required for processing, allowing for a better estimation of the net benefit of this in situ resource utilization approach.

Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers.

PubMed

Ochi, Shinji

2011-02-25

The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms.

Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers

PubMed Central

Ochi, Shinji

2011-01-01

The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms. PMID:28880000

Biodegradation of BTEX mixture by Pseudomonas putida YNS1 isolated from oil-contaminated soil.

PubMed

You, Youngnam; Shim, Jaehong; Cho, Choa-Hyoung; Ryu, Moon-Hee; Shea, Patrick J; Kamala-Kannan, Seralathan; Chae, Jong-Chan; Oh, Byung-Taek

2013-05-01

The presence of mixed contaminants, such as BTEX (benzene, toluene, ethylbenzene and xylene isomers) can affect the biodegradation, fate and environmental impacts of each compound. To understand the influence of interactions among BTEX compounds on their biodegradation, four bacteria were isolated from oil-contaminated soil and assayed for BTEX biodegradation in vitro. The isolate exhibiting maximum biodegradation was identified as Pseudomonas putida based on the 16S rDNA sequence. The biodegradation of the BTEX compounds was greatly influenced by pH, temperature, and salinity. Substrate mixture studies (binary, tertiary and quaternary) revealed that the presence of toluene increased the biodegradation rate of benzene, ethylbenzene, and xylene. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compound-Specific Carbon and Hydrogen Isotope Analysis - Field Evidence of MTBE Bioremediation

NASA Astrophysics Data System (ADS)

Kuder, T.; Kolhatkar, R. V.; Philp, P.; Wilson, J. T.; Landmeyer, J. E.; Allen, J.

2002-12-01

Compound-specific stable isotope analysis allows opportunity to determine the isotopic ratios of individual contaminants. The technique has been applied to confirm biodegradation in studies of chlorinated solvents and recently BTEX, MTBE and TBA. Chemical reactions (including bio- and inorganic degradation) tend to favor molecules with the lighter isotopic species (e.g., 12C, 1H), resulting with enrichment of the unreacted substrate in the heavier isotopic species (13C, D), referred to as kinetic isotopic fractionation, so that the extent of fractionation may be used as a proxy for biodegradation. Processes such as volatilization, sorption etc., result in minimal degree of fractionation and do not interfere with the isotopic signal due to biodegradation. The results presented here show the first successful applications of compound-specific isotope analysis to understanding MTBE biodegradation in the field, at both aerobic and anaerobic sites. Observed fractionations suggest that two different biodegradation pathways may be involved. At a number of anaerobic locations major fractionation effects were observed for both C and H; enrichment factors Ÿnfor both elements were approaching or exceeding -10. A laboratory microcosm study using an enrichment culture yielded similar results (C data only). A characteristic feature of these sites was the presence of high concentrations of TBA. Conversely, at a number of sites, the C composition remained stable with little fractionation and stayed within the analytical precision range or changed minimally, while H displayed significant fractionation in excess of 60 per mil. Moderate agreement of the data with Rayleigh fractionation model was observed, suggesting that biodegradation effect was distorted by variability at the source or the plume was not homogeneous. The enrichment factor calculated for these data is similar to the one Ÿnpublished for aerobic microcosm of MTBE-degrading culture from Vandenberg AFB by Gray et al. (Env. Sci. Tech., 2002, 36, 1931-1938) and appears to be in excess of -60 for H and under -2 for C. The high H fractionation observed under aerobic conditions may be attributed to the initial, monooxygenase transformation of MTBE (cf., Deeb et al., Biodegradation, 2000, 11, 171-186). The anaerobic enzymatic reactions were not characterized yet, but a hydrolytic process may be responsible. Interestingly, isotopic fractionation at an anaerobic site, which was treated by oxygen injection, did not show differences between aerobic and anaerobic parts of the plume. Despite oxygen addition, there was no evidence for monooxygenase activity.

Post monitoring of a cyclodextrin remeditated chlorinated solvent contaminated aquifer

NASA Astrophysics Data System (ADS)

Blanford, W. J.

