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Sample records for aerobic biodegradation kinetics

  1. Kinetics and thermodynamics of biodegradation of hydrolyzed polyacrylamide under anaerobic and aerobic conditions.

    PubMed

    Zhao, Lanmei; Bao, Mutai; Yan, Miao; Lu, Jinren

    2016-09-01

    Kinetics and thermodynamics of hydrolyzed polyacrylamide (HPAM) biodegradation in anaerobic and aerobic activated sludge biochemical treatment systems were explored to determine the maximum rate and feasibility of HPAM biodegradation. The optimal nutrient proportions for HPAM biodegradation were determined to be 0.08g·L(-1) C6H12O6, 1.00g·L(-1) NH4Cl, 0.36g·L(-1) NaH2PO4 and 3.00g·L(-1) K2HPO4 using response surface methodology (RSM). Based on the kinetics, the maximum HPAM biodegradation rates were 16.43385mg·L(-1)·d(-1) and 2.463mg·L(-1)·d(-1) in aerobic and anaerobic conditions, respectively. The activation energy (Ea) of the aerobic biodegradation was 48.9897kJ·mol(-1). Entropy changes (ΔS) of biochemical treatment system decreased from 216.21J·K(-1) to 2.39J·K(-1). Thermodynamic windows of opportunity for HPAM biodegradation were drawn. And it demonstrated HPAM was biodegraded into acetic acid and CO2 under laboratory conditions. Growth-process equations for functional bacteria anaerobically grown on polyacrylic acid were constructed and it confirmed electron equivalence between substrate and product. PMID:27235971

  2. Aerobic Biodegradation Kinetics And Mineralization Of Six Petrodiesel/Soybean-Biodiesel Blends

    EPA Science Inventory

    The aerobic biodegradation kinetics and mineralization of six petrodiesel/soybean-biodiesel blends (B0, B20, B40, B60, B80, and B100), where B100 is 100% biodiesel, were investigated by acclimated cultures. The fatty acid methyl esters (FAMEs) of biodiesel were found to undergo ...

  3. BIODEGRADATION KINETICS AND TOXICITY OF VEGETABLE OIL TRIACYLGLYCEROLS UNDER AEROBIC CONDITIONS

    EPA Science Inventory

    The aerobic biodegradation of five triacylglycerols (TAGs), three liquids [triolein (OOO), trilinolein (LLL), and trilinolenin (LnLnLn)] and two solids [tripalmitin (PPP) and tristearin (SSS)] was studied in water. Respirometry tests were designed and conducted to determine the b...

  4. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    PubMed

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. PMID:26874310

  5. Microrespirometric determination of the effectiveness factor and biodegradation kinetics of aerobic granules degrading 4-chlorophenol as the sole carbon source.

    PubMed

    Vital-Jacome, Miguel; Buitrón, Germán; Moreno-Andrade, Ivan; Garcia-Rea, Victor; Thalasso, Frederic

    2016-08-01

    In this study, a microrespirometric method was used, i.e., pulse respirometry in microreactors, to characterize mass transfer and biodegradation kinetics in aerobic granules. The experimental model was an aerobic granular sludge in a sequencing batch reactor (SBR) degrading synthetic wastewater containing 4-chlorophenol as the sole carbon source. After 15 days of acclimation, the SBR process degraded 4-chlorophenol at a removal rate of up to 0.9kg CODm(-3)d(-1), and the degradation kinetics were well described by the Haldane model. The microrespirometric method consisted of injecting pulses of 4-chlorophenol into the 24 wells of a microreactor system containing the SBR samples. From the respirograms obtained, the following five kinetic parameters were successfully determined during reactor operation: (i) Maximum specific oxygen uptake rate, (ii) substrate affinity constant, (iii) substrate inhibition constant, (iv) maximum specific growth rate, and (v) cell growth yield. Microrespirometry tests using granules and disaggregated granules allowed for the determination of apparent and intrinsic parameters, which in turn enabled the determination of the effectiveness factor of the granular sludge. It was concluded that this new high-throughput method has the potential to elucidate the complex biological and physicochemical processes of aerobic granular biosystems. PMID:27054670

  6. Aerobic biodegradation kinetics of solid organic wastes on earth and for applications in space

    NASA Astrophysics Data System (ADS)

    Ramirez Perez, Javier Christian

    Aerobic biodegradation plays an important role in recycling organic matter and nutrients on earth. It is also a candidate technology for waste processing and resource recovery in Advanced Life Support (ALS) systems, such as a proposed planetary base on Mars. Important questions are how long should wastes be treated, and what is the quality (stability/maturity) of the product. To address these questions two aerobic composting systems were evaluated. One treated (252 days) horse manure and cranberry fruit in duplicate open windrows (HCC) as a reference earth application. The other was a pilot-scale (330 L) enclosed, in-vessel system treating (162 days) inedible biomass collected from plant growth systems at NASA, amended with food and human wastes simulant for potential space application (ALSC). Samples were taken from both systems over time and product quality assessed with a range of physical, chemical, biological, toxicological, respirometry and plant growth analyses that were developed and standardized. Because plant growth analyses take so long, a hypothesis was that some parameters could be used to predict compost quality and suitability for growing plants. Maximum temperatures in the thermophilic range were maintained for both systems (HCC > 60°C for >129 days, ALSC > 55°C for >40 days. Fecal streptococci were reduced by 4.8 log-units for HCC and 7.8 for ALSC. Volume/mass reductions achieved were 63%/62% for HCC and 79%/67% for ALSC. Phytotoxicity tests performed on aqueous extracts to recover plant nutrients found decreasing sensitivity: arabidopsis > lettuce > tomato > wheat > cucumber, corresponding with seed size and food reserve capacity. The germination index (GI) of HCC increased over composting time indicating decreasing phytotoxicity. However, GIs for ALSC leachate decreased or fluctuated over composting time. Selected samples of HCC at 31, 157 and 252 days alone and combined with promix (1:1), and of ALSC at 7, 14, 21, 28, 40 and 84 days, or fresh

  7. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  8. Aerobic biodegradation of trichloroethene without auxiliary substrates.

    PubMed

    Schmidt, Kathrin R; Gaza, Sarah; Voropaev, Andrey; Ertl, Siegmund; Tiehm, Andreas

    2014-08-01

    Trichloroethene (TCE) represents a priority pollutant and is among the most frequently detected contaminants in groundwater. The current bioremediation measures have certain drawbacks like e.g. the need for auxiliary substrates. Here, the aerobic biodegradation of TCE as the sole growth substrate is demonstrated. This new process of metabolic TCE degradation was first detected in groundwater samples. TCE degradation was stable in an enriched mixed bacterial culture in mineral salts medium for over five years and repeated transfers of the culture resulting in a 10(10) times dilution of the original groundwater. Aerobic TCE degradation resulted in stoichiometric chloride formation. Stable carbon isotope fractionation was observed providing a reliable analytical tool to assess this new biodegradation process at field sites. The results suggest that aerobic biodegradation of TCE without auxiliary substrate could be considered as an option for natural attenuation or engineered bioremediation of contaminated sites. PMID:24793109

  9. New Routes for Aerobic Biodegradation of Dimethylsulfoniopropionate

    PubMed Central

    Taylor, Barrie F.; Gilchrist, Darrin C.

    1991-01-01

    Dimethylsulfoniopropionate (DMSP), an osmolyte in marine plants, is biodegraded by cleavage of dimethyl sulfide (DMS) or by demethylation to 3-methiolpropionate (MMPA) and 3-mercaptopropionate (MPA). Sequential demethylation has been observed only with anoxic slurries of coastal sediments. Bacteria that grew aerobically on MMPA and DMSP were isolated from marine environments and phytoplankton cultures. Enrichments with DMSP selected for bacteria that generated DMS, whereas MMPA enrichments selected organisms that produced methanethiol (CH3SH) from either DMSP or MMPA. A bacterium isolated on MMPA grew on MMPA and DMSP, but rapid production of CH3SH from DMSP occurred only with DMSP-grown cells. Low levels of MPA accumulated during growth on MMPA, indicating demethylation as well as demethiolation of MMPA. The alternative routes for DMSP biodegradation via MMPA probably impact on net DMS fluxes to the marine atmosphere. PMID:16348607

  10. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  11. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  12. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  13. Stable carbon isotope fractionation during aerobic biodegradation of chlorinated ethenes

    SciTech Connect

    Chu, Kung-Hui; Mahendra, Shaily; Song, Donald L.; Conrad, Mark E.; Alvarez-Cohen, Lisa

    2003-06-01

    Stable isotope analysis is recognized as a powerful tool for monitoring, assessing, and validating in-situ bioremediation processes. In this study, kinetic carbon isotope fractionation factors () associated with the aerobic biodegradation of vinyl chloride (VC), cis-1,2-dichloroethylene (cDCE), and trichloroethylene (TCE) were examined. Of the three solvents, the largest fractionation effects were observed for biodegradation of VC. Both metabolic and cometabolic VC degradation were studied using Mycobacterium aurum L1 (grown on VC), Methylosinus trichosporium OB3b (grown on methane), Mycobacterium vaccae JOB 5 (grown on propane), and two VC enrichment cultures seeded from contaminated soils of Alameda Point and Travis Air Force Base, CA. M. aurum L1 caused the greatest fractionation (= -5.7) while for the cometabolic cultures, values ranged from -3.2 to -4.8. VC fractionation patterns for the enrichment cultures were within the range of those observed for the metabolic and cometabolic cultures (= -4.5 to -5.5). The fractionation for cometabolic degradation of TCE by Me. trichosporium OB3b was low (= -1.1), while no quantifiable carbon isotopic fractionation was observed during the cometabolic degradation of cDCE. For all three of the tested chlorinated ethenes, isotopic fractionation measured during aerobic degradation was significantly smaller than that reported for anaerobic reductive dechlorination. This study suggests that analysis of compound-specific isotopic fractionation could assist in determining whether aerobic or anaerobic degradation of VC and cDCE predominates in field applications of in-situ bioremediation. In contrast, isotopic fractionation effects associated with metabolic and cometabolic reactions are not sufficiently dissimilar to distinguish these processes in the field.

  14. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    NASA Astrophysics Data System (ADS)

    Suchowska-Kisielewicz, Monika; Jędrczak, Andrzej; Sadecka, Zofia

    2014-12-01

    An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

  15. Aerobic biodegradation of vinyl chloride in groundwater samples

    SciTech Connect

    Davis, J.W.; Carpenter, C.L. )

    1990-12-01

    Studies were conducted to examine the biodegradation of {sup 14}C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to {sup 14}CO{sub 2}.

  16. Comparison of Aerobic and Anaerobic Biodegradation of Sugarcane Vinasse.

    PubMed

    Mota, V T; Araújo, T A; Amaral, M C S

    2015-07-01

    Vinasse is the main liquid waste from ethanol production, and it has a considerable pollution potential. Biological treatment is a promising alternative to reduce its organic load. The aim of this study was to analyze the biodegradation of sugarcane juice vinasse in aerobic and anaerobic conditions. The content of carbohydrates, proteins and volatile fatty acids was evaluated. Vinasse samples showed a high biodegradability (>96.5 %) and low percentage of inert chemical oxygen demand (COD) (<3.2 %) in both aerobic and anaerobic conditions. The rates of substrate utilization were slightly higher in aerobic reactors, but COD stabilization occurred simultaneously in the anaerobic reactors, confirming its suitability for anaerobic digestion. Inert COD in anaerobic conditions was lower than in aerobic conditions. On the other hand, COD from metabolic products in the anaerobic reactors was higher than in the aerobic ones, indicating an increased release of soluble microbial products (SMPs) by anaerobic microorganisms. The results indicated that carbohydrates were satisfactorily degraded and protein-like substances were the major components remaining after biological degradation of vinasse. PMID:25957273

  17. Biodegradation of Asphalt Cement-20 by Aerobic Bacteria

    PubMed Central

    Pendrys, John P.

    1989-01-01

    Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-degrading bacterium, Acinetobacter calcoaceticus NAV2, excretes an emulsifier which is capable of emulsifying the saturate and naphthene aromatic fractions of asphalt cement-20. This emulsifier is not denatured by phenol. PMID:16347928

  18. Parallel pathways of ethoxylated alcohol biodegradation under aerobic conditions.

    PubMed

    Zembrzuska, Joanna; Budnik, Irena; Lukaszewski, Zenon

    2016-07-01

    Non-ionic surfactants (NS) are a major component of the surfactant flux discharged into surface water, and alcohol ethoxylates (AE) are the major component of this flux. Therefore, biodegradation pathways of AE deserve more thorough investigation. The aim of this work was to investigate the stages of biodegradation of homogeneous oxyethylated dodecanol C12E9 having 9 oxyethylene subunits, under aerobic conditions. Enterobacter strain Z3 bacteria were chosen as biodegrading organisms under conditions with C12E9 as the sole source of organic carbon. Bacterial consortia of river water were used in a parallel test as an inoculum for comparison. The LC-MS technique was used to identify the products of biodegradation. Liquid-liquid extraction with ethyl acetate was selected for the isolation of C12E9 and metabolites from the biodegradation broth. The LC-MS/MS technique operating in the multiple reaction monitoring (MRM) mode was used for quantitative determination of C12E9, C12E8, C12E7 and C12E6. Apart from the substrate, the homologues C12E8, C12E7 and C12E6, being metabolites of C12E9 biodegradation by shortening of the oxyethylene chain, as well as intermediate metabolites having a carboxyl end group in the oxyethylene chain (C12E8COOH, C12E7COOH, C12E6COOH and C12E5COOH), were identified. Poly(ethylene glycols) (E) having 9, 8 and 7 oxyethylene subunits were also identified, indicating parallel central fission of C12E9 and its metabolites. Similar results were obtained with river water as inoculum. It is concluded that AE, under aerobic conditions, are biodegraded via two parallel pathways: by central fission with the formation of PEG, and by Ω-oxidation of the oxyethylene chain with the formation of carboxylated AE and subsequent shortening of the oxyethylene chain by a single unit. PMID:27037882

  19. Enhancement of aerobic biodegradability potential of municipal waste activated sludge by ultrasonic aided bacterial disintegration.

    PubMed

    Kavitha, S; Jessin Brindha, G M; Sally Gloriana, A; Rajashankar, K; Yeom, Ick Tae; Rajesh Banu, J

    2016-01-01

    An investigation was performed to study the influence of ultrasonic aided bacterial disintegration on the aerobic degradability of sludge. In first phase of the study, effective floc disruption was achieved at an ultrasonic specific energy input of 2.45kJ/kg TS with 44.5mg/L of Extracellular Polymeric Substance (EPS) release including 0.035U/mL and 0.025U/mL protease and amylase activity respectively. In second phase, experimental outcomes revealed bacterial disintegration of floc disrupted-sludge showing a maximum solubilization of about 23% and was observed to be superior to bacterially disintegrated (11%) and control (6%), respectively. The result of aerobic biodegradability of ultrasonic aided bacterially pretreated sludge showed volatile solids (VS) degradation of about 40.2%. The kinetic study of aerobic biodegradability through non linear regression modelling reveals that floc disrupted sludge showed better biodegradability with decay constant of about 0.19d(-1) relatively higher than the control (0.14d(-1)) and bacterially disintegrated (0.17d(-1)) sludges. PMID:26479431

  20. Biodegradation of o-nitrophenol by aerobic granules with glucose as co-substrate.

    PubMed

    Basheer, Farrukh; Isa, M H; Farooqi, I H

    2012-01-01

    Aerobic granules to treat wastewater containing o-nitrophenol were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. Stable aerobic granules were obtained with a clearly defined shape and diameters ranging from 2 to 6 mm after 122 days of operation. The integrity coefficient (IC) and granules density was found to be 98% and 1,054 kg m(-3) respectively. After development of aerobic granules, o-nitrophenols were successfully degraded to an efficiency of 78% at a concentration of 70 mg L(-1). GC-MS study revealed that the biodegradation of o-nitrophenol occurred via catechol via nitrobenzene pathway. Specific o-nitrophenol biodegradation rates followed the Haldane model and the associated kinetic parameters were found as follows: V(max) = 3.96 g o-nitrophenol g(-1)VSS(-1)d(-1), K(s) = 198.12 mg L(-1), and K(i) = 31.16 mg L(-1). The aerobic granules proved to be a feasible and effective way to degrade o-nitrophenol containing wastewater. PMID:22643407

  1. Substrate inhibition kinetics of phenol biodegradation

    SciTech Connect

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

    2000-02-01

    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}, 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.

  2. Effects of Rate-Limited Mass Transfer on Modeling Vapor Intrusion with Aerobic Biodegradation.

    PubMed

    Chen, Yiming; Hou, Deyi; Lu, Chunhui; Spain, Jim C; Luo, Jian

    2016-09-01

    Most of the models for simulating vapor intrusion accept the local equilibrium assumption for multiphase concentration distributions, that is, concentrations in solid, liquid and vapor phases are in equilibrium. For simulating vapor transport with aerobic biodegradation controlled by counter-diffusion processes, the local equilibrium assumption combined with dual-Monod kinetics and biomass decay may yield near-instantaneous behavior at steady state. The present research investigates how predicted concentration profiles and fluxes change as interphase mass transfer resistances are increased for vapor intrusion with aerobic biodegradation. Our modeling results indicate that the attenuation coefficients for cases with and without mass transfer limitations can be significantly different by orders of magnitude. Rate-limited mass transfer may lead to larger overlaps of contaminant vapor and oxygen concentrations, which cannot be simulated by instantaneous reaction models with local equilibrium mass transfer. In addition, the contaminant flux with rate-limited mass transfer is much smaller than that with local equilibrium mass transfer, indicating that local equilibrium mass transfer assumption may significantly overestimate the biodegradation rate and capacity for mitigating vapor intrusion through the unsaturated zone. Our results indicate a strong research need for field tests to examine the validity of local equilibrium mass transfer, a widely accepted assumption in modeling vapor intrusion. PMID:27486832

  3. In situ stimulation of aerobic PCB biodegradation in Hudson River sediments

    SciTech Connect

    Harkness, M.R.; McDermott, J.B.; Abramowicz, D.A.; Salvo, J.J.; Flanagan, W.P.; Stephens, M.L.; Mondello, F.J.; May, R.J.; Lobos, J.H.; Carroll, K.M.; Brennan, M.J.; Bracco, A.A.; Fish, K.M.; Warner, G.L.; Wilson, P.R.; Dietrich, D.K.; Lin, D.T.; Morgan, C.B.; Gately, W.L. )

    1993-01-22

    A 73-day field study of in situ aerobic biodegradation of polychlorinated biphenyls (PCBs) in the Hudson River shows that indigenous aerobic microorganisms can degrade the lightly chlorinated PCBs present in these sediments. Addition of inorganic nutrients, biphenyl, and oxygen enhanced PCB biodegradation, as indicated both by a 37 to 55 percent loss of PCBs and by the production of chlorobenzoates, intermediates in the PCB biodegradation pathway. Repeated inoculation with a purified PCB-degrading bacterium failed to improve biodegradative activity. Biodegradation was also observed under mixed but unamended conditions, which suggests that this process may occur commonly in river sediments, with implications for PCB fate models and risk assessments.

  4. Aerobic biodegradation of organic compounds in hydraulic fracturing fluids.

    PubMed

    Kekacs, Daniel; Drollette, Brian D; Brooker, Michael; Plata, Desiree L; Mouser, Paula J

    2015-07-01

    Little is known of the attenuation of chemical mixtures created for hydraulic fracturing within the natural environment. A synthetic hydraulic fracturing fluid was developed from disclosed industry formulas and produced for laboratory experiments using commercial additives in use by Marcellus shale field crews. The experiments employed an internationally accepted standard method (OECD 301A) to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from an aqueous solution by activated sludge and lake water microbial consortia for two substrate concentrations and four salinities. Microbial degradation removed from 57 % to more than 90 % of added DOC within 6.5 days, with higher removal efficiency at more dilute concentrations and little difference in overall removal extent between sludge and lake microbe treatments. The alcohols isopropanol and octanol were degraded to levels below detection limits while the solvent acetone accumulated in biological treatments through time. Salinity concentrations of 40 g/L or more completely inhibited degradation during the first 6.5 days of incubation with the synthetic hydraulic fracturing fluid even though communities were pre-acclimated to salt. Initially diverse microbial communities became dominated by 16S rRNA sequences affiliated with Pseudomonas and other Pseudomonadaceae after incubation with the synthetic fracturing fluid, taxa which may be involved in acetone production. These data expand our understanding of constraints on the biodegradation potential of organic compounds in hydraulic fracturing fluids under aerobic conditions in the event that they are accidentally released to surface waters and shallow soils. PMID:26037076

  5. Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

    PubMed

    Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

    2009-05-15

    The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards. PMID:18799262

  6. 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. PMID:21144726

  7. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.; Baker, R.J.

    1999-01-01

    Aerobic biodegradation and volatilization near the water table constitute a coupled pathway that contributes significantly to the natural attenuation of hydrocarbons at gasoline spill sites. Rates of hydrocarbon biodegradation and volatilization were quantified by analyzing vapor transport in the unsaturated zone at a gasoline spill site in Beaufort, South Carolina. Aerobic biodegradation rates decreased with distance above the water table, ranging from 0.20 to 1.5g m-3 d-1 for toluene, from 0.24 to 0.38 g m-3 d-1 for xylene, from 0.09 to 0.24 g m-3 d-1 for cyclohexene, from 0.05 to 0.22 g m-3 d-1 for ethylbenzene, and from 0.02 to 0.08 g m-3 d-1 for benzene. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Hydrocarbons were nearly completely degraded within 1 m above the water table. This large loss underscores the importance of aerobic biodegradation in limiting the transport of hydrocarbon vapors in the unsaturated zone and implies that vapor-plume migration to basements and other points of contact may only be significant if a source of free product is present. Furthermore, because transport of the hydrocarbon in the unsaturated zone can be limited relative to that of oxygen and carbon dioxide, soil, gas surveys conducted at hydrocarbon-spill sites would benefit by the inclusion of oxygen- and carbon-dioxide-gas concentration measurements. Aerobic degradation kinetics in the unsaturated zone were approximately first-order. First-order rate constants near the water table were highest for cyctohexene (0.21-0.65 d-1) and nearly equivalent for ethylbenzene (0.11-20.31 d-1), xylenes (0.10-0.31 d-1), toluene (0.09-0.30 d-1), and benzene (0.07,0.31 d-1). Hydrocarbon mass loss rates at the water table resulting from the coupled aerobic biodegradation and volatilization process were determined by extrapolating gas transport rates through the capillary zone. Mass

  8. Potential waste minimization of trichloroethylene and perchloroethylene via aerobic biodegradation.

    PubMed

    Wang, Jian; Cutright, Teresa J

    2005-01-01

    Trichloroethylene (TCE) and perchloroethylene (PCE) are two of the most frequently detected chlorinated organics found in groundwater. Biodegradation with a new aerobic consortium was used to ascertain the viability of bioremediation for waste minimization applications. After 1 week of treatment, the degradation rate constants, k, were between 0.004 and 0.012 d(-1) for initial concentrations of 54-664 microM TCE. When PCE was used as the sole contaminant, the k values were approximately 0.01 d(-1) regardless of the initial concentration. The addition of 0.2 microM toluene or phenol as an inducer dramatically increased TCE degradation. For instance, at 200 microM TCE the k value when toluene was added (0.03 d(-1)) was 2.2 times higher than without inducers (0.009 d(-1)). The addition of 0.2 microM phenol increased the rate constant by 58%. However, PCE degradation rates were not changed significantly. PMID:15991724

  9. Aerobic biodegradation of iso-butanol and ethanol and their relative effects on BTEX biodegradation in aquifer materials.

    PubMed

    Schaefer, Charles E; Yang, Xiaomin; Pelz, Oliver; Tsao, David T; Streger, Sheryl H; Steffan, Robert J

    2010-11-01

    The aerobic biodegradability of iso-butanol, a new biofuel, and its impact on benzene, toluene, ethylbenzene and xylenes (BTEX) degradation was investigated in aerobic microcosms consisting of groundwater and sediment from a California site with a history of gasoline contamination. To the best of our knowledge this is the first study directly examining the effects of iso-butanol on BTEX degradation. Microcosms that received either low (68 μM) or high (3400 μM) concentrations of iso-butanol showed complete biodegradation of iso-butanol within 7 and 23 d, respectively, of incubation at 15°C under aerobic conditions. A maximum utilization rate coefficient of 2.3±0.1×10⁻⁷ μmol cell⁻¹ h⁻¹ and a half saturation constant of 610±54 μM were regressed from the iso-butanol data. Iso-butanol biodegradation resulted in transient formation of the degradation intermediate products iso-butylaldehyde and iso-butyric acid, and both compounds were subsequently degraded within the timeframe of the experiments. Ethanol was biodegraded more slowly than iso-butanol. Ethanol also exhibited greater adverse impacts on BTEX biodegradation than iso-butanol. Results of the study suggest that iso-butanol added to fuels will be readily biodegraded in the environment under aerobic conditions without the accumulation of major intermediate products (iso-butylaldehyde and iso-butyric acid), and that it will pose less impacts on BTEX biodegradation than ethanol. PMID:20875664

  10. Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs?

    PubMed Central

    2011-01-01

    Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses. PMID:22196374

  11. Involvement of Linear Plasmids in Aerobic Biodegradation of Vinyl Chloride

    SciTech Connect

    BRIGMON, ROBINL.

    2004-06-14

    Pseudomonas putida strain AJ and Ochrobactrum strain TD were isolated from hazardous waste sites based on their ability to use vinyl chloride (VC) as a sole source of carbon and energy under aerobic conditions. Strains AJ and TD also use ethene and ethylene oxide as growth substrates. Strain AJ contained a linear megaplasmid (approximately 260 kb) when grown on VC or ethene, but no circular plasmids. While growing on ethylene oxide, the size of the linear plasmid in strain AJ decreased to approximately 100 kb, although its ability to use VC as a substrate was retained. The linear plasmids in strain AJ were cured and its ability to consume VC, ethene, and ethylene oxide was lost following growth on a rich substrate (Luria-Bertani broth) through at least three transfers. Strain TD contained three linear plasmids, ranging in size from approximately 100 kb to 320 kb, when growing on VC or ethene. As with strain AJ, the linear plasmids in strain TD were cured following growth on Luria -Bertani broth and its ability to consume VC and ethene was lost. Further analysis of these linear plasmids may help reveal the pathway for VC biodegradation in strains AJ and TD and explain why this process occurs at many but not all sites where groundwater is contaminated with chloroethenes. Metabolism of VC and ethene by strains AJ and TD is initiated by an alkene monooxygenase. Their yields during growth on VC (0.15-0.20 mg total suspended solids per mg VC) are similar to the yields reported for other isolates i.e., Mycobacterium sp., Nocardioides sp., and Pseudomonas sp.

  12. RESPIROMETRIC METHODS FOR DETERMINATION OF BIODEGRADABILITY AND BIODEGRADATION KINETICS FOR HAZARDOUS ORGANIC POLLUTANT COMPOUNDS

    EPA Science Inventory

    Electrolytic respirometry involving natural sewage, sludge and soil microbiota is becoming prominent in fate studies of priority pollutant and RCRA toxic organics to generate biodegradation/inhibition kinetic data. eveloped multi-level protocol is presented for determination of s...

  13. Aerobic biodegradation process of petroleum and pathway of main compounds in water flooding well of Dagang oil field.

    PubMed

    Cai, Minmin; Yao, Jun; Yang, Huaijun; Wang, Ruixia; Masakorala, Kanaji

    2013-09-01

    Aerobic biodegradation of crude oil and its pathways were investigated via in vitro culture and GC-MS analysis in water flooding wells of Dagang oil field. The in vitro aerobic culture lasted 90 days when 99.0% of n-alkanes and 43.03-99.9% of PAHs were degraded and the biomarkers and their ratios were changed. The spectra of components in the residual oil showed the similar biodegradation between aerobic process of 90 days and degradation in reservoir which may last for some millions years, and the potential of serious aerobic biodegradation of petroleum in reservoir. 24 Metabolites compounds were separated and identified from aerobic culture, including fatty acid, naphthenic acid, aromatic carboxylic acid, unsaturated acid, alcohols, ketones and aldehydes. The pathways of alkanes and aromatics were proposed, which suggests that oxidation of hydrocarbon to organic acid is an important process in the aerobic biodegradation of petroleum. PMID:23867530

  14. Aerobic biodegradation of the brominated flame retardants, dibromoneopentyl glycol and tribromoneopentyl alcohol.

    PubMed

    Segev, Osnat; Meusel, Wolfram; Friedenberger, Melanie; Brenner, Asher; Kushmaro, Ariel

    2009-09-01

    Halogenated organic compounds constitute one of the largest and most diverse groups of chemicals in the environment. Many of these compounds are toxic, persistent and, as a result of their often limited biodegradability, tend to bioaccumulate in the environment. Dibromoneopentyl glycol (DBNPG) and tribromoneopentyl alcohol (TBNPA) are brominated flame retardants commonly used as additives during the manufacture of plastic polymers and as chemical intermediates in the synthesis of other flame retardants. Both are classified as not readily biodegradable. In this paper, we demonstrate the biodegradation of both DBNPG and TBNPA by a common bacterial consortium under aerobic conditions in enrichment cultures containing yeast extract. DBNPG and TBNPA biodegradation is accompanied by a release of bromide into the medium, due to a biological debromination reaction. Molecular analysis of the clone library PCR amplified 16S rRNA gene was used to characterize the bacterial consortium involved in the biodegradation. PMID:19205903

  15. AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

    EPA Science Inventory

    The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

  16. Biodegradation of 14C-dicofol in wastewater aerobic treatment and sludge anaerobic biodigestion.

    PubMed

    Oliveira, Jaime L da M; Silva, Denise P; Martins, Edir M; Langenbach, Tomaz; Dezotti, Marcia

    2012-01-01

    Organic micropollutants are often found in domestic and industrial effluents. Thus, it is important to learn their fate, the metabolites generated and their sorption during biological treatment processes. This work investigated the biodegradation of 14C-dicofol organochloride during wastewater aerobic treatment and sludge anaerobic biodigestion. The performance of these processes was evaluated by physical-chemical parameters. Radioactivity levels were monitored in both treatments, and residues of dicofol (DCF) and dichlorobenzophenone (DBP) were quantified by HPLC/UV. The efficiency of the aerobic and anaerobic processes was slightly reduced in the presence of DCF and DBP. After aerobic treatment, only 0.1% of DCF was mineralized, and 57% of radioactivity remained sorbed on biological sludge as DBP. After 18 days of anaerobiosis, only 3% of DCF and 5% of DBP were detected in the sludge. However, 70% of radioactivity remained in the sludge, probably as other metabolites. Dicofol was biodegraded in the investigated process, but not mineralized. PMID:22629645

  17. Biodegradation of dimethyl phthalate by Sphingomonas sp. isolated from phthalic-acid-degrading aerobic granules.

    PubMed

    Zeng, Ping; Moy, Benjamin Yan-Pui; Song, Yong-Hui; Tay, Joo-Hwa

    2008-10-01

    Phthalic acid esters (PAEs) contamination in water, air, and soil is one of the major environmental concerns in many countries. Besides the PAE biodegradation process, the PAE degrading bacteria have become one of the focuses of study. This study reports the successful isolation of one kind of indigenous bacterium PA-02 from phthalic acid (PA)-degrading aerobic granules. Based on its 16S ribosomal DNA sequence, isolate PA-02 was identified as Sphingomonas genus with 100% similarity to Sphingomonas sp. strain D84532. Strain PA-02 was a Gram-negative, rod-shaped bacterium with strong auto-aggregation ability. In particular, the strain PA-02 possessed PAE-degrading ability without acclimation. Results of growth tests showed that strain PA-02 could degrade dimethyl phthalate (DMP), dibutyl phthalate, and diethylhexyl phthalate. The specific degradation rates of DMP and PA were concentration-dependent with maximum values of 0.4 g-DMP g(-1) biomass h(-1) and 1.3 g-PA g(-1) biomass h(-1), respectively. Kinetic studies also revealed that PA-02 was robust under high concentrations of DMP and PA. Even when the PA concentration was increased to 1,000.0 mg l(-1), the specific PA degradation rate was about 0.25 g-PA g(-1) biomass h(-1). The corresponding value for DMP was 0.067 g-DMP g(-1) biomass h(-1) at 1,000 mg l(-1). PMID:18751698

  18. 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. PMID:15497834

  19. COMPARISON OF FIELD AEROBIC BIODEGRADATION RATES TO LABORATORY

    EPA Science Inventory

    It is common to use bioventing as a polishing step for soil vapor extraction. It was originally planned to use soil vapor extraction and bioventing at a former landfill site in Delaware but laboratory scale biodegradation studies indicated that most of the volatile organic compou...

  20. AEROBIC BIODEGRADABILITY AND TOXICITY OF NON-PETROLEUM OILS.

    EPA Science Inventory

    Vegetable oil spills are a widely known phenomenon, but are the least understood. These spills can be as devastating to the environment as petroleum oil spills. Previous laboratory research results have indicated that as vegetable oils degrade aerobically, the aqueous solutions b...

  1. AEROBIC BIODEGRADATION OF GASOLINE OXYGENATES MTBE AND TBA

    EPA Science Inventory

    MTBE degradation was investigated using a continuously stirred tank reactor (CSTR) with biomass retention (porous pot reactor) operated under aerobic conditions. MTBE was fed to the reactor at an influent concentration of 150 mg/l (1.70 mmol/l). A second identifical rector was op...

  2. Biodegradation of tributyl phosphate, an organosphate triester, by aerobic granular biofilms.

    PubMed

    Nancharaiah, Y V; Kiran Kumar Reddy, G; Krishna Mohan, T V; Venugopalan, V P

    2015-01-01

    Tributyl phosphate (TBP) is commercially used in large volumes for reprocessing of spent nuclear fuel. TBP is a very stable compound and persistent in natural environments and it is not removed in conventional wastewater treatment plants. In this study, cultivation of aerobic granular biofilms in a sequencing batch reactor was investigated for efficient biodegradation of TBP. Enrichment of TBP-degrading strains resulted in efficient degradation of TBP as sole carbon or along with acetate. Complete biodegradation of 2mM of TBP was achieved within 5h with a degradation rate of 0.4 μmol mL(-1) h(-1). TBP biodegradation was accompanied by release of inorganic phosphate in stoichiometric amounts. n-Butanol, hydrolysed product of TBP was rapidly biodegraded. But, dibutyl phosphate, a putative intermediate of TBP degradation was only partially degraded pointing to an alternative degradation pathway. Phosphatase activity was 22- and 7.5-fold higher in TBP-degrading biofilms as compared to bioflocs and acetate-fed aerobic granules. Community analysis by terminal restriction length polymorphism revealed presence of 30 different bacterial strains. Seven bacterial stains, including Sphingobium sp. a known TBP degrader were isolated. The results show that aerobic granular biofilms are promising for treatment of TBP-bearing wastes or ex situ bioremediation of TBP-contaminated sites. PMID:25464313

  3. Aerobic granular sludge mediated biodegradation of an organophosphorous ester, dibutyl phosphite.

    PubMed

    Kiran Kumar Reddy, G; Nancharaiah, Yarlagadda Venkata; Venugopalan, Vayalam Purath

    2014-10-01

    Dibutyl phosphite, an organophosphorous compound, finds applications in different chemical industries and processes. Here, we report an efficient approach of biodegradation to be eventually used in bioremediation of dibutyl phosphite. Aerobic granules capable of dibutyl phosphite biodegradation were cultivated in a sequencing batch reactor (SBR). The SBR was operated with a 24-h cycle by feeding with dibutyl phosphite as a cosubstrate along with acetate. During the course of the SBR operation, aerobic granules of 0.9 ± 0.3 mm size were developed. Complete biodegradation of 1.4, 2 and 3 mM of dibutyl phosphite was achieved in 4, 5 and 8 h, respectively, accompanied by stoichiometric release of phosphite (H3 PO3). Phosphatase activity in the dibutyl phosphite-degrading granular biomass was 3- and 1.5-fold higher as compared to the activated sludge (seed biomass) and acetate-fed aerobic granules, respectively, indicating involvement in the hydrolysis of dibutyl phosphite. Microbial community analysis by t-RFLP showed the presence of 12 different bacterial types. Two bacterial strains capable of growth on dibutyl phosphite as sole carbon source were isolated and characterized as Acidovorax sp. and Sphingobium sp. The results show that aerobic microbial granules based process is suitable for the treatment of dibutyl phosphite contaminated water. PMID:25135363

  4. Kinetics of trichloroethylene cometabolism and toluene biodegradation: Model application to soil batch experiments

    SciTech Connect

    El-Farhan, Y.H.; Scow, K.M.; Fan, S.; Rolston, D.E.