2006-12-01

Hydroxypropyl-â-cyclodextrin (HPâCD) has been tested successfully in the laboratory and in the field for enhanced flushing of low-polarity contaminants from aquifers. The cyclodextrin molecule forms a toroidal structure, which has a hydrophobic cavity. Within this cavity, organic compounds of appropriate shape and size can form inclusion complexes, which is the basis for the use of cyclodextrin in groundwater remediation. The hydrophilic exterior of the molecule makes cyclodextrin highly water-soluble. The solubility of cyclodextrins can be further enhanced by adding functional groups, such as hydroxypropyl groups, to the cyclodextrin core. The aqueous solubility of HPâCD exceeds 950 g/L. These high solubilities are advantageous for field applications because they permit relatively high concentrations of the flushing agent. In order for cyclodextrin to become a feasible remediative alternative, it must be demonstrate a short term resistance to biodegradation during field application, but ultimately biodegrade so as not to pose a long term presence in the aquifer. The potential for degradation of cyclodextrin as well as changes in the chlorinated solvents and groundwater geochemistry were examined during the post monitoring of a field demonstration in a shallow aquifer at Little Creek Naval Amphibious Base in Virginia. It was found that a portion of the cyclodextrin remaining in the aquifer after the cessation of field activities biodegraded during the 425 days of post monitoring. This degradation also led to the degradation of the chlorinated solvents trichloroethylene and 1,1-trichloroethane through both biological and chemical processes. The aquifer remained anaerobic with average dissolved oxygen levels below 0.5 mg/L. Dissolved nitrate and sulfate concentrations within the cyclodextrin plume decreased due their being used as terminal electron acceptors during the degradation of the cyclodextrin. The concentrations of total iron at the field site showed no change over time. It can be concluded from this research that cyclodextrin remaining in the subsurface after cessation of active remediation will degrade due to microbial processes. The chlorinated solvents will also degrade through both chemical and biological processes to their daughter products. The terminal electron acceptors present within the cyclodextrin plume will also be used for energy during the degradation processes.

Effect of biodegradation on the consolidation properties of a dewatered municipal sewage sludge.

PubMed

O'Kelly, Brendan C

2008-01-01

The effect of biodegradation on the consolidation characteristics of an anaerobically digested, dewatered municipal sewage sludge was studied. Maintained-load oedometer consolidation tests that included measurement of the pore fluid pressure response were conducted on moderately degraded sludge material and saturated bulk samples that had been stored under static conditions and allowed to anaerobically biodegrade further (simulating what would happen in an actual sewage sludge monofill or lagoon condition). Strongly degraded sludge material was produced after a storage period of 13 years at ambient temperatures of 5-15 degrees C, with the total volatile solids reducing from initially 70% to 55%. The sludge materials were highly compressible, although impermeable for practical purposes. Primary consolidation generally occurred very slowly, which was attributed to the microstructure of the solid phase, the composition and viscosity of the pore fluid, ongoing biodegradation and the high organic contents. The coefficient of primary consolidation values decreased from initially about 0.35m2/yr to 0.003-0.03m2/yr with increasing effective stress (sigmav'=3-100kPa). Initially, the strongly degraded sludge material was slightly more permeable, although both the moderately and strongly degraded materials became impermeable for practical purposes (k=10(-9)-10(-12)m/s) below about 650% and 450% water contents, respectively. Secondary compression became more dominant with increasing effective stress with a mean secondary compression index (Calphae) value of 0.9 measured for both the moderately and strongly degraded materials.

Removal of crude oil polycyclic aromatic hydrocarbons via organoclay-microbe-oil interactions.

PubMed

Ugochukwu, Uzochukwu C; Fialips, Claire I

2017-05-01

Clay minerals are quite vital in biogeochemical processes but the effect of organo-clays in the microbial degradation of crude oil polycyclic aromatic hydrocarbons is not well understood. The role of organo-saponite and organo-montmorillonite in comparison with the unmodified clays in crude oil polycyclic aromatic hydrocarbons (PAHs) removal via adsorption and biodegradation was studied by carrying out microcosm experiments in aqueous clay/oil systems with a hydrocarbon degrading microbial community that is predominantly alcanivorax spp. Montmorillonite and saponite samples were treated with didecyldimethylammonium bromide to produce organo-montmorillonite and organo-saponite used in this study. Obtained results indicate that clays with high cation exchange capacity (CEC) such as montmorillonite produced organo-clay (organomontmorillonite) that was not stimulatory to biodegradation of crude oil polycyclic aromatic compounds, especially the low molecular weight (LMW) ones, such as dimethylnaphthalenes. It is suggested that interaction between the organic phase of the organo-clay and the crude oil PAHs which is hydrophobic in nature must have reduced the availability of the polycyclic aromatic hydrocarbons for biodegradation. Organo-saponite did not enhance the microbial degradation of dimethylnaphthalenes but enhanced the biodegradation of some other PAHs such as phenanthrene. The unmodified montmorillonite enhanced the microbial degradation of the PAHs and is most likely to have done so as a result of its high surface area that allows the accumulation of microbes and nutrients enhancing their contact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonylphenol biodegradation characterizations and bacterial composition analysis of an effective consortium NP-M2.