    2000-06-01

    Trichloroethylene (TCE) biodegradation in soil under aerobic conditions requires the presence of another compound, such as toluene, to support growth of microbial populations and enzyme induction. The biodegradation kinetics of TCE and toluene were examined by conducting three groups of experiments in soil: toluene only, toluene combined with low TCE concentrations, and toluene with TCE concentrations similar to or higher than toluene. The biodegradation of TCE and toluene and their interrelationships were modeled using a combination of several biodegradation functions. In the model, the pollutants were described as existing in the solid, liquid, and gas phases of soil, with biodegradation occurring only in the liquid phase. The distribution of the chemicals between the solid and liquid phase was described by a linear sorption isotherm, whereas liquid-vapor partitioning was described by Henry's law. Results from 12 experiments with toluene only could be described by a single set of kinetic parameters. The same set of parameters could describe toluene degradation in 10 experiments where low TCE concentrations were present. From these 10 experiments a set of parameters describing TCE cometabolism induced by toluene also was obtained. The complete set of parameters was used to describe the biodegradation of both compounds in 15 additional experiments, where significant TCE toxicity and inhibition effects were expected. Toluene parameters were similar to values reported for pure culture systems. Parameters describing the interaction of TCE with toluene and biomass were different from reported values for pure cultures, suggesting that the presence of soil may have affected the cometabolic ability of the indigenous soil microbial populations.

  5. ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIXED BED REACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME

    EPA Science Inventory

    An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to approximately equimolar concentrations (>99%) of chlorophenol (CP) in a granular activa...

  6. Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures.

    PubMed

    Zhang, Shu; Gedalanga, Phillip B; Mahendra, Shaily

    2016-09-01

    This study investigated the impacts of individual chlorinated solvents and their mixtures on aerobic 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190. The established association of these co-occurring compounds suggests important considerations for their respective biodegradation processes. Our kinetics and mechanistic studies demonstrated that individual solvents inhibited biodegradation of 1,4-dioxane in the following order: 1,1-dichloroethene (1,1-DCE) > cis-1,2-diochloroethene (cDCE) > trichloroethene (TCE) > 1,1,1-trichloroethane (TCA). The presence of 5 mg L(-1) 1,1-DCE completely inhibited 1,4-dioxane biodegradation. Subsequently, we determined that 1,1-DCE was the strongest inhibitor of 1,4-dioxane biodegradation by bacterial pure cultures exposed to chlorinated solvent mixtures as well as in environmental samples collected from a site contaminated with chlorinated solvents and 1,4-dioxane. Inhibition of 1,4-dioxane biodegradation rates by chlorinated solvents was attributed to delayed ATP production and down-regulation of both 1,4-dioxane monooxygenase (dxmB) and aldehyde dehydrogenase (aldH) genes. Moreover, increasing concentrations of 1,1-DCE and cis-1,2-DCE to 50 mg L(-1) respectively increased 5.0-fold and 3.5-fold the expression of the uspA gene encoding a universal stress protein. In situ natural attenuation or enhanced biodegradation of 1,4-dioxane is being considered for contaminated groundwater and industrial wastewater, so these results will have implications for selecting 1,4-dioxane bioremediation strategies at sites where chlorinated solvents are present as co-contaminants. PMID:27486928

  7. Aerobic and anaerobic PCB biodegradation in the environment

    SciTech Connect

    Abramowicz, D.A.

    1995-06-01

    Studies have identified two distinct biological processes capable of biotransforming polychlorinated biphenyls (PCBs): aerobic oxidative processes and anaerobic reductive processes. It is now known that these two complementary activities are occurring naturally in the environment. Anaerobic PCB dechlorination, responsible for the conversion of highly chlorinated PCBs to lightly chlorinated ortho-enriched congeners, has been documented extensively in the Hudson River and has been observed at many other sites throughout the world. The products from this anaerobic process are readily degradable by a wide range of aerobic bacteria, and it has now been shown that this process is occurring in surficial sediments in the Hudson River. The widespread anaerobic dechlorination of PCBs that has been observed in many river and marine sediments results in reduction of both the potential risk from and potential exposure to PCBs. The reductions in potential risk include reduced dioxin like toxicity and reduced carcinogenicity. The reduced PCB exposure realized upon dechlorination is manifested by reduced bioaccumulation in the food chain and by the increased anaerobic degradability of these products. 27 refs., 1 fig., 1 tab.

  8. A comparison of the effects of two methods of acclimation of aerobic biodegradability

    SciTech Connect

    Watson, H.M. . Environmental Sciences Section)

    1993-11-01

    The acclimation or adaptation of microorganisms to organic chemicals is an important factor influencing both the rate and the extent of biodegradation. In this study two acclimation procedures were evaluated in terms of their effectiveness in enhancing biodegradation, their relative ease of use in the laboratory, and the implications for biodegradability testing. In the single-flask procedure, microorganisms were acclimated for 2 to 7 d in a single acclimation flask at constant or increasing concentrations of the test chemical without transfer of microorganisms. In the second procedure, the enrichment procedure, microorganisms were acclimated in a series of flasks over a 21-d period by making adaptive transfers to increasing concentrations of the test chemical. Acclimated microorganisms from each procedure were used as the source of inoculum for subsequent biodegradation tests in which carbon dioxide evolution was measured. Six chemicals were tested: quinoline, p-nitrophenol, N-methylaniline, N,N-dimethylaniline, acrylonitrile, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. Microorganisms acclimated in the single-flask procedure were much more effective than those acclimated in the enrichment procedure in degrading the test chemicals. The single-flask procedure is more convenient to use, and it permits monitoring of the time needed for acclimation. The results from these studies have implications for the methodology used in biodegradation test systems and suggest caution before adopting a multiple-flask, enrichment acclimation procedure before the performance of standardized tests for aerobic biodegradability.

  9. Hydrogen Isotope Fractionation As a Tool to Identify Aerobic and Anaerobic PAH Biodegradation.

    PubMed

    Kümmel, Steffen; Starke, Robert; Chen, Gao; Musat, Florin; Richnow, Hans H; Vogt, Carsten

    2016-03-15

    Aerobic and anaerobic polycyclic aromatic hydrocarbon (PAH) biodegradation was characterized by compound specific stable isotope analysis (CSIA) of the carbon and hydrogen isotope effects of the enzymatic reactions initiating specific degradation pathways, using naphthalene and 2-methylnaphtalene as model compounds. Aerobic activation of naphthalene and 2-methylnaphthalene by Pseudomonas putida NCIB 9816 and Pseudomonas fluorescens ATCC 17483 containing naphthalene dioxygenases was associated with moderate carbon isotope fractionation (εC = -0.8 ± 0.1‰ to -1.6 ± 0.2‰). In contrast, anaerobic activation of naphthalene by a carboxylation-like mechanism by strain NaphS6 was linked to negligible carbon isotope fractionation (εC = -0.2 ± 0.2‰ to -0.4 ± 0.3‰). Notably, anaerobic activation of naphthalene by strain NaphS6 exhibited a normal hydrogen isotope fractionation (εH = -11 ± 2‰ to -47 ± 4‰), whereas an inverse hydrogen isotope fractionation was observed for the aerobic strains (εH = +15 ± 2‰ to +71 ± 6‰). Additionally, isotope fractionation of NaphS6 was determined in an overlaying hydrophobic carrier phase, resulting in more reliable enrichment factors compared to immobilizing the PAHs on the bottle walls without carrier phase. The observed differences especially in hydrogen fractionation might be used to differentiate between aerobic and anaerobic naphthalene and 2-methylnaphthalene biodegradation pathways at PAH-contaminated field sites. PMID:26855125

  10. Design and construction of a medium-scale automated direct measurement respirometric system to assess aerobic biodegradation of polymers

    NASA Astrophysics Data System (ADS)

    Castro Aguirre, Edgar

    A medium-scale automated direct measurement respirometric (DMR) system was designed and built to assess the aerobic biodegradation of up to 30 materials in triplicate simultaneously. Likewise, a computer application was developed for rapid analysis of the data generated. The developed DMR system was able to simulate different testing conditions by varying temperature and relative humidity, which are the major exposure conditions affecting biodegradation. Two complete tests for determining the aerobic biodegradation of polymers under composting conditions were performed to show the efficacy and efficiency of both the DMR system and the DMR data analyzer. In both cases, cellulose reached 70% mineralization at 139 and 45 days. The difference in time for cellulose to reach 70% mineralization was attributed to the composition of the compost and water availability, which highly affect the biodegradation rate. Finally, among the tested materials, at least 60% of the organic carbon content of the biodegradable polymers was converted into carbon dioxide by the end of the test.

  11. A new approach for development of kinetics of wastewater treatment in aerobic biofilm reactor

    NASA Astrophysics Data System (ADS)

    Goswami, S.; Sarkar, S.; Mazumder, D.

    2016-02-01

    Biofilm process is widely used for the treatment of a variety of wastewater especially containing slowly biodegradable substances. It provides resistance against toxic environment and is capable of retaining biomass under continuous operation. Development of kinetics is very much pertinent for rational design of a biofilm process for the treatment of wastewater with or without inhibitory substances. A simple approach for development of such kinetics for an aerobic biofilm reactor has been presented using a novel biofilm model. The said biofilm model is formulated from the correlations between substrate concentrations in the influent/effluent and at biofilm liquid interface along with substrate flux and biofilm thickness complying Monod's growth kinetics. The methodology for determining the kinetic coefficients for substrate removal and biomass growth has been demonstrated stepwise along with graphical representations. Kinetic coefficients like K, k, Y, b t, b s, and b d are determined either from the intercepts of X- and Y-axis or from the slope of the graphical plots.

  12. Hydrolytic kinetics of biodegradable polyester monolayers

    SciTech Connect

    Lee, W.K.; Gardella, J.A. Jr.

    2000-04-04

    The rate of hydrolysis of Langmuir monolayer films of a series of biodegradable polyesters was investigated at the air/water interface. The present study investigated parameters such as degradation medium, pH, and time. The hydrolysis of polyester monolayers strongly depended on both the degradation medium used to control subphase pH and the concentration of active ions. Under the conditions studied here, polymer monolayers showed faster hydrolysis when they were exposed to a basic subphase rather than that of acidic or neutral subphase. The basic (pH = 10) hydrolysis of [poly(l-lactide)/polycaprolactone](l-PLA/PCL 1/1 by mole) blend was faster than that of each homopolymer at the initial stage. This result is explained by increasing numbers of base attack sites per unit area owing to the very slow hydrolysis of PCL, a dilution effect on the concentration of l-PLA monolayers. Conversely the hydrolytic behavior of l-lactide-co-caprolactone (1/1 by mole) was similar to that of PCL even though the chemical compositions of the blend and the copolymer are very similar to each other. The resistance of the copolymer to hydrolysis might be attributed to the hydrophobicity and the steric hindrance of caprolactone unit in the copolymer.

  13. Aerobic Degradation of Sulfadiazine by Arthrobacter spp.: Kinetics, Pathways, and Genomic Characterization.

    PubMed

    Deng, Yu; Mao, Yanping; Li, Bing; Yang, Chao; Zhang, Tong

    2016-09-01

    Two aerobic sulfadiazine (SDZ) degrading bacterial strains, D2 and D4, affiliated with the genus Arthrobacter, were isolated from SDZ-enriched activated sludge. The degradation of SDZ by the two isolates followed first-order decay kinetics. The half-life time of complete SDZ degradation was 11.3 h for strain D2 and 46.4 h for strain D4. Degradation kinetic changed from nongrowth to growth-linked when glucose was introduced as the cosubstrate, and accelerated biodegradation rate was observed after the adaption period. Both isolates could degrade SDZ into 12 biodegradation products via 3 parallel pathways, of which 2-amino-4-hydroxypyrimidine was detected as the principal intermediate product toward the pyrimidine ring cleavage. Compared with five Arthrobacter strains reported previously, D2 and D4 were the only Arthrobacter strains which could degrade SDZ as the sole carbon source. The draft genomes of D2 and D4, with the same completeness of 99.7%, were compared to other genomes of related species. Overall, these two isolates shared high genomic similarities with the s-triazine-degrading Arthrobacter sp. AK-YN10 and the sulfonamide-degrading bacteria Microbacterium sp. C448. In addition, the two genomes contained a few significant regions of difference which may carry the functional genes involved in sulfonamide degradation. PMID:27477918

  14. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions. PMID:1418936

  15. Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth.

    PubMed

    Abreu, Lilian D V; Johnson, Paul C

    2006-04-01

    Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed

  16. Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes.

    PubMed

    Lade, Harshad; Kadam, Avinash; Paul, Diby; Govindwar, Sanjay

    2015-01-01

    Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L(-1) concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn't show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic/aerobic

  17. Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes

    PubMed Central

    Lade, Harshad; Kadam, Avinash; Paul, Diby; Govindwar, Sanjay

    2015-01-01

    Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L-1 concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn’t show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic/aerobic

  18. Biodegradation of Free Phytol by Bacterial Communities Isolated from Marine Sediments under Aerobic and Denitrifying Conditions

    PubMed Central

    Rontani, Jean-François; Bonin, Patricia C.; Volkman, John K.

    1999-01-01

    Biodegradation of (E)-phytol [3,7,11,15-tetramethylhexadec-2(E)-en-1-ol] by two bacterial communities isolated from recent marine sediments under aerobic and denitrifying conditions was studied at 20°C. This isoprenoid alcohol is metabolized efficiently by these two bacterial communities via 6,10,14-trimethylpentadecan-2-one and (E)-phytenic acid. The first step in both aerobic and anaerobic bacterial degradation of (E)-phytol involves the transient production of (E)-phytenal, which in turn can be abiotically converted to 6,10,14-trimethylpentadecan-2-one. Most of the isoprenoid metabolites identified in vitro could be detected in a fresh sediment core collected at the same site as the sediments used for the incubations. Since (E)-phytenal is less sensitive to abiotic degradation at the temperature of the sediments (15°C), the major part of (E)-phytol appeared to be biodegraded in situ via (E)-phytenic acid. (Z)- and (E)-phytenic acids are present in particularly large quantities in the upper section of the core, and their concentrations quickly decrease with depth in the core. This degradation (which takes place without significant production of phytanic acid) is attributed to the involvement of alternating β-decarboxymethylation and β-oxidation reaction sequences induced by denitrifiers. Despite the low nitrate concentration of marine sediments, denitrifying bacteria seem to play a significant role in the mineralization of (E)-phytol. PMID:10584007

  19. Kinetics of phthalate ester biodegradation by Chlorella pyrenoidosa

    SciTech Connect

    Yan, H.; Ye, C.; Yin, C.

    1995-06-01

    Experimental results show that Chlorella pyrenoidosa has an ability to accumulate and biodegrade phthalate esters. Bioconcentration factors of dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP) reached their maxima of 162 at 24 h, 205 at 12 h, and 4,077 at 12 h. The average biodegradation rates of DMP, DEP, and DBP per day were found to be 13.4 mg/L, 7.3 mg/L, and 2.1 mg/L, respectively. Based on the experimental data, a second-order kinetic equation was formulated as {minus}dC/dt = KNr, with a factor r indicating the rate of algal growth. Calculation of this equation fits well with the observed data, and the standard deviations between calculated and observed values were 1.72 mg/L, 1.80 mg/L, and 0.26 mg/L for DMP, DEP, DBP, respectively.

  20. Aerobic biodegradation potential of subsurface microorganisms from a jet fuel-contaminated aquifer

    USGS Publications Warehouse

    Aelion, C.M.; Bradley, P.M.

    1991-01-01

    In 1975, a leak of 83,000 gallons (314,189 liters) of jet fuel (JP-4) contaminated a shallow water-table aquifer near North Charleston, S.C. Laboratory experiments were conducted with contaminated sediments to assess the aerobic biodegradation potential of the in situ microbial community. Sediments were incubated with 14C-labeled organic compounds, and the evolution of 14CO2 was measured over time. Gas chromatographic analyses were used to monitor CO2 production and O2 consumption under aerobic conditions. Results indicated that the microbes from contaminated sediments remained active despite the potentially toxic effects of JP-4. 14CO2 was measured from [14C]glucose respiration in unamended and nitrate-amended samples after 1 day of incubation. Total [14C]glucose metabolism was greater in 1 mM nitrate-amended than in unamended samples because of increased cellular incorporation of 14C label. [14C]benzene and [14C]toluene were not significantly respired after 3 months of incubation. With the addition of 1 mM NO3, CO2 production measured by gas chromatographic analysis increased linearly during 2 months of incubation at a rate of 0.099 ??mol g-1 (dry weight) day-1 while oxygen concentration decreased at a rate of 0.124 ??mol g-1 (dry weight) day-1. With no added nitrate, CO2 production was not different from that in metabolically inhibited control vials. From the examination of selected components of JP-4, the n-alkane hexane appeared to be degraded as opposed to the branched alkanes of similar molecular weight. The results suggest that the in situ microbial community is active despite the JP-4 jet fuel contamination and that biodegradation may be compound specific. Also, the community is strongly nitrogen limited, and nitrogen additions may be required to significantly enhance hydrocarbon biodegradation.

  1. Simultaneous biodegradation of carbon tetrachloride and trichloroethylene in a coupled anaerobic/aerobic biobarrier.

    PubMed

    Kwon, Kiwook; Shim, Hojae; Bae, Wookeun; Oh, Juhyun; Bae, Jisu

    2016-08-01

    Simultaneous biodegradation of carbon tetrachloride (CT) and trichloroethylene (TCE) in a biobarrier with polyethylene glycol (PEG) carriers was studied. Toluene/methanol and hydrogen peroxide (H2O2) were used as electron donors and an electron acceptor source, respectively, in order to develop a biologically active zone. The average removal efficiencies for TCE and toluene were over 99.3%, leaving the respective residual concentrations of ∼12 and ∼57μg/L, which are below or close to the groundwater quality standards. The removal efficiency for CT was ∼98.1%, with its residual concentration (65.8μg/L) slightly over the standards. TCE was aerobically cometabolized with toluene as substrate while CT was anaerobically dechlorinated in the presence of electron donors, with the respective stoichiometric amount of chloride released. The oxygen supply at equivalent to 50% chemical oxygen demand of the injected electron donors supported successful toluene oxidation and also allowed local anaerobic environments for CT reduction. The originally augmented (immobilized in PEG carriers) aerobic microbes were gradually outcompeted in obtaining substrate and oxygen. Instead, newly developed biofilms originated from indigenous microbes in soil adapted to the coupled anaerobic/aerobic environment in the carrier for the simultaneous and almost complete removal of CT, TCE, and toluene. The declined removal rates when temperature fell from 28 to 18°C were recovered by doubling the retention time (7.2 days). PMID:27054665

  2. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.

    1996-01-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 g yr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 g m-2 yr-1 (1.45 x 10-3 and 1.51 x 10-3 gal. ft.-2 yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  3. 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. PMID:21600691

  4. Effects of exogenous aerobic bacteria on methane production and biodegradation of municipal solid waste in bioreactors.

    PubMed

    Ge, Sai; Liu, Lei; Xue, Qiang; Yuan, Zhiming

    2016-09-01

    Landfill is the most common and efficient ways of municipal solid waste (MSW) disposal and the landfill biogas, mostly methane, is currently utilized to generate electricity and heat. The aim of this work is to study the effects and the role of exogenous aerobic bacteria mixture (EABM) on methane production and biodegradation of MSW in bioreactors. The results showed that the addition of EABM could effectively enhance hydrolysis and acidogenesis processes of MSW degradation, resulting in 63.95% reduction of volatile solid (VS), the highest methane production rate (89.83Lkg(-1) organic matter) ever recorded and a threefold increase in accumulative methane production (362.9L) than the control (127.1L). In addition, it is demonstrated that white-rot fungi (WRF) might further promote the methane production through highly decomposing lignin, but the lower pH value in leachate and longer acidogenesis duration may cause methane production reduced. The data demonstrated that methane production and biodegradation of MSW in bioreactors could be significantly enhanced by EABM via enhanced hydrolysis and acidogenesis processes, and the results are of great economic importance for the future design and management of landfill. PMID:26601890

  5. Numerical simulation of competitive aerobic / anaerobic hydrocarbon plume biodegradation in two-dimensional bench scale lab-experiments

    NASA Astrophysics Data System (ADS)

    Beyer, C.; Ballarini, E.; Bauer, R.; Griebler, C.; Bauer, S.

    2011-12-01

    The biodegradation of oxidizable hydrocarbon contaminants in the subsurface requires the presence of compatible microbial communities as well as sufficient amounts of electron acceptors and nutrients. In this context, transverse mixing, driven by dispersion and diffusion, is one of the main mechanisms governing the availability of dissolved electron acceptors at a hydrocarbon plume fringe. Aerobic and anaerobic biodegradation of hydrocarbons limited by transverse mixing has been studied experimentally in 2D bench-scale flow-through tanks, filled with a saturated porous medium. Flow of groundwater through the tanks was induced by pumping water at one side through injection ports, and simultaneously extracting water at the other side of the tank. An ethylbenzene plume was established by injection through the central inlet port. A mixture of unlabeled and fully deuterium-labeled isotopomers was used in order to investigate the spatial distribution of degradation processes via monitoring of compound-specific stable isotope fractionation. In the first phase of the experiment, aerobic biodegradation was studied. For this purpose, the tank was recharged with water containing oxygen as a dissolved electron acceptor and the aerobic strain Pseudomonas putida F1 was inoculated. Later, nitrate was added to the recharge water as an additional electron acceptor and the denitrifying strain Aromatoleum aromaticum EbN1 was amended to study competitive aerobic/anaerobic biodegradation. A numerical reactive transport model of the experiment was set up for a model based interpretation of the observed degradation patterns. In a sensitivity analysis, the influence of the relevant hydrodynamic parameters on the observable distributions of ethylbenzene isotopomers, oxygen and nitrate was studied. Subsequent model calibration allowed for a good agreement with ethylbenzene concentrations measured at the tank outlet ports as well as oxygen concentrations, which were measured at several

  6. Substrate interaction during aerobic biodegradation of creosote-related compounds in columns of sandy aquifer material

    NASA Astrophysics Data System (ADS)

    Millette, Denis; Butler, Barbara J.; Frind, E. O.; Comeau, Yves; Samon, Réjean

    1998-01-01

    A column study was initiated to study the effect of phenanthrene, fluorene, and p-cresol on the aerobic biodegradation of carbazole in columns of sandy aquifer material. Biodegradation of the contaminant mixture was sequential in space with p-cresol being preferentially degraded, followed by phenanthrene, then the other compounds. Both p-cresol and phenanthrene were completely biotransformed to non-detectable levels during passage through the 46 cm sand column but some carbazole and fluorene persisted throughout the approximately 3 month experiments. Influent p-cresol (10000ppb) was the only compound that affected adaptation of the microbial community to carbazole biodegradation, but its effect was of little practical importance, amounting to a 4.5 day difference in carbazole breakthrough. However, when influent p-cresol was at high levels (70 000 ppb), biotransformation of the other co-substrates in the mixture never ensued because p-cresol caused complete dissolved oxygen depletion. Conversely, influent p-cresol ultimately enhanced biotransformation of the other co-substrates in the mixture when present at a concentration (10000ppb) that did not deplete all available oxygen. The concentrations of the other, more recalcitrant compounds, ranging between 33 and 238 ppb, were probably too low to support bacterial growth so that slow, limited biotransformation resulted, although addition of an auxiliary substrate (i.e. the p-cresol) stimulated their biotransformation. Under quasi-steady-state conditions, the presence of phenanthrene in the influent inhibited fluorene biotransformation and possibly carbazole biotransformation. Results of the present study demonstrated also that interactions identified in static batch microcosms and in a hydrodynamic saturated column system can differ.

  7. Biodegradation of ethylene vinyl alcohol by aerobic organisms in an aqueous environment

    SciTech Connect

    Rhoades, J.J. Jr.; Young, J.C.

    1996-11-01

    Ethylene vinyl alcohol (EVOH) is a thermoplastic used extensively in laminates for food containers. This study investigates the biodegradability of EVOH utilizing ASTM Test Method D5271. This method indicates the extent and rate of biodegradation of plastic materials by aerobic microorganisms in an aqueous environment and is performed in a respirometer. The ethylene derived segments of the EVOH contain {sup 14}C which acts as tracer to measure biodegradation as indicated by the {sup 14}C-CO{sub 2} given off by microbial metabolism. Liquid scintillation counting measured the activity of the respired {sup 14}C-CO{sub 2} converted from the ethylene segments of the EVOH. Three physical forms of EVOH were tested: a pure EVOH, a high surface area EVOH, and a blended form of EVOH with polyvinyl alcohol (PVOH). The reactors with these EVOH forms were set up to receive a weekly influx of microorganisms (inoculum), or various amounts of POH as a co-substrate. Results to date have indicated that an increased surface area for the EVOH increases conversion of {sup 14}C relative to the pure EVOH. Some cases with blended EVOH/PVOH reactors have also showed increased conversion of {sup 14}C relative to the pure EVOH cases. The addition of inoculum to the reactors did not seem to significantly increase the conversion of {sup 14}C as compared to the effect of PVOH addition. PVOH co-substrate addition increased {sup 14}C conversion. Also, increasing the amount of PVOH co-substrate addition further increases the conversion of {sup 14}C.

  8. Degradation kinetics and metabolites in continuous biodegradation of isoprene.

    PubMed

    Srivastva, Navnita; Singh, Ram S; Upadhyay, Siddh N; Dubey, Suresh K

    2016-04-01

    The kinetic parameters of isoprene biodegradation were studied in a bioreactor, comprising of bioscrubber and polyurethane foam packed biofilter in series and inoculated with Pseudomonas sp., using a Michaelis-Menten type model. The maximum elimination capacity, ECmax; substrate constant, Ks and ECmax/Ks values for bioscrubber were found to be 666.7 g m(-3) h(-1), 9.86 g m(-3) and 67.56 h(-1), respectively while those for biofilter were 3333 g m(-3) h(-1), 13.96 g m(-3) and 238.7 h(-1), respectively. The biofilter section exhibited better degradation efficiency compared to the bioscrubber unit. Around 62-75% of the feed isoprene got converted to carbon dioxide, indicating the efficient capability of bacteria to mineralize isoprene. The FTIR and GC-MS analyses of degradation products indicated oxidative cleavage of unsaturated bond of isoprene. These results were used for proposing a plausible degradation pathway for isoprene. PMID:26883059

  9. PREDICTION OF BIODEGRADATION KINETICS USING A NONLINEAR GROUP CONTRIBUTION METHOD

    EPA Science Inventory

    The fate of organic chemicals in the environment depends on their susceptibility to biodegradation. ence, development of regulations concerning their manufacture and use requires information on the extent and rate of biodegradation. ecent studies have attempted to correlate the k...

  10. Effect of soil and a nonionic surfactant on BTE-oX and MTBE biodegradation kinetics.

    PubMed

    Acuna-Askar, K; Gracia-Lozano, M V; Villarreal-Chiu, J F; Marmolejo, J G; Garza-Gonzalez, M T; Chavez-Gomez, B

    2005-01-01

    The biodegradation kinetics of BTE-oX and MTBE, mixed all together, in the presence of 905 mg/L VSS of BTEX-acclimated biomass was evaluated. Effects of soil and Tergitol NP-10 in aqueous samples on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 36 hours, every 6 hours. MTBE biodegradation followed a first-order one-phase kinetic model in all samples, whereas benzene, toluene and ethylbenzene biodegradation followed a first-order two-phase kinetic model in all samples. O-xylene biodegradation followed a first-order two-phase kinetic model in the presence of biomass only. Interestingly, o-xylene biodegradation was able to switch to a first-order one-phase kinetic model when either soil or soil and Tergitol NP-10 were added. The presence of soil in aqueous samples retarded benzene, toluene and ethylbenzene removal rates. O-xylene and MTBE removal rates were enhanced by soil. 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 77-99.8% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged 50.1-65.3% and 9.9-43.0%, respectively. PMID:16312957

  11. Aerobic biodegradation potential of endocrine-disrupting chemicals in surface-water sediment at Rocky Mountain National Park, USA.

    PubMed

    Bradley, Paul M; Battaglin, William A; Iwanowicz, Luke R; Clark, Jimmy M; Journey, Celeste A

    2016-05-01

    Endocrine-disrupting chemicals (EDCs) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDCs, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountain National Park (Colorado, USA). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 (14) C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. Bed sediment microbial communities in Rocky Mountain National Park also effectively degraded the xenoestrogens bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The present study's results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged. Environ Toxicol Chem 2016;35:1087-1096. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. PMID:26588039

  12. Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

    USGS Publications Warehouse

    Bradley, Paul M.; Battaglin, William A.; Iwanowicz, Luke; Clark, Jimmy M.; Journey, Celeste A.

    2016-01-01

    Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

  13. 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). PMID:27000317

  14. Aerobic biodegradability of methyldiethanolamine (MDEA) used in natural gas sweetening plants in batch tests and continuous flow experiments.

    PubMed

    Fürhacker, M; Pressl, A; Allabashi, R

    2003-09-01

    Mixtures of different amines including tertiary amines (methyldiethanolamine, MDEA) are commonly used for the removal of CO2 from gas mixtures or in gas sweetening processes for the extraction of CO2 and H2S. The absorber solutions used can be released into the industrial waste water due to continuous substitution of degraded MDEA, periodically cleaning processes or an accidental spill. In this study, the aerobic biodegradability of MDEA was investigated in a standardised batch test and a continuous flow experiment (40 l/d). The results of the batch test indicated that the MDEA-solution was non-biodegradable during the test period of 28 days, whereas the continuous flow experiments showed biodegradation of more than 96% based on TOC-measurements. This was probably due to the adaptation of the microorganisms to this particular waste water contamination during continuous flow experiment. PMID:12871741

  15. Inhibition of aerobic metabolic cis-1,2-di-chloroethene biodegradation by other chloroethenes.

    PubMed

    Zhao, He-Ping; Schmidt, Kathrin R; Tiehm, Andreas

    2010-04-01

    The presence of other chloroethenes influences aerobic metabolic biodegradation of cis-1,2-dichloroethene (cDCE). A new metabolically cDCE degrading enrichment culture was identified as also being capable of degrading vinyl chloride (VC), but not 1,1-dichloroethene (1,1DCE), trans-1,2-dichloroethene (tDCE), trichloroethene (TCE), or tetrachloroethene (PCE). The fastest degradation of cDCE was observed in the absence of any other chloroethene. In the presence of a second chloroethene (40-90 microM), the rate of cDCE (60 microM) degradation decreased in the following order: cDCE (+PCE) > cDCE (+tDCE) > cDCE (+VC)>cDCE (+1,1DCE) approximately cDCE (+TCE). With increasing concentrations of VC, ranging from 10 to 110 microM, the rate of cDCE (60 microM) degradation decreased. This study demonstrates that the inhibiting effects of chloroethene mixtures have to be considered during laboratory studies and bioremediation approaches based on metabolic cDCE degradation. PMID:20079512

  16. DETERMINATION OF BIODEGRADABILITY KINETICS OF RCRA COMPOUNDS USINGRESPIROMETRY FOR STRUCTURE-ACTIVITY RELATIONSHIPS

    EPA Science Inventory

    Electrolytic respirometry is attaining prominence in biodegradationstudies and is becoming one of the more suitable experimentalmethods for measuring the biodegradability and the kinetics ofbiodegradation of toxic organic compounds by the sewage, sludge andsoil microbiota and for...

  17. MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

  18. Biodegradation kinetics of neutralized Sarin by two different consortia

    SciTech Connect

    Zhang, Y.; Autenrieth, R.L.; Bonner, J.S.; Harvey, S.P.; Wild, J.R.; Rainina, E.L.

    1995-12-31

    Sarin (o-isopropyl methylphosphonofluoridate), one of the several highly toxic chemical warfare agents, can be readily neutralized in sodium hydroxide solution forming large quantities of brine solution containing IMPA (o-isopropyl methylphosphonic acid) and sodium fluoride that must be further processed and disposed. Two mixed cultures were successfully acclimated to use IMPA as a phosphorus source. The medium formula was chosen to provide the reactors with adequate alternative carbon sources so that the only limiting factor of the bacterial growth is phosphorus. Kinetic studies of the two cultures both in suspended and encapsulated forms were done with the initial IMPA concentrations ranged from 15 mg/L to 1,280 mg/L. Kinetic parameters were estimated based on IMPA and biomass concentrations measured over time using Monod equation and the least square method. For both cultures IMPA was not inhibitive under the tested conditions. For the free cells, n{sub max} was 131.3 mg/l/day for the APG swamp microorganisms and 120.9 mg/l/day for the soil extracted microorganisms. For the encapsulated cells, n{sub max} was 81.7 mg/l/day for the APG swamp microorganisms and 67.1 mg/l/day for the soil extracted microorganisms. The smaller values of n{sub max} for both types of the encapsulated microorganisms were very likely caused by substrate and nutrient transport limitation. For both cultures and both cell forms, it was observed that the degradation of IMPA formed MPA and phosphate sequentially. This led to the proposal of an IMPA biodegradative pathway involving an organophosphate hydrolase catalyzed reaction forming MPA. This would then be followed by C-P lyase catalyzed reaction transforming MPA to orthophosphate.

  19. Chloroform and dichloromethane biodegradation kinetics with methanol as primary substrate

    SciTech Connect

    Sharma, D.; Suidan, M.T.; Gupta, M.; Sayles, G.D.

    1996-12-31

    Chloroform and dichloromethane biodegradation was studied in a methanogenic environment with methanol as the primary substrate. The rate of chloroform degradation was studied in an anaerobic chemostat containing a mixed microbial culture. A constant concentration of 1.93 g/l of methanol was fed to the chemostat and the chloroform concentration was varied up to 16.74 {mu}M. Biochemical Methane Potential (BMP) tests were conducted in serum bottles to study the kinetics of chloroform and dichloromethane degradation. The maximum rate of chloroform degradation of 0.45 {mu}M/hr was seen at an initial chloroform concentration of 3.85 {mu}M. Chloroform was degraded even without methanol, but the presence of methanol greatly increased the rate of chloroform degradation. However, an increase in methanol concentration beyond 50 mg/l did not increase the rate of degradation of chloroform. Chloroform concentration higher than 6.7{mu}M inhibited the degradation of methanol. The maximum rate of dichloromethane degradation of 0.25 {mu}M/hr was observed corresponding to an initial dichloromethane concentration of 3.34 {mu}M. Methanol was not inhibited even at high concentrations of dichloromethane.