PubMed

Bai, Naling; Abuduaini, Rexiding; Wang, Sheng; Zhang, Meinan; Zhu, Xufen; Zhao, Yuhua

2017-01-01

Nonylphenol (NP), ubiquitously detected as the degradation product of nonionic surfactants nonylphenol polyethoxylates, has been reported as an endocrine disrupter. However, most pure microorganisms can degrade only limited species of NP with low degradation efficiencies. To establish a microbial consortium that can effectively degrade different forms of NP, in this study, we isolated a facultative microbial consortium NP-M2 and characterized the biodegradation of NP by it. NP-M2 could degrade 75.61% and 89.75% of 1000 mg/L NP within 48 h and 8 days, respectively; an efficiency higher than that of any other consortium or pure microorganism reported so far. The addition of yeast extract promoted the biodegradation more significantly than that of glucose. Moreover, surface-active compounds secreted into the extracellular environment were hypothesized to promote high-efficiency metabolism of NP. The detoxification of NP by this consortium was determined. The degradation pathway was hypothesized to be initiated by oxidization of the benzene ring, followed by step-wise side-chain biodegradation. The bacterial composition of NP-M2 was determined using 16S rDNA library, and the consortium was found to mainly comprise members of the Sphingomonas, Pseudomonas, Alicycliphilus, and Acidovorax genera, with the former two accounting for 86.86% of the consortium. The high degradation efficiency of NP-M2 indicated that it could be a promising candidate for NP bioremediation in situ. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic Biodegradation of soybean biodiesel and diesel ...

EPA Pesticide Factsheets

Biotransformation of soybean biodiesel and its biodiesel/petrodiesel blends were investigated under sulfate-reducing conditions. Three blends of biodiesel, B100, B50, and B0, were treated using microbial cultures pre-acclimated to B100 (biodiesel only) and B80 (80% biodiesel and 20% petrodiesel). Results indicate that the biodiesel could be effectively biodegraded in the presence or absence of petrodiesel, whereas petrodiesel could not be biodegraded at all under sulfate-reducing conditions. The kinetics of biodegradation of individual Fatty Acid Methyl Ester (FAME) compounds and their accompanying sulfate-reduction rates were studied using a serum bottle test. As for the biodegradation of individual FAME compounds, the biodegradation rates for the saturated FAMEs decreased with increasing carbon chain length. For unsaturated FAMEs, biodegradation rates increased with increasing number of double bonds. The presence of petrodiesel had a greater effect on the rate of biodegradation of biodiesel than on the extent of removal. The objective of this study was to investigate anaerobic biodegradation of soybean biodiesel and petrodiesel blends in a sulfate-reducing environment, which is a prevalent condition in anaerobic sediments.

Wet air oxidation induced enhanced biodegradability of distillery effluent.

PubMed

Malik, S N; Saratchandra, T; Tembhekar, P D; Padoley, K V; Mudliar, S L; Mudliar, S N

2014-04-01

The present study reports the feasibility of Wet Air Oxidation (WAO) as a pretreatment option for enhanced biodegradation of complex distillery effluent. Initially, the distillery effluent was pretreated by WAO at different process conditions (pressure, temperature and time) to facilitate enhancement in the biodegradability index (BI = BOD5: COD ratio). The biodegradability of WAO pretreated effluent was evaluated by subjecting it to aerobic biodegradation and anaerobic followed by aerobic biodegradation. Aerobic biodegradation of pretreated effluent with enhanced biodegradability index (BI = 0.4-0.8) showed enhanced COD reduction of up to 67.7%, whereas the untreated effluent (BI = 0.17) indicated poor COD reduction of only 22.5%. Anaerobic followed by aerobic biodegradation of pretreated effluent has shown up to 87.9% COD reduction, while the untreated effluent has shown only 43.1% COD reduction. Bio-kinetic parameters also confirmed the increased rate of bio-oxidation at enhanced BIs. The results indicate that the WAO pretreatment facilitates enhanced bio-oxidation/bio-degradation of complex effluents like the distillery spent wash. Copyright © 2014 Elsevier Ltd. All rights reserved.