  20. KINETICS OF ETHANOL BIODEGRADATION UNDER METHANOGENIC CONDITIONS IN GASOLINE SPILLS

    EPA Science Inventory

    Ethanol is commonly used as a fuel oxygenate. A concern has been raised that biodegradation of ethanol from a spill of gasoline may inhibit the natural biodegradation of fuel hydrocarbons, including benzene. Ethanol is miscible in water, and ethanol is readily metabolized by mi...

  1. 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. PMID:25845997

  2. 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.

  3. 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. PMID:24140354

  4. Aquatic photochemistry, abiotic and aerobic biodegradability of thalidomide: identification of stable transformation products by LC-UV-MS(n).

    PubMed

    Mahmoud, Waleed M M; Trautwein, Christoph; Leder, Christoph; Kümmerer, Klaus

    2013-10-01

    Thalidomide (TD), besides being notorious for its teratogenicity, was shown to have immunomodulating and anti-inflammatory activities. This is why recently TD became a promising drug for the treatment of different cancers and inflammatory diseases. Yet nothing is known about the environmental fate of TD, which therefore was assessed experimentally and by in silico prediction programs (quantitative structure activity relationship (QSAR) models) within this study. Photolytic degradation was tested with two different light sources (medium-pressure mercury lamp; xenon lamp) and aerobic biodegradability was investigated with two OECD tests (Closed Bottle test (CBT), Manometric Respirometry test (MRT)). An additional CBT was performed for TD samples after 16 min of UV-photolysis. The primary elimination of TD was monitored and the structures of its photo-, abiotic and biodegradation products were elucidated by HPLC-UV-Fluorescence-MS(n). Furthermore, elimination of dissolved organic carbon was monitored in the photolysis experiment. LC-MS revealed that new photolytic transformation products (TPs) were identified, among them two isomers of TD with the same molecular mass. These TPs were different to the products formed by biodegradation. The experimental findings were compared with the results obtained from the in silico prediction programs where e.g. a good correlation for TD biodegradation in the CBT was confirmed. Moreover, some of the identified TPs were also structurally predicted by the MetaPC software. These results demonstrate that TD and its TPs are not readily biodegradable and not fully mineralized by photochemical treatment. They may therefore pose a risk to the aquatic environment due to the pharmacological activity of TD and unknown properties of its TPs. The applied techniques within this study emphasize the importance of QSAR models as a tool for estimating environmental risk assessments. PMID:23792256

  5. Biodegradation kinetics of benzene, toluene and xylene compounds: microbial growth and evaluation of models.

    PubMed

    Feisther, Vódice Amoroz; Ulson de Souza, Antônio Augusto; Trigueros, Daniela Estelita Goes; de Mello, Josiane Maria Muneronde; de Oliveira, Déborade; Guelli Ulson de Souza, Selene M A

    2015-07-01

    The biodegradation kinetics of BTX compounds (benzene, toluene, and xylene) individually and as mixtures was studied using models with different levels of sophistication. To compare the performance of the unstructured models applied in this work we used experimental data obtained here and some results published in the literature. The system description was based on the material balances of key components for batch operations, where the Monod and Andrews models were applied to predict the biodegradation of individual substrates. To simulate the biodegradation kinetics of substrate mixtures, models of substrate inhibition were applied along with the Sum Kinetics with Interaction Parameters (SKIP) models, where for two-component association toluene-xylene SKIP model presented better performance and for tri-component association benzene-toluene-xylene, the uncompetitive inhibition model was better. The kinetic parameters were estimated via a global search method known as Particle Swarm Optimization (PSO). The main result of this study is that the sophisticated biodegradation kinetics of BTX mixtures can be successfully described by applying the SKIP model, with the main advantage being the consideration of the substrate interactions. PMID:25627469

  6. AEROBIC BIODEGRADATION OF NATURAL AND XENOBIOTIC ORGANIC COMPOUNDS BY SUBSURFACE MICROBIAL COMMUNITIES

    EPA Science Inventory

    Studies were conducted to characterize the diversity of degradative abilities of microbial communities from pristine aquifer solids samples. Biodegradation was measured in aquifer solids slurries as both the conversion of radiolabeled substrate to (14)CO2 and the incorporation of...

  7. Removal of imidazolium ionic liquids by microbial associations: study of the biodegradability and kinetics.

    PubMed

    Liwarska-Bizukojc, Ewa; Gendaszewska, Dorota

    2013-01-01

    The aim of this study was to estimate the biodegradability of the selected imidazolium ionic liquids and to determine the kinetic parameters for the biological treatment of wastewater containing these ionic liquids. Biodegradability was evaluated with the help of the Organisation for Economic Co-operation and Development (OECD) tests, while oxygen uptake rate (OUR) tests were made in order to calculate the values of Monod kinetic parameters. The results obtained from both types of the tests showed that ionic liquids of chemical structure of 1-alkyl-3-methyl imidazolium bromide were poorly biodegradable and co-biodegradable compounds, although their biodegradability increased with the elongation of the alkyl chain length. At the same time the presence of the imidazolium-based ionic liquids in wastewater at concentration of 50 mg l(-1) did not inhibit biomass growth as well as did not decrease the affinity of substrate to biomass. The values of both Monod kinetic parameters, i.e., maximum specific growth rate (μ(max)) and half saturation constant (K(S)), increased with the increase in chain length of the alkyl substituent. PMID:22925899

  8. Biosorption of Malachite Green from aqueous solutions onto aerobic granules: kinetic and equilibrium studies.

    PubMed

    Sun, Xue-Fei; Wang, Shu-Guang; Liu, Xian-Wei; Gong, Wen-Xin; Bao, Nan; Gao, Bao-Yu; Zhang, Hua-Yong

    2008-06-01

    Batch experiments were conducted to study the biosorption characteristics of a cationic dye, Malachite Green (MG), onto aerobic granules. Effects of pH, aerobic granule dosage, contact time and solution temperature on MG biosorption by aerobic granules were evaluated. Simultaneity the thermodynamic analysis was also performed. The results showed that alkaline pH was favorable for the biosorption of MG and chemisorption seemed to play a major role in the biosorption process. Kinetic studies indicate that MG biosorption on aerobic granules in the system follows the pseudo-second order kinetics. The equilibrium time was 60 min for both 50 and 60 mg/L and 120 min for both 70 and 80 mg/L MG concentrations, respectively. Moreover, the experimental equilibrium data have been analyzed using the linearized forms of Langmuir, Freundlich, and Redlich-Peterson isotherms and the Langmuir isotherm was found to provide the best theoretical correlation of the experimental data for the biosorption of MG. The monolayer biosorption (saturation) capacities were determined to be 56.8 mg of MG per gram of aerobic granules at 30 degrees C. Thermodynamic analysis show that biosorption follows an endothermic path of the positive value of Delta H( composite function) and spontaneous with negative value of Delta G( composite function). PMID:17855080

  9. Denitrification kinetics in anoxic/aerobic activated sludge systems

    SciTech Connect

    Horne, G.M.

    1998-12-11

    Nitrogen removal needs at municipal wastewater treatment plants (WWTPs) have increased due to greater concerns about eutrophication and increased interest in reuse of treated municipal effluents. Biological processes are the most cost-effective method for nitrogen removal. Biological nitrogen removal is accomplished in two distinctly different processes by the conversion of nitrogen in the wastewater from organic nitrogen and ammonia to nitrate, followed by reduction of the nitrate to nitrogen gas. Nitrate production occurs in an aerobic activated sludge treatment zone during a process called nitrification. The nitrate is then converted through a series of intermediate steps to nitrogen gas in an anoxic zone (an anaerobic condition with nitrate present) during a process called denitrification, effectively removing the nitrogen from the wastewater. Many different WWTP designs have been developed to incorporate these two conditions for nitrogen removal.

  10. Hydrocarbon Specificity During Aerobic oil Biodegradation Revealed in Marine Microcosms With the use of Comprehensive, Two-Dimensional Gas Chromatography.

    NASA Astrophysics Data System (ADS)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Valentine, D. L.

    2008-12-01

    In 2003 the National Research Council reported more than 380 million gallons of oil is emitted into the ocean each year from natural seepage and as a result of anthropogenic activities. Many of the hydrocarbons making up this oil are persistent and toxic to marine life. Petroleum emitted into biologically sensitive areas can lead to environmental stress and ecosystem collapse. As a result many studies and a substantial amount of resources have been devoted to creating efficient and effective remediation tools and developing a better understanding of natural hydrocarbon weathering processes occurring in marine environments. The goal of this study is to elucidate patterns and extent of aerobic hydrocarbon degradation in marine sediments. In order to assess the specific molecular transformations occurring in petroleum emitted into oxic marine environments, we prepared microcosm experiments using sediments and seawater collected from the natural oil seeps offshore Coal Oil Point, California. Petroleum recovered from Platform Holly in the Santa Barbara Channel, was added to a sediment-seawater mixture and the microcosm bottles were allowed to incubate under aerobic conditions for slightly more than 100 days. Comprehensive, two-dimensional gas chromatography was employed in this study to quantify changes in the concentrations of individual hydrocarbon compounds because of the increased resolution and resolving power provided with this robust analytical method. We show significant hydrocarbon mass loss due to aerobic biodegradation for hundreds of tracked compounds in the microcosm bottles. The results shown here provide quantitative evidence for broad-scale metabolic specificity during aerobic hydrocarbon degradation in surface and shallow subsurface marine sediments.

  11. DEVELOPMENT OF QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIPS FOR PREDICTING BIODEGRADATION KINETICS

    EPA Science Inventory

    Results have been presented on the development of a structure-activity relationship for biodegradation using a group contribution approach. sing this approach, reported results of the kinetic rate constant agree within 20% with the predicted values. dditional compound studies are...

  12. 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. PMID:16862790

  13. TBA biodegradation in surface-water sediments under aerobic and anaerobic conditions

    USGS Publications Warehouse

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    2002-01-01

    The potential for [U-14C] TBA biodegradation was examined in laboratory microcosms under a range of terminal electron accepting conditions. TBA mineralization to CO2 was substantial in surface-water sediments under oxic, denitrifying, or Mn(IV)-reducing conditions and statistically significant but low under SO4-reducing conditions. Thus, anaerobic TBA biodegradation may be a significant natural attenuation mechanism for TBA in the environment, and stimulation of in situ TBA bioremediation by addition of suitable terminal electron acceptors may be feasible. No degradation of [U-14C] TBA was observed under methanogenic or Fe(III)-reducing conditions.

  14. [Biodegradation characteristics of organic pollutants contained in tannery wastewater].

    PubMed

    Wang, Yong; Li, Wei-Guang; Yang, Li; Su, Cheng-Yuan

    2013-02-01

    In the batch experiments inoculated with activated sludge from tannery wastewater treatment plant, biodegradation characteristics and kinetics of three tanning agents, naphthalene-2-sulfonic sodium, tannic acid and bayberry tannin, were studied under aerobic and anaerobic conditions. And the aerobic/anaerobic biodegradation laws of real tannery wastewater with respect to COD change were also investigated using the same batch experiments. The results showed aerobic degradation was superior to anaerobic degradation for tanning agent removal and mineralization. The removal rates of naphthalene-2-sulfonic sodium, tannic acid and bayberry tannin by aerobic biodegradation were >90% , >90% and 50% -75% , respectively whereas 10%-40%, >95% and 20% -30%, respectively by anaerobic degradation. In terms of COD removal about tannic acid biodegradation, the removal rates under aerobic and anaerobic conditions were >75% and < 75% ,respectively. The first-order kinetic constants during aerobic biodegradation of tannic acid and bayberry tannin were slightly influenced by initial concentrations while initial concentration had a significant effect on the first-order kinetics rate in the case of naphthalene-2-sulfonic sodium aerobic-biodegradation because naphthalene- 2-sulfonic sodium with initial concentration >or= 70 mg.L-1 was toxic to microorganism leading to a significant decline of kinetic constants. Biodegradation of real tannery wastewater under aerobic and anaerobic conditions represented obvious stage characteristics and the COD concentration had a good linear correlation with reaction time in the phases of fast degradation and slow degradation. The aerobic maximum specific degradation rate wqas 11.6 times higher of anaerobic degradation. PMID:23668129

  15. Biodegradation kinetics of tetrahydrofuran, benzene, toluene, and ethylbenzene as multi-substrate by Pseudomonas oleovorans DT4.

    PubMed

    Chen, Dong-Zhi; Ding, Yun-Feng; Zhou, Yu-Yang; Ye, Jie-Xu; Chen, Jian-Meng

    2015-01-01

    The biodegradation kinetics of tetrahydrofuran, benzene (B), toluene (T), and ethylbenzene (E) were systematically investigated individually and as mixtures by a series of aerobic batch degradation experiments initiated by Pseudomonas oleovorans DT4. The Andrews model parameters, e.g., maximum specific growth rates (μmax), half saturation, and substrate inhibition constant, were obtained from single-substrate experiments. The interaction parameters in the sum kinetics model (SKIP) were obtained from the dual substrates. The μmax value of 1.01 for tetrahydrofuran indicated that cell growth using tetrahydrofuran as carbon source was faster than the growth on B (μmax, B = 0.39) or T (μmax, T = 0.39). The interactions in the dual-substrate experiments, including genhancement, inhibition, and co-metabolism, in the mixtures of tetrahydrofuran with B or T or E were identified. The degradation of the four compounds existing simultaneously could be predicted by the combination of SKIP and co-metabolism models. This study is the first to quantify the interactions between tetrahydrofuran and BTE. PMID:25561017

  16. Biodegradation Kinetics of Tetrahydrofuran, Benzene, Toluene, and Ethylbenzene as Multi-substrate by Pseudomonas oleovorans DT4

    PubMed Central

    Chen, Dong-Zhi; Ding, Yun-Feng; Zhou, Yu-Yang; Ye, Jie-Xu; Chen, Jian-Meng

    2014-01-01

    The biodegradation kinetics of tetrahydrofuran, benzene (B), toluene (T), and ethylbenzene (E) were systematically investigated individually and as mixtures by a series of aerobic batch degradation experiments initiated by Pseudomonas oleovorans DT4. The Andrews model parameters, e.g., maximum specific growth rates (μmax), half saturation, and substrate inhibition constant, were obtained from single-substrate experiments. The interaction parameters in the sum kinetics model (SKIP) were obtained from the dual substrates. The μmax value of 1.01 for tetrahydrofuran indicated that cell growth using tetrahydrofuran as carbon source was faster than the growth on B (μmax, B = 0.39) or T (μmax, T = 0.39). The interactions in the dual-substrate experiments, including genhancement, inhibition, and co-metabolism, in the mixtures of tetrahydrofuran with B or T or E were identified. The degradation of the four compounds existing simultaneously could be predicted by the combination of SKIP and co-metabolism models. This study is the first to quantify the interactions between tetrahydrofuran and BTE. PMID:25561017

  17. Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Horváth, Anikó; Futó, István; Palcsu, László

    2014-05-01

    Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.

  18. Biodrying of pulp and paper secondary sludge: kinetics of volatile solids biodegradation.

    PubMed

    Huiliñir, Cesar; Villegas, Manuel

    2014-04-01

    This study focuses on the kinetics of volatile solids (VS) biodegradation of the biodrying process using pulp and paper secondary sludge. The experiments were carried out with air-flow rates of 0.51, 1.61, 3.25 and 5.26L/minkgVS) and initial moisture content of 64-66% w.b. Using five kinetic models and a nonlinear regression method, kinetic parameters were estimated and the models were analyzed with two statistical indicators. Higher air-flow rates cause greater moisture content reduction, lower temperature in the matrix, and lower VS reduction. At an air-flow rate as high as 5.26L/minkgVS there is no biodrying but only convective drying. The kinetic models used successfully simulate the VS biodegradation under biodrying conditions, with a root mean square error (RMSE) between 0.007929 and 0.02744. In conclusion, we show for the first time that VS biodegradation in the biodrying process can be successfully modeled with a kinetic model. PMID:24561626

  19. RESPIROMETRIC MULTI-LEVEL BIODEGRADATION TESTING PROTOCOL ANDMETHODOLOGY FOR DETERMINING BIODEGRADATION KINETIC DATA

    EPA Science Inventory

    Electrolytic respirometry involving natural sewage, sludge and soilmicrobiota is becoming prominent in fate studies of prioritypollutant and RCRA toxic organics to generatebiodegradation/inhibition kinetics data. he paper discusses theexperimental design and procedural steps for ...

  20. Modeling biodegradation and kinetics of glyphosate by artificial neural network.

    PubMed

    Nourouzi, Mohsen M; Chuah, Teong G; Choong, Thomas S Y; Rabiei, F

    2012-01-01

    An artificial neural network (ANN) model was developed to simulate the biodegradation of herbicide glyphosate [2-(Phosphonomethylamino) acetic acid] in a solution with varying parameters pH, inoculum size and initial glyphosate concentration. The predictive ability of ANN model was also compared with Monod model. The result showed that ANN model was able to accurately predict the experimental results. A low ratio of self-inhibition and half saturation constants of Haldane equations (< 8) exhibited the inhibitory effect of glyphosate on bacteria growth. The value of K(i)/K(s) increased when the mixed inoculum size was increased from 10(4) to 10(6) bacteria/mL. It was found that the percentage of glyphosate degradation reached a maximum value of 99% at an optimum pH 6-7 while for pH values higher than 9 or lower than 4, no degradation was observed. PMID:22424071

  1. Biodegradation of phenols in a sandstone aquifer under aerobic conditions and mixed nitrate and iron reducing conditions

    NASA Astrophysics Data System (ADS)

    Broholm, Mette M.; Arvin, Erik

    2000-08-01

    Ammonia liquor with very high concentrations of phenol and alkylated phenols is known to have leaked into the subsurface at a former coal carbonization plant in the UK, giving high concentrations of ammonium in the groundwater. In spite of this, no significant concentrations of phenols were found in the groundwater. The potential for biodegradation of the phenols in the sandstone aquifer at the site has been investigated in laboratory microcosms under aerobic (oxygen amended) and mixed nitrate and iron reducing (nitrate enriched and unamended) anaerobic conditions, at a range of concentrations (low: ˜5 mg l -1, high: ˜60 mg l -1, and very high: ˜600 mg l -1) and in the presence of other organic coal-tar compounds (mono- and polyaromatic hydrocarbons (BTEXs and PAHs) and heterocyclic compounds (NSOs)) and ammonia liquor. Sandstone cores and groundwater for the microcosms were collected from within the anaerobic ammonium plume at the field site. Fast and complete degradation of phenol, o- and p-cresol, 2,5- and 3,4-xylenol with no or very short initial lag-phases was observed under aerobic conditions at low concentrations. 2,6- and 3,5-Xylenol were degraded more slowly and 3,5-xylenol degradation was only just complete after about 1 year. The maximum rates of total phenols degradation in duplicate aerobic microcosms were 1.06 and 1.76 mg l -1 day -1. The degradation of phenols in nitrate enriched and unamended anaerobic microcosms was similar. Fast and complete biodegradation of phenol, cresols, 3,4-xylenol and 3,5-xylenol was observed after short lag-phases in the anaerobic microcosms. 2,5-xylenol was partially degraded after a longer lag-phase and 2,6-xylenol persisted throughout the 3 month long experiments. The maximum rates of total phenols degradation in duplicate nitrate enriched and unamended anaerobic microcosms were 0.30-0.38 and 0.29-0.31 mg l -1 day -1, respectively. The highest phenols concentrations in the anaerobic microcosms apparently required

  2. Aerobic biodegradation of chlorinated ethenes in a fractured bedrock aquifer: quantitative assessment by compound-specific isotope analysis (CSIA) and reactive transport modeling.

    PubMed

    Pooley, Kathryn E; Blessing, Michaela; Schmidt, Torsten C; Haderlein, Stefan B; Macquarrie, Kerry T B; Prommer, Henning

    2009-10-01

    A model-based analysis of concentration and isotope data was carried out to assess natural attenuation of chlorinated ethenes in an aerobic fractured bedrock aquifer. Tetrachloroethene (PCE) concentrations decreased downgradient of the source, but constant delta13C signatures indicated the absence of PCE degradation. In contrast, geochemical and isotopic data demonstrated degradation of trichloroethene (TCE) and cis-1,2-dichloroethene (DCE) under the prevailing oxic conditions. Numerical modeling was employed to simulate isotopic enrichment of chlorinated ethenes and to evaluate alternative degradation pathway scenarios. Existing field information on groundwater flow, solute transport, geochemistry, and delta13C signatures of the chlorinated ethenes was integrated via reactive transport simulations. The results provided strong evidence for the occurrence of aerobic TCE and DCE degradation. The chlorinated ethene concentrations together with stable carbon isotope data allowed us to reliably constrain the assessment of the extent of biodegradation at the site and plume simulations quantitatively linked aerobic biodegradation with isotope signatures in the field. Our investigation provides the first quantitative assessment of aerobic biodegradation of chlorinated ethenes in a fractured rock aquifer based on compound specific stable isotope measurements and reactive transport modeling. PMID:19848161

  3. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure. PMID:23138064

  4. Biodegradation of pulp and paper mill effluent using anaerobic followed by aerobic digestion.

    PubMed

    Bishnoi, Narsi R; Khumukcham, R K; Kumar, Rajender

    2006-05-01

    An experimental study was carried to find out the degradability of black liquor of pulp and paper mill wastewater for biomethanogenesis in continuous stirred tank reactor (CSTR) and followed by activated sludge process (ASP). Continuous stirred tank reactor was used in present study for anaerobic digestion of black liquor, while completely mixed activated sludge system was used for aerobic digestion. A maximum methane production was found up to 430 ml/day, chemical oxygen demand was reduced up to 64% and total volatile fatty acid increased up to 1500 mg/l from 975 mg/l at 7.3 pH, 37 degrees C temperature and 8 days hydraulic retention time during anaerobic digestion. In activated sludge process (aerobic digestion) chemical oxygen demand and biological oxygen demand reduction were 81% and 86% respectively at 72 hr hydraulic retention time. PMID:17436533

  5. Integrated anaerobic-aerobic process for the biodegradation of chlorinated aromatic compounds

    SciTech Connect

    Armenante, P.M.; Lewandowski, G.; Chengming Kung ); Kafkewitz, D. )

    1992-05-01

    An integrated anaerobic-aerobic process for the complete mineralization of 2,4,6-trichlorophenol was successfully tested and operated. The sludge obtained from the anaerobic digester of a commercial treatment plant was used to obtain an anaerobic consortium capable of partially dechlorinating 2,4,6-trichlorophenol (2,4,6-TCP). The clarified and sterilized effluent from the same anaerobic digester was used as the medium for the anaerobic consortium. During the anaerobic process 2,4,6-TCP was first dechlorinated to 2,4-dichlorophenol and then to 4-chlorophenol (4CP). Stoichiometric amounts of 4-CP were recovered. Similar results were obtained when the anaerobic microorganisms were immobilized on Manville R-635 silica beads. After immobilization, the consortium was able to dechlorinate 150{mu}M of 2,4,6-TCP in four days. Pseudomonas Glathei and an indigenous culture obtained from same sludge used to produce the anaerobic enrichment culture were shown to be able to degrade the 4-CP produced from the anaerobic dechlorination of 2,4,6-TCP. However, for the aerobic 4-CP mineralization to occur the medium had to be buffered with phosphate, since high pH would inhibit the aerobic bacterial activity. It is expected that the proposed approach will be used to treat recalcitrant halogenated compounds that are not amenable to conventional biological treatment.

  6. Kinetic study of the anaerobic biodegradation of alkyl polyglucosides and the influence of their structural parameters.

    PubMed

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

    2016-05-01

    This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L(-1), are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment. PMID:26820643

  7. Kinetics of phenolic and phthalic acid esters biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate.

    PubMed

    Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2016-05-01

    The kinetic of phenolic and phthalic acid esters (PAEs) biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate was investigated. Laboratory-scale MBR was fed with mixture of fresh and stabilized landfill leachate containing carbon to nitrogen (C/N) ratio of 10, 6, 3 and operated under different solid retention time (SRT) of 90, 15 and 5 d. Batch experiments using MBR sludge obtained from each steady-state operating condition revealed highest biodegradation rate constant (k) of 0.059-0.092 h(-1) of the phenolic and PAEs compounds at C/N of 6. Heterotrophic bacteria were the major group responsible for biodegradation of compounds whereas the presence of ammonia-oxidizing bacteria (AOB) helped accelerating their removals. Heterotrophic nitrifying bacteria found under high ammonia condition had an important role in enhancing the biodegradation of phenols and PAEs by releasing phenol hydroxylase (PH), esterase (EST) and phthalate dioxygenase (PDO) enzymes and the presence of AOB helped improving biodegradation of phenolic and PAEs compounds through their co-metabolism. PMID:26908045

  8. Biodegradation of semiconductor volatile organic compounds by four novel bacterial strains: a kinetic analysis.

    PubMed

    Su, Tien-Tsai; Lin, Chi-Wen; I, Yet-Po; Wu, Chih-Hung

    2012-09-01

    This study isolated pure microorganisms for further bioreactor applications. Four novel strains of Pseudomonas citronellolis YAIP521, Paracoccus versutus HSAC51, Burkholderia sp. HUEL671, and Pseudomonas aeruginosa JUPG561 were isolated and tested for biodegradation of isopropyl alcohol (IPA), acetone, ethyl lactate (EL), and propylene glycol mono methyl ether acetate (PGMEA), respectively. The maximum biodegradation rates for IPA, acetone, EL, and PGMEA were 5.27, 3.87, 26.86, and 48.93 mg L(-1) h(-1), respectively. The Haldane kinetic parameters determined for these strains when degrading targeted volatile organic compounds were maximum specific growth rate, half-saturation constant, and inhibition constant. The isolated strains have potential application in various bioreactors. The kinetic parameters obtained in this study provide a basis for further bioreactor experiments. PMID:22322527

  9. Aerobic composting of waste activated sludge: Kinetic analysis for microbiological reaction and oxygen consumption

    SciTech Connect

    Yamada, Y.; Kawase, Y. . E-mail: bckawase@mail.eng.toyo.ac.jp

    2006-07-01

    In order to examine the optimal design and operating parameters, kinetics for microbiological reaction and oxygen consumption in composting of waste activated sludge were quantitatively examined. A series of experiments was conducted to discuss the optimal operating parameters for aerobic composting of waste activated sludge obtained from Kawagoe City Wastewater Treatment Plant (Saitama, Japan) using 4 and 20 L laboratory scale bioreactors. Aeration rate, compositions of compost mixture and height of compost pile were investigated as main design and operating parameters. The optimal aerobic composting of waste activated sludge was found at the aeration rate of 2.0 L/min/kg (initial composting mixture dry weight). A compost pile up to 0.5 m could be operated effectively. A simple model for composting of waste activated sludge in a composting reactor was developed by assuming that a solid phase of compost mixture is well mixed and the kinetics for microbiological reaction is represented by a Monod-type equation. The model predictions could fit the experimental data for decomposition of waste activated sludge with an average deviation of 2.14%. Oxygen consumption during composting was also examined using a simplified model in which the oxygen consumption was represented by a Monod-type equation and the axial distribution of oxygen concentration in the composting pile was described by a plug-flow model. The predictions could satisfactorily simulate the experiment results for the average maximum oxygen consumption rate during aerobic composting with an average deviation of 7.4%.

  10. Aerobic biodegradation of 2,2'-dithiodibenzoic acid produced from dibenzothiophene metabolites

    SciTech Connect

    Young, R.F.; Cheng, S.M.; Fedorak, P.M.

    2006-01-15

    Dibenzothiophene is a sulfur heterocycle found in crude oils and coal. The biodegradation of dibenzothiophene through the Kodama pathway by Pseudomonas sp. strain BT1d leads to the formation of three disulfides: 2-oxo-2-(2-thiophenyl)ethanoic acid disulfide, 2-oxo-2-(2-thiophenyl)ethanoic acid-2-benzoic acid disulfide, and 2,2'-dithiodibenzoic acid. When provided as the carbon and sulfur source in liquid medium, 2,2'-dithiodibenzoic acid was degraded by soil enrichment cultures. Two bacterial isolates, designated strains RM1 and RM6, degraded 2,2'-dithiodibenzoic acid when combined in the medium. Isolate RM6 was found to have an absolute requirement for vitamin B{sub 12}, and it degraded 2,2'-dithiodibenzoic acid in pure culture when the medium was supplemented with this vitamin. Isolate RM6 also degraded 2,2'-dithiodibenzoic acid in medium containing sterilized supernatants from cultures of isolate RM1 grown on glucose or benzoate. Isolate RM6 was identified as a member of the genus Variovorax using the Biolog system and 16S rRNA gene analysis. Although the mechanism of disulfide metabolism could not be determined, benzoic acid was detected as a transient metabolite of 2,2'-dithiodibenzoic acid biodegradation by Variovorax sp. strain RM6. In pure culture, this isolate mineralized 2,2'-dithiodibenzoic acid, releasing 59% of the carbon as carbon dioxide and 88% of the sulfur as sulfate.

  11. Kinetics of phenol biodegradation by an immobilized methanogenic consortium

    SciTech Connect

    Dwyer, D.F.; Krumme, M.L.; Boyd, S.A.; Tiedje, J.M.

    1986-08-01

    A phenol-degrading methanogenic enrichment was successfully immobilized in agar as shown by the stoichiometric conversion of phenol to CH/sub 4/ and CO/sub 2/. The enrichment contained members of three physiological groups necessary for the syntrophic mineralization of phenol: a phenol-oxidizing bacterium, a Methanothrix-like bacterium, and an H/sub 2/-utilizing methanogen. The immobilization technique resulted in the cells being embedded in a long, thin agar strans (1 mm in diameter by 2 to 50 cm in length) that resembled spaghetti. Immobilization had three effects as shown by a comparative kinetic analysis of phenol degradation by free versus immobilized cells. (1) The maximum rate of degradation was reduced from 14.8 to 10.0 ..mu..g of phenol per h; (2) the apparent K/sub m/ for the overall reaction was reduced from 90 to 46 ..mu..g of phenol per ml. probably because of the retention of acetate, H/sub 2/ and CO/sub 2/ in the proximity of immobilized methanogens; and (3) the cells were protected from substrate inhibition caused by high concentrations of phenol, which increased the apparent K/sub i/ value from 900 to 1725 ..mu..g of phenol per ml. Estimates for the kinetic parameters K/sub m/, K/sub i/, and V/sub max/ were used in a modified substrate inhibition model that simulated rates of phenol degradation for given phenol concentrations. The simulated rates were in close agreement with experimentally derived rates for both stimulatory and inhibitory concentrations of phenol.

  12. Phylogenetic and Kinetic Diversity of Aerobic Vinyl Chloride-Assimilating Bacteria from Contaminated Sites

    PubMed Central

    Coleman, Nicholas V.; Mattes, Timothy E.; Gossett, James M.; Spain, Jim C.

    2002-01-01

    Aerobic bacteria that grow on vinyl chloride (VC) have been isolated previously, but their diversity and distribution are largely unknown. It is also unclear whether such bacteria contribute to the natural attenuation of VC at chlorinated-ethene-contaminated sites. We detected aerobic VC biodegradation in 23 of 37 microcosms and enrichments inoculated with samples from various sites. Twelve different bacteria (11 Mycobacterium strains and 1 Nocardioides strain) capable of growth on VC as the sole carbon source were isolated, and 5 representative strains were examined further. All the isolates grew on ethene in addition to VC and contained VC-inducible ethene monooxygenase activity. The Mycobacterium strains (JS60, JS61, JS616, and JS617) all had similar growth yields (5.4 to 6.6 g of protein/mol), maximum specific growth rates (0.17 to 0.23 day−1), and maximum specific substrate utilization rates (9 to 16 nmol/min/mg of protein) with VC. The Nocardioides strain (JS614) had a higher growth yield (10.3 g of protein/mol), growth rate (0.71 day−1), and substrate utilization rate (43 nmol/min/mg of protein) with VC but was much more sensitive to VC starvation. Half-velocity constant (Ks) values for VC were between 0.5 and 3.2 μM, while Ks values for oxygen ranged from 0.03 to 0.3 mg/liter. Our results indicate that aerobic VC-degrading microorganisms (predominantly Mycobacterium strains) are widely distributed at sites contaminated with chlorinated solvents and are likely to be responsible for the natural attenuation of VC. PMID:12450841

  13. Aerobic Biodegradation of 2,4-Dinitroanisole by Nocardioides sp. Strain JS1661

    PubMed Central

    Fida, Tekle Tafese; Palamuru, Shannu; Pandey, Gunjan

    2014-01-01

    2,4-Dinitroanisole (DNAN) is an insensitive munition ingredient used in explosive formulations as a replacement for 2,4,6-trinitrotoluene (TNT). Little is known about the environmental behavior of DNAN. There are reports of microbial transformation to dead-end products, but no bacteria with complete biodegradation capability have been reported. Nocardioides sp. strain JS1661 was isolated from activated sludge based on its ability to grow on DNAN as the sole source of carbon and energy. Enzyme assays indicated that the first reaction involves hydrolytic release of methanol to form 2,4-dinitrophenol (2,4-DNP). Growth yield and enzyme assays indicated that 2,4-DNP underwent subsequent degradation by a previously established pathway involving formation of a hydride-Meisenheimer complex and release of nitrite. Identification of the genes encoding the key enzymes suggested recent evolution of the pathway by recruitment of a novel hydrolase to extend the well-characterized 2,4-DNP pathway. PMID:25281383

  14. Factors Affecting the Success of Enhanced Aerobic Biodegradation of MTBE and BTEX

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

    At a gasoline-release site in South Carolina, a proprietary form of MgO2 injected into the subsurface in a former underground storage tank (UST) area to increase dissolved oxygen (DO) levels did not elevate low (0 mg/L) DO levels nor decrease concentrations of benzene, toluene, or methyl tert-butyl ether (MTBE). In contrast, MgO2 injected less than 200 meters downgradient rapidly increased DO, and benzene, toluene, and MTBE concentrations decreased up to 87%. These different results following oxygen addition to an anoxic fuel-contaminated aquifer can be related to differences in ambient hydrologic conditions between the two areas that supported different microbial communities with respect to contaminant degradation prior to oxygen-based remediation. For example, although fuel-contaminated ground water downgradient of the source area was anoxic, infiltration of DO-rich recharge occurred through overlying permeable sediments for some time before oxygen injection. In contrast, this natural input of DO does not occur in the paved, former UST area. Moreover, the absence of recharge in the source area permitted the accumulation of reduced mineral- and soluble-inorganic species, a significant oxygen sink that competed with contaminant biodegradation demand for the injected oxygen. This talk will describe the relation that exists between hydrologic and microbiologic conditions in contaminated shallow ground-water systems exhibited at this site, and why certain parameters should be measured as part of any oxygen-based remedial strategies.

  15. Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

    PubMed

    Tuovinen, Olli H; Deshmukh, Vaidehi; Özkaya, Bestamin; Radosevich, Mark

    2015-01-01

    The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another. PMID:26273756

  16. Kinetics and mechanism of the biodegradation of PLA/clay nanocomposites during thermophilic phase of composting process.