Introduction of Environmentally Degradable Parameters to Evaluate the Biodegradability of Biodegradable Polymers

PubMed Central

Yang, Chao; Song, Cunjiang; Geng, Weitao; Li, Qiang; Wang, Yuanyuan; Kong, Meimei; Wang, Shufang

2012-01-01

Environmentally Degradable Parameter (Ed K) is of importance in the describing of biodegradability of environmentally biodegradable polymers (BDPs). In this study, a concept Ed K was introduced. A test procedure of using the ISO 14852 method and detecting the evolved carbon dioxide as an analytical parameter was developed, and the calculated Ed K was used as an indicator for the ultimate biodegradability of materials. Starch and polyethylene used as reference materials were defined as the Ed K values of 100 and 0, respectively. Natural soil samples were inoculated into bioreactors, followed by determining the rates of biodegradation of the reference materials and 15 commercial BDPs over a 2-week test period. Finally, a formula was deduced to calculate the value of Ed K for each material. The Ed K values of the tested materials have a positive correlation to their biodegradation rates in the simulated soil environment, and they indicated the relative biodegradation rate of each material among all the tested materials. Therefore, the Ed K was shown to be a reliable indicator for quantitatively evaluating the potential biodegradability of BDPs in the natural environment. PMID:22675455

Performance of mechanical biological treatment of residual municipal waste in Poland

NASA Astrophysics Data System (ADS)

den Boer, Emilia; Jędrczak, Andrzej

2017-11-01

The number and capacity of mechanical-biological treatment (MBT) plants in Europe increased significantly in the past two decades as a response to the legal obligation to limit the landfilling of biodegradable waste in landfills and to increase recycling and energy recovery from waste. The aim of these plants is to prepare residual municipal waste for recovery and disposal operations, including especially separation and stabilization of the easily biodegradable fraction (the biofraction). The final products of MBP technology are recyclables, stabilate, high calorific fraction which is used for the production of refuse derived fuel (RDF) and the remaining residual fraction. The shares of the output fractions, especially of the recyclables and RDF determine the overall efficiency of MBT technology in diverting waste from landfills. In this paper results of an assessment of one exemplary MBT plant are provided. The analysis was performed within a comparative study in which 20 selected MBT plants in Poland were subject to a detailed analysis, focusing, both at the design parameters as well as operational ones. The selected plant showed relatively higher overall materials recovery efficiency. With the view to circular economy targets, increased automation of the mechanical waste treatment will be required to support achieving high level diversion from landfills. The study reviled that stabilisation of biofraction should be improved by a better control of process conditions, especially moisture content.

Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

NASA Astrophysics Data System (ADS)

Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

2009-05-01

SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not contaminated before. The 2D flow-through microcosms facilitated to combine a number of physicochemical and microbiological methods, such as high-resolution non-invasive oxygen measurements, conservative tracer tests, compound-specific isotope analysis (CSIA), fluorescence in situ hybridization (FISH), and numerical transport modelling, to name a few. Moreover, due to the defined and well-controlled operating conditions, these bench-scale flow-through systems allow to investigate theoretical concepts and to develop and test predictive models. They represent a valuable tool in helping to bridge the current knowledge gap concerning transport and degradation of contaminants in groundwater from the small-scale (i.e. oversimplified batch systems, disregarding transport processes) to the highly complex field conditions. The promising potential of applications is by far not exhausted. Further possibilities include testing ecological theories such as the resource-ratio theory, island biogeography, area-species richness relationships and relations between community structure, microbial abundance and process rates as well as the importance and effects of bacterial chemotaxis.

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... to determine the organic biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The... Where: Rbio = Organic biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as... to determine the actual organic mass biodegradation rate (MRbio) for a treated hazardous waste. (i...

Anaerobic Biodegradation of Soybean Biodiesel and Diesel ...

EPA Pesticide Factsheets

Biotransformation of soybean biodiesel and the inhibitory effect of petrodiesel were studied under methanogenic conditions. Biodiesel removal efficiency of more than 95% was achieved in a chemostat with influent biodiesel concentrations up to 2.45 g/L. The kinetics of anaerobic biodegradation of soybean biodiesel B100 (biodiesel only) with different petrodiesel loads were studied using biomass pre-acclimated to B100 and B80 (80% biodiesel and 20 petrodiesel). The results indicated that the biodiesel fraction of the blend could be effectively biodegraded, whereas petrodiesel was not biodegraded at all under methanogenic conditions. The presence of petrodiesel in blends with biodiesel had a greater inhibitory effect on the rate of biodegradation than the biodegradation efficiency (defined as the efficiency of methane production). Both the biodegradation rate coefficient and the methane production efficiency increased almost linearly with the increasing fraction of biodiesel. With the increasing fraction of petrodiesel, the biodegradation rate and efficiency were correlated with the concentration of soluble FAMEs in the water. The objective of this study was to investigate the anaerobic biodegradation of soybean biodiesel blends under methanogenic conditions. Biological methane potential (BMP) tests were conducted in serum bottles to determine the anaerobic biodegradation kinetics of biodiesel in the absence and presence of different concentrations of petrod

Accelerating Quinoline Biodegradation and Oxidation with Endogenous Electron Donors.

PubMed

Bai, Qi; Yang, Lihui; Li, Rongjie; Chen, Bin; Zhang, Lili; Zhang, Yongming; Rittmann, Bruce E

2015-10-06

Quinoline, a recalcitrant heterocyclic compound, is biodegraded by a series of reactions that begin with mono-oxygenations, which require an intracellular electron donor. Photolysis of quinoline can generate readily biodegradable products, such as oxalate, whose bio-oxidation can generate endogenous electron donors that ought to accelerate quinoline biodegradation and, ultimately, mineralization. To test this hypothesis, we compared three protocols for the biodegradation of quinoline: direct biodegradation (B), biodegradation after photolysis of 1 h (P1h+B) or 2 h (P2h+B), and biodegradation by adding oxalate commensurate to the amount generated from photolysis of 1 h (O1+B) or 2 h (O2+B). The experimental results show that P1h+B and P2h+B accelerated quinoline biodegradation by 19% and 50%, respectively, compared to B. Protocols O1+B and O2+B also gave 19% and 50% increases, respectively. During quinoline biodegradation, its first intermediate, 2-hydroxyquinoline, accumulated gradually in parallel to quinoline loss but declined once quinoline was depleted. Mono-oxygenation of 2-hydroxyquinoline competed with mono-oxygenation of quinoline, but the inhibition was relieved when extra electrons donors were added from oxalate, whether formed by UV photolysis or added exogenously. Rapid oxalate oxidation stimulated both mono-oxygenations, which accelerated the overall quinoline oxidation that provided the bulk of the electron donor.

Removal of heavy metal species from industrial sludge with the aid of biodegradable iminodisuccinic acid as the chelating ligand.

PubMed

Wu, Qing; Duan, Gaoqi; Cui, Yanrui; Sun, Jianhui

2015-01-01

High level of heavy metals in industrial sludge was the obstacle of sludge disposal and resource recycling. In this study, iminodisuccinic acid (IDS), a biodegradable chelating ligand, was used to remove heavy metals from industrial sludge generated from battery industry. The extraction of cadmium, copper, nickel, and zinc from battery sludge with aqueous solution of IDS was studied under various conditions. It was found that removal efficiency greatly depends on pH, chelating agent's concentration, as well as species distribution of metals. The results showed that mildly acidic and neutral systems were not beneficial to remove cadmium. About 68 % of cadmium in the sample was extracted at the molar ratio of IDS to heavy metals 7:1 without pH adjustment (pH 11.5). Copper of 91.3 % and nickel of 90.7 % could be removed by IDS (molar ratio, IDS: metals = 1:1) with 1.2 % phosphoric acid effectively. Removal efficiency of zinc was very low throughout the experiment. Based on the experimental results, IDS could be a potentially useful chelant for heavy metal removal from battery industry sludge.