    PubMed

    Stloukal, Petr; Pekařová, Silvie; Kalendova, Alena; Mattausch, Hannelore; Laske, Stephan; Holzer, Clemens; Chitu, Livia; Bodner, Sabine; Maier, Guenther; Slouf, Miroslav; Koutny, Marek

    2015-08-01

    The degradation mechanism and kinetics of polylactic acid (PLA) nanocomposite films, containing various commercially available native or organo-modified montmorillonites (MMT) prepared by melt blending, were studied under composting conditions in thermophilic phase of process and during abiotic hydrolysis and compared to the pure polymer. Described first order kinetic models were applied on the data from individual experiments by using non-linear regression procedures to calculate parameters characterizing aerobic composting and abiotic hydrolysis, such as carbon mineralization, hydrolysis rate constants and the length of lag phase. The study showed that the addition of nanoclay enhanced the biodegradation of PLA nanocomposites under composting conditions, when compared with pure PLA, particularly by shortening the lag phase at the beginning of the process. Whereas the lag phase of pure PLA was observed within 27days, the onset of CO2 evolution for PLA with native MMT was detected after just 20days, and from 13 to 16days for PLA with organo-modified MMT. Similarly, the hydrolysis rate constants determined tended to be higher for PLA with organo-modified MMT, particularly for the sample PLA-10A with fastest degradation, in comparison with pure PLA. The acceleration of chain scission in PLA with nanoclays was confirmed by determining the resultant rate constants for the hydrolytical chain scission. The critical molecular weight for the hydrolysis of PLA was observed to be higher than the critical molecular weight for onset of PLA mineralization, suggesting that PLA chains must be further shortened so as to be assimilated by microorganisms. In conclusion, MMT fillers do not represent an obstacle to acceptance of the investigated materials in composting facilities. PMID:25981155

  17. Biodegradation of bisphenol A and other bisphenols by a gram-negative aerobic bacterium

    SciTech Connect

    Lobos, J.H.; Leib, T.K. ); Tahmun Su )

    1992-06-01

    A novel bacterium designated strain MV1 was isolated from a sludge enrichmet takes from the wastewater treatment plant at a plastics manufacturing facility and shown to degrade 2,2-bis(4-hydroxyphenyl)propane (4,4[prime]-isopropylidenediphenol or bisphenol A). Strain MV1 is a gram-negative, aerobic bacillus that grows on bisphenol A as a sole source of carbon and energy. Total carbon analysis for bisphenol A degradation demonstrated that 60% of the carbon was mineralized to CO[sub 2], 20% was associated with the bacterial cells, and 20% was converted to soluble organic compounds. Metabolic intermediates detected in the culture medium during growth on bisphenol A were identified as 4-hydroxybenzoic acid, 4-hydroxyacetophenone, 2,2-bis(4-hydroxyphenyl)-1-propanol, and 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Most of the bisphenol A degraded by strain MV1 is cleaved in some way to form 4-hydroxybenzoic acid and 4-hydroxyacetophenone, which are subsequently mineralized or assimilated into cell carbon. In addition, about 20% of the bisphenol A is hydroxylated to form 2,2-bis(4-hydroxyphenyl)-1-propanol, which is slowly biotransformed to 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Cells that were grown on bisphenol A degraded a variety of bisphenol alkanes, hydroxylated benzoic acids, and hydroxylated acetophenones during resting-cell assays. Transmission electron microscopy of cells grown on bisphenol A revealed lipid storage granules and intracytoplasmic membranes.

  18. Biodegradation of bisphenol A and other bisphenols by a gram-negative aerobic bacterium.

    PubMed

    Lobos, J H; Leib, T K; Su, T M

    1992-06-01

    A novel bacterium designated strain MV1 was isolated from a sludge enrichment taken from the wastewater treatment plant at a plastics manufacturing facility and shown to degrade 2,2-bis(4-hydroxyphenyl)propane (4,4'-isopropylidenediphenol or bisphenol A). Strain MV1 is a gram-negative, aerobic bacillus that grows on bisphenol A as a sole source of carbon and energy. Total carbon analysis for bisphenol A degradation demonstrated that 60% of the carbon was mineralized to CO2, 20% was associated with the bacterial cells, and 20% was converted to soluble organic compounds. Metabolic intermediates detected in the culture medium during growth on bisphenol A were identified as 4-hydroxybenzoic acid, 4-hydroxyacetophenone, 2,2-bis(4-hydroxyphenyl)-1-propanol, and 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Most of the bisphenol A degraded by strain MV1 is cleaved in some way to form 4-hydroxybenzoic acid and 4-hydroxyacetophenone, which are subsequently mineralized or assimilated into cell carbon. In addition, about 20% of the bisphenol A is hydroxylated to form 2,2-bis(4-hydroxyphenyl)-1-propanol, which is slowly biotransformed to 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Cells that were grown on bisphenol A degraded a variety of bisphenol alkanes, hydroxylated benzoic acids, and hydroxylated acetophenones during resting-cell assays. Transmission electron microscopy of cells grown on bisphenol A revealed lipid storage granules and intracytoplasmic membranes. PMID:1622258

  19. Biodegradable polymers from organic acids by using activated sludge enriched by aerobic periodic feeding.

    PubMed

    Dionisi, Davide; Majone, Mauro; Papa, Viviana; Beccari, Mario

    2004-03-20

    This article describes a new process for the production of biopolymers (polyhydroxyalkanoates, PHAs) based on the aerobic enrichment of activated sludge to obtain mixed cultures able to store PHAs at high rates and yields. Enrichment was obtained through the selective pressure established by feeding the carbon source in a periodic mode (feast and famine regime) in a sequencing batch reactor. A concentrated mixture of acetic, lactic, and propionic acids (overall concentration of 8.5 gCOD L(-1)) was fed every 2 h at 1 day(-1) overall dilution rate. Even at such high organic load (8.5 gCOD L(-1) day(-1)), the selective pressure due to periodic feeding was effective in obtaining a biomass with a storage ability much higher than activated sludges. The immediate biomass response to substrate excess (as determined thorough short-term batch tests) was characterized by a storage rate and yield of 649 mgPHA (as COD) g biomass (as COD)(-1) h(-1) and 0.45 mgPHA (as COD) mg removed substrates (as COD(-1)), respectively. When the substrate excess was present for more than 2 h (long-term batch tests), the storage rate and yield decreased, whereas growth rate and yield significantly increased due to biomass adaptation. A maximum polymer fraction in the biomass was therefore obtained at about 50% (on COD basis). As for the PHA composition, the copolymer poly(beta-hydroxybutyrate/beta-hydroxyvalerate) with 31% of hydroxyvalerate monomer was produced from the substrate mixture. Comparison of the tests with individual and mixed substrates seemed to indicate that, on removing the substrate mixture for copolymer production, propionic acid was fully utilized to produce propionylCoA, whereas the acetylCoA was fully provided by acetic and lactic acid. PMID:14966798

  20. Estimation of kinetic rate coefficients for 2,4-D biodegradation during transport in soil columns

    SciTech Connect

    Maier, R.S.; Estrella, R.; Brusseau, M.L.

    1996-12-31

    The Monod model is used increasingly to simulate the kinetics of biodegradation in soil environments with distinctly different hydraulic properties than the well-mixed batch reactor environments for which the model is known to be appropriate. This paper investigates the use of a transport model with Monod kinetics to describe the fate of 2,4-D in soil columns. The research includes development of a mathematical model for the biodegradation of 2,4-D in the presence of an acclimated biological population and an optimization model to calibrate results of the mathematical model with experimental observations. The model is applied to experimental data from two independent soil column experiments to qualify the generality of the numerical results. Fitted kinetic parameters are compared with well-mixed batch reactor test data and goodness of fit is compared with a linear model of transport with first-order substrate decay. The fitted model is used to discuss strategies to minimize transport of 2,4-D into lower soil horizons and groundwater.

  1. Activated sludge mass reduction and biodegradability of the endogenous residues by digestion under different aerobic to anaerobic conditions: Comparison and modeling.

    PubMed

    Martínez-García, C G; Fall, C; Olguín, M T

    2016-03-01

    This study was performed to identify suitable conditions for the in-situ reduction of excess sludge production by intercalated digesters in recycle-activated sludge (RAS) flow. The objective was to compare and model biological sludge mass reduction and the biodegradation of endogenous residues (XP) by digestion under hypoxic, aerobic, anaerobic, and five intermittent-aeration conditions. A mathematical model based on the heterotrophic endogenous decay constant (bH) and including the biodegradation of XP was used to fit the long-term data from the digesters to identify and estimate the parameters. Both the bH constant (0.02-0.05 d(-1)) and the endogenous residue biodegradation constant (bP, 0.001-0.004 d(-1)) were determined across the different mediums. The digesters with intermittent aeration cycles of 12 h-12 h and 5 min-3 h (ON/OFF) were the fastest, compared to the aerobic reactor. The study provides a basis for rating RAS-digester volumes to avoid the accumulation of XP in aeration tanks. PMID:26720137

  2. Effects of aerobic fitness on oxygen uptake kinetics in heavy intensity swimming.

    PubMed

    Reis, Joana F; Alves, Francisco B; Bruno, Paula M; Vleck, Veronica; Millet, Gregoire P

    2012-05-01

    This study aimed to characterise both the VO2 kinetics within constant heavy-intensity swimming exercise, and to assess the relationships between VO2 kinetics and other parameters of aerobic fitness, in well-trained swimmers. On separate days, 21 male swimmers completed: (1) an incremental swimming test to determine their maximal oxygen uptake (VO2 max), first ventilatory threshold (VT), and the velocity associated with VO2max (vVO(2 max)) and (2) two square-wave transitions from rest to heavy-intensity exercise, to determine their VO2 kinetics. All the tests involved breath-by-breath analysis of freestyle swimming using a swimming snorkel. VO2 kinetics was modelled with two exponential functions. The mean values for the incremental test were 56.0 ± 6.0 ml min(-1) kg(-1), 1.45 ± 0.08 m s(-1); and 42.1 ± 5.7 ml min(-1) kg(-1) for VO2 max, vVO(2 max) and VT, respectively. For the square-wave transition, the time constant of the primary phase (sp) averaged 17.3 ± 5.4 s and the relevant slow component (A'sc) averaged 4.8 ± 2.9 ml min(-1) kg(-1) [representing 8.9% of the end-exercise VO2 (%A'sc)]. sp was correlated with vVO(2 max) (r = -0.55, P = 0.01), but not with either VO2max (r = 0.05, ns) or VT (r = 0.14, ns). The %A' sc did not correlate with either VO2max (r = -0.14, ns) or vVO(2 max) (r = 0.06, ns), but was inversely related with VT (r = -0.61, P < 0.01). This study was the first to describe the VO2 kinetics in heavy-intensity swimming using specific swimming exercise and appropriate methods. As has been demonstrated in cycling, faster VO2 kinetics allow higher aerobic power outputs to be attained. The slow component seems to be reduced in swimmers with higher ventilatory thresholds. PMID:21879352

  3. Biodegradation of organic contaminants in subsurface systems: Kinetic and metabolic considerations

    SciTech Connect

    Morris, M.S.

    1988-01-01

    Groundwater contaminated by organic chemicals from industrial spills, leaking underground gasoline storage tanks and landfills has caused concern about the future of a major source of drinking water. A potential alternative to expensive groundwater reclamation projects is the use of natural soil bacteria to degrade organic contaminants. This study was designed to measure the kinetic response of tertiary butyl alcohol (TBA), determine the biological degradation rates of methanol, ethanol, propanol, l-butanol, TBA, pentanol, phenol and 2,4-dichlorophenol; describe site specific conditions which enhance or inhibit degradation and compare biodegradation rates with thermodynamic predictions. Each of the test compounds except TBA was readily degraded in the Blacksburg soil. Inhibition of sulfate reduction by the addition of molybdate stimulated degradation of all compounds including TBA, whereas, inhibition of methanogenesis with BESA slowed the degradation rates. The addition of nitrate did not affect the biodegradation in Blacksburg soil. In the Newport News soil, all of the test compounds were biodegraded at substantially higher rates than was observed in the Blacksburg soil. The presence of the metabolic inhibitors did not affect degradation, however, the addition of nitrate increased the degradation rates of the alcohols but not the phenols. The degradation rates in each of the soils did not correlate with the bacterial population size or free energies of the reactions.

  4. BIODEGRADATION PROBABILITY PROGRAM (BIODEG)

    EPA Science Inventory

    The Biodegradation Probability Program (BIODEG) calculates the probability that a chemical under aerobic conditions with mixed cultures of microorganisms will biodegrade rapidly or slowly. It uses fragment constants developed using multiple linear and non-linear regressions and d...

  5. Microbial Kinetic Model for the Degradation of Poorly Soluble Organic Materials

    EPA Science Inventory

    A novel mechanistic model is presented that describes the aerobic biodegradation kinetics of soybean biodiesel and petroleum diesel in batch experiments. The model was built on the assumptions that biodegradation takes place in the aqueous phase according to Monod kinetics, and ...

  6. Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation

    PubMed Central

    2013-01-01

    Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models. PMID:23369455

  7. Crystallization kinetics and thermal resistance of bamboo fiber reinforced biodegradable polymer composites

    NASA Astrophysics Data System (ADS)

    Thumsorn, S.; Srisawat, N.; On, J. Wong; Pivsa-Art, S.; Hamada, H.

    2014-05-01

    Bamboo fiber reinforced biodegradable polymer composites were prepared in this study. Biodegradable poly(butylene succinate) (PBS) was blended with bamboo fiber in a twin screw extruder with varied bamboo content from 20-0wt%. PBS/bamboo fiber composites were fabricated by compression molding process. The effect of bamboo fiber contents on properties of the composites was investigated. Non-isothermal crystallization kinetic study of the composites was investigated based on Avrami equation. The kinetic parameters indicated that bamboo fiber acted as heterogeneous nucleation and enhanced crystallinity of the composites. Bamboo fiber was well dispersed on PBS matrix and good adhered with the matrix. Tensile strength of the composites slightly deceased with adding bamboo fiber. However, tensile modulus and impact strength of the composites increased when increasing bamboo fiber contents. It can be noted that bamboo fiber promoted crystallization and crystallinity of PBS in the composites. Therefore, the composites were better in impact load transferring than neat PBS, which exhibited improving on impact performance of the composites.

  8. Kinetic Behavior of Salmonella on Low NaNO2 Sausages during Aerobic and Vacuum Storage

    PubMed Central

    Ha, Jimyeong; Gwak, Eunji; Oh, Mi-Hwa; Park, Beomyoung; Lee, Jeeyeon; Kim, Sejeong; Lee, Heeyoung; Lee, Soomin; Yoon, Yohan; Choi, Kyoung-Hee

    2016-01-01

    This study evaluated the growth kinetics of Salmonella spp. in processed meat products formulated with low sodium nitrite (NaNO2). A 5-strain mixture of Salmonella spp. was inoculated on 25-g samples of sausages formulated with sodium chloride (NaCl) (1.0%, 1.25%, and 1.5%) and NaNO2 (0 and 10 ppm) followed by aerobic or vacuum storage at 10℃ and 15℃ for up to 816 h or 408 h, respectively. The bacterial cell counts were enumerated on xylose lysine deoxycholate agar, and the modified Gompertz model was fitted to the Salmonella cell counts to calculate the kinetic parameters as a function of NaCl concentration on the growth rate (GR; Log CFU/g/h) and lag phase duration (LPD; h). A linear equation was then fitted to the parameters to evaluate the effect of NaCl concentration on the kinetic parameters. The GR values of Salmonella on sausages were higher (p<0.05) with 10 ppm NaNO2 concentration than with 0 ppm NaNO2. The GR values of Salmonella decreased (p<0.05) as NaCl concentration increased, especially at 10℃. This result indicates that 10 ppm NaNO2 may increase Salmonella growth at low NaCl concentrations, and that NaCl plays an important role in inhibiting Salmonella growth in sausages with low NaNO2. PMID:27194936

  9. Kinetic Behavior of Salmonella on Low NaNO2 Sausages during Aerobic and Vacuum Storage.

    PubMed

    Ha, Jimyeong; Gwak, Eunji; Oh, Mi-Hwa; Park, Beomyoung; Lee, Jeeyeon; Kim, Sejeong; Lee, Heeyoung; Lee, Soomin; Yoon, Yohan; Choi, Kyoung-Hee

    2016-01-01

    This study evaluated the growth kinetics of Salmonella spp. in processed meat products formulated with low sodium nitrite (NaNO2). A 5-strain mixture of Salmonella spp. was inoculated on 25-g samples of sausages formulated with sodium chloride (NaCl) (1.0%, 1.25%, and 1.5%) and NaNO2 (0 and 10 ppm) followed by aerobic or vacuum storage at 10℃ and 15℃ for up to 816 h or 408 h, respectively. The bacterial cell counts were enumerated on xylose lysine deoxycholate agar, and the modified Gompertz model was fitted to the Salmonella cell counts to calculate the kinetic parameters as a function of NaCl concentration on the growth rate (GR; Log CFU/g/h) and lag phase duration (LPD; h). A linear equation was then fitted to the parameters to evaluate the effect of NaCl concentration on the kinetic parameters. The GR values of Salmonella on sausages were higher (p<0.05) with 10 ppm NaNO2 concentration than with 0 ppm NaNO2. The GR values of Salmonella decreased (p<0.05) as NaCl concentration increased, especially at 10℃. This result indicates that 10 ppm NaNO2 may increase Salmonella growth at low NaCl concentrations, and that NaCl plays an important role in inhibiting Salmonella growth in sausages with low NaNO2. PMID:27194936

  10. Semi-aerobic stabilized landfill leachate treatment by ion exchange resin: isotherm and kinetic study

    NASA Astrophysics Data System (ADS)

    Zamri, Mohd Faiz Muaz Ahmad; Kamaruddin, Mohamad Anuar; Yusoff, Mohd Suffian; Aziz, Hamidi Abdul; Foo, Keng Yuen

    2015-03-01

    This study was carried out to investigate the treatability of ion exchange resin (Indion MB 6 SR) for the removal of chromium (VI), aluminium (III), zinc (II), copper (II), iron (II), and phosphate (PO4)3-, chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and colour from semi-aerobic stabilized leachate by batch test. A range of ion exchange resin dosage was tested towards the removal efficiency of leachate parameters. It was observed that equilibrium data were best represented by the Langmuir model for metal ions and Freundlich was ideally fit for COD, NH3-N and colour. Intra particle diffusion model, pseudo first-order and pseudo second-order isotherm models were found ideally fit with correlation of the experimental data. The findings revealed that the models could describe the ion exchange kinetic behaviour efficiently, which further suggests comprehensive outlook for the future research in this field.

  11. Ruthenium(salen)-catalyzed aerobic oxidative desymmetrization of meso-diols and its kinetics.

    PubMed

    Shimizu, Hideki; Onitsuka, Satoaki; Egami, Hiromichi; Katsuki, Tsutomu

    2005-04-20

    Chiral (nitrosyl)ruthenium(salen) complexes were found to be efficient catalysts for aerobic oxidative desymmetrization of meso-diols under photoirradiation to give optically active lactols. The scope of the applicability of this reaction ranges widely from acyclic diols to mono-cyclic diols, although fine ligand-tuning of the ruthenium(salen) complexes was required to attain high enantioselectivity (up to 93% ee). In particular, the nature of the apical ligand was found to affect not only enantioselectivity but also kinetics of the desymmetrization reaction. Spectroscopic analysis of the oxidation disclosed that irradiation of visible light is indispensable not only for dissociation of the nitrosyl ligand but also for single electron transfer from the alcohol-bound ruthenium ion to dioxygen. PMID:15826178

  12. Bacterial energetics, stoichiometry, and kinetic modeling of 2,4-dinitrotoluene biodegradation in a batch respirometer.

    PubMed

    Zhang, Chunlong; Hughes, Joseph B

    2004-12-01

    A stoichiometric equation and kinetic model were developed and validated using experimental data from batch respirometer studies on the biodegradation of 2,4-dinitrotoluene (DNT). The stoichiometric equation integrates bacterial energetics and is revised from that in a previous study by including the mass balance of phosphorus (P) in the biomass. Stoichiometric results on O2 consumption, CO2 evolution, and nitrite evolution are in good agreement with respirometer data. However, the optimal P requirement is significantly higher than the stoichiometrically derived P, implying potentially limited bioavailability of P and the need for buffering capacity in the media to mitigate the adverse pH effect for optimal growth of DNT-degrading bacteria. An array of models was evaluated to fit the O2/CO2 data acquired experimentally and the DNT depletion data calculated from derived stoichiometric coefficients and cell yield. The deterministic, integrated Monod model provides the goodness of fit to the test data on DNT depletion, and the Monod model parameters (Ks, X0, mumax, and Y) were estimated by nonlinear regression. Further analyses with an equilibrium model (MINTEQ) indicate the interrelated nature of medium chemical compositions in controlling the rate and extent of DNT biodegradation. Results from the present batch respirometer study help to unravel some key factors in controlling DNT biodegradation in complex remediation systems, in particular the interactions between acidogenic DNT bacteria and various parameters, including pH and P, the latter of which could serve as a nutrient, a buffer, and a controlling factor on the bioavailable fractions of minerals (Ca, Fe, Zn, and Mo) in the medium. PMID:15648752

  13. Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils

    PubMed Central

    Greenwood, Mark H; Sims, Ronald C; McLean, Joan E; Doucette, William J

    2007-01-01

    Background Remediation of tert-butyl alcohol (TBA) in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-butyl formate (TBF). The effect of temperature on TBA biodegradation has not been not been published in the literature. Methods Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms. Results First order mineralization rate constants of TBA at 5°C, 15°C and 25°C were 7.84 ± 0.14 × 10-3, 9.07 ± 0.09 × 10-3, and 15.3 ± 0.3 × 10-3 days-1, respectively (or 2.86 ± 0.05, 3.31 ± 0.03, 5.60 ± 0.14 years-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day-1 and 23,006 mol/J, respectively. Conclusion Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature. PMID:17877835

  14. KINETIC DISTRIBUTION MODEL OF EVAPORATION, BIOSORPTION AND BIODEGRADATION OF POLYCHLORINATED BIPHENYLS (PCBS) IN THE SUSPENSION OF PSEUDOMONAS STUTZERI. (R826652)

    EPA Science Inventory

    Abstract

    Kinetics of distribution of PCBs in an active bacterial suspension of Pseudomonas stutzeri was studied by monitoring the evaporated amounts and the concentration remaining in the liquid medium with the biomass. To determine the biodegradation rate const...

  15. Biodegradation kinetic constants and sorption coefficients of micropollutants in membrane bioreactors.

    PubMed

    Fernandez-Fontaina, Eduardo; Pinho, Ines; Carballa, Marta; Omil, Francisco; Lema, Juan M

    2013-04-01

    In order to elucidate the capability of biomass developed in membrane bioreactors (MBR) to degrade and sorb emerging micropollutants, biodegradation (kbiol) and sorption (ksor) kinetic constants as well as solid-liquid partition coefficients (Kd) of 13 selected pharmaceutical and personal care products (PPCPs) were determined with MBR heterotrophic biomass adding a pulse (100 ppb of each compound) and following the liquid and solid phase concentrations over time. The results obtained were compared to literature data referring to conventional activated sludge (CAS) systems. Two experiments were performed: one in the MBR itself and the second one in a batch reactor with the same type and concentration of biomass as in the MBR. Overall, both biodegradation and sorption coefficients were in the same range as previously reported by other studies in CAS systems, indicating that MBR biomass does not show better capabilities for the biological degradation and/or sorption of PPCPs compared to the biomass developed in CAS reactors. Therefore, the higher PPCPs removal efficiencies found in MBRs are explained by the high biomass concentrations obtained at the long sludge retention times at which this type of reactors are usually operated. PMID:22773131

  16. Modified kinetic-hydraulic UASB reactor model for treatment of wastewater containing biodegradable organic substrates.

    PubMed

    El-Seddik, Mostafa M; Galal, Mona M; Radwan, A G; Abdel-Halim, Hisham S

    2016-01-01

    This paper addresses a modified kinetic-hydraulic model for up-flow anaerobic sludge blanket (UASB) reactor aimed to treat wastewater of biodegradable organic substrates as acetic acid based on Van der Meer model incorporated with biological granules inclusion. This dynamic model illustrates the biomass kinetic reaction rate for both direct and indirect growth of microorganisms coupled with the amount of biogas produced by methanogenic bacteria in bed and blanket zones of reactor. Moreover, the pH value required for substrate degradation at the peak specific growth rate of bacteria is discussed for Andrews' kinetics. The sensitivity analyses of biomass concentration with respect to fraction of volume of reactor occupied by granules and up-flow velocity are also demonstrated. Furthermore, the modified mass balance equations of reactor are applied during steady state using Newton Raphson technique to obtain a suitable degree of freedom for the modified model matching with the measured results of UASB Sanhour wastewater treatment plant in Fayoum, Egypt. PMID:27054727

  17. Kinetics of model high molecular weight organic compounds biodegradation in soil aquifer treatment.

    PubMed

    Fox, Peter; Makam, Roshan

    2011-10-01

    Soil Aquifer Treatment (SAT) is a process where treated wastewater is purified during transport through unsaturated and saturated zones. Easily biodegradable compounds are rapidly removed in the unsaturated zone and the residual organic carbon is comprised of primarily high molecular weight compounds. This research focuses on flow in the saturated zone where flow conditions are predictable and high molecular weight compounds are degraded. Flow through the saturated zone was investigated with 4 reactors packed with 2 different particle sizes and operated at 4 different flow rates. The objective was to evaluate the kinetics of transformation for high molecular weight organics during SAT. Dextran was used as a model compound to eliminate the complexity associated with studying a mixture of high molecular weight organics. The hydrolysis products of dextran are easily degradable sugars. Batch experiments with media taken from the reactors were used to determine the distribution of microbial activity in the reactors. Zero-order kinetics were observed for the removal of dextran in batch experiments which is consistent with hydrolysis of high molecular weight organics where extracellular enzymes limit the substrate utilization rate. Biomass and microbial activity measurements demonstrated that the biomass was independent of position in the reactors. A Monod based substrate/biomass growth kinetic model predicted the performance of dextran removal in the reactors. The rate limiting step appears to be hydrolysis and the overall rate was not affected by surface area even though greater biomass accumulation occurred as the surface area decreased. PMID:21723581

  18. Modelling the biodegradation kinetics of the herbicide propanil and its metabolite 3,4-dichloroaniline.

    PubMed

    Marques, Ricardo; Oehmen, Adrian; Carvalho, Gilda; Reis, Maria A M

    2015-05-01

    This study models the biodegradation kinetics of two toxic xenobiotic compounds in enriched mixed cultures: a commonly applied herbicide (3,4-dichloropropionanilide or propanil) and its metabolite (3,4-dichloroaniline or DCA). The dependence of the metabolite degradation kinetics on the presence of the parent compound was investigated, as well as the influence of the feeding operation strategy. Model equations were proposed incorporating substrate inhibition of the parent compound and the metabolite during dump feed operation of a sequencing batch reactor (SBR). The kinetic parameters of the biomass were compared to step feed degradation of the SBR. The relationship between propanil and DCA degradation rates with the concentration of each compound was studied. A statistical comparison was carried out between the model predictions and experimental results. Substrate inhibition by both propanil and DCA was prominent during dump feed operation but insignificant during step feed. With both feeding strategies, the metabolite degradation was found to be dependent on the concentration of both the parent compound and the metabolite, suggesting that the DCA degrading enzymatic activity was independent of the detachment of the propionate moiety from the propanil molecule. After incorporating this finding into the model equations, the model was able to describe well the propanil and DCA degradation profiles, with an r (2) correlation >0.95 for each case. A kinetic model was developed for the degradation of the herbicide propanil and its metabolite DCA. An exponential inhibition term was incorporated to describe the substrate inhibition during dump feeding. The kinetics of metabolite degradation was dependent of the sum of the concentrations of metabolite and parent compound, which could also be of relevance to future xenobiotic modelling applications from wastewater. PMID:25422118

  19. Kinetics and Yields of Pesticide Biodegradation at Low Substrate Concentrations and under Conditions Restricting Assimilable Organic Carbon

    PubMed Central

    Hammes, Frederik; Egli, Thomas; Kohler, Hans-Peter E.

    2014-01-01

    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. PMID:24317077

  20. 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. PMID:24317077

  1. Biodegradation of gasoline: kinetics, mass balance and fate of individual hydrocarbons.

    PubMed

    Solano-Serena, F; Marchal, R; Ropars, M; Lebeault, J M; Vandecasteele, J P

    1999-06-01

    The degradation of gasoline by a microflora from an urban waste water activated sludge was investigated in detail. Degradation kinetics were studied in liquid cultures at 30 degrees C by determination of overall O2 consumption and CO2 production and by chromatographic analysis of all 83 identifiable compounds. In a first fast phase (2 d) of biodegradation, 74% of gasoline, involving mostly aromatic hydrocarbons, was consumed. A further 20%, involving other hydrocarbons, was consumed in a second slow phase (23 d). Undegraded compounds (6% of gasoline) were essentially some branched alkanes with a quaternary carbon or/and alkyl chains on consecutive carbons but cycloalkanes, alkenes and C10- and C11-alkylated benzenes were degraded. The degradation kinetics of individual hydrocarbons, determined in separate incubations, followed patterns similar to those observed in cultures on gasoline. Carbon balance experiments of gasoline degradation were performed. The carbon of degraded gasoline was mainly (61.7%) mineralized into CO2, the remaining carbon being essentially converted into biomass. PMID:10389248

  2. Stoichiometry and kinetics of poly-{beta}-hydroxybutyrate metabolism in aerobic, slow growing, activated sludge cultures

    SciTech Connect

    Beun, J.J.; Paletta, F.; Loosdrecht, M.C.M. Van; Heijnen, J.J.

    2000-02-20

    This paper discusses the poly-{beta}-hydroxybutyrate (PHB) metabolism in aerobic, slow growing, activated sludge cultures, based on experimental data and on a metabolic model. The dynamic conditions which occur in activated sludge processes were simulated in a 2-L sequencing batch reactor (SBR) by subjecting a mixed microbial population to successive periods of external substrate availability (feast period) and no external substrate availability (famine period). Under these conditions intracellular storage and consumption of PHB was observed. It appeared that in the feast period, 66% to almost 100% of the substrate consumed is used for storage of PHB, the remainder is used for growth and maintenance processes. Furthermore, it appeared that at high sludge retention time (SRT) the growth rate in the feast and famine periods was the same. With decreasing SRT the growth rate in the feast period increased relative to the growth rate in the famine period. Acetate consumption and PHB production in the feast period both proceeded with a zero-order rate in acetate and PHB concentration respectively. PHB consumption in the famine period could best be described kinetically with a nth order degradation equation in PHB concentration. The obtained results are discussed in the context of the general activated sludge models.

  3. Assessment of the aerobic preparation and bottom ash addition as pretreatment steps before landfilling: impact on methanogenesis kinetics and leachate parameters.

    PubMed

    Mansour, Alicia A; Motte, Antoine; Pallier, Virginie; Feuillade-Cathalifaud, Geneviève; Ponthieux, Arnaud

    2012-10-01

    This work focuses on assessing the impact of two types of waste pretreatment: addition of bottom ashes and aerobic pretreatment on both the onset and kinetics of methanogenesis and the evolution of different parameters in the leachate. It also studies the correlation between methane production and the different parameters measured in the leachate produced. A total of six 68-L pilots were thus used with fresh municipal solid waste (MSW) shredded to a 40-mm size. After 14 months of landfilling, the control has produced less than 10 NLkg(-1)DM, which corresponds to around 7% of its biochemical methane potential (BMP). Nevertheless, on one hand for aerobically pretreated waste, the lag phase before the onset of methanogenesis is significantly reduced to 0.9 month compared to more than 1 year for the control. In addition to that, on average 110 NLkg(-1)DM (90% of the BMP) is produced within around 6.5 months. On the other hand, the waste with added bottom ash shows a slight improvement of the lag phase over the control for one of the duplicate: 6.1 months of lag phase. At this stage, on average of 26 NLkg(-1)DM waste are detected (22% of the BMP) no final conclusion concerning the impact of bottom ashes could be made. The data obtained for the leachate parameters agrees with the observations on methane production. Statistical correlation study shows that the two components of the corrected PCA interpret 76% of the variability of the data: SUVA (specific UV absorbance at 254 nm) and HPI(*) (% of hydrophilic compounds) are identified as interesting parameters for following up the biodegradation in landfill conditions. PMID:22640801

  4. Mathematical modelling of oil spill fate and transport in the marine environment incorporating biodegradation kinetics of oil droplets

    NASA Astrophysics Data System (ADS)

    Spanoudaki, Katerina

    2016-04-01

    Oil biodegradation by native bacteria is one of the most important natural processes that can attenuate the environmental impacts of marine oil spills. However, very few numerical models of oil spill fate and transport include biodegradation kinetics of spilled oil. Furthermore, in models where biodegradation is included amongst the oil transformation processes simulated, it is mostly represented as a first order decay process neglecting the effect of several important parameters that can limit biodegradation rate, such as oil composition and oil droplets-water interface. To this end, the open source numerical model MEDSKIL-II, which simulates oil spill fate and transport in the marine environment, has been modified to include biodegradation kinetics of oil droplets dispersed in the water column. MEDSLIK-II predicts the transport and weathering of oil spills following a Lagrangian approach for the solution of the advection-diffusion equation. Transport is governed by the 3D sea currents and wave field provided by ocean circulation models. In addition to advective and diffusive displacements, the model simulates several physical and chemical processes that transform the oil (evaporation, emulsification, dispersion in the water column, adhesion to coast). The fate algorithms employed in MEDSLIK-II consider the oil as a uniform substance whose properties change as the slick weathers, an approach that can lead to reduced accuracy, especially in the estimation of oil evaporation and biodegradation. Therefore MEDSLIK-II has been modified by adopting the "pseudo-component" approach for simulating weathering processes. Spilled oil is modelled as a relatively small number of discrete, non-interacting components (pseudo-components). Chemicals in the oil mixture are grouped by physical-chemical properties and the resulting pseudo-component behaves as if it were a single substance with characteristics typical of the chemical group. The fate (evaporation, dispersion

  5. Current trends in trichloroethylene biodegradation: a review.

    PubMed

    Shukla, Awadhesh Kumar; Upadhyay, Siddh Nath; Dubey, Suresh Kumar

    2014-06-01

    Over the past few years biodegradation of trichloroethylene (TCE) using different microorganisms has been investigated by several researchers. In this review article, an attempt has been made to present a critical summary of the recent results related to two major processes--reductive dechlorination and aerobic co-metabolism used for TCE biodegradation. It has been shown that mainly Clostridium sp. DC-1, KYT-1, Dehalobacter, Dehalococcoides, Desulfuromonas, Desulfitobacterium, Propionibacterium sp. HK-1, and Sulfurospirillum bacterial communities are responsible for the reductive dechlorination of TCE. Efficacy of bacterial communities like Nitrosomonas, Pseudomonas, Rhodococcus, and Xanthobacter sp. etc. for TCE biodegradation under aerobic conditions has also been examined. Mixed cultures of diazotrophs and methanotrophs have been used for TCE degradation in batch and continuous cultures (biofilter) under aerobic conditions. In addition, some fungi (Trametes versicolor, Phanerochaete chrysosporium ME-446) and Actinomycetes have also been used for aerobic biodegradation of TCE. The available information on kinetics of biofiltration of TCE and its degradation end-products such as CO2 are discussed along with the available results on the diversity of bacterial community obtained using molecular biological approaches. It has emerged that there is a need to use metabolic engineering and molecular biological tools more intensively to improve the robustness of TCE degrading microbial species and assess their diversity. PMID:23057686

  6. Central Role of Dynamic Tidal Biofilms Dominated by Aerobic Hydrocarbonoclastic Bacteria and Diatoms in the Biodegradation of Hydrocarbons in Coastal Mudflats

    PubMed Central

    Coulon, Frédéric; Chronopoulou, Panagiota-Myrsini; Fahy, Anne; Païssé, Sandrine; Goñi-Urriza, Marisol; Peperzak, Louis; Acuña Alvarez, Laura; McKew, Boyd A.; Brussaard, Corina P. D.; Underwood, Graham J. C.; Timmis, Kenneth N.; Duran, Robert

    2012-01-01

    Mudflats and salt marshes are habitats at the interface of aquatic and terrestrial systems that provide valuable services to ecosystems. Therefore, it is important to determine how catastrophic incidents, such as oil spills, influence the microbial communities in sediment that are pivotal to the function of the ecosystem and to identify the oil-degrading microbes that mitigate damage to the ecosystem. In this study, an oil spill was simulated by use of a tidal chamber containing intact diatom-dominated sediment cores from a temperate mudflat. Changes in the composition of bacteria and diatoms from both the sediment and tidal biofilms that had detached from the sediment surface were monitored as a function of hydrocarbon removal. The hydrocarbon concentration in the upper 1.5 cm of sediments decreased by 78% over 21 days, with at least 60% being attributed to biodegradation. Most phylotypes were minimally perturbed by the addition of oil, but at day 21, there was a 10-fold increase in the amount of cyanobacteria in the oiled sediment. Throughout the experiment, phylotypes associated with the aerobic degradation of hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs) (Cycloclasticus) and alkanes (Alcanivorax, Oleibacter, and Oceanospirillales strain ME113), substantively increased in oiled mesocosms, collectively representing 2% of the pyrosequences in the oiled sediments at day 21. Tidal biofilms from oiled cores at day 22, however, consisted mostly of phylotypes related to Alcanivorax borkumensis (49% of clones), Oceanospirillales strain ME113 (11% of clones), and diatoms (14% of clones). Thus, aerobic hydrocarbon biodegradation is most likely to be the main mechanism of attenuation of crude oil in the early weeks of an oil spill, with tidal biofilms representing zones of high hydrocarbon-degrading activity. PMID:22407688

  7. Active heterotrophic biomass and sludge retention time (SRT) as determining factors for biodegradation kinetics of pharmaceuticals in activated sludge.