Biodegradation of the cyclic nitramine explosives RDX, HMX, and CL-20.

PubMed

Crocker, Fiona H; Indest, Karl J; Fredrickson, Herbert L

2006-11-01

Cyclic nitramine explosives are synthesized globally mainly as military munitions, and their use has resulted in environmental contamination. Several biodegradation pathways have been proposed, and these are based mainly on end-product characterization because many of the metabolic intermediates are hypothetical and unstable in water. Biodegradation mechanisms for cyclic nitramines include (a) formation of a nitramine free radical and loss of nitro functional groups, (b) reduction of nitro functional groups, (c) direct enzymatic cleavage, (d) alpha-hydroxylation, or (e) hydride ion transfer. Pathway intermediates spontaneously decompose in water producing nitrite, nitrous oxide, formaldehyde, or formic acid as common end-products. In vitro enzyme and functional gene expression studies have implicated a limited number of enzymes/genes involved in cyclic nitramine catabolism. Advances in molecular biology methods such as high-throughput DNA sequencing, microarray analysis, and nucleic acid sample preparation are providing access to biochemical and genetic information on cultivable and uncultivable microorganisms. This information can provide the knowledge base for rational engineering of bioremediation strategies, biosensor development, environmental monitoring, and green biosynthesis of explosives. This paper reviews recent developments on the biodegradation of cyclic nitramines and the potential of genomics to identify novel functional genes of explosive metabolism.

Arsenic Speciation and Extraction and the Significance of Biodegradable Acid on Arsenic Removal—An Approach for Remediation of Arsenic-Contaminated Soil

PubMed Central

Nguyen Van, Thinh; Osanai, Yasuhito; Do Nguyen, Hai; Kurosawa, Kiyoshi

2017-01-01

A series of arsenic remediation tests were conducted using a washing method with biodegradable organic acids, including oxalic, citric and ascorbic acids. Approximately 80% of the arsenic in one sample was removed under the effect of the ascorbic and oxalic acid combination, which was roughly twice higher than the effectiveness of the ascorbic and citric acid combination under the same conditions. The soils treated using biodegradable acids had low remaining concentrations of arsenic that are primarily contained in the crystalline iron oxides and organic matter fractions. The close correlation between extracted arsenic and extracted iron/aluminum suggested that arsenic was removed via the dissolution of Fe/Al oxides in soils. The fractionation of arsenic in four contaminated soils was investigated using a modified sequential extraction method. Regarding fractionation, we found that most of the soil contained high proportions of arsenic (As) in exchangeable fractions with phosphorus, amorphous oxides, and crystalline iron oxides, while a small amount of the arsenic fraction was organic matter-bound. This study indicated that biodegradable organic acids can be considered as a means for arsenic-contaminated soil remediation.

Remediation of soil-bound polynuclear aromatic hydrocarbons using nonionic surfactants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeom, IckTae; Ghosh, Mriganka; Cox, C.

1996-12-31

The solubilization and biodegradation of soil-bound PAHs from a manufactured gas plant (MGP) site soil was investigated using surfactants. Three nonionic polyoxyethylene (POE) surfactants, Triton X-100, Tween 80, and Brij 35, were used. The fate of four PAHs, phenanthrene, anthracene, pyrene, and benzo(a)pyrene were monitored during the remediation process. The measured concentrations of solubilized PAHs agreed well with those estimated using micelle-water partitioning coefficient, K{sub m}, and Raoult`s law. The solubilization of soil-bound PAHs by surfactants is a slow, nonequilibrium process. Diffusion of PAH molecules within the weathered soil-tar matrix is proposed as the rate-limiting step in solubilizing PAHs frommore » such soils. A radial diffusion model is used to describe solubilization of PAHs by surfactant washing. The model predicts experimental results fairly well at low surfactant dosages while at high dosages it somewhat overestimates the extent of solubilization. Biodegradation studies were performed using a natural consortium of microorganisms enriched from PAH-contaminated soils. Surfactants enhanced biodegradation of PAHs except for Tween 80. However, biodegradation of surfactants themselves appear to attenuate the beneficial effects of surfactant-mediated bioremediation.« less

Study of weathering effects on the distribution of aromatic steroid hydrocarbons in crude oils and oil residues.