    PubMed

    Majewsky, Marius; Gallé, Tom; Yargeau, Viviane; Fischer, Klaus

    2011-08-01

    The present study investigates the biodegradation of pharmaceutically active compounds (PhACs) by active biomass in activated sludge. Active heterotrophs (X(bh)) which are known to govern COD removal are suggested as a determining factor for biological PhAC removal as well. Biodegradation kinetics of five polar PhACs were determined in activated sludge of two wastewater treatment plants which differed in size, layout and sludge retention time (SRT). Results showed that active fractions of the total suspended solids (TSS) differed significantly between the two sludges, indicating that TSS does not reveal information about heterotrophic activity. Furthermore, PhAC removal was significantly faster in the presence of high numbers of heterotrophs and a low SRT. Pseudo first-order kinetics were modified to include X(bh) and used to describe decreasing PhAC elimination with increasing SRT. PMID:21652206

  8. Comparison of Sampling Methods to Determine the Impact of Aerobic Biodegradation on Benzene Concentrations at UST Sites

    EPA Science Inventory

    This material will be interesting to regulators and contractors who collect samples of soil gas to estimate the potential for vapor intrusion of buildings. In the absence of biodegradation, transport of vapors through the unsaturated zone is expected to be by diffusion, and t...

  9. Betaine removal during thermo- and mesophilic aerobic batch biodegradation of beet molasses vinasse: influence of temperature and pH on the progress and efficiency of the process.

    PubMed

    Cibis, Edmund; Ryznar-Luty, Agnieszka; Krzywonos, Małgorzata; Lutosławski, Krzysztof; Miśkiewicz, Tadeusz

    2011-07-01

    The key issue in achieving a high extent of biodegradation of beet molasses vinasse is to establish the conditions for the assimilation of betaine, which is the main pollutant in this high-strength industrial effluent. In the present study, aerobic batch biodegradation was conducted over the temperature range of 27-63°C (step 9°C), at a pH of 6.5 and 8.0, using a mixed culture of bacteria of the genus Bacillus. Betaine was assimilated at 27-54°C and the pH of 8.0, as well as at 27-45°C and the pH of 6.5. The processes where betaine was assimilated produced a high BOD(5) removal, which exceeded 99.40% over the temperature range of 27-45°C at the pH of 8.0, as well as at 27°C and the pH of 6.5. Maximal COD removal (88.73%) was attained at 36°C and the pH of 6.5. The results indicate that the process can be applied on an industrial scale as the first step in the treatment of beet molasses vinasse. PMID:21367516

  10. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments.

    PubMed

    Singh, Arvind K; Sherry, Angela; Gray, Neil D; Jones, D Martin; Bowler, Bernard F J; Head, Ian M

    2014-01-01

    Availability of inorganic nutrients, particularly nitrogen and phosphorous, is often a primary control on crude oil hydrocarbon degradation in marine systems. Many studies have empirically determined optimum levels of inorganic N and P for stimulation of hydrocarbon degradation. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax) for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N and P are not limiting. In the marine sediments studied, crude oil degradation was limited by both N and P availability. In sediments treated with 12.5 mg/g of oil but with no addition of N and P, hydrocarbon degradation rates, assessed on the basis of CO2 production, were 1.10 ± 0.03 μmol CO2/g wet sediment/day which were comparable to rates of CO2 production in sediments to which no oil was added (1.05 ± 0.27 μmol CO2/g wet sediment/day). When inorganic nitrogen was added alone maximum rates of CO2 production measured were 4.25 ± 0.91 μmol CO2/g wet sediment/day. However, when the same levels of inorganic nitrogen were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment) maximum rates of measured CO2 production increased more than four-fold to 18.40 ± 1.04 μmol CO2/g wet sediment/day. Ks and qmax estimates for inorganic N (in the form of sodium nitrate) when P was not limiting were 1.99 ± 0.86 μmol/g wet sediment and 16.16 ± 1.28 μmol CO2/g wet sediment/day respectively. The corresponding values for P were 63 ± 95 nmol/g wet sediment and 12.05 ± 1.31 μmol CO2/g wet sediment/day. The qmax values with respect to N and P were not significantly different (P < 0.05). When N and P

  11. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments

    PubMed Central

    Singh, Arvind K.; Sherry, Angela; Gray, Neil D.; Jones, D. Martin; Bowler, Bernard F. J.; Head, Ian M.

    2014-01-01

    Availability of inorganic nutrients, particularly nitrogen and phosphorous, is often a primary control on crude oil hydrocarbon degradation in marine systems. Many studies have empirically determined optimum levels of inorganic N and P for stimulation of hydrocarbon degradation. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax) for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N and P are not limiting. In the marine sediments studied, crude oil degradation was limited by both N and P availability. In sediments treated with 12.5 mg/g of oil but with no addition of N and P, hydrocarbon degradation rates, assessed on the basis of CO2 production, were 1.10 ± 0.03 μmol CO2/g wet sediment/day which were comparable to rates of CO2 production in sediments to which no oil was added (1.05 ± 0.27 μmol CO2/g wet sediment/day). When inorganic nitrogen was added alone maximum rates of CO2 production measured were 4.25 ± 0.91 μmol CO2/g wet sediment/day. However, when the same levels of inorganic nitrogen were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment) maximum rates of measured CO2 production increased more than four-fold to 18.40 ± 1.04 μmol CO2/g wet sediment/day. Ks and qmax estimates for inorganic N (in the form of sodium nitrate) when P was not limiting were 1.99 ± 0.86 μmol/g wet sediment and 16.16 ± 1.28 μmol CO2/g wet sediment/day respectively. The corresponding values for P were 63 ± 95 nmol/g wet sediment and 12.05 ± 1.31 μmol CO2/g wet sediment/day. The qmax values with respect to N and P were not significantly different (P < 0.05). When N and P

  12. Biodegradation of chlorinated and non-chlorinated VOCs from pharmaceutical industries.

    PubMed

    Balasubramanian, P; Philip, Ligy; Bhallamudi, S Murty

    2011-02-01

    Biodegradation studies were conducted for major organic solvents such as methanol, ethanol, isopropanol, acetone, acetonitrile, toluene, chloroform, and carbon tetrachloride commonly used in pharmaceutical industries. Various microbial isolates were enriched and screened for their biodegradation potential. An aerobic mixed culture that had been previously enriched for biodegradation of mixed pesticides was found to be the most effective. All the organic solvents except chloroform and carbon tetrachloride were consumed as primary substrates by this mixed culture. Biodegradation rates of methanol, ethanol, isopropanol, acetone, acetonitrile, and toluene were measured individually in batch systems. Haldane model was found to best fit the kinetics of biodegradation. Biokinetic parameters estimated from single-substrate experiments were utilized to simulate the kinetics of biodegradation of mixture of substrates. Among the various models available for simulating the kinetics of biodegradation of multi-substrate systems, competitive inhibition model performed the best. Performance of the models was evaluated statistically using the dimensionless modified coefficient of efficiency (E). This model was used for simulating the kinetics of biodegradation in binary, ternary, and quaternary substrate systems. This study also reports batch experiments on co-metabolic biodegradation of chloroform, with acetone and toluene as primary substrates. The Haldane model, modified for inhibition due to chloroform, could satisfactorily predict the biodegradation of primary substrate, chloroform, and the microbial growth. PMID:20799072

  13. Quantifying RDX biodegradation in groundwater using δ15N isotope analysis

    NASA Astrophysics Data System (ADS)

    Bernstein, Anat; Adar, Eilon; Ronen, Zeev; Lowag, Harald; Stichler, Willibald; Meckenstock, Rainer U.

    2010-01-01

    Isotope analysis was used to examine the extent of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) biodegradation in groundwater along a ca. 1.35-km contamination plume. Biodegradation was proposed as a natural attenuating remediation method for the contaminated aquifer. By isotope analysis of RDX, the extent of biodegradation was found to reach up to 99.5% of the initial mass at a distance of 1.15-1.35 km down gradient from the contamination sources. A range of first-order biodegradation rates was calculated based on the degradation extents, with average half-life values ranging between 4.4 and 12.8 years for RDX biodegradation in the upper 15 m of the aquifer, assuming purely aerobic biodegradation, and between 10.9 and 31.2 years, assuming purely anaerobic biodegradation. Based on the geochemical data, an aerobic biodegradation pathway was suggested as the dominant attenuation process at the site. The calculated biodegradation rate was correlated with depth, showing decreasing degradation rates in deeper groundwater layers. Exceptionally low first-order kinetic constants were found in a borehole penetrating the bottom of the aquifer, with half life ranging between 85.0 to 161.5 years, assuming purely aerobic biodegradation, and between 207.5 and 394.3 years, assuming purely anaerobic biodegradation. The study showed that stable isotope fractionation analysis is a suitable tool to detect biodegradation of RDX in the environment. Our findings clearly indicated that RDX is naturally biodegraded in the contaminated aquifer. To the best of our knowledge, this is the first reported use of RDX isotope analysis to quantify its biodegradation in contaminated aquifers.

  14. Comparison of PAH Biodegradation and Desorption Kinetics During Bioremediation of Aged Petroleum Hydrocarbon Contaminated Soils

    SciTech Connect

    Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

    2000-09-20

    It is commonly assumed that mass-transfer limitations are the cause for slow and incomplete biodegradation of PAHs in aged soils. In order to test this hypothesis, the biodegradation rate and the abiotic release rate were measured and compared for selected PAHs in three different soils. It was found that PAH biodegradation was not mass-transfer limited during slurry bioremediation of an aged loamy soil. By contrast, PAH biodegradation rates were much larger than abiotic release rates in kaolinite clay indicating that sorbed-phase PAHs can apparently be biodegraded directly from mineral surfaces without prior desorption or dissolution into the aqueous phase. A comparison of PAH biodegradation rates and abiotic release rates at termination of the slurry bioremediation treatment revealed that abiotic release rates are much larger than the respective biodegradation rates. In addition, it was found that the number of hydrocarbon degraders decreased by four orders of magnitude during the bioremediation treatment. It can therefore be concluded that the slow and incomplete biodegradation of PAHs is not caused by mass-transfer limitations but rather by microbial factors. Consequently, the residual PAHs that remain after extensive bioremediation treatment are still bioavailable and for that reason could pose a greater risk to environmental receptors than previously thought.

  15. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: kinetics and biodegradability enhancement.

    PubMed

    Suárez-Ojeda, María Eugenia; Kim, Jungkwon; Carrera, Julián; Metcalfe, Ian S; Font, Josep

    2007-06-18

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15 bar of oxygen partial pressure (P(O2)) and at 180, 200 and 220 degrees C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P(O2) were 140-160 degrees C and 2-9 bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160 degrees C and 2 bar of P(O2), which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD(RB)) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture. PMID:17363148

  16. Kinetics of 1,2-Dichloroethane and 1,2-Dibromoethane Biodegradation in Anaerobic Enrichment Cultures

    PubMed Central

    Yu, Rong; Peethambaram, Hari S.; Falta, Ronald W.; Verce, Matthew F.; Henderson, James K.; Bagwell, Christopher E.; Brigmon, Robin L.

    2013-01-01

    1,2-Dichloroethane (1,2-DCA) and 1,2-dibromoethane (ethylene dibromide [EDB]) contaminate groundwater at many hazardous waste sites. The objectives of this study were to measure yields, maximum specific growth rates (μ̂), and half-saturation coefficients (KS) in enrichment cultures that use 1,2-DCA and EDB as terminal electron acceptors and lactate as the electron donor and to evaluate if the presence of EDB has an effect on the kinetics of 1,2-DCA dehalogenation and vice versa. Biodegradation was evaluated at the high concentrations found at some industrial sites (>10 mg/liter) and at lower concentrations found at former leaded-gasoline sites (1.9 to 3.7 mg/liter). At higher concentrations, the Dehalococcoides yield was 1 order of magnitude higher when bacteria were grown with 1,2-DCA than when they were grown with EDB, while μ̂'s were similar for the two compounds, ranging from 0.19 to 0.52 day−1 with 1,2-DCA to 0.28 to 0.36 day−1 for EDB. KS was larger for 1,2-DCA (15 to 25 mg/liter) than for EDB (1.8 to 3.7 mg/liter). In treatments that received both compounds, EDB was always consumed first and adversely impacted the kinetics of 1,2-DCA utilization. Furthermore, 1,2-DCA dechlorination was interrupted by the addition of EDB at a concentration 100 times lower than that of the remaining 1,2-DCA; use of 1,2-DCA did not resume until the EDB level decreased close to its maximum contaminant level (MCL). In lower-concentration experiments, the preferential consumption of EDB over 1,2-DCA was confirmed; both compounds were eventually dehalogenated to their respective MCLs (5 μg/liter for 1,2-DCA, 0.05 μg/liter for EDB). The enrichment culture grown with 1,2-DCA has the advantage of a more rapid transition to 1,2-DCA after EDB is consumed. PMID:23263950

  17. The potential for hydrocarbon biodegradation and production of extracellular polymeric substances by aerobic bacteria isolated from a Brazilian petroleum reservoir.

    PubMed

    Vasconcellos, S P; Dellagnezze, B M; Wieland, A; Klock, J-H; Santos Neto, E V; Marsaioli, A J; Oliveira, V M; Michaelis, W

    2011-06-01

    Extracellular polymeric substances (EPS) can contribute to the cellular degradation of hydrocarbons and have a huge potential for application in biotechnological processes, such as bioremediation and microbial enhanced oil recovery (MEOR). Four bacterial strains from a Brazilian petroleum reservoir were investigated for EPS production, emulsification ability and biodegradation activity when hydrocarbons were supplied as substrates for microbial growth. Two strains of Bacillus species had the highest EPS production when phenanthrene and n-octadecane were offered as carbon sources, either individually or in a mixture. While Pseudomonas sp. and Dietzia sp., the other two evaluated strains, had the highest hydrocarbon biodegradation indices, EPS production was not detected. Low EPS production may not necessarily be indicative of an absence of emulsifier activity, as indicated by the results of a surface tension reduction assay and emulsification indices for the strain of Dietzia sp. The combined results gathered in this work suggest that a microbial consortium consisting of bacteria with interdependent metabolisms could thrive in petroleum reservoirs, thus overcoming the limitations imposed on each individual species by the harsh conditions found in such environments. PMID:25187151

  18. Metaproteomics reveals major microbial players and their biodegradation functions in a large-scale aerobic composting plant.

    PubMed

    Liu, Dongming; Li, Mingxiao; Xi, Beidou; Zhao, Yue; Wei, Zimin; Song, Caihong; Zhu, Chaowei

    2015-11-01

    Composting is an appropriate management alternative for municipal solid waste; however, our knowledge about the microbial regulation of this process is still scare. We employed metaproteomics to elucidate the main biodegradation pathways in municipal solid waste composting system across the main phases in a large-scale composting plant. The investigation of microbial succession revealed that Bacillales, Actinobacteria and Saccharomyces increased significantly with respect to abundance in composting process. The key microbiologic population for cellulose degradation in different composting stages was different. Fungi were found to be the main producers of cellulase in earlier phase. However, the cellulolytic fungal communities were gradually replaced by a purely bacterial one in active phase, which did not support the concept that the thermophilic fungi are active through the thermophilic phase. The effective decomposition of cellulose required the synergy between bacteria and fungi in the curing phase. PMID:25989417

  19. Metaproteomics reveals major microbial players and their biodegradation functions in a large-scale aerobic composting plant

    PubMed Central

    Liu, Dongming; Li, Mingxiao; Xi, Beidou; Zhao, Yue; Wei, Zimin; Song, Caihong; Zhu, Chaowei

    2015-01-01

    Composting is an appropriate management alternative for municipal solid waste; however, our knowledge about the microbial regulation of this process is still scare. We employed metaproteomics to elucidate the main biodegradation pathways in municipal solid waste composting system across the main phases in a large-scale composting plant. The investigation of microbial succession revealed that Bacillales, Actinobacteria and Saccharomyces increased significantly with respect to abundance in composting process. The key microbiologic population for cellulose degradation in different composting stages was different. Fungi were found to be the main producers of cellulase in earlier phase. However, the cellulolytic fungal communities were gradually replaced by a purely bacterial one in active phase, which did not support the concept that the thermophilic fungi are active through the thermophilic phase. The effective decomposition of cellulose required the synergy between bacteria and fungi in the curing phase. PMID:25989417

  20. Biodegradation and detoxification of melanoidin from distillery effluent using an aerobic bacterial strain SAG5 of Alcaligenes faecalis.

    PubMed

    Santal, Anita Rani; Singh, N P; Saharan, Baljeet Singh

    2011-10-15

    Distillery effluent retains very dark brown color even after anaerobic treatment due to presence of various water soluble, recalcitrant and coloring compounds mainly melanoidins. In laboratory conditions, melanoidin decolorizing bacteria was isolated and optimized the cultural conditions at various incubation temperatures, pH, carbon sources, nitrogen sources and combined effect of both carbon and nitrogen sources. The optimum decolorization (72.6 ± 0.56%) of melanoidins was achieved at pH 7.5 and temperature 37 °C on 5th day of cultivation. The toxicity evaluation with mung bean (Vigna radiata) revealed that the raw distillery effluent was environmentally highly toxic as compared to biologically treated distillery effluent, which indicated that the effluent after bacterial treatment is environmentally safe. This proves to be novel biological treatment technique for biodegradation and detoxification of melanoidin from distillery effluent using the bacterial strain SAG(5). PMID:21880418

  1. Systems Characterization of Temperature, Ph and Electrical Conductivity in Aerobic Biodegradation of Wheat Biomass at Differing Mixing Rates

    NASA Technical Reports Server (NTRS)

    Calhoun, M.; Trotman, A.; Aglan, H.

    1998-01-01

    The purpose of this preliminary study is to observe and relate the rate of mixing to pH and electrical conductivity in an aerobic, continuously stirred bioreactor. The objective is to use data collected from successive experiments as a means of a system characterization. Tests were conducted to obtain these data using a continuously stirred 20 L Cytostir glass reaction vessel as a bioreactor operated without built-in temperature or pH control. The tests were conducted on the lab bench at ambient temperatures. The substrate in the bioreactor was ground wheat biomass obtained from the Biomass Production Chamber at NASA Kennedy Space Center. In this study, the data reflect characteristics of the native (uninoculated) systems as well as inoculated systems. In the native systems, it was found that pi levels became stable after approximately 2 to 3 days. The electrical conductivity levels for the native systems tended to decrease over time. In contrast, ion activity was increased after the introduction of bacteria into the system. This could be correlated with the release of nutrients, due to the activity of the bacteria. Also, there were slight increases in pH in the inoculated system, a result which is expected for a system with no active pr controls. The data will be used to test a mathematical model in an automated system.

  2. Kinetics of microbial growth and biodegradation of methanol and toluene in biofilters and an analysis of the energetic indicators.

    PubMed

    Avalos Ramirez, Antonio; Bénard, Sandrine; Giroir-Fendler, Anne; Jones, J Peter; Heitz, Michèle

    2008-11-25

    The kinetics of microbial growth and the biodegradation of methanol and toluene in (a) biofilters (BFs), and (b) biotrickling filters (BTFs), packed with inert materials, has been studied and analyzed. The specific growth rate, mu, for the treatment of methanol was 0.037h(-1) for a wide range of operating conditions. In the BF, mu was found to be a function of the methanol and toluene concentrations in the biofilm. In the BF used for treating methanol, mu was found to be affected by (1) the nitrogen concentration present in the nutrient solution, and (2) the kind of packing material employed. The kinetics of the methanol and toluene biodegradations were also analyzed using "mixed order" models. A Michaelis-Menten model type provided a good fit for the elimination capacity (EC) of the BTF treating methanol, while a Haldane model type provided a good fit to the EC of the BF treating methanol and toluene. The carbon dioxide production rate was related to the packed bed temperature and the content of the volatile solids within the biofilm. For the BF, the ratio of temperature/carbon dioxide production rate (PCO(2)) was 0.024 degrees C per unit of PCO(2), and for the BTF it was 0.15 degrees C per unit of PCO(2). PMID:18778740

  3. Wet oxidation lumped kinetic model for wastewater organic burden biodegradability prediction.

    PubMed

    Verenich, Svetlana; Kallas, Juha

    2002-08-01

    In many cases, treatment of wastewaters requires a combination of processes that very often includes biological treatment. Wet oxidation (WO) in combination with biotreatment has been successfully used for the treatment of refractory wastes. Therefore, information about the biodegradability of wastewater solutes and particulates after wet oxidation is very important. The present work proposes a model that can describe the oxidation process via organic concentration characteristics such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and immediately available BOD (IA BOD) and so can allow the prediction of biodegradability (i.e., BOD/COD ratio). The reaction mechanism includes the destruction of nonbiodegradable substances bytwo pathways: oxidation to carbon dioxide and water and oxidation to larger biodegradable compounds with their further degradation to smaller ones measured via IA BOD. The destruction of small biodegradable compounds to end products is also included in the model. The experiments were performed at different temperatures (170-200 degrees C) and partial oxygen pressures (0.5-1.5 MPa) in a batch stainless steel high-pressure autoclave. The model of concentrated thermomechanical pulp circulation water was selected for the experiments. The proposed model correlates with the experimental data well and it is compared with other WO models in the literature. PMID:12188362

  4. Comparison of biodegradation of low-weight hydroentangled raw cotton nonwoven fabric and that of commonly used disposable nonwoven fabrics in the aerobic Captina silt loam soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increasing use of disposable nonwovens made of petroleum-based materials generates a large amount of non-biodegradable, solid waste in the environment. As an effort to enhance the usage of biodegradable cotton in nonwovens, this study analyzed the biodegradability of mechanically pre-cleaned gr...

  5. Using 13C-labeled benzene and Raman gas spectroscopy to investigate respiration and biodegradation kinetics following soil contamination

    NASA Astrophysics Data System (ADS)

    Jochum, Tobias; Popp, Juergen; Frosch, Torsten

    2016-04-01

    Soil and groundwater contamination with benzene can cause serious environmental damages. However, many soil microorganisms are capable to adapt and known to strongly control the fate of organic contamination. Cavity enhanced Raman gas spectroscopy (CERS) was applied to investigate the short-term response of indigenous soil bacteria to a sudden surface contamination with benzene regarding the temporal variations of gas products and their exchange rates with the adjacent atmosphere. 13C-labeled benzene was spiked on a silty-loamy soil column (sampled from Hainich National Park, Germany) in order to track and separate the changes in heterotrophic soil respiration - involving 12CO2 and O2 - from the microbial process of benzene degradation, which ultimately forms 13CO2.1 The respiratory quotient (RQ) of 0.98 decreased significantly after the spiking and increased again within 33 hours to a value of 0.72. This coincided with maximum 13CO2 concentration rates (0.63 μ mol m-2 s-1), indicating highest benzene degradation at 33 hours after the spiking event. The diffusion of benzene in the headspace and the biodegradation into 13CO2 were simultaneously monitored and 12 days after the benzene spiking no measurable degradation was detected anymore.1 The RQ finally returned to a value of 0.96 demonstrating the reestablished aerobic respiration. In summary, this study shows the potential of combining Raman gas spectroscopy and stable isotopes to follow soil microbial biodegradation dynamics while simultaneously monitoring the underlying respiration behavior. Support by the Collaborative Research Center 1076 Aqua Diva is kindly acknowledged. We thank Beate Michalzik for soil analysis and discussion. 1. T. Jochum, B. Michalzik, A. Bachmann, J. Popp and T. Frosch, Analyst, 2015, 140, 3143-3149.

  6. [Research advances in aerobic denitrifiers].

    PubMed

    Wang, Wei; Cai, Zu-cong; Zhong, Wen-hui; Wang, Guo-xiang

    2007-11-01

    This paper reviewed the varieties and characteristics of aerobic denitrifiers, their action mechanisms, and the factors affecting aerobic denitrification. Aerobic denitrifiers mainly include Pseudomonas, Alcaligenes, Paracoccus and Bacillus, which are either aerobic or facultative aerobic, and heterotrophic. They can denitrify under aerobic conditions, with the main product being N2O. They can also convert NH4+ -N to gas product. The nitrate reductase which catalyzes the denitrification is periplasmic nitrate reductase rather than membrane-bound nitrate reductase. Dissolved oxygen concentration and C/N ratio are the main factors affecting aerobic denitrification. The main methods for screening aerobic denitrifiers, such as intermittent aeration and selected culture, were also introduced. The research advances in the application of aerobic denitrifiers in aquaculture, waste water processing, and bio-degradation of organic pollutants, as well as the contributions of aerobic denitrifiers to soil nitrogen emission were summarized. PMID:18260473

  7. Grey water biodegradability.

    PubMed

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively. PMID:20658309

  8. Characterization and biodegradation kinetics of a new cold-adapted carbamazepine-degrading bacterium, Pseudomonas sp. CBZ-4.

    PubMed

    Li, Ang; Cai, Rui; Di, Cui; Qiu, Tian; Pang, Changlong; Yang, Jixian; Ma, Fang; Ren, Nanqi

    2013-11-01

    Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature (10 degreeC) from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions: pH 7.0, 10 degreeC, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr-1 and 32.5 mg/L, respectively. PMID:24552057

  9. Treatment of Slaughter House Wastewater in a Sequencing Batch Reactor: Performance Evaluation and Biodegradation Kinetics

    PubMed Central

    Kundu, Pradyut; Debsarkar, Anupam; Mukherjee, Somnath

    2013-01-01

    Slaughterhouse wastewater contains diluted blood, protein, fat, and suspended solids, as a result the organic and nutrient concentration in this wastewater is vary high and the residues are partially solubilized, leading to a highly contaminating effect in riverbeds and other water bodies if the same is let off untreated. The performance of a laboratory-scale Sequencing Batch Reactor (SBR) has been investigated in aerobic-anoxic sequential mode for simultaneous removal of organic carbon and nitrogen from slaughterhouse wastewater. The reactor was operated under three different variations of aerobic-anoxic sequence, namely, (4+4), (5+3), and (3+5) hr. of total react period with two different sets of influent soluble COD (SCOD) and ammonia nitrogen (NH4+-N) level 1000 ± 50 mg/L, and 90 ± 10 mg/L, 1000 ± 50 mg/L and 180 ± 10 mg/L, respectively. It was observed that from 86 to 95% of SCOD removal is accomplished at the end of 8.0 hr of total react period. In case of (4+4) aerobic-anoxic operating cycle, a reasonable degree of nitrification 90.12 and 74.75% corresponding to initial NH4+-N value of 96.58 and 176.85 mg/L, respectively, were achieved. The biokinetic coefficients (k, Ks, Y, kd) were also determined for performance evaluation of SBR for scaling full-scale reactor in future operation. PMID:24027751

  10. The impact of chlorinated solvent co-contaminants on the biodegradation kinetics of 1,4-dioxane.

    PubMed

    Mahendra, Shaily; Grostern, Ariel; Alvarez-Cohen, Lisa

    2013-03-01

    1,4-Dioxane (dioxane), a probable human carcinogen, is used as a solvent stabilizer for 1,1,1-trichloroethane (TCA) and other chlorinated solvents. Consequently, TCA and its abiotic breakdown product 1,1-dichloroethene (DCE) are common co-contaminants of dioxane in groundwater. The aerobic degradation of dioxane by microorganisms has been demonstrated in laboratory studies, but the potential effects of environmentally relevant chlorinated solvent co-contaminants on dioxane biodegradation have not yet been investigated. This work evaluated the effects of TCA and DCE on the transformation of dioxane by dioxane-metabolizing strain Pseudonocardia dioxanivorans CB1190, dioxane co-metabolizing strain Pseudonomas mendocina KR1, as well as Escherichia coli expressing the toluene monooxygenase of strain KR1. In all experiments, both TCA and DCE inhibited the degradation of dioxane at the tested concentrations. The inhibition was not competitive and was reversible for strain CB1190, which did not transform the chlorinated solvents. For both strain KR1 and toluene monooxygenase-expressing E. coli, inhibition of dioxane degradation by chlorinated solvents was competitive and irreversible, and the chlorinated solvents were degraded concurrently with dioxane. These data suggest that the strategies for biostimulation or bioaugmentation of dioxane will need to consider the presence of chlorinated solvents during site remediation. PMID:23237300

  11. Nitrite-driven nitrous oxide production under aerobic soil conditions: Kinetics and biochemical controls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrite (NO2-) can accumulate during nitrification in soil following fertilizer application. While the role of NO2- as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a functi...

  12. Nitrite-Driven Nitrous Oxide Production Under Aerobic Soil Conditions: Kinetics and Biochemical Controls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrite (NO2-) can accumulate during nitrification in soil following fertilizer application. While the role of NO2- as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a functi...

  13. Stereoselective fate kinetics of chiral neonicotinoid insecticide paichongding in aerobic soils.

    PubMed

    Fu, Qiuguo; Wang, Wei; Wang, Haiyan; Zhang, Jianbo; Shen, Jiajun; Li, Zhong; Ye, Qingfu

    2015-11-01

    Man-made chemicals such as pesticides, when released into the soil environment, are transformed into extractable residue (ER), bound residue (BR), or mineralized. These processes all play a pivotal role in the risk assessment for the use of man-made chemicals. In this study, BR, ER, and mineralization of a novel chiral pesticide, paichongding (IPP), 1-((6-chloropyridin-3-yl)methyl)-7-methyl-8-nitro-5-propoxy-1,2,3,5,6,7-hexahydro-imidazo[1,2-a]pyridine, were investigated in different soils under aerobic conditions. Significant specificity was observed for diastereoisomers of IPP in the formation of BR or mineralization in neutral and alkaline soils. In contrast, no significant difference was found between enantiomers. The overall mineralization was less than 8% of the applied radioactivity and was related to soil pH. Our findings suggest that the environmental fate of chiral pesticides may be influenced by many factors such as soil properties (e.g. pH). More comprehensive and individualized risk assessments should be carried out for individual stereoisomers of a chiral product. PMID:26070081

  14. Biodegradation potential of a modified natural product

    SciTech Connect

    Sajjad, W.

    1996-12-31

    Biodegradation potential of a modified natural product for treating petroleum contaminated soils was investigated along with some commercially available microbial cultures in three different scales from a laboratory to pilot to case studies. The modified natural product is lignocellulosic in nature and proprietary product of a company in Iowa. The production process of this product involves mechanical size reduction, blending/coating, and aerobic digestion of hay, corn cob residue, straw or crop residue in presence of poultry manure. The degradation kinetics of the petroleum products in the contaminated soils were measured both directly and indirectly. Residual petroleum products in different soils (treated and untreated) at various time periods were quantified by gas chromatographic (GC) analysis on extracted samples. The indirect assessment of the kinetics of biological activity involved the measurement of CO{sub 2} evolved from flasks (250 ml capacity) containing contaminated soil (about 50 ml) with various treatments. The results indicated that the biodegradation kinetics of petroleum products in the contaminated soils were significantly improved by treatment with this modified natural product. In most cases tested, this product performed significantly better than the available commercial bacterial cultures for biological removal of petroleum products from contaminated soils. This study also demonstrated the significance of temperature and moisture content in biodegradation kinetics.

  15. KINETIC MODEL OF BIOSURFACTANT ENHANCED HEXADECANE BIODEGRADATION BY PSEUDOMONAS AERUGINOSA. (R827132)

    EPA Science Inventory

    Many sites of environmental concern contain groundwater contaminated with nonaqueous phase liquids (NAPL). In such sites interfacial processes may affect both the equilibrium and kinetic behavior of the system. In particular, insoluble hydrocarbon partitioning and microbial biode...

  16. The role of sorption and biodegradation in the removal of acetaminophen, carbamazepine, caffeine, naproxen and sulfamethoxazole during soil contact: A kinetics study.

    PubMed

    Martínez-Hernández, Virtudes; Meffe, Raffaella; Herrera López, Sonia; de Bustamante, Irene

    2016-07-15

    In countries like Spain, where water is a limited resource, reusing effluents from wastewater treatment plants may imply the introduction of incompletely eliminated pollutants into the environment. Therefore, this work identified the role of sorption and biodegradation in attenuating pharmaceutical compounds (acetaminophen, carbamazepine, caffeine, naproxen and sulfamethoxazole) in natural soil. It also determined which sorption and removal ("sorption+biodegradation") kinetics models describe the behaviour of these substances in the water-soil system. Presence of potential transformation products (TPs) as a result of pharmaceuticals biodegradation was also studied. To this end, serial batch-type experiments were performed with a soil:water ratio of 1:4 and an initial pharmaceutical concentration of 100μgL(-1). Despite results are dependent on soil characteristics, they revealed that, for those substances with a higher affinity to the soil used (loamy sand), sorption seems to play a key role during the first 48h of contact with soil, and gives way to biodegradation afterwards. The sorption of the pharmaceuticals studied follows a pseudo second-order kinetics. Caffeine and sulfamethoxazole displayed the fastest initial sorption velocities (h=2055 and h=228μgkg(-1)h(-1), respectively). The removal kinetics experiments, satisfactorily simulated by the first-order kinetics model, indicated the presence of potential microbial adaptation to degradation. Indeed, half-lives decreased from 1.6- to 11.7-fold with respect to initial values. The microbial capacity to degrade sulfamethoxazole could be a matter of concern if bacteria have developed resistance to this antibiotic. Caffeine, acetaminophen and sulfamethoxazole were mitigated to a greater extent, whereas the removal of naproxen and carbamazepine was more limited. The appearance of epoxy-carbamazepine and N4-acetyl-sulfamethoxazole as possible TPs of carbamazepine and sulfamethoxazole, respectively, indicated that

  17. Kinetics of the biodegradation of phenol in wastewaters from the chemical industry by covalently immobilized Trichosporon cutaneum cells.

    PubMed

    Yotova, Lyubov; Tzibranska, Irene; Tileva, Filadia; Markx, G H; Georgieva, Nelly

    2009-03-01

    A simple method for the preparation of the biocatalyst with whole cells is presented, and the applicability of the technique for biodegradation of phenol in wastewater from the chemical industries using the basidomycetes yeast Trichosporon cutaneum is explored. Kinetic studies of the influence of other compounds contained in wastewater as naphthalene, benzene, toluene and pyridine indicate that apart from oil fraction, which is removed, the phenol concentration is the only major factor limiting the growth of immobilized cells. Mathematical models are applied to describe the kinetic behavior of immobilized yeast cells. From the analysis of the experimental curves was shown that the obtained values for the apparent rate parameters vary depending on the substrate concentration (mu(maxapp) from 0.35 to 0.09 h(-1) and K (sapp) from 0.037 to 0.4 g dm(-3)). The inhibitory effect of the phenol on the obtained yield coefficients was investigated too. It has been shown that covalent immobilization of T. cutaneum whole cells to plastic carrier beads is possible, and that cell viability and phenol degrading activity are maintained after the chemical modification of cell walls during the binding procedure. The results obtained indicate a possible future application of immobilized T. cutaneum for destroying phenol in industrial wastewaters. PMID:19052785

  18. Effects of Antibiotic Physicochemical Properties on their Release Kinetics from Biodegradable Polymer Microparticles

    PubMed Central

    Shah, Sarita R.; Henslee, Allan M.; Spicer, Patrick P.; Yokota, Shun; Petrichenko, Sophia; Allahabadi, Sachin; Bennett, George N.; Wong, Mark E.; Kasper, F. Kurtis; Mikos, Antonios G.

    2014-01-01

    Purpose This study investigated the effects of the physicochemical properties of antibiotics on the morphology, loading efficiency, size, release kinetics, and antibiotic efficacy of loaded poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (MPs) at different loading percentages. Methods Cefazolin, ciprofloxacin, clindamycin, colistin, doxycycline, and vancomycin were loaded at 10 and 20 weight percent into PLGA MPs using a water-in-oil-in water double emulsion fabrication protocol. Microparticle morphology, size, loading efficiency, release kinetics, and antibiotic efficacy were assessed. Results The results from this study demonstrate that the chemical nature of loaded antibiotics, especially charge and molecular weight, influence the incorporation into and release of antibiotics from PLGA MPs. Drugs with molecular weights less than 600 Da displayed biphasic release while those with molecular weights greater than 1000 Da displayed triphasic release kinetics. Large molecular weight drugs also had a longer delay before release than smaller molecular weight drugs. The negatively charged antibiotic cefazolin had lower loading efficiency than positively charged antibiotics. Microparticle size appeared to be mainly controlled by fabrication parameters, and partition and solubility coefficients did not appear to have an obvious effect on loading efficiency or release. Released antibiotics maintained their efficacy against susceptible strains over the duration of release. Duration of release varied between 17–49 days based on the type of antibiotic loaded. Conclusions The data from this study indicate that the chemical nature of antibiotics affects properties of antibiotic-loaded PLGA MPs and allows for general prediction of loading and release kinetics. PMID:24874603

  19. Kinetics and Mechanism of Fenpropathrin Biodegradation by a Newly Isolated Pseudomonas aeruginosa sp. Strain JQ-41.

    PubMed

    Song, Haihai; Zhou, Zhiren; Liu, Yuanxiu; Deng, Si; Xu, Heng

    2015-09-01

    A soil bacterium designated strain JQ-41, capable of growth on fenpropathrin as the sole carbon source and energy source, was isolated from a long-term pyrethroid insecticide-treated orchard. Based on the morphology, physio-biochemical characteristics, and 16S rDNA gene analysis, as well as the G+C content of the genomic DNA, the strain JQ-41 was identified as Pseudomonas aeruginosa. Up to 92.3% of 50 mg l(-1) fenpropathrin was degraded by P. aeruginosa strain at 30°C and pH 7 within 7 days. The kinetic parameters q max, K s, and K i were established to be 1.14 day(-1), 38.41 mg l(-1), and 137.67 mg l(-1), respectively, and the critical inhibitor concentration was determined to be 72.72 mg l(-1). Cell surface hydrophobicity of P. aeruginosa strain was enhanced during growth on fenpropathrin. Three metabolites from fenpropathrin degradation were identified by gas chromatography mass spectrometry, and then a possible degradation pathway was proposed. In addition, this isolate was also able to degrade a wide range of synthetic pyrethroid insecticides including cypermethrin, deltamethrin, bifenthrin, and cyhalothrin with the degradation process following the first-order kinetic model. Taken together, our results provide insights into the kinetics and mechanism of fenpropathrin degradation by P. aeruginosa strain and also highlight its promising potential in bioremediation of pyrethroid-contaminated environment. PMID:26068594

  20. Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters.

    PubMed

    Xie, Wen-Jie; Zhou, Xiao-Ming

    2015-01-01

    Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by (1)H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t1/2, Zc and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. PMID:25491999

  1. A new model for the biodegradation kinetics of oil droplets: application to the Deepwater Horizon oil spill in the Gulf of Mexico.

    PubMed

    Vilcáez, Javier; Li, Li; Hubbard, Susan S

    2013-01-01

    Oil biodegradation by native bacteria is one of the most important natural processes that can attenuate the environmental impacts of marine oil spills. Existing models for oil biodegradation kinetics are mostly for dissolved oil. This work developed a new mathematical model for the biodegradation of oil droplets and applied the model to estimate the time scale for oil biodegradation under conditions relevant to the Deepwater Horizon oil spill in the Gulf of Mexico. In the model, oil is composed of droplets of various sizes following the gamma function distribution. Each oil droplet shrinks during the microbe-mediated degradation at the oil-water interface. Using our developed model, we find that the degradation of oil droplets typically goes through two stages. The first stage is characterized by microbial activity unlimited by oil-water interface with higher biodegradation rates than that of the dissolved oil. The second stage is governed by the availability of the oil-water interface, which results in much slower rates than that of soluble oil. As a result, compared to that of the dissolved oil, the degradation of oil droplets typically starts faster and then quickly slows down, ultimately reaching a smaller percentage of degraded oil in longer time. The availability of the water-oil interface plays a key role in determining the rates and extent of degradation. We find that several parameters control biodegradation rates, including size distribution of oil droplets, initial microbial concentrations, initial oil concentration and composition. Under conditions relevant to the Deepwater Horizon spill, we find that the size distribution of oil droplets (mean and coefficient of variance) is the most important parameter because it determines the availability of the oil-water interface. Smaller oil droplets with larger variance leads to faster and larger extent of degradation. The developed model will be useful for evaluating transport and fate of spilled oil, different

  2. A new model for the biodegradation kinetics of oil droplets: application to the Deepwater Horizon oil spill in the Gulf of Mexico

    PubMed Central

    2013-01-01

    Oil biodegradation by native bacteria is one of the most important natural processes that can attenuate the environmental impacts of marine oil spills. Existing models for oil biodegradation kinetics are mostly for dissolved oil. This work developed a new mathematical model for the biodegradation of oil droplets and applied the model to estimate the time scale for oil biodegradation under conditions relevant to the Deepwater Horizon oil spill in the Gulf of Mexico. In the model, oil is composed of droplets of various sizes following the gamma function distribution. Each oil droplet shrinks during the microbe-mediated degradation at the oil-water interface. Using our developed model, we find that the degradation of oil droplets typically goes through two stages. The first stage is characterized by microbial activity unlimited by oil-water interface with higher biodegradation rates than that of the dissolved oil. The second stage is governed by the availability of the oil-water interface, which results in much slower rates than that of soluble oil. As a result, compared to that of the dissolved oil, the degradation of oil droplets typically starts faster and then quickly slows down, ultimately reaching a smaller percentage of degraded oil in longer time. The availability of the water-oil interface plays a key role in determining the rates and extent of degradation. We find that several parameters control biodegradation rates, including size distribution of oil droplets, initial microbial concentrations, initial oil concentration and composition. Under conditions relevant to the Deepwater Horizon spill, we find that the size distribution of oil droplets (mean and coefficient of variance) is the most important parameter because it determines the availability of the oil-water interface. Smaller oil droplets with larger variance leads to faster and larger extent of degradation. The developed model will be useful for evaluating transport and fate of spilled oil, different

  3. Mechanisms, Chemistry, and Kinetics of Anaerobic Biodegradation of cDCE and VC

    SciTech Connect

    Mcarty, Perry L.; Sporman, Alfred M.

    2000-06-01

    Biological reductive dehalogenation of the chlorinated ethenes, tetrachloroethene (PCE) and trichloroethene (TCE) to cis-1,2-dichloroethene (cDCE), vinyl chloride (VC) and then ethene is of great interest both for natural attenuation and engineered remediation of these hazardous contaminants in groundwater. This study was directed towards a better understanding of the factors affecting the rate and extent of conversions of cDCE and VC to ethene, which are generally considered the rate limiting steps in the overall process. The objectives of this study are to (1) determine the biochemical pathways for reductive dehalogenation of cDCE and VC, including identification of the enzymes involved, (2) determine the chemical requirements, especially the type and quantity of electron donors needed by the microorganisms for reductive dehalogenation, and (3) evaluate the kinetics of the process with respect to the concentration of both the electron donors and the electron acceptors (cDCE and VC).

  4. Mechanisms, Chemistry, and Kinetics of Anaerobic Biodegradation of cDCE and VC

    SciTech Connect

    McCarty, Perry L.; Spormann, Alfred M.

    1999-06-01

    Biological reductive dehalogenation of the chlorinated ethenes, tetrachloroethene (PCE) and trichloroethene (TCE) to cis-1,2-dichloroethene (cDCE), vinyl chloride (VC) and then ethene is of great interest both for natural attenuation and engineered remediation of these hazardous 2 contaminants in groundwater. This study was directed towards a better understanding of the factors affecting the rate and extent of conversions of cDCE and VC to ethene, which are generally considered the rate limiting steps in the overall process. The objectives of this study are to (1) determine the biochemical pathways for reductive dehalogenation of cDCE and VC, including identification of the enzymes involved, (2) determine the chemical requirements, especially the type and quantity of electron donors needed by the microorganisms for reductive dehalogenation, and (3) evaluate the kinetics of the process with respect to the concentration of both the electron donors and the electron acceptors (c DCE and VC).

  5. Toward Understanding Drug Release From Biodegradable Polymer Microspheres of Different Erosion Kinetics Modes.

    PubMed

    You, Siming; Yang, Zichao; Wang, Chi-Hwa

    2016-06-01

    Two generalized modes of erosion kinetics, that is, the power law mode and root type mode, respectively, were found to be able to better describe the reported weight loss data compared to the existing linear mode, for commonly used surface-eroding polymer microspheres. Based on the newly identified modes, a set of drug release models were developed by extending the existing model. Model validation was achieved by comparing the model predictions to the reported experimental data for surface-eroding polymer microspheres (poly(ortho esters) and polyanhydrides), and good consistency was found. Parameter investigation was conducted to reveal the effects of various important parameters (the dimensionless ratio between diffusion and erosion rates (Er), the dimensionless ratio between erosion and dissolution rates (p), the dimensionless drug loading concentration (q), and the fitting parameter of erosion kinetics (a)) on drug release behavior, which has rarely been examined previously. In general, the effects of these parameters were more significant for an earlier stage, and p, q, and a could effectively vary the drug release percentage. Design-of-experiments-based sensitivity analysis was further carried out and it was found that the most sensitive parameters were p (2.97%) and q (2.97%) for the cases of the power law mode, while it was a (-7.07%) for the cases of the root type mode. The information from the parameter investigation and sensitivity analysis could serve as a straightforward data bank for the practical designing of drug delivery processes. The proposed models are potential mathematical frameworks for the designing of drugs that are based on surface-eroding polymer microspheres in the future. PMID:27238490

  6. Degradation pathway, toxicity and kinetics of 2,4,6-trichlorophenol with different co-substrate by aerobic granules in SBR.

    PubMed

    Khan, Mohammad Zain; Mondal, Pijush Kanti; Sabir, Suhail; Tare, Vinod

    2011-07-01

    The present study deals with cultivation of 2,4,6-trichlorophenol (TCP) degrading aerobic granules in two SBR systems based on glucose and acetate as co-substrate. Biodegradation of TCP containing wastewater starting from 10 to 360 mg L(-1) with more than 90% efficiency was achieved. Sludge volume index decreases as the operation proceeds to stabilize at 35 and 30 mL g(-1) while MLVSS increases from 4 to 6.5 and 6.2 g L(-1) for R1 (with glucose as co-substrate) and R2 (with sodium acetate as co-substrate), respectively. FTIR, GC and GC/MS spectral studies shows that the biodegradation occurred via chlorocatechol pathway and the cleavage may be at ortho-position. Haldane model for inhibitory substrate was applied to the system and it was observed that glucose fed granules have a high specific degradation rate and efficiency than acetate fed granules. Genotoxicity studies shows that effluent coming from SBRs was non-toxic. PMID:21565491

  7. Kinetics of phenol biodegradation at high concentration by a metabolically versatile isolated yeast Candida tropicalis PHB5.

    PubMed

    Basak, Bikram; Bhunia, Biswanath; Dutta, Subhasish; Chakraborty, Samayita; Dey, Apurba

    2014-01-01

    A highly tolerant phenol-degrading yeast strain PHB5 was isolated from wastewater effluent of a coke oven plant and identified as Candida tropicalis based on phylogenetic analysis. Biodegradation experiments with C. tropicalis PHB5 showed that the strain was able to utilize 99.4% of 2,400 mg l(-1) phenol as sole source of carbon and energy within 48 h. Strain PHB5 was also observed to grow on 18 various aromatic hydrocarbons. Haldane model was used to fit the exponential growth data and the following kinetic parameters were obtained: μ max = 0.3407 h(-1), K S = 15.81 mg l(-1), K i = 169.0 mg l(-1) (R (2) = 0.9886). The true specific growth rate, calculated from μ max, was 0.2113. A volumetric phenol degradation rate (V max) was calculated by fitting the phenol consumption data with Gompertz model and specific degradation rate (q) was calculated from V max. The q values were fitted with Haldane model, yielding following parameters: q max = 0.2766 g g(-1) h(-1), K S ' = 2.819 mg l(-1), K i ' = 2,093 (R (2) = 0.8176). The yield factor (Y X/S ) varied between 0.185 to 0.96 g g(-1) for different initial phenol concentrations. Phenol degradation by the strain proceeded through a pathway involving production of intermediates such as catechol and cis,cis-muconic acid which were identified by enzymatic assays and HPLC analysis. PMID:23917743

  8. Simulations of Flow, Transport, and Biodegradation in Landfills

    NASA Astrophysics Data System (ADS)

    Oldenburg, C. M.; Borglin, S. E.; Hazen, T. C.

    2002-12-01

    Biotreatment of landfill materials may involve coupled nonisothermal flow and transport of water and gas in the refuse mass. With the objective of carrying out analyses that depend on flow and transport processes, we are developing T2LBM, a module for the TOUGH2 multiphase flow and transport simulator that implements a Landfill Bioreactor Model. T2LBM models the processes of aerobic and anaerobic biodegradation of municipal solid waste and the associated three-dimensional flow and transport of gas, liquid, and heat through the refuse mass. The components modeled in T2LBM are water, acetic acid, carbon dioxide, methane, oxygen, and nitrogen in aqueous and gas phases, with partitioning specified by temperature-dependent Henry's coefficients. The local oxygen concentration is used to control whether aerobic or anaerobic biodegradation reactions occur to produce carbon dioxide, or methane and carbon dioxide, respectively. Acetic acid is used as a proxy for all of the biodegradable components in the refuse. The biodegradation rate of acetic acid is modeled using a Monod kinetic rate law for the exothermic reactions in the aqueous phase. The compaction rate is specified by the user and modeled as a linear decrease with time of porosity and contraction of the vertical grid dimension by generation of a new grid at each time step. Local differences in moisture content, pressure, gas composition, aerobicity, and temperature, among other properties, within the heterogeneous refuse can be modeled with T2LBM. Comparison of simulation results against observations of an aerobic landfill bioreactor laboratory experiment and an anaerobic field pilot study show good agreement for oxygen consumption and gas production. Predictions and sensitivity analyses of different biotreatments can be made using this new simulation capability. This work was supported by Laboratory Directed Research and Development Funds at Lawrence Berkeley National Laboratory under Department of Energy Contract

  9. Process Modeling of Flow, Transport, and Biodegradation in Landfill Bioreactors

    NASA Astrophysics Data System (ADS)

    Oldenburg, C. M.; Borglin, S. E.; Hazen, T. C.

    2001-12-01

    The need to control gas and leachate production and minimize refuse volume has motivated laboratory experiments and model development for design and assessment of bioremediation treatment processes. In parallel with landfill bioreactor laboratory experiments, we have developed T2LBM, a module for the TOUGH2 multiphase flow and transport simulator that implements a Landfill Bioreactor Model. T2LBM provides simulation capability for the processes of aerobic or anaerobic biodegradation of municipal solid waste and the associated three-dimensional flow and transport of gas, liquid, and heat through the refuse mass. T2LBM considers the components water, acetic acid, carbon dioxide, methane, oxygen, and nitrogen in aqueous and gas phases, with partitioning specified by temperature-dependent Henry's coefficients. T2LBM incorporates a Monod kinetic rate law for the exothermic biodegradation of acetic acid in the aqueous phase by either aerobic or anaerobic microbes as controlled by the local oxygen concentration. Methane and carbon dioxide generation due to biodegradation with corresponding thermal effects are modeled. Acetic acid is considered a proxy for all biodegradable substrates in the refuse. Aerobic and anaerobic microbes are assumed to be immobile and not limited by nutrients in their growth. Although a simplification of complex landfill processes, T2LBM shows reasonable agreement to published laboratory experiments of biodegradation and gas production depending on the choice of numerous input parameters. Simulations of the landfill bioreactor laboratory experiments show that the mechanistic approach of T2LBM can be used to model bioremediation assessment indicators such as oxygen consumption associated with respiration tests. This work was supported by Laboratory Directed Research and Development Funds at Lawrence Berkeley National Laboratory under Department of Energy Contract No. DE-AC03-76SF00098.

  10. Microbial degradation of 4-monobrominated diphenyl ether in an aerobic sludge and the DGGE analysis of diversity.

    PubMed

    Chen, Chun-Yao; Wang, Chun-Kang; Shih, Yang-Hsin

    2010-07-01

    Polybrominated diphenyl ethers (PBDEs) were applied as flame retardant additives in polymers for many plastic and electronic products. Due to their ubiquitous distribution in the environment, potential toxicity to human and tendency for bioaccumulation, PBDEs have raised public safety concern. In this study we examined the degradation of 4-monobrominated diphenyl ether (4-BDE) in aerobic sludge, as a model for PBDE biodegradation. Degradation of 4-BDE was observed in aerobic sludge. Co-metabolism with toluene or diphenyl ether facilitated 4-BDE biodegradation in terms of kinetics and efficiency. Diphenyl ether seems to perform slightly better as an auxiliary carbon source than toluene in facilitating 4-BDE degradation. During the experiment we identified diphenyl ether by gas chromatography/mass spectrometry(GC/MS), which indicates that an anaerobic debromination has occurred. Bacterial community composition was monitored with denaturing gradient gel electrophoresis. The fragments enriched in 4-BDE-degrading aerobic sludge samples belong to presumably a novel anaerobic Clostridiales species distantly related to all known debrominating microbes. This suggests that 4-BDE biodegradation can occur in anaerobic micro-niche in an apparently aerobic environment, by a previously unknown bacterial species. These findings can provide better understandings of biodegradation of brominated diphenyl ethers and can facilitate the prediction of the fate of PBDEs in the environment. PMID:20512728

  11. Revealing the halide effect on the kinetics of the aerobic oxidation of Cu(I) to Cu(II)

    SciTech Connect

    Deng, Yi; Zhang, Guanghui; Qi, Xiaotian; Liu, Chao; Miller, Jeffrey T.; Kropf, A. Jeremy; Bunel, Emilio E.; Lan, Yu; Lei, Aiwen

    2015-01-01

    In situ infrared (IR) and X-ray absorption near-edge structure (XANES) spectroscopic investigations reveal that different halide ligands have distinct effects on the aerobic oxidation of Cu(I) to Cu(II) in the presence of TMEDA (tetramethylethylenediamine). The iodide ligand gives the lowest rate and thus leads to the lowest catalytic reaction rate of aerobic oxidation of hydroquinone to benzoquinone. Further DFT calculations suggest that oxidation of CuI–TMEDA involves a side-on transition state, while oxidation of CuCl–TMEDA involves an end-on transition state which has a lower activation energy.

  12. Biodegradation of Reactive blue 13 in a two-stage anaerobic/aerobic fluidized beds system with a Pseudomonas sp. isolate.

    PubMed

    Lin, Jun; Zhang, Xingwang; Li, Zhongjian; Lei, Lecheng

    2010-01-01

    Pseudomonas sp. strain L1 capable of degrading the azo textile dye Reactive blue 13, was isolated from activated sludge in a sequencing batch reactor. A continuous two-stage anaerobic/aerobic biological fluidized bed system was used to decolorize and mineralize Reactive blue 13. The key factors affecting decolorization were investigated and the efficiency of degradation was also optimized. An overall color removal of 83.2% and COD removal of 90.7% was achieved at pH 7, a residence time of 70 h and a glucose concentration of 2 g/L, HRT=70 h and C(glucose)=2000 mg/L. Oxygen was contributing to blocking the azo bond cleavage. Consequently, decolorization occurred in the anaerobic reactor while partial mineralization was achieved in the aerobic reactor. A possible degradation pathway based on the analysis of intermediates and involving azoreduction, desulfonation, deamination and further oxidation reactions is presented. PMID:19713103

  13. Multiphase Modeling of Flow, Transport, and Biodegradation in a Mesoscale Landfill Bioreactor

    SciTech Connect

    Oldenburg, Curtis M.; Borglin, Sharon E.; Hazen, Terry C.

    2002-02-01

    The need to control gas and leachate production and minimize refuse volume in municipal solid waste landfills has motivated the development of landfill simulation models to predict and design optimal treatment processes. We have developed a multiphase and multicomponent nonisothermal module called T2LBM for the three-dimensional TOUGH2 flow and transport simulator. T2LBM can be used to simulate aerobic or anaerobic biodegradation of municipal solid waste and the associated flow and transport of gas and liquid through the refuse mass. Acetic acid is used as a proxy for all biodegradable substrates in the refuse. T2LBM incorporates a Monod kinetic rate law for the biodegradation of acetic acid by either aerobic or anaerobic microbes as controlled by the local oxygen concentration. We have verified the model against published data, and applied it to our own mesoscale laboratory aerobic landfill bioreactor experiments. We observe spatial variability of flow and biodegradation consistent with permeability heterogeneity and the geometry of the radial grid. The model is capable of matching results of a shut-in test where the respiration of the system is measured over time.

  14. 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. PMID:24083899

  15. Effect of temperature on solids reductions and on degradation kinetics during thermophilic aerobic digestion of a simulated sludge.

    PubMed

    Toki, C J

    2008-07-01

    Laboratory-scale experiments were conducted to determine the influence of higher thermophilic temperatures on thermophilic aerobic digestion treatment of a simulated sludge. The efficiency of the process was evaluated in respect of solids removal and degradation rate constants at four thermophilic temperatures. Batch runs were operated at a retention time of one day and temperatures of 65, 70, 72 and 75 degrees C. The results indicated that temperature increase did not impart any significant benefits to the digestion operation in terms of suspended solids and biochemichal oxygen demand reduction. The findings from this research also suggested that the treatment would not appear to benefit from temperatures higher than 65 degrees C, as classically suggested by Van't Hoff-Arrhenius. Therefore, increase of thermophilic temperature in the tested 65-75 degrees C range does not enhance the efficiency of thermophilic, aerobic sludge digestion treatment. PMID:18697516

  16. Physiological and functional diversity of phenol degraders isolated from phenol-grown aerobic granules: Phenol degradation kinetics and trichloroethylene co-metabolic activities.

    PubMed

    Zhang, Yi; Tay, Joo Hwa

    2016-03-15

    Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates' kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9-449 mg DO g DW(-1) h(-1), in phenol concentration range of 4.8-406 mg L(-1). Both Michaelis-Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04-21.1 mg TCE g DW(-1) h(-1) occurring between TCE concentrations of 0.42-4.90 mg L(-1). The TCE transformation capacities and growth yields on phenol ranged from 20-115 mg TCE g DW(-1) and 0.46-1.22 g DW g phenol(-1), respectively, resulting in TCE transformation yields of 10-70 mg TCE g phenol(-1). Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions. PMID:26720328

  17. ENHANCED BIODEGRADATION THROUGH IN-SITU AERATION

    EPA Science Inventory

    This presentation provided an overview of enhanced aerobic bioremediation using in-situ aeration or venting. The following topics were covered: (1) Basic discussion on biodegradation and respiration testing; (2) Basic discussion on volatilization, rate-limited mass transport, an...

  18. Removal of the anti-cancer drug methotrexate from water by advanced oxidation processes: Aerobic biodegradation and toxicity studies after treatment.

    PubMed

    Lutterbeck, Carlos Alexandre; Baginska, Ewelina; Machado, Ênio Leandro; Kümmerer, Klaus

    2015-12-01

    Anti-cancer drugs are discussed as high risk substances in regard to human health and considered as problematic for the environment. They are of potential environmental relevance due to their poor biodegradability and toxicological properties. Methotrexate (MTX) is an antimetabolite that was introduced in the pharmaceutical market in the 40's and still today is one of the most consumed cytotoxic compounds around the world. In the present study MTX was only partially biodegraded in the closed bottle test (CBT). Therefore, it was submitted to three different advanced oxidation processes (AOPs): UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. The irradiation was carried out with a Hg medium-pressure lamp during 256min whereas the analytical monitoring was done through LC-UV-MS/MS and DOC analysis. MTX was easily removed in all the irradiation experiments, while the highest mineralization values and rates were achieved by the UV/Fe(2+)/H2O2 treatment. The lowest resulted from the UV/H2O2 reactions. The UV/H2O2 treatment resulted in little biodegradable transformation products (TPs). However, the same treatment resulted in a reduction of the toxicity of MTX by forming less toxic TPs. Analysis by LC-UV-MS/MS revealed the existence of nine TPs formed during the photo-catalytic treatments. The pH of the solutions decreased from 6.4 (t 0min) to 5.15 in the UV/H2O2 and from 6.4 (t 0min) to 5.9 in the UV/TiO2 at the end of the experiments. The initial pH of the UV/Fe(2+)/H2O2 experiments was adjusted to 5 and after the addition of H2O2 the pH decreased to around 3 and remained in this range until the end of the treatments. PMID:26298026

  19. EFFECTS OF FERRIC HYDROXIDE ON THE ANAEROBIC BIODEGRADATION KINETICS AND TOXICITY OF VEGETABLE OIL IN FRESHWATER SEDIMENTS

    EPA Science Inventory

    Biodegradation of vegetable oil in freshwater sediments exhibits self-inhibitory characteristics when it occurs under methanogenic conditions but not under iron-reducing conditions. The basis of the protective effect of iron was investigated by comparing its effects on oil biodeg...

  20. Sorption and biodegradation of selected benzotriazoles and hydroxybenzothiazole in activated sludge and estimation of their fate during wastewater treatment.

    PubMed

    Mazioti, Aikaterini A; Stasinakis, Athanasios S; Gatidou, Georgia; Thomaidis, Nikolaos S; Andersen, Henrik R

    2015-07-01

    Biodegradation of benzotriazole (BTR), 5-chlorobenzotriazole (CBTR), xylytriazole (XTR), 4-methyl-1H-benzotriazole (4TTR), 5-methy-1H-lbenzotriazole (5TTR) and 2-hydroxybenzothiazole (OHBTH) was studied in activated sludge batch experiments under aerobic and anoxic conditions, presence of organic substrate and different sludge residence times (SRTs). Their sludge-water distribution coefficients were also calculated in sorption experiments and ranged between 87 and 220 L kg(-1). Significant biodegradation of BTR, CBTR, XTR and OHBTH was observed in all biotic experiments. Half-life values ranged between 23 and 45 h (BTR), 18 and 47 h (CBTR), 14 and 26 h (XTR), 6.5 and 24 h (OHBTH). The addition of substrate did not suppress biodegradation kinetics; whereas in some cases accelerated biodegradation of microcontaminants. Except for CBTR, no effect of SRT on biodegradation constants was observed. Prediction of micropollutants removal in Sewage Treatment Plants (STPs) indicated that they will be partially removed, mainly due to aerobic biodegradation. Higher removal is expected at STPs operating at higher SRT and higher suspended solids concentrations. PMID:25828067

  1. /sup 31/P NMR saturation-transfer and /sup 13/C NMR kinetic studies of glycolytic regulation during anaerobic and aerobic glycolysis

    SciTech Connect

    Campbell-Burk, S.L.; den Hollander, J.A.; Alger, J.R.; Shulman, R.G.

    1987-11-17

    /sup 31/P NMR saturation-transfer techniques have been employed in glucose-gown derepressed yeast to determine unidirectional fluxes in the upper part of the Embden-Meyerhof-Parnas pathway. The experiments were performed during anaerobic and aerobic glycolysis by saturating the ATP/sub ..gamma../ resonances and monitoring changes in the phosphomonoester signals from glucose 6-phosphate and fructose 1,6-bisphosphate. These experiments were supplemented with /sup 13/C NMR measurements of glucose utilization rates and /sup 13/C NMR label distribution studies. Combined with data obtained previously from radioisotope measurement, these /sup 31/P and /sup 13/C NMR kinetic studies allowed estimation of the net glycolytic flow in addition to relative flows through phosphofructokinase (PFK) and Fru-1,6-P/sub 2/ase during anaerobic and aerobic glycolysis. The /sup 31/P NMR saturation-transfer results are consistent with previous results obtained from measurements of metabolite levels, radioisotope data, and /sup 13/C NMR studies, providing additional support for in vivo measurement of the flows during glycolysis.

  2. Model based evaluation of a contaminant plume development under aerobic and anaerobic conditions in 2D bench-scale tank experiments.

    PubMed

    Ballarini, E; Beyer, C; Bauer, R D; Griebler, C; Bauer, S

    2014-06-01

    The influence of transverse mixing on competitive aerobic and anaerobic biodegradation of a hydrocarbon plume was investigated using a two-dimensional, bench-scale flow-through laboratory tank experiment. In the first part of the experiment aerobic degradation of increasing toluene concentrations was carried out by the aerobic strain Pseudomonas putida F1. Successively, ethylbenzene (injected as a mixture of unlabeled and fully deuterium-labeled isotopologues) substituted toluene; nitrate was added as additional electron acceptor and the anaerobic denitrifying strain Aromatoleum aromaticum EbN1 was inoculated to study competitive degradation under aerobic /anaerobic conditions. The spatial distribution of anaerobic degradation was resolved by measurements of compound-specific stable isotope fractionation induced by the anaerobic strain as well as compound concentrations. A fully transient numerical reactive transport model was employed and calibrated using measurements of electron donors, acceptors and isotope fractionation. The aerobic phases of the experiment were successfully reproduced using a double Monod kinetic growth model and assuming an initial homogeneous distribution of P. putida F1. Investigation of the competitive degradation phase shows that the observed isotopic pattern cannot be explained by transverse mixing driven biodegradation only, but also depends on the inoculation process of the anaerobic strain. Transient concentrations of electron acceptors and donors are well reproduced by the model, showing its ability to simulate transient competitive biodegradation. PMID:24122285

  3. Development of a novel kinetic model for the analysis of PAH biodegradation in the presence of lead and cadmium co-contaminants.

    PubMed

    Deary, Michael E; Ekumankama, Chinedu C; Cummings, Stephen P

    2016-04-15

    We report on the results of a 40 week study in which the biodegradation of 16 US EPA polycyclic aromatic hydrocarbons (PAHs) was followed in microcosms containing soil of high organic carbon content (11%) in the presence and absence of lead and cadmium co-contaminants. The total spiked PAH concentration was 2166mg/kg. Mercury amendment was also made to give an abiotic control. A novel kinetic model has been developed to explain the observed biphasic nature of PAH degradation. The model assumes that PAHs are distributed across soil phases of varying degrees of bioaccessibility. The results of the analysis suggest that overall percentage PAH loss is dependent on the respective rates at which the PAHs (a) are biodegraded by soil microorganisms in pore water and bioaccessible soil phases and (b) migrate from bioaccessible to non-bioaccessible soil phases. In addition, migration of PAHs to non-bioaccessible and non-Soxhlet-extractable soil phases associated with the humin pores gives rise to an apparent removal process. The presence of metal co-contaminants shows a concentration dependent inhibition of the biological degradation processes that results in a reduction in overall degradation. Lead appears to have a marginally greater inhibitory effect than cadmium. PMID:26785214

  4. Sequential anaerobic-aerobic biodegradation of 2,3,7,8-TCDD contaminated soil in the presence of CMC-coated nZVI and surfactant.

    PubMed

    Binh, Nguyen Duy; Imsapsangworn, Chaiyaporn; Kim Oanh, Nguyen Thi; Parkpian, Preeda; Karstensen, Kare; Giao, Pham Huy; DeLaune, Ronald D

    2016-01-01

    Enriched microorganisms in sediment collected from a dioxin-contaminated site in Vietnam (Bien Hoa airbase) were used for examining the effectiveness in biological treatment of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in soil. Four bio-treatments were investigated using a sequential anaerobic (17 weeks) followed by an aerobic (6 weeks) incubation. The maximum removal efficiency was approximately 60% even at an extremely low pH (approx. 3.6) condition. Surfactant Tween-80 was added to enhance the bioavailability of dioxin in two treatments, but it appeared to biostimulate methanogens rather than dechlorinators. As a result, methane production was the highest while the dioxin removal efficiency was the lowest, as compared with the other bio-treatments. Carboxymethylcellulose (CMC) coated on nanoscale zero valent iron (nZVI) surface used in two treatments could prevent the direct contact between bacterial cell surface and nZVI which prevented cell death and lysis, hence enhancing dioxin removal. The presence of CMC--_nZVI in bio-treatments gradually released H2 required for microbiological processes, but the amount used in the experiments were likely too high to maintain optimum H2 levels for biostimulating dechlorinators rather than methanogens. PMID:26179214

  5. Predicting kinetic model of biogas production and biodegradability organic materials: biogas production from vinasse at variation of COD/N ratio.

    PubMed

    Syaichurrozi, Iqbal; Budiyono; Sumardiono, Siswo

    2013-12-01

    The biogas fermentation of vinasse (TS 7.015 ± 0.007%) was investigated within a wide range of COD (Chemical Oxygen Demand)/N (Total Nitrogen) ratio. Urea (46% nitrogen content) was added into substrate to adjust COD/N ratio of 400/7-700/7. This study used batch anaerobic digesters in laboratory-scale that were operated at room temperature in 60 days. The results showed that control variable, 400/7, 500/7, 600/7, 700/7 generated total biogas of 107.45, 123.87, 133.82, 139.17, 113.27 mL/g COD and had the value of COD removal of 31.274 ± 0.887, 33.483 ± 0.266, 36.573 ± 1.689, 38.088 ± 0.872, 32.714 ± 0.881%, respectively. Variable with COD/N ratio of 600/7 was the best variable. In the kinetic model of biogas production, variable with COD/N of 600/7 had kinetic constant of A (mL/g COD), μ (mL/g COD.day), λ (days) of 132.580, 15.200, 0.213, respectively. The model equation of kinetic of biodegradability organic materials obtained was [formula in text]. PMID:24128402

  6. Kinetic and Spectroscopic Studies of Aerobic Copper(II)-Catalyzed Methoxylation of Arylboronic Esters and Insights into Aryl Transmetalation to Copper(II).