PubMed

Wang, Chuanyuan; Chen, Bing; Zhang, Baiyu; Guo, Ping; Zhao, Mingming

2014-01-01

The composition and distribution of triaromatic steroid hydrocarbons in oil residues after biodegradation and photo-oxidation processes were detected, and the diagnostic ratios for oil spill identification were developed and evaluated based on the relative standard deviation (RSD) and the repeatability limit. The preferential loss of C27 methyl triaromatic steranes (MTAS) relative to C28 MTAS and C29 MTAS was shown during the photo-oxidation process. In contrast to the photochemical degradation, the MTAS with the original 20R biological configuration was preferentially degraded during the biodegradation process. The RSD of most of the diagnostic ratios of MTAS ranged from 9 to 84% during the photo-oxidation process. However, the RSDs of such ratios derived from MTAS were all <5% even in high biodegradation, and such parameters may also provide new methods on oil spill identification. The parameters of monoaromatic sterane and monoaromatic sterane are not used well for oil spill identification after photo-oxidation. The triaromatic steroid hydrocarbons retained their molecular compositions after biodegradation and photo-oxidation and most of the diagnostic ratios derived from them could be efficiently used in oil spill identification.

Performance of trichlorfon degradation by a novel Bacillus tequilensis strain PA F-3 and its proposed biodegradation pathway.

PubMed

Tian, Jiang; Yu, Chenlei; Xue, Yingwen; Zhao, Ruixue; Wang, Jing; Chen, Lanzhou

2016-11-01

The novel trichlorfon (TCF)-degrading bacterium PA F-3, identified as Bacillus tequilensis, was isolated from pesticide-polluted soils by using an effective screening and domesticating procedure. The TCF biodegradation pathways of PA F-3 were also systematically elucidated. As revealed by high-performance liquid chromatography, the TCF residues in the mineral salt medium demonstrated that PA F-3 can utilize TCF as its sole carbon source and reach the highest degradation of 71.1 % at an initial TCF concentration of 200 mg/L within 5 days. The TCF degradation conditions were optimized using response surface methodology as follows: temperature, 28 °C; inoculum amount, 4 %; and initial TCF concentration, 125 mg/L. Biodegradation treatments supplemented with exogenous carbon sources and yeast extract markedly increased the microbial dry weights and TCF-degrading performance of PA F-3, respectively. Meanwhile, five metabolic products of TCF were identified through gas chromatography/mass spectrometry, and a biodegradation pathway was proposed. Results indicated that deoxidation and dehydration (including the cleavage of the P-C phosphonate bond and the C-O bond) were the preferred metabolic reactions of TCF in this TCF-degrading bacterium.

Biodegradable synthetic bone composites

DOEpatents

Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

2013-01-01

The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

PubMed

Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

2015-06-01

Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly. Copyright © 2015 Elsevier Ltd. All rights reserved.

In silico models for predicting ready biodegradability under REACH: a comparative study.

PubMed

Pizzo, Fabiola; Lombardo, Anna; Manganaro, Alberto; Benfenati, Emilio

2013-10-01

REACH (Registration Evaluation Authorization and restriction of Chemicals) legislation is a new European law which aims to raise the human protection level and environmental health. Under REACH all chemicals manufactured or imported for more than one ton per year must be evaluated for their ready biodegradability. Ready biodegradability is also used as a screening test for persistent, bioaccumulative and toxic (PBT) substances. REACH encourages the use of non-testing methods such as QSAR (quantitative structure-activity relationship) models in order to save money and time and to reduce the number of animals used for scientific purposes. Some QSAR models are available for predicting ready biodegradability. We used a dataset of 722 compounds to test four models: VEGA, TOPKAT, BIOWIN 5 and 6 and START and compared their performance on the basis of the following parameters: accuracy, sensitivity, specificity and Matthew's correlation coefficient (MCC). Performance was analyzed from different points of view. The first calculation was done on the whole dataset and VEGA and TOPKAT gave the best accuracy (88% and 87% respectively). Then we considered the compounds inside and outside the training set: BIOWIN 6 and 5 gave the best results for accuracy (81%) outside training set. Another analysis examined the applicability domain (AD). VEGA had the highest value for compounds inside the AD for all the parameters taken into account. Finally, compounds outside the training set and in the AD of the models were considered to assess predictive ability. VEGA gave the best accuracy results (99%) for this group of chemicals. Generally, START model gave poor results. Since BIOWIN, TOPKAT and VEGA models performed well, they may be used to predict ready biodegradability. Copyright © 2013 Elsevier B.V. All rights reserved.