    PubMed

    King, Amanda E; Ryland, Bradford L; Brunold, Thomas C; Stahl, Shannon S

    2012-11-26

    We previously reported a preliminary mechanistic study of aerobic Cu(OAc)(2)-catalyzed methoxylation of 4-tolylboronic ester (King, et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to Cu(II) is the turnover-limiting step. In the present study, more-thorough kinetic and spectroscopic studies provide additional insights into transmetalation pathway and the identity of the Cu(II) catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions and their relative populations vary as a function of reaction time and acidity of the arylboronic ester, and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and (11)B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic Cu(II) species, mediated by a methoxide-bridge. PMID:23204631

  7. Low Probability of Initiating nirS Transcription Explains Observed Gas Kinetics and Growth of Bacteria Switching from Aerobic Respiration to Denitrification

    PubMed Central

    Hassan, Junaid; Bergaust, Linda L.; Wheat, I. David; Bakken, Lars R.

    2014-01-01

    In response to impending anoxic conditions, denitrifying bacteria sustain respiratory metabolism by producing enzymes for reducing nitrogen oxyanions/-oxides (NOx) to N2 (denitrification). Since denitrifying bacteria are non-fermentative, the initial production of denitrification proteome depends on energy from aerobic respiration. Thus, if a cell fails to synthesise a minimum of denitrification proteome before O2 is completely exhausted, it will be unable to produce it later due to energy-limitation. Such entrapment in anoxia is recently claimed to be a major phenomenon in batch cultures of the model organism Paracoccus denitrificans on the basis of measured e−-flow rates to O2 and NOx. Here we constructed a dynamic model and explicitly simulated actual kinetics of recruitment of the cells to denitrification to directly and more accurately estimate the recruited fraction (). Transcription of nirS is pivotal for denitrification, for it triggers a cascade of events leading to the synthesis of a full-fledged denitrification proteome. The model is based on the hypothesis that nirS has a low probability (, h−1) of initial transcription, but once initiated, the transcription is greatly enhanced through positive feedback by NO, resulting in the recruitment of the transcribing cell to denitrification. We assume that the recruitment is initiated as [O2] falls below a critical threshold and terminates (assuming energy-limitation) as [O2] exhausts. With  = 0.005 h−1, the model robustly simulates observed denitrification kinetics for a range of culture conditions. The resulting (fraction of the cells recruited to denitrification) falls within 0.038–0.161. In contrast, if the recruitment of the entire population is assumed, the simulated denitrification kinetics deviate grossly from those observed. The phenomenon can be understood as a ‘bet-hedging strategy’: switching to denitrification is a gain if anoxic spell lasts long but is a waste of energy if anoxia

  8. Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions.

    PubMed

    Lytou, Anastasia; Panagou, Efstathios Z; Nychas, George-John E

    2016-05-01

    The aim of this study was the development of a model to describe the growth kinetics of aerobic microbial population of chicken breast fillets marinated in pomegranate juice under isothermal and dynamic temperature conditions. Moreover, the effect of pomegranate juice on the extension of the shelf life of the product was investigated. Samples (10 g) of chicken breast fillets were immersed in marinades containing pomegranate juice for 3 h at 4 °C following storage under aerobic conditions at 4, 10, and 15 °C for 10 days. Total Viable Counts (TVC), Pseudomonas spp and lactic acid bacteria (LAB) were enumerated, in parallel with sensory assessment (odor and overall appearance) of marinated and non-marinated samples. The Baranyi model was fitted to the growth data of TVC to calculate the maximum specific growth rate (μmax) that was further modeled as a function of temperature using a square root-type model. The validation of the model was conducted under dynamic temperature conditions based on two fluctuating temperature scenarios with periodic changes from 6 to 13 °C. The shelf life was determined both mathematically and with sensory assessment and its temperature dependence was modeled by an Arrhenius type equation. Results showed that the μmax of TVC of marinated samples was significantly lower compared to control samples regardless temperature, while under dynamic temperature conditions the model satisfactorily predicted the growth of TVC in both control and marinated samples. The shelf-life of marinated samples was significantly extended compared to the control (5 days extension at 4 °C). The calculated activation energies (Ea), 82 and 52 kJ/mol for control and marinated samples, respectively, indicated higher temperature dependence of the shelf life of control samples compared to marinated ones. The present results indicated that pomegranate juice could be used as an alternative ingredient in marinades to prolong the shelf life of chicken. PMID:26742613

  9. [Degradation Characteristics of Three Aniline Compounds in Simulated Aerobic Sewage Treat System].

    PubMed

    Gu, Wen; Zhou, Lin-jun; Liu, Ji-ning; Chen, Guo-song; Shi, Li-li; Xu, Yan-hua

    2016-01-15

    The removal rates of 4-nitroaniline, 4-isopropyl aniline and 2-chloro-4-nitroaniline under different hydraulic retention time (HRT) were tested by employing a simulation method of aerobic biochemical sewage treatment technology in this study. The results showed that when HRT was 6 h, 12 h, and 24 h, the removal rates of dissolved organic carbon (DOC) were 70.2%, 80.3% and 88.3%, the removal rates of 4-nitroaniline were 48%, 64.7% and 75%; and the removal rates of 4-isopropyl aniline were 66%, 76% and 91%, respectively. It was concluded that increasing HRT could promote the removal rates of DOC and aniline chemicals. In contrast, 2-chloro-4-nitroaniline was difficult to be removed. The removal rates were less than 20% under all tested conditions. The kinetics analysis showed that the biodegradation of 4-nitroaniline, 4-isopropyl aniline and 2-chloro-4-nitroaniline in aerobic activated sewage (3 g x L(-1)) accorded with the first order kinetics and the regression coefficients were > 0.95. The half-life time of biodegradation was 6.01 h, 16.16 h, 123.75 h, respectively. In general, functional groups such as isopropyl had a positive effect on the biodegradation of aniline chemicals, whereas substituents such as nitro group and chlorine atom had an inhibitory effect. PMID:27078963

  10. Reaction progress kinetic analysis of a copper-catalyzed aerobic oxidative coupling reaction with N-phenyl tetrahydroisoquinoline.

    PubMed

    Scott, Martin; Sud, Abhishek; Boess, Esther; Klussmann, Martin

    2014-12-19

    The results from a kinetic investigation of a Cu-catalyzed oxidative coupling reaction between N-phenyl tetrahydroisoquinoline and a silyl enol ether using elemental oxygen as oxidant are presented. By using reaction progress kinetic analysis as an evaluation method for the obtained data, we discovered information regarding the reaction order of the substrates and catalysts. Based on this information and some additional experiments, a refined model for the initial oxidative activation of the amine substrate and the activation of the nucleophile by the catalyst was developed. The mechanistic information also helped to understand why silyl nucleophiles have previously failed in a related Cu-catalyzed reaction using tert-butyl hydroperoxide as oxidant and how to overcome this limitation. PMID:25203932

  11. 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. PMID:16153825

  12. Mechanism and kinetics of organic matter degradation based on particle structure variation during pig manure aerobic composting.

    PubMed

    Ge, Jinyi; Huang, Guangqun; Huang, Jing; Zeng, Jianfei; Han, Lujia

    2015-07-15

    Characterization of the dynamic structure of composting particles may facilitate our understanding of the mechanisms of organic matter degradation during pig manure-wheat straw aerobic composting. In this study, changes in the size, shape, pores, chemical compositions, and crystal structures of pig manure particles during composting were investigated. The results showed that the median diameter (D50) decreased exponentially, while the particle aspect ratio and sphericity were unchanged, suggesting that particles were degraded uniformly along different radial directions. Pores had a mean diameter of 15-30 μm and were elliptical. The particle porosity increased linearly mainly because of hemicellulose degradation. Furthermore, the influence of particle structure variation on the first order rate constant (k) of organic matter degradation was corrected, which may facilitate the optimization of operation conditions. The k value was proportional to the reciprocal of D50 according to the specific surface area of particles, and it decreased with increased porosity due to the stabilized chemical compositions and crystal structures of particles. However, the applicability of these data to other composting materials should be verified. PMID:25781372

  13. Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

    PubMed Central

    Mancini, Silvia A.; Ulrich, Ania C.; Lacrampe-Couloume, Georges; Sleep, Brent; Edwards, Elizabeth A.; Sherwood Lollar, Barbara

    2003-01-01

    Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors (ɛ) for carbon (range of −1.9 to −3.6‰) and hydrogen (range of −29 to −79‰) fractionation were observed during biodegradation of benzene under nitrate-reducing, sulfate-reducing, and methanogenic conditions. These differences are not related to differences in initial biomass or in rates of biodegradation. Carbon isotopic enrichment factors for anaerobic benzene biodegradation in this study are comparable to those previously published for aerobic benzene biodegradation. In contrast, hydrogen enrichment factors determined for anaerobic benzene biodegradation are significantly larger than those previously published for benzene biodegradation under aerobic conditions. A fundamental difference in the previously proposed initial step of aerobic versus proposed anaerobic biodegradation pathways may account for these differences in hydrogen isotopic fractionation. Potentially, C-H bond breakage in the initial step of the anaerobic benzene biodegradation pathway may account for the large fractionation observed compared to that in aerobic benzene biodegradation. Despite some differences in reported enrichment factors between cultures with different terminal-electron-accepting processes, carbon and hydrogen isotope analysis has the potential to provide direct evidence of anaerobic biodegradation of benzene in the field. PMID:12513995

  14. Fate of estrogen conjugate 17α-estradiol-3-sulfate in dairy wastewater: comparison of aerobic and anaerobic degradation and metabolite formation.

    PubMed

    Zheng, Wei; Zou, Yonghong; Li, Xiaolin; Machesky, Michael L

    2013-08-15

    Irrigation with concentrated animal feeding operation (CAFO) wastewater on croplands has been identified as a major source discharging steroid hormones into the environment. To assess the potential risks on this irrigation practice, the degradation kinetics and mechanisms of 17α-estradiol-3-sulfate were systematically investigated in aqueous solutions blended with dairy wastewater. Dissipation of the conjugated estrogen was dominated by biodegradation under both aerobic and anaerobic conditions. The half-lives for the biodegradation of 17α-estradiol-3-sulfate under aerobic and anaerobic conditions from 15 to 45°C varied from 1.70 to 415 d and 22.5 to 724 d, respectively. Under the same incubation conditions, anaerobic degradation rates of 17α-estradiol-3-sulfate were significantly less than aerobic degradation rates, suggesting that this hormone contaminant may accumulate in anaerobic or anoxic environments. Three degradation products were characterized under both aerobic and anaerobic conditions at 25°C, with estrone-3-sulfate and 17α-estradiol identified as primary metabolites and estrone identified as a secondary metabolite. However, the major degradation mechanisms under aerobic and anaerobic conditions were distinctly different. For aerobic degradation, oxidation at position C17 of the 17α-estradiol-3-sulfate ring was a major degradation mechanism. In contrast, deconjugation of the 17α-estradiol-3-sulfate thio-ester bond at position C3 was a major process initiating degradation under anaerobic conditions. PMID:23708453

  15. Oxygen uptake kinetics and maximal aerobic power are unaffected by inspiratory muscle training in healthy subjects where time to exhaustion is extended.

    PubMed

    Edwards, A M; Cooke, C B

    2004-10-01

    The aim of this study was to determine whether 4 weeks of inspiratory muscle training (IMT) would be accompanied by alteration in cardiopulmonary fitness as assessed through moderate intensity oxygen uptake (V(.)O(2)) kinetics and maximal aerobic power (V(.)O(2max)). Eighteen healthy males agreed to participate in the study [training group (Tra) n=10, control group (Con) n=8]. Measurements of spirometry and maximal static inspiratory mouth pressure ( PI(max)) were taken pre- and post-training in addition to: (1) an incremental test to volitional exhaustion, (2) three square-wave transitions from walking to running at a moderate intensity (80% ventilatory threshold) and (3) a maximal aerobic constant-load running test to volitional fatigue for the determination of time to exhaustion ( T(lim)). Training was performed using an inspiratory muscle trainer (Powerbreathe). There were no significant differences in spirometry either between the two groups or when comparing the post- to pre-training results within each group. Mean PI(max) increased significantly in Tra ( P<0.01) and showed a trend for improvement ( P<0.08) in Con. Post-training T(lim) was significantly extended in both Tra [232.4 (22.8) s and 242.8 (20.1) s] ( P<0.01) and Con [224.5 (19.6) and 233.5 (12.7) s] ( P<0.05). Post-training T(lim) was significantly extended in Tra compared to Con ( P<0.05). In conclusion, the most plausible explanation for the stability in V(.)O(2) kinetics and V(.)O(2max) following IMT is that it is due to insufficient whole-body stress to elicit either central or peripheral cardiopulmonary adaptation. The extension of post-training T(lim) suggests that IMT might be useful as a stratagem for producing greater volumes of endurance work at high ventilatory loads, which in turn could improve cardiopulmonary fitness. PMID:15322855

  16. Biodegradation of the High Explosive Hexanitrohexaazaiso-wurtzitane (CL-20)

    PubMed Central

    Karakaya, Pelin; Christodoulatos, Christos; Koutsospyros, Agamemnon; Balas, Wendy; Nicolich, Steve; Sidhoum, Mohammed

    2009-01-01

    The aerobic biodegradability of the high explosive CL-20 by activated sludge and the white rot fungus Phanerochaete chrysosporium has been investigated. Although activated sludge is not effective in degrading CL-20 directly, it can mineralize the alkaline hydrolysis products. Phanerochaete chrysosporium degrades CL-20 in the presence of supplementary carbon and nitrogen sources. Biodegradation studies were conducted using various nutrient media under diverse conditions. Variables included the CL-20 concentration; levels of carbon (as glycerol) and ammonium sulfate and yeast extract as sources of nitrogen. Cultures that received CL-20 at the time of inoculation transformed CL-20 completely under all nutrient conditions studied. When CL-20 was added to pre-grown cultures, degradation was limited. The extent of mineralization was monitored by the 14CO2 time evolution; up to 51% mineralization was achieved when the fungus was incubated with [14C]-CL-20. The kinetics of CL-20 biodegradation by Phanerochaete chrysosporium follows the logistic kinetic growth model. PMID:19440524

  17. Free [ADP] and aerobic muscle work follow at least second order kinetics in rat gastrocnemius in vivo.

    PubMed

    Cieslar, J H; Dobson, G P

    2000-03-01

    The relationship between free cytosolic [ADP] (and [P(i)]) and steady-state aerobic muscle work in rat gastrocnemius muscle in vivo using (31)P NMR was investigated. Anesthetized rats were ventilated and placed in a custom-built cradle fitted with a force transducer that could be placed into a 7-tesla NMR magnet. Muscle work was induced by supramaximal sciatic nerve stimulation that activated all fibers. Muscles were stimulated at 0.1, 0.2, 0.3, 0.4, 0.5, 0.8, 1.0, and 2.0 Hz until twitch force, phosphocreatine, and P(i) were unchanged between two consecutive spectra acquired in 4-min blocks (8-12 min). Parallel bench experiments were performed to measure total tissue glycogen, lactate, total creatine, and pyruvate in freeze-clamped muscles after 10 min of stimulation at each frequency. Up to 0.5 Hz, there was no significant change in muscle glycogen, lactate, and the lactate/pyruvate ratios between 8-12 min. At 0.8 Hz, there was a 17% fall in glycogen and a 65% rise in the muscle lactate with a concomitant fall in pH. Above this frequency, glycogen fell rapidly, lactate continued to rise, and ATP and pH declined. On the basis of these force and metabolic measurements, we estimated the maximal mitochondrial capacity (V(max)) to be 0.8 Hz. Free [ADP] was then calculated at each submaximal workload from measuring all the reactants of the creatine kinase equilibrium after adjusting the K'(CK) to the muscle temp (30 degrees C), pH, and pMg. We show that ADP (and P(i)) and tension-time integral follow a Hill relationship with at least a second order function. The K(0.5) values for free [ADP] and [P(i)] were 48 microM and 9 mM, respectively. Our data did not fit any form of the Michaelis-Menten equation. We therefore conclude that free cytosolic [ADP] and [P(i)] could potentially control steady-state oxidative phosphorylation in skeletal muscle in vivo. PMID:10692403

  18. Understanding the Differences in Molecular Conformation of Carbohydrate and Protein in Endosperm Tissues of Grains with Different Biodegradation Kinetics Using Advanced Synchrotron Technology

    SciTech Connect

    Yu, P.; Block, H; Doiron, K

    2009-01-01

    Conventional 'wet' chemical analyses rely heavily on the use of harsh chemicals and derivatization, thereby altering native seed structures leaving them unable to detect any original inherent structures within an intact tissue sample. A synchrotron is a giant particle accelerator that turns electrons into light (million times brighter than sunlight) which can be used to study the structure of materials at the molecular level. Synchrotron radiation-based Fourier transform IR microspectroscopy (SR-FTIRM) has been developed as a rapid, direct, non-destructive and bioanalytical technique. This technique, taking advantage of the brightness of synchrotron light and a small effective source size, is capable of exploring the molecular chemistry within the microstructures of a biological tissue without the destruction of inherent structures at ultraspatial resolutions within cellular dimensions. This is in contrast to traditional 'wet' chemical methods, which, during processing for analysis, often result in the destruction of the intrinsic structures of feeds. To date there has been very little application of this technique to the study of plant seed tissue in relation to nutrient utilization. The objective of this study was to use novel synchrotron radiation-based technology (SR-FTIRM) to identify the differences in the molecular chemistry and conformation of carbohydrate and protein in various plant seed endosperms within intact tissues at cellular and subcellular level from grains with different biodegradation kinetics. Barley grain (cv. Harrington) with a high rate (31.3%/h) and extent (78%), corn grain (cv. Pioneer) with a low rate (9.6%/h) and extent of (57%), and wheat grain (cv. AC Barrie) with an intermediate rate (23%/h) and extent (72%) of ruminal DM degradation were selected for evaluation. SR-FTIRM evaluations were performed at the National Synchrotron Light Source at the Brookhaven National Laboratory (Brookhaven, NY). These results suggest that SR-FTIRM plus

  19. Transcriptional kinetics of the cross-talk between the ortho-cleavage and TOL pathways of toluene biodegradation in Pseudomonas putida mt-2.

    PubMed

    Tsipa, Argyro; Koutinas, Michalis; Pistikopoulos, Efstratios N; Mantalaris, Athanasios

    2016-06-20

    The TOL plasmid promoters are activated by toluene leading to gene expression responsible for the degradation of the environmental signal. Benzoate is formed as an intermediate, activating the BenR protein of the chromosomal ortho-cleavage pathway that up-regulates the chromosomal PbenA promoter and the TOL Pm promoter resulting in cross-talk between the two networks. Herein, the transcriptional kinetics of the PbenR and PbenA promoters in conjunction with TOL promoters was monitored by real-time PCR during toluene biodegradation of different concentrations in batch cultures. The cross-talk between the two pathways was indicated by the simultaneous maximal expression of the Pm and PbenR promoters, as well as the transcriptional activation from PbenA occurring prior to PbenR, which indicates the potential up-regulation of PbenA by the TOL XylS protein. The repressory effect of toluene on Pr was evident for concentrations higher than 0.3mM suggesting a threshold value for restoring the promoter's activity, while all the other promoters followed a specific expression pattern, regardless of the initial inducer concentration. Induction of the system with higher toluene concentrations revealed an oscillatory behaviour of Pm, the expression of which remained at high levels until the late exponential phase, demonstrating a novel function of this network. PMID:27046069

  20. Enantiomeric fractionation as a tool for quantitative assessment of biodegradation: The case of metoprolol.

    PubMed

    Souchier, Marine; Benali-Raclot, Dalel; Casellas, Claude; Ingrand, Valérie; Chiron, Serge

    2016-05-15

    An efficient chiral liquid chromatography high resolution mass spectrometry method has been developed for the determination of metoprolol (MTP) and three of its major metabolites, namely O-desmethylmetoprolol (O-DMTP), α-hydroxymetoprolol (α-HMTP) and metoprolol acid (MTPA) in wastewater treatment plant (WWTP) influents and effluents. The optimized analytical method has been validated with good quality parameters including resolution >1.3 and method quantification limits down to the ng/L range except for MTPA. On the basis of this newly developed analytical method, the stereochemistry of MTP and its metabolites was studied over time in effluent/sediment biotic and sterile microcosms under dark and light conditions and in influents and effluents of 5 different WWTPs. MTP stereoselective degradation was exclusively observed under biotic conditions, confirming the specificity of enantiomeric fraction variations to biodegradation processes. MTP was always biotransformed into MTPA with a (S)-enantiomer enrichment. The results of enantiomeric enrichment pointed the way for a quantitative assessment of in situ biodegradation processes due to a good fit (R(2) > 0.98) of the aerobic MTP biodegradation to the Rayleigh dependency in all the biotic microcosms and in WWTPs because both MTP enantiomers followed the same biodegradation kinetic profiles. These results demonstrate that enantiomeric fractionation constitutes a very interesting quantitative indicator of MTP biodegradation in WWTPs and probably in the environment. PMID:26978718

  1. Evaluation of biodegradation-promoting additives for plastics.

    PubMed

    Selke, Susan; Auras, Rafael; Nguyen, Tuan Anh; Castro Aguirre, Edgar; Cheruvathur, Rijosh; Liu, Yan

    2015-03-17

    Biodegradation-promoting additives for polymers are increasingly being used around the world with the claim that they effectively render commercial polymers biodegradable. However, there is a lot of uncertainty about their effectiveness in degrading polymers in different environments. In this study, we evaluated the effect of biodegradation-promoting additives on the biodegradation of polyethylene (PE) and polyethylene terephthalate (PET). Biodegradation was evaluated in compost, anaerobic digestion, and soil burial environments. None of the five different additives tested significantly increased biodegradation in any of these environments. Thus, no evidence was found that these additives promote and/or enhance biodegradation of PE or PET polymers. So, anaerobic and aerobic biodegradation are not recommended as feasible disposal routes for nonbiodegradable plastics containing any of the five tested biodegradation-promoting additives. PMID:25723056

  2. Substrate interactions during aerobic biodegradation of benzene

    SciTech Connect

    Arvin, E.; Jensen, B.K.; Gundersen, A.T. )

    1989-12-01

    This study dealt with the interactions with benzene degradation of the following aromatic compounds in a mixed substrate: toluene, o-xylene, naphthalene, 1,4-dimethylnaphthalene, phenanthrene, and pyrrole. The experiment was performed as a factorial experiment with simple batch cultures. The effect of two different types of inocula was tested. One type of inoculum was grown on a mixture of aromatic hydrocarbons; the other was grown on a mixture of aromatic hydrocarbons and nitrogen-, sulfur-, and oxygen-containing aromatic compounds (NSO compounds), similar to some of the compounds identified in creosote waste. The culture grown on the aromatic hydrocarbons and NSO compounds was much less efficient in degrading benzene than the culture grown on only aromatic hydrocarbons. The experiments indicated that toluene- and o-xylene-degrading bacteria are also able to degrade benzene, whereas naphthalene-, 1,,4-dimethylnaphthalene-, and phenanthrene-degrading bacteria have no or very little benzene-degrading ability. Surprisingly, the stimulating effect of toluene and o-xylene was true only if the two compounds were present alone. In combination an antagonistic effect was observed, i.e., the combined effect was smaller than the sum from each of the compounds. The reason for this behavior has not been identified. Pyrrole strongly inhibited benzene degradation even at concentrations of about 100 to 200 micrograms/liter. Future studies will investigate the generality of these findings.

  3. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  4. Mechanisms, chemistry, and kinetics of anaerobic biodegradation of cis-dichloroethylene and vinyl chloride. 1998 annual progress report

    SciTech Connect

    McCarty, P.L.; Spormann, A.M.

    1998-06-01

    'The objectives of this study are to: (1) determine the biochemical pathways for reductive dehalogenation of cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC), including identification of the enzymes involved, (2) determine the chemical requirements, especially the type and quantity of electron donors needed by the microorganisms for reductive dehalogenation, and (3) evaluate the kinetics of the process with respect to the concentration of both the electron donors and the electron acceptors (cDCE and VC). Progress has been made under each of the three primary objectives. One manuscript related to the first objective has been published. Manuscripts related to the other two objectives have been submitted for publication. Findings related to the three objectives are summarized.'

  5. Kinetic models for the release of the anticancer drug doxorubicin from biodegradable polylactide/metal oxide-based hybrids.

    PubMed

    Mhlanga, Nikiwe; Ray, Suprakas Sinha

    2015-01-01

    For decades, studies on drug-release kinetics have been an important topic in the field of drug delivery because they provide important insights into the mechanism of drug release from carriers. In this work, polylactide (PLA), doxorubicin (DOX), and metal oxide (MO) (titanium dioxide, magnetic iron oxide, and zinc oxide) spheres were synthesised using the solvent-evaporation technique and were tested for sustained drug release. The efficacy of a dosage system is determined by its ability to deliver the drug at a sustained rate, afford an increased plasma half-life, a minimum exposure of toxic drugs to healthy cells and a high drug pay load. Mathematical models were used to elucidate the release mechanism of the drug from the spheres. The release fitted a zero-order model with a correlation coefficient in the range of 0.9878-0.9891 and the release mechanism followed an anomalous release, meaning drug release was afforded through both diffusion and the dissolution of PLA. Therefore, PLA/DOX/MO released the same amount of drug per unit time. Consequently, the potential for PLA use as a carrier was ascertained. PMID:25450549

  6. Bio-energy conversion performance, biodegradability, and kinetic analysis of different fruit residues during discontinuous anaerobic digestion.

    PubMed

    Zhao, Chen; Yan, Hu; Liu, Yan; Huang, Yan; Zhang, Ruihong; Chen, Chang; Liu, Guangqing

    2016-06-01

    Huge amounts of fruit residues are produced and abandoned annually. The high moisture and organic contents of these residues makes them a big problem to the environment. Conversely, they are a potential resource to the world. Anaerobic digestion is a good way to utilize these organic wastes. In this study, the biomethane conversion performances of a large number of fruit residues were determined and compared using batch anaerobic digestion, a reliable and easily accessible method. The results showed that some fruit residues containing high contents of lipids and carbohydrates, such as loquat peels and rambutan seeds, were well fit for anaerobic digestion. Contrarily, residues with high lignin content were strongly recommended not to be used as a single substrate for methane production. Multiple linear regression model was adopted to simulate the correlation between the organic component of these fruit residues and their experimental methane yield, through which the experimental methane yield could probably be predicted for any other fruit residues. Four kinetic models were used to predict the batch anaerobic digestion process of different fruit residues. It was shown that the modified Gompertz and Cone models were better fit for the fruit residues compared to the first-order and Fitzhugh models. The first findings of this study could provide useful reference and guidance for future studies regarding the applications and potential utilization of fruit residues. PMID:27039123

  7. Understanding the differences in molecular conformation of carbohydrate and protein in endosperm tissues of grains with different biodegradation kinetics using advanced synchrotron technology

    NASA Astrophysics Data System (ADS)

    Yu, P.; Block, H. C.; Doiron, K.

    2009-01-01

    Conventional "wet" chemical analyses rely heavily on the use of harsh chemicals and derivatization, thereby altering native seed structures leaving them unable to detect any original inherent structures within an intact tissue sample. A synchrotron is a giant particle accelerator that turns electrons into light (million times brighter than sunlight) which can be used to study the structure of materials at the molecular level. Synchrotron radiation-based Fourier transform IR microspectroscopy (SR-FTIRM) has been developed as a rapid, direct, non-destructive and bioanalytical technique. This technique, taking advantage of the brightness of synchrotron light and a small effective source size, is capable of exploring the molecular chemistry within the microstructures of a biological tissue without the destruction of inherent structures at ultraspatial resolutions within cellular dimensions. This is in contrast to traditional 'wet' chemical methods, which, during processing for analysis, often result in the destruction of the intrinsic structures of feeds. To date there has been very little application of this technique to the study of plant seed tissue in relation to nutrient utilization. The objective of this study was to use novel synchrotron radiation-based technology (SR-FTIRM) to identify the differences in the molecular chemistry and conformation of carbohydrate and protein in various plant seed endosperms within intact tissues at cellular and subcellular level from grains with different biodegradation kinetics. Barley grain (cv. Harrington) with a high rate (31.3%/h) and extent (78%), corn grain (cv. Pioneer) with a low rate (9.6%/h) and extent of (57%), and wheat grain (cv. AC Barrie) with an intermediate rate (23%/h) and extent (72%) of ruminal DM degradation were selected for evaluation. SR-FTIRM evaluations were performed at the National Synchrotron Light Source at the Brookhaven National Laboratory (Brookhaven, NY). The molecular structure spectral analysis

  8. Mechanisms, chemistry and kinetics of the anaerobic biodegradation of cis-dichloroethylene and vinyl chloride. First annual progress report, September 15, 1996--September 14, 1997

    SciTech Connect

    McCarty, P.L.; Spormann, A.

    1997-01-01

    'This three-year project is to study the anaerobic biological conversion of cis-1,2- dichloroethene (cDCE) and vinyl Chloride (VC) to ethene. The study is being conducted in three separate phases, the first to better understand the mechanisms involved in cDCE and VC biodegradation, the second to evaluate the chemistry of the processes involved, and the third, to study factors affecting reaction kinetics. Major funding is being provided by the US Department of Energy, but the DuPont Chemical Company has also agreed to directly cost-share on the project at a rate of $75,000 per year for the three year period. Tetrachloroethylene (PCE) and trichloroethylene (TCE) are solvents that are among the most widely occurring organic groundwater contaminants. The biological anaerobic reduction-of chlorinated aliphatic hydrocarbons (CAHs) such as PCE and TCE to cDCE and VC in groundwater was reported in the early 1980s. Further reduction of PCE and its intermediates to ethene was reported in 1989. Several pure cultures of anaerobic bacteria have been found to reductively dehalogenate PCE to cDCE Rates of reduction of PCE and TCE to cDCE are high and the need for electron donor addition for the reactions is small. However, the subsequent reduction of cDCE to VC, and then of VC to the harmless end product, ethene, is much slower and only recently has a pure culture been reported that is capable of reducing cDCE to VC or VC to ethene. There are numerous. reports of such conversions in mixed cultures. The reduction of cDCE and VC to ethene is where basic research is most needed and is the subject of this study.'

  9. Effects of hydraulic retention time on aerobic granulation and granule growth kinetics at steady state with a fast start-up strategy.

    PubMed

    Liu, Yong-Qiang; Zhang, Xing; Zhang, Rui; Liu, Wen-Tso; Tay, Joo-Hwa

    2016-01-01

    A hydraulic retention time (HRT) of 4, 6, and 8 h was employed, respectively, in three reactors to study the effects of HRT on granulation with a newly developed fast granulation strategy, i.e., a strategy by combining strong hydraulic selection pressure with high organic loading rate (OLR). Granules with clear boundary appeared within 24 h after reactor start-up and all reactors reached a pseudo steady state after 6-day operation. A 4-h HRT resulted in a relatively higher increasing rate in terms of granule size during granule development period, i.e., 208 μm day(-1), and the bigger granule size and the higher sludge volume index at the pseudo steady state. For HRT of 6 or 8 h, no obvious difference was observed. However, it was found that HRT influenced sludge retention time (SRT) and kinetics significantly. A HRT changing from 4 to 8 h led to an increased SRT from 3 to 21 days, a decreased observed specific biomass growth rate (μ obs) and an decreased observed biomass yield (Y obs) of stable granules from 0.37 to 0.062 days(-1), and 0.177 to 0.055 g MLVSS g(-1) COD, respectively. Both μ obs and Y obs had a linear relationship with the reciprocal of HRT. In addition, the great difference of microbial community between seed sludge, sludge retained in the reactors, and sludge washed out indicated a strong microbial selection for fast granulation within 24 h. However, during the granule development period from day 1 to 6, no more microbial selection was observed except an adjustment of microbial community. Little influence of HRT on microbial population in granular sludge indicated a minor role of HRT played for granulation with the fast start-up strategy adopted in this study. The results demonstrated that hydraulic selection pressure for granulation was mainly from short settling time, which led to strong microbial selection during the granulation period. Meanwhile, although HRT did not affect granulation with the fast start-up strategy, it played an

  10. DEVELOPMENT OF BIOPLUME 4 MODEL FOR FUELS AND CHLORINATED SOLVENT BIODEGRADATION

    EPA Science Inventory

    The Bioplume model has been in development and use for modeling biodegradation and natural attenuation since the late 1980s. Bioplume 1 focused on aerobic biodegradation of BTEX. Bioplume II simulated oxygen and hydrocarbons and simulated biodegradation using an instantaneous r...

  11. DEVELOPMENT OF BIOPLUME4 MODEL FOR FUELS AND CHLORINATED SOLVENT BIODEGRADATION

    EPA Science Inventory

    The Bioplume model has been in development and use for modeling biodegradation and natural attenuation since the late 80's. Bioplume I focused on aerobic biodegradation of BTEX. Bioplume II simulated oxygen and hydrocarbons and simulated biodegradation using an instantaneous re...

  12. Aerobic and anaerobic microbial degradation of crude (4-methylcyclohexyl)methanol in river sediments.

    PubMed

    Yuan, Li; Zhi, Wei; Liu, Yangsheng; Smiley, Elizabeth; Gallagher, Daniel; Chen, Xi; Dietrich, Andrea; Zhang, Husen

    2016-03-15

    Cyclohexane and some of its derivatives have been a major concern because of their significant adverse human health effects and widespread occurrence in the environment. The 2014 West Virginia chemical spill has raised public attention to (4-methylcyclohexyl)methanol (4-MCHM), one cyclohexane derivative, which is widely used in coal processing but largely ignored. In particular, the environmental fate of its primary components, cis- and trans-4-MCHM, remains largely unexplored. This study aimed to investigate the degradation kinetics and mineralization of cis- and trans-4-MCHM by sediment microorganisms under aerobic and anaerobic conditions. We found the removal of cis- and trans-4-MCHM was mainly attributed to biodegradation with little contribution from sorption. A nearly complete aerobic degradation of 4-MCHM occurred within 14 days, whereas the anaerobic degradation was reluctant with residual percentages of 62.6% of cis-4-MCHM and 85.0% of trans-4-MCHM after 16-day incubation. The cis-4-MCHM was degraded faster than the trans under both aerobic and anaerobic conditions, indicating an isomer-specific degradation could occur during the 4-MCHM degradation. Nitrate addition enhanced 4-MCHM mineralization by about 50% under both aerobic and anaerobic conditions. Both cis- and trans-4-MCHM fit well with the first-order kinetic model with respective degradation rates of 0.46-0.52 and 0.19-0.31 day(-)(1) under aerobic condition. Respective degradation rates of 0.041-0.095 and 0.013-0.052 day(-)(1) occurred under anaerobic condition. One bacterial strain capable of effectively degrading 4-MCHM isomers was isolated from river sediments and identified as Bacillus pumilus at the species level based on 16S rRNA gene sequence and 97% identity. Our findings will provide critical information for improving the prediction of the environmental fate of 4-MCHM and other cyclohexane derivatives with similar structure as well as enhancing the development of feasible treatment

  13. Photoacoustic methods for in vitro study of kinetics progesterone release from the biodegradation of polyhydroxybutyrate/polycaprolactone used as intravaginal devices

    SciTech Connect

    Souza Filho, N. E.; Mariucci, V. V. G.; Dias, G. S.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Bento, A. C.

    2013-09-30

    Intravaginal devices composed of polyhydroxybutyrate/polycaprolactone blends incorporating progesterone were used over eight days in crossbred cow ovariectomized, and then analyzed with photoacoustic methods, measuring the absorption spectra, thermal diffusivity, and inspecting its degradation by means of scanning electron microscopy. The characteristic time found for progesterone release was TR ∼ 53 h, and the typical time found for biodegradation was TB ∼ 30 h. Morphological analysis complements the study showing that release of progesterone and biodegradation of the blend occurs on sample surface.

  14. Photoacoustic methods for in vitro study of kinetics progesterone release from the biodegradation of polyhydroxybutyrate/polycaprolactone used as intravaginal devices

    NASA Astrophysics Data System (ADS)

    Souza Filho, N. E.; Mariucci, V. V. G.; Dias, G. S.; Szpak, W.; Miguez, P. H. P.; Madureira, E. H.; Medina, A. N.; Baesso, M. L.; Bento, A. C.

    2013-09-01

    Intravaginal devices composed of polyhydroxybutyrate/polycaprolactone blends incorporating progesterone were used over eight days in crossbred cow ovariectomized, and then analyzed with photoacoustic methods, measuring the absorption spectra, thermal diffusivity, and inspecting its degradation by means of scanning electron microscopy. The characteristic time found for progesterone release was TR ˜ 53 h, and the typical time found for biodegradation was TB ˜ 30 h. Morphological analysis complements the study showing that release of progesterone and biodegradation of the blend occurs on sample surface.

  15. Degradation of di(2-ethyl hexyl) phthalate by Fusarium culmorum: Kinetics, enzymatic activities and biodegradation pathway based on quantum chemical modelingpathway based on quantum chemical modeling.

    PubMed

    Ahuactzin-Pérez, Miriam; Tlecuitl-Beristain, Saúl; García-Dávila, Jorge; González-Pérez, Manuel; Gutiérrez-Ruíz, María Concepción; Sánchez, Carmen

    2016-10-01

    Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the manufacture of plastics, and it is an environmental contaminant. The specific growth rate (μ), maximum biomass (Xmax), biodegradation constant of DEHP (k), half-life (t1/2) of DEHP biodegradation and removal efficiency of DEHP, esterase and laccase specific activities, and enzymatic yield parameters were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000mg/L). The greatest μ and the largest Xmax occurred in media supplemented with 1000mg of DEHP/L. F. culmorum degraded 95% of the highest amount of DEHP tested (1000mg/L) within 60h of growth. The k and t1/2 were 0.024h(-1) and 28h, respectively, for both DEHP concentrations. The removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500mg/L, respectively. Much higher specific esterase activity than specific laccase activity was observed in all media tested. The compounds of biodegradation of DEHP were identified by GC-MS. A DEHP biodegradation pathway by F. culmorum was proposed on the basis of the intermolecular flow of electrons of the identified intermediate compounds using quantum chemical modeling. DEHP was fully metabolized by F. culmorum with butanediol as the final product. This fungus offers great potential in bioremediation of environments polluted with DEHP. PMID:27277206

  16. Mixing-controlled biodegradation in a toluene plume — Results from two-dimensional laboratory experiments

    NASA Astrophysics Data System (ADS)

    Bauer, Robert D.; Maloszewski, Piotr; Zhang, Yanchun; Meckenstock, Rainer U.; Griebler, Christian

    2008-02-01

    Various abiotic and biotic processes such as sorption, dilution, and degradation are known to affect the fate of organic contaminants, such as petroleum hydrocarbons in saturated porous media. Reactive transport modeling of such plumes indicates that the biodegradation of organic pollutants is, in many cases, controlled by mixing and therefore occurs locally at the plume's fringes, where electron donors and electron-acceptors mix. Herein, we aim to test whether this hypothesis can be verified by experimental results obtained from aerobic and anaerobic degradation experiments in two-dimensional sediment microcosms. Toluene was selected as a model compound for oxidizable contaminants. The two-dimensional microcosm was filled with quartz sand and operated under controlled flow conditions simulating a contaminant plume in otherwise uncontaminated groundwater. Aerobic degradation of toluene by Pseudomonas putida mt-2 reduced a continuous 8.7 mg L - 1 toluene concentration by 35% over a transport distance of 78 cm in 15.5 h. In comparison, under similar conditions Aromatoleum aromaticum strain EbN1 degraded 98% of the toluene infiltrated using nitrate (68.5 ± 6.2 mg L - 1 ) as electron acceptor. A major part of the biodegradation activity was located at the plume fringes and the slope of the electron-acceptor gradient was steeper during periods of active biodegradation. The distribution of toluene and the significant overlap of nitrate at the plume's fringe indicate that biokinetic and/or microscale transport processes may constitute additional limiting factors. Experimental data is corroborated with results from a reactive transport model using double Monod kinetics. The outcome of the study shows that in order to simulate degradation in contaminant plumes, detailed data sets are required to test the applicability of models. These will have to deal with the incorporation of existing parameters coding for substrate conversion kinetics and microbial growth.

  17. 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. PMID:26698270

  18. [Fluorescence fingerprint transformation of municipal wastewater caused by aerobic treatment].

    PubMed

    Wu, Jing; Cui, Shuo; Xie, Chao-bo; Cao, Zhi-ping; Chen, Mao-fu; Lü, Yan-li

    2011-12-01

    The conventional parameters such as COD and BOD only could represent information about total organic content. Fluorescence spectrum can display organic composition and it is unique for each sample, so it is referred as "fluorescence fingerprint". In the present study transformation of excitation-emission matrix of municipal wastewater with sewage as major components after aerobic treatment was investigated and then the zones of biodegradable and non-biodegradable organic matters were figured out: the fluorescence at excitation wavelength/emission wavelength of about 280/340 nm and 225/240 nm derived from biodegradable organics and those of the zone of excitation wavelength above 300 nm and the zone of excitation wavelength below 300 nm and emission wavelength above 400 nm were mainly related with non-biodegradable organics. The above-mentioned results indicated that fluorescence fingerprint could be used to evaluate the performance and instruct design and operation of aerobic systems. PMID:22295782

  19. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  20. Lab-scale experimental strategy for determining micropollutant partition coefficient and biodegradation constants in activated sludge.

    PubMed

    Pomiès, M; Choubert, J M; Wisniewski, C; Miège, C; Budzinski, H; Coquery, M

    2015-03-01

    The nitrifying/denitrifying activated sludge process removes several micropollutants from wastewater by sorption onto sludge and/or biodegradation. The objective of this paper is to propose and evaluate a lab-scale experimental strategy for the determination of partition coefficient and biodegradation constant for micropollutant with an objective of modelling their removal. Four pharmaceutical compounds (ibuprofen, atenolol, diclofenac and fluoxetine) covering a wide hydrophobicity range (log Kow from 0.16 to 4.51) were chosen. Dissolved and particulate concentrations were monitored for 4 days, inside two reactors working under aerobic and anoxic conditions, and under different substrate feed conditions (biodegradable carbon and nitrogen). We determined the mechanisms responsible for the removal of the target compounds: (i) ibuprofen was biodegraded, mainly under aerobic conditions by cometabolism with biodegradable carbon, whereas anoxic conditions suppressed biodegradation; (ii) atenolol was biodegraded under both aerobic and anoxic conditions (with a higher biodegradation rate under aerobic conditions), and cometabolism with biodegradable carbon was the main mechanism; (iii) diclofenac and fluoxetine were removed by sorption only. Finally, the abilities of our strategy were evaluated by testing the suitability of the parameters for simulating effluent concentrations and removal efficiency at a full-scale plant. PMID:25300180

  1. Biodegradable Polydepsipeptides

    PubMed Central

    Feng, Yakai; Guo, Jintang

    2009-01-01

    This paper reviews the synthesis, characterization, biodegradation and usage of bioresorbable polymers based on polydepsipeptides. The ring-opening polymerization of morpholine-2,5-dione derivatives using organic Sn and enzyme lipase is discussed. The dependence of the macroscopic properties of the block copolymers on their structure is also presented. Bioresorbable polymers based on polydepsipeptides could be used as biomaterials in drug controlled release, tissue engineering scaffolding and shape-memory materials. PMID:19333423

  2. BIODEGRADATION OF SEDIMENT-BOUND PAHS IN FIELD-CONTAMINATED SEDIMENT

    EPA Science Inventory

    The biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been reported to occur under aerobic, sulfate reducing, and denitrifying conditions. PAHs present in contaminated sites, however, are known for their persistence. Most published studies were conducted in systems wh...

  3. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion

    PubMed Central

    Yao, Yijun; Shen, Rui; Pennel, Kelly G.; Suuberg, Eric M.

    2013-01-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation showed that oxygen could play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration in biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law. PMID:24197079

  4. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion.

    PubMed

    Yao, Yijun; Shen, Rui; Pennel, Kelly G; Suuberg, Eric M

    2013-12-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation has shown that oxygen can play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration on biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law. PMID:24197079

  5. 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.

  6. Laundry greywater treatment using a fluidized bed reactor: a proposed model based on greywater biodegradation and residence time distribution approach.

    PubMed

    David, Pierre-luc; Bulteau, Gaëlle; Humeau, Philippe; Gérente, Claire; Andrès, Yves

    2013-01-01

    The increasing demand for water and the decrease in global water resources require research into alternative solutions to preserve them. The present study deals with the optimization of a treatment process, i.e. an aerobic fluidized bed reactor and the modelling of the degradation that takes place within it. The methodology employed is based on the hydrodynamics of the treatment process linked to the biodegradation kinetics of greywater coming from a washing machine. The residence time distribution (RTD) approach is selected for the hydrodynamic study. Biodegradation kinetics are quantified by respirometry and dissolved organic carbon (DOC) analysis on several mass quantities of colonized particles. RTD determinations show that there are no dysfunctions in the fluidized bed. Its hydrodynamic behaviour is similar to the one of a continuous stirred-tank reactor. A first-order reaction is obtained from the DOC biodegradation study. A model describing the degradation that takes place into the reactor is proposed, and from a sensitive study, the influence of the operating conditions on DOC biodegradation is defined. The theoretical results calculated from the first-order equation C(t) = 0.593 x C(0) x e(-kt) are compared with the experimental results and validated by a Student test. The value of the kinetic constant k is 0.011 h(-1) in the presence of a biomass carrier. The results highlight that it is possible to design a reactor in order to obtain a carbon content lower than 15 mg C L(-1) when the characteristics of raw greywater are known. PMID:24617067

  7. Bio-pretreatment of municipal solid waste prior to landfilling and its kinetics.

    PubMed

    Mahar, Rasool Bux; Liu, Jianguo; Li, Huan; Nie, Yongfeng

    2009-06-01

    The conventional landfilling does not promote sustainable waste management due to uncontrolled emissions which potentially degrade the environment. Pretreatment of municipal solid waste prior to landfilling significantly enhances waste stabilization, reduces the emissions and provides many advantages. Therefore, pretreatment of municipal solid waste methods were investigated. The major objectives of biological pretreatment are to degrade most easily degradable organic matters of MSW in a short duration under controlled conditions so as to produce desired quality for landfill. To investigate the suitable pretreatment method prior to landfilling for developing countries four pretreatment simulators were developed in the laboratory: (i) anaerobic simulator (R(1)), (ii) aerobic pretreatment simulator by natural convection of air (R(2)), (iii) aerobic pretreatment simulator by natural convection of air with leachate recirculation (R(3)) and (iv) forced aeration and leachate recirculation (R(4)). During the pretreatment organic matter, elemental composition, i.e., carbon, hydrogen, nitrogen and settlement were determined for bench scale experiments. A two-component kinetic model is proposed for the biodegradation of organic matter. Biodegradation kinetic constants were determined for readily and slowly degradable organic matter. The biodegradation of organic matter efficiency in terms of kinetic rate constants for the pretreatment simulators was observed as R(4) > R(3) > R(2) > R(1). Biodegradation rate constants for readily degradable matter in simulators R(4) and R(3) were 0.225 and 0.222 per day. R(3) and R(4) simulators were more effective in reducing methane emissions about 45% and 55%, respectively, as compared to anaerobic simulator R(1). Pretreatment of MSW, by natural convection of air with leachate recirculation R(3) is sustainable method to reduce the emissions and to stabilize the waste prior to landfilling. PMID:18923914

  8. Biodegradation of biodiesel fuels

    SciTech Connect

    Zhang, X.; Haws, R.; Wright, B.; Reese, D.; Moeller, G.; Peterson, C.

    1995-12-31

    Biodiesel fuel test substances Rape Ethyl Ester (REE), Rape Methyl Ester (RME), Neat Rape Oil (NR), Say Methyl Ester (SME), Soy Ethyl Ester (SEE), Neat Soy Oil (NS), and proportionate combinations of RME/diesel and REE/diesel were studied to test the biodegradability of the test substances in an aerobic aquatic environment using the EPA 560/6-82-003 Shake Flask Test Method. A concurrent analysis of Phillips D-2 Reference Diesel was also performed for comparison with a conventional fuel. The highest rates of percent CO{sub 2} evolution were seen in the esterified fuels, although no significant difference was noted between them. Ranges of percent CO{sub 2} evolution for esterified fuels were from 77% to 91%. The neat rape and neat soy oils exhibited 70% to 78% CO{sub 2} evolution. These rates were all significantly higher than those of the Phillips D-2 reference fuel which evolved from 7% to 26% of the organic carbon to CO{sub 2}. The test substances were examined for BOD{sub 5} and COD values as a relative measure of biodegradability. Water Accommodated Fraction (WAF) was experimentally derived and BOD{sub 5} and COD analyses were carried out with a diluted concentration at or below the WAF. The results of analysis at WAF were then converted to pure substance values. The pure substance BOD{sub 5} and COD values for test substances were then compared to a control substance, Phillips D-2 Reference fuel. No significant difference was noted for COD values between test substances and the control fuel. (p > 0.20). The D-2 control substance was significantly lower than all test substances for BCD, values at p << 0.01. RME was also significantly lower than REE (p < 0.05) and MS (p < 0.01) for BOD{sub 5} value.

  9. Biodegradation of benzene and a BTX mixture using immobilized activated sludge

    SciTech Connect

    Lodaya, M.P.

    1989-01-01

    Aerobic biodegradation of benzene was studied using activated sludge immobilized in calcium alginate (immobilization by entrapment), and also attached to a silica based catalyst support (immobilization by attachment). Hydrogen peroxide was used as a source of dissolved oxygen to eliminate physical removal of benzene due to aeration. Abiotic losses of benzene were accounted for. A recirculation reactor, run in both batch and continuous feed mode, was used to determine the kinetic parameters. The system response was examined by following changes in benzene concentration, flow rate, and biomass loading. The system was modeled mathematically and the kinetic parameters were determined. Biological removal of a mixture of benzene, toluene and o, m and p-xylene (BTX) was also studied. In a typical batch experiment starting with 100 ppm benzene, the substrate utilization rate (k{sub M}), when expressed per unit weight of dry catalyst, had a value of 0.4453 ppm/h/g dry beads for the alginate system, and 0.067 ppm/h/g dry beads for the celite catalyst carrier. Activated sludge was characterized for biodegradation of benzene. Isolations were done for unacclimated, acclimated and end run samples. About 67% of the isolates could be assigned to a genus. These were Bacillus, Microbacterium, Plesiomonas, Kurthia, Klebsiella, Lactobacillus, and Pseudomonas. From among the fifteen isolates found in the end run group, an isolate identified as Pseudomonas was established as a primary degrader of benzene.

  10. MONITORING POLYCHLORINATED BIPHENYLS (PCBS) BIODEGRADATION USING CONTINUOUS-FLOW ISOTOPE RATIO MASS SPECTROMETRY

    EPA Science Inventory

    Research has shown that polychlorinated biphenyls (PCBs) in some cases can be removed from the environment by biodegradation. Aerobic and anaerobic biological processes have been determined in previous research to be capable of degrading PCBs. During the aerobic and anaerobic d...

  11. Evaluation and Optimization of MTBE Biodegradation in Aquifers, Final Report

    SciTech Connect

    Legler, T; Balser, L; Koester, C; Wilson, W

    2004-02-13

    This study was focused on meeting the following objectives concerning the process of methyl tertiary butyl ether (MTBE) biodegradation, with the goal of optimizing this process in situ: 1. Assess whether intrinsic bioattenuation of MTBE is feasible under aerobic conditions across several contaminated sites. 2. Determine the effect of co-contaminants, specifically water-soluble gasoline components (most notably benzene, toluene, ethylbenzene and xylenes [BTEX]) on MTBE biodegradation. 3. Determine whether microbial and/or chemical factors contribute to different MTBE degradative activities. 4. Isolate and characterize MTBE-degrading microorganisms from sediments in which MTBE biodegradation was observed.

  12. 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. PMID:12491727

  13. Influence of Low Oxygen Tensions and Sorption to Sediment Black Carbon on Biodegradation of Pyrene ▿

    PubMed Central

    Ortega-Calvo, José-Julio; Gschwend, Philip M.

    2010-01-01

    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 14C-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 (Kom) of 14.1 μM and a dissolved pyrene half-saturation constant (Kpm) of 6 nM. The fluorescence of 14C-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 14CO2 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. PMID:20472733

  14. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  15. Elimination and fate of selected micro-organic pollutants in a full-scale anaerobic/anoxic/aerobic process combined with membrane bioreactor for municipal wastewater reclamation.

    PubMed

    Xue, Wenchao; Wu, Chunying; Xiao, Kang; Huang, Xia; Zhou, Haidong; Tsuno, Hiroshi; Tanaka, Hiroaki

    2010-12-01

    The occurrence and elimination of 19 micro-organic pollutants including endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) in a full-scale anaerobic/anoxic/aerobic-membrane bioreactor process was investigated. The investigated process achieved over 70% removal of the target EDCs and 50%-100% removal of most of the PPCPs, with influent concentration ranging from ng/L to μg/L. Three PPCPs, carbamazepine, diclofenac and sulpiride were not well removed, with the removal efficiency below 20%. A rough mass balance suggests that the targets were eliminated through sludge-adsorption and/or biodegradation, the former of which was particularly significant for the removal of hydrophobic compounds. The two-phase fate model was employed to describe the kinetics of sludge-adsorption and biodegradation. It was found that the fast sludge adsorption (indicated by mass-transfer rates greater than 10 for most compounds) is responsible for the rapid decline of the aqueous concentration of the targets in the first compartment of the treatment process (i.e. in the anaerobic tank). In contrast, the slow biodegradation proved to be the rate-determining step for the entire degradation process, and the rates are generally positively related to the dissolved oxygen level. On the other hand, this study showed that the removal rates of most targets can reach a quasi-plateau in 5 h under aerobic conditions, indicating that hydraulic retention time of ca. 5 h in aerobic tanks should be sufficient for the elimination of most targets. PMID:20723962

  16. Crystallization kinetics and morphology studies of biodegradable poly(butylene succinate-co-butylene adipate)/multi-walled carbon nanotubes nanocomposites.

    PubMed

    Qiu, Zhaobin; Zhu, Siyu; Yang, Wantai

    2009-08-01

    Biodegradable poly(butylene succinate-co-butylene adipate) (PBSA)/carboxyl-functionalized multi-walled carbon nanotubes (f-MWNTs) nanocomposites were prepared through solution casting method with different f-MWNTs contents ranging from 0.5 to 2 wt%. Scanning electron microscopic observations reveal a fine dispersion of f-MWNTs throughout the PBSA matrix. Effect of f-MWNTs on the crystallization behavior of PBSA was investigated in detail via various techniques and different crystallization conditions including nonisothermal crystallization at different cooling rates and isothermal crystallization at different crystallization temperatures in this work. For both nonisothermal and isothermal melt crystallization, the addition of f-MWNTs enhances the crystallization of PBSA apparently due to their heterogeneous nucleation effect. However, the crystal structure of PBSA does not change in the nanocomposites. Moreover, an attempt was made to study the effect of the presence of f-MWNTs and their contents on the nucleation activity and crystallizability of PBSA in the nanocomposites quantitatively. PMID:19928174

  17. Inflammatory cytokine kinetics to single bouts of acute moderate and intense aerobic exercise in women with active and inactive systemic lupus erythematosus.

    PubMed

    Perandini, L A; Sales-de-Oliveira, D; Mello, Sbv; Camara, N O; Benatti, F B; Lima, F R; Borba, E; Bonfa, E; Roschel, H; Sá-Pinto, A L; Gualano, B

    2015-01-01

    the end of exercise and at the 30th minute of recovery (P<0.05). The SLE(ACTIVE) group also showed higher levels of TNF-α at all time points when compared with the HC group (P<0.05), (except after 90 min, 120 min and 24 hours of recovery) (P>0.05). Importantly, the levels of all cytokine and soluble TNF receptors returned to baseline 24 hours after the end of acute exercise, irrespective of its intensity, in all three groups (P>0.05). This study demonstrated that both the single bouts of acute moderate and intense exercise induced mild and transient changes in cytokine levels in both SLE(INACTIVE) and SLE(ACTIVE) women, providing novel evidence that acute aerobic exercise does not trigger inflammation in patients with this disease. PMID:25825870

  18. Non-linear dynamics of stable carbon and hydrogen isotope signatures based on a biological kinetic model of aerobic enzymatic methane oxidation.

    PubMed

    Vavilin, Vasily A; Rytov, Sergey V; Shim, Natalia; Vogt, Carsten

    2016-06-01

    The non-linear dynamics of stable carbon and hydrogen isotope signatures during methane oxidation by the methanotrophic bacteria Methylosinus sporium strain 5 (NCIMB 11126) and Methylocaldum gracile strain 14 L (NCIMB 11912) under copper-rich (8.9 µM Cu(2+)), copper-limited (0.3 µM Cu(2+)) or copper-regular (1.1 µM Cu(2+)) conditions has been described mathematically. The model was calibrated by experimental data of methane quantities and carbon and hydrogen isotope signatures of methane measured previously in laboratory microcosms reported by Feisthauer et al. [ 1 ] M. gracile initially oxidizes methane by a particulate methane monooxygenase and assimilates formaldehyde via the ribulose monophosphate pathway, whereas M. sporium expresses a soluble methane monooxygenase under copper-limited conditions and uses the serine pathway for carbon assimilation. The model shows that during methane solubilization dominant carbon and hydrogen isotope fractionation occurs. An increase of biomass due to growth of methanotrophs causes an increase of particulate or soluble monooxygenase that, in turn, decreases soluble methane concentration intensifying methane solubilization. The specific maximum rate of methane oxidation υm was proved to be equal to 4.0 and 1.3 mM mM(-1) h(-1) for M. sporium under copper-rich and copper-limited conditions, respectively, and 0.5 mM mM(-1) h(-1) for M. gracile. The model shows that methane oxidation cannot be described by traditional first-order kinetics. The kinetic isotope fractionation ceases when methane concentrations decrease close to the threshold value. Applicability of the non-linear model was confirmed by dynamics of carbon isotope signature for carbon dioxide that was depleted and later enriched in (13)C. Contrasting to the common Rayleigh linear graph, the dynamic curves allow identifying inappropriate isotope data due to inaccurate substrate concentration analyses. The non-linear model pretty adequately described experimental

  19. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge.

    PubMed

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan

    2016-01-01

    Activated sludge contains complex microorganisms, which are highly effective biodegrading agents. In this study, the kinetics of biodegradation of cyclohexane carboxylic acid (CHCA) by an acclimated aerobic activated sludge were investigated. The results showed that after 180 days of acclimation, the activated sludge could steadily degrade >90% of the CHCA in 120 h. The degradation of CHCA by the acclimated activated sludge could be modeled using a first-order kinetics equation. The equations for the degradation kinetics for different initial CHCA concentrations were also obtained. The kinetics constant, kd, decreased with an increase in the CHCA concentration, indicating that, at high concentrations, CHCA had an inhibiting effect on the microorganisms in the activated sludge. The effects of pH on the degradation kinetics of CHCA were also investigated. The results showed that a pH of 10 afforded the highest degradation rate, indicating that basic conditions significantly promoted the degradation of CHCA. Moreover, it was found that the degradation efficiency for CHCA increased with an increase in temperature and concentration of dissolved oxygen under the experimental conditions. PMID:27191578

  20. Kinetic and inhibition studies for the aerobic cometabolism of 1,1,1-trichloroethane, 1,1-dichloroethylene, and 1,1-dichloroethane by a butane-grown mixed culture.

    PubMed

    Kim, Young; Arp, Daniel J; Semprini, Lewis

    2002-12-01

    Batch kinetic and inhibition studies were performed for the aerobic cometabolism of 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethylene (1,1-DCE), and 1,1-dichloroethane (1,1-DCA) by a butane-grown mixed culture. These chlorinated aliphatic hydrocarbons (CAHs) are often found together as cocontaminants in groundwater. The maximum degradation rates (k(max)) and half-saturation coefficients (K(s)) were determined in single compound kinetic tests. The highest k(max) was obtained for butane (2.6 micromol/mg TSS/h) followed by 1,1-DCE (1.3 micromol/mg TSS/h), 1,1-DCA (0.49 micromol/mg TSS/h), and 1,1,1-TCA (0.19 micromol/mg TSS/h), while the order of K(s) from the highest to lowest was 1,1-DCA (19 microM), butane (19 microM), 1,1,1-TCA (12 microM) and 1,1-DCE (1.5 microM). The inhibition types were determined using direct linear plots, while inhibition coefficients (K(ic) and K(iu)) were estimated by nonlinear least squares regression (NLSR) fits to the kinetic model of the identified inhibition type. Two different inhibition types were observed among the compounds. Competitive inhibition among CAHs was indicated from direct linear plots, and the CAHs also competitively inhibited butane utilization. 1,1-DCE was a stronger inhibitor than the other CAHs. Mixed inhibition of 1,1,1-TCA, 1,1-DCA, and 1,1-DCE transformations by butane was observed. Thus, both competitive and mixed inhibitions are important in cometabolism of CAHs by this butane culture. For competitive inhibition between CAHs, the ratio of the K(s) values was a reasonable indicator of competitive inhibition observed. Butane was a strong inhibitor of CAH transformation, having a much lower inhibition coefficient than the K(s) value of butane, while the CAHs were weak inhibitors of butane utilization. Model simulations of reactor systems where both the growth substrate and the CAHs are present indicate that reactor performance is significantly affected by inhibition type and inhibition coefficients. Thus

  1. Kinetic and microbiological characterization of aerobic granules performing partial nitritation of a low-strength wastewater at 10 °C.

    PubMed

    Reino, Clara; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián

    2016-09-15

    A granular airlift reactor enriched in ammonia oxidizing bacteria (AOB) was operated at 10 °C performing stable partial nitritation in the long-term. The reactor treated a synthetic low-strength influent during 250 days with an average nitrogen loading rate of 0.63 ± 0.06 g N L(-1) d(-1). Nitrate production was barely detected, being the average concentration in the effluent of 0.6 ± 0.3 mg N-NO3 L(-1). Furthermore, a suitable effluent for a subsequent reactor performing the anammox process was achieved. A maximum specific growth rate as high as 0.63 ± 0.05 d(-1) was determined by performing kinetic experiments with the granular sludge in a chemostat and fitting the results to the Monod model. Pyrosequencing analysis showed a high enrichment in AOB (41 and 65% of the population were identified as Nitrosomonas genus on day 98 and 233, respectively) and an effective repression of nitrite oxidizing bacteria in the long-term. Pyrosequencing analysis also identified the coexistence of nitrifying bacteria and heterotrophic psychrotolerant microorganisms in the granular sludge. Some psychrotolerant microorganisms are producers of cryoprotective extracellular polymeric substances that could explain the better survival of the whole consortia at cold temperatures. PMID:27262119

  2. PCB biodegradation: Laboratory studies transitioned into the field

    SciTech Connect

    Abramowicz, D.A.

    1993-12-31

    Two distinct bacterial systems are known to be involved in PCB biotransformations. Both aerobic PCB biodegradation (Oxidative attack) and anaerobic PCB dechlorination (reductive attack) have been demonstrated in the laboratory. These results have been successfully reproducted in recent experiments performed in aquatic sediments. In 1991, GE performed a large scale test of in situ aerobic PCB biodegradation in the Upper Hudson River. The experiments involved six sealed caissons (six feet in diameter) lowered into Aroclor 1242 contaminated sediments that had already undergone extensive anaerobic PCB dechlorination. Stimulation of indigenous PCB-degrading microorganisms resulted in >50% biodegradation over 10 weeks. A large scale stimulation of in situ anaerobic PCB dechlorination in Housatonic River sediments contaminated with untransformed Aroclor 1260 was initiated in 1992. The experiments similarly involve six sealed caissons (six feet in diameter) lowered into contaminated sediments to investigate new methods developed to accelerate PCB dechlorination in the field. Preliminary results from this ongoing field test will be discussed.

  3. Incorporation of aqueous reaction kinetics and biodegradation intoTOUGHREACT: Application of a multi-region model to hydrobiogeoChemicaltransport of denitrification and sulfate reduction

    SciTech Connect

    Xu, Tianfu

    2006-07-13

    The need to consider aqueous and sorption kinetics andmicrobiological processes arises in many subsurface problems. Ageneral-rate expression has been implemented into the TOUGHREACTsimulator, which considers multiple mechanisms (pathways) and includesmultiple product, Monod, and inhibition terms. This paper presents aformulation for incorporating kinetic rates among primary species intomass-balance equations. The space discretization used is based on aflexible integral finite difference approach that uses irregular griddingto model bio-geologic structures. A general multi-region model forhydrological transport interacted with microbiological and geochemicalprocesses is proposed. A 1-D reactive transport problem with kineticbiodegradation and sorption was used to test the enhanced simulator,which involves the processes that occur when a pulse of water containingNTA (nitrylotriacetate) and cobalt is injected into a column. The currentsimulation results agree very well with those obtained with othersimulators. The applicability of this general multi-region model wasvalidated by results from a published column experiment ofdenitrification and sulfate reduction. The matches with measured nitrateand sulfate concentrations were adjusted with the interficial areabetween mobile hydrological and immobile biological regions. Resultssuggest that TOUGHREACT can not only be a useful interpretative tool forbiogeochemical experiments, but also can produce insight into processesand parameters of microscopic diffusion and their interplay withbiogeochemical reactions. The geometric- and process-based multi-regionmodel may provide a framework for understanding field-scalehydrobiogeochemical heterogeneities and upscaling parameters.

  4. Biodegradation of polyethoxylated nonylphenols.

    PubMed

    Ruiz, Yassellis; Medina, Luis; Borusiak, Margarita; Ramos, Nairalith; Pinto, Gilberto; Valbuena, Oscar

    2013-01-01

    Polyethoxylated nonylphenols, with different ethoxylation degrees (NPEO x ), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native NPEO x and its derivatives. In this paper, the isolation of five bacterial strains, capable of using NPEO 15 , as unique carbon source, is described. The most efficient NPEO 15 degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% NPEO 15 medium. The NPEO 15 degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the NPEO 15 biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant (k) and half life time (τ) for this biotransformation were estimated to be 0.0072 h(-1) and 96.3 h, respectively. PMID:23936727

  5. Biodegradation of Polyethoxylated Nonylphenols

    PubMed Central

    Ruiz, Yassellis; Medina, Luis; Borusiak, Margarita; Ramos, Nairalith; Pinto, Gilberto; Valbuena, Oscar

    2013-01-01

    Polyethoxylated nonylphenols, with different ethoxylation degrees (NPEOx), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native NPEOx and its derivatives. In this paper, the isolation of five bacterial strains, capable of using NPEO15, as unique carbon source, is described. The most efficient NPEO15 degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% NPEO15 medium. The NPEO15 degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the NPEO15 biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant (k) and half life time (τ) for this biotransformation were estimated to be 0.0072 h−1 and 96.3 h, respectively. PMID:23936727

  6. Microbial kinetic model for the degradation of poorly soluble organic materials.

    PubMed

    Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

    2013-03-15

    A novel mechanistic model is presented that describes the aerobic biodegradation kinetics of soybean biodiesel and petroleum diesel in batch experiments. The model was built on the assumptions that biodegradation takes place in the aqueous phase according to Monod kinetics, and that the substrate dissolution kinetics at the oil/water interface is intrinsically fast compared to biodegradation kinetics. Further, due to the very low aqueous solubility of these compounds, the change in the substrate aqueous-phase concentration over time was assumed to approaches zero, and that substrate aqueous concentration remains close to the saturation level while the non-aqueous phase liquid (NAPL) is still significant. No former knowledge of the saturation substrate concentration (S(sat)) and the Monod half-saturation constant (K(s)) was required, as the term S(sat)/(K(s) + S(sat)) in the Monod equation remained constant during this phase. The n-alkanes C10-C24 of petroleum diesel were all utilized at a relatively constant actual specific utilization rate of 0.01-0.02 mg-alkane/mg-biomass-hr, while the fatty acid methyl esters (FAMEs) of biodiesel were utilized at actual specific rates significantly higher with increasing carbon chain length and lower with increasing number of double bonds. The results were found to be in agreement with kinetic, genetic, and metabolic evidence reported in the literature pertaining to microbial decay rates, uptake mechanisms, and the metabolic pathway by which these compounds are assimilated into microorganisms. The presented model can be applied, without major modifications, to estimate meaningful kinetic parameters from batch experiments, as well as near source zone field application. We suggest the estimated actual microbial specific utilization rate (kC) of such materials to be a better measure of the degradation rate when compared to the maximum specific utilization rate (k), which might be orders of magnitude higher than kC and might never

  7. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  8. APPLICATIONS FOR DNA PROBES IN BIODEGRADATION RESEARCH

    EPA Science Inventory

    The use of DNA:DNA hybridization technology in biodegradation studies is investigated. The rate constants for sediments exposed to synthetic oils could be calculated from the NAH(1+) genotypes and this approach would be useful in predicting the kinetics of aromatic hydrocarbon de...

  9. Preparation and crystallization kinetics of new structurally well-defined star-shaped biodegradable poly(L-lactide)s initiated with diverse natural sugar alcohols.

    PubMed

    Hao, Qinghui; Li, Faxue; Li, Qiaobo; Li, Yang; Jia, Lin; Yang, Jing; Fang, Qiang; Cao, Amin

    2005-01-01

    This study presents syntheses, structural characterization, and crystallization kinetic investigation of new structurally well-defined star-shaped poly(l-lactide)s (PLLAs). First, a series of new 3- to 6-arm star-shaped PLLAs were synthesized through SnOct(2) catalyzed ring-opening polymerization of (l)-lactide with natural sugar alcohols of glycerol, erythritol, xylitol, and sorbitol as the favorable initiators. Subsequently, their chemical structures were characterized by means of GPC, NMR, and viscometer with respect to the star-shaped structures, demonstrating the well-defined arm structures as evidenced on the g(1/2)/g' values, where g and g' denote the ratios of mean-square radius of gyration and intrinsic viscosity of a star-shaped polymer to those of a linear structural reference with similar absolute molecular weight. Furthermore, spherulite morphologies and growth rates were studied by a polarized microscopy (POM) for the synthesized star-shaped PLLAs with different molecular weights, and it was found that the more arms of a star-shaped PLLA finally resulted in a lower spherulite growth rate. With regard to the crystallization kinetics of these star-shaped PLLAs, isothermal and nonisothermal crystallization were examined by differential scanning calorimeter (DSC). It was found that Avrami exponent n values of isothermal crystallization were almost independent of the isothermal crystallization temperature T(c) for different series of star-shaped PLLAs. In contrast, the values of Avrami exponent n were observed to strongly depend on the star-shaped structures with different arms, implying their distinct nucleation mechanisms, and the more arms of a star-shaped PLLA led to a slower isothermal crystallization rate. On the basis of a modified Avrami equation, new light was shed on the nonisothermal