Two-Dimensional Stable Isotope Fractionation During Aerobic and Anaerobic Alkane Biodegradation and Implications for the Field

NASA Astrophysics Data System (ADS)

El Morris, Brandon; Suflita, Joseph M.; Richnow, Hans-Hermann

2010-05-01

Quantitatively, n-alkanes comprise a major portion of most crude oils. In petroliferous formations, it may be possible to relate the loss of these compounds to the levels of biodegradation occurring in situ [1]. Moreover, it is important to develop indicators of alkane degradation that may be used to monitor bioremediation of hydrocarbon-impacted environments. Desulfoglaeba alkanexedens and Pseudomonas putida GPo1 were used to determine if carbon and hydrogen stable isotope fractionation could differentiate between n-alkane degradation under anaerobic and aerobic conditions, respectively in the context of the Rayleigh equation model [2]. Bacterial cultures were sacrificed by acidification and headspace samples were analyzed for stable isotope composition using gas chromatography-isotope ratio mass spectrometry. Carbon enrichment factors (bulk) for anaerobic and aerobic biodegradation of hexane were -5.52 ± 0.2‰ and -4.34 ± 0.3‰, respectively. Hydrogen enrichment during hexane degradation was -43.14 ± 6.32‰ under sulfate-reducing conditions, and was too low for quantification during aerobiosis. Collectively, this indicates that the correlation between carbon and hydrogen stable isotope fractionation (may be used to help elucidate in situ microbial processes in oil reservoirs, and during intrinsic as well as engineered remediation efforts. References 1. Asif, M.; Grice, K.; Fazeelat, T., Assessment of petroleum biodegradation using stable hydrogen isotopes of individual saturated hydrocarbon and polycyclic aromatic hydrocarbon distributions in oils from the Upper Indus Basin, Pakistan. Organic Geochemistry 2009, 40, (3), 301-311. 2. Fischer, A.; Herklotz, I.; Herrmann, S.; Thullner, M.; Weelink, S. A. B.; Stams, A., J. M.; Schloemann, M.; Richnow, H.-H.; Vogt, C., Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways. Environ. Sci. Technol. 2008, 42, 4356-4363.

Evaluation of the river die-away biodegradation test

USGS Publications Warehouse

Wylie, Glenn D.; Jones, John R.; Johnson, B. Thomas

1982-01-01

The reliability of the river die-away (RDA) test for establishing the biodegradability of chemicals was assessed. Reproducibility of biodegradation in the RDA test was analyzed under conditions in which the test is commonly done. Biodegradation results were not reproducible for di-2-ethylexyl phthalate (DEHP) and phthalic acid in replicated RDA tests using Missouri River water. Chemical and biological changes during the RDA tests probably reflected relative laboratory conditions. Initial suspended solids and subsequent DEHP biodegradation were directly related. Interpretation of RDA test results is enhanced by replicating experiments and comparing biodegradation of the test compound with a compound whose degradation properties are known. However, biodegradation measured with the RDA test is too variable and too dependent on laboratory treatment of samples to apply results directly to the aquatic environment.

Use of the University of Minnesota Biocatalysis/Biodegradation Database for study of microbial degradation

PubMed Central

2012-01-01

Microorganisms are ubiquitous on earth and have diverse metabolic transformative capabilities important for environmental biodegradation of chemicals that helps maintain ecosystem and human health. Microbial biodegradative metabolism is the main focus of the University of Minnesota Biocatalysis/Biodegradation Database (UM-BBD). UM-BBD data has also been used to develop a computational metabolic pathway prediction system that can be applied to chemicals for which biodegradation data is currently lacking. The UM-Pathway Prediction System (UM-PPS) relies on metabolic rules that are based on organic functional groups and predicts plausible biodegradative metabolism. The predictions are useful to environmental chemists that look for metabolic intermediates, for regulators looking for potential toxic products, for microbiologists seeking to understand microbial biodegradation, and others with a wide-range of interests. PMID:22587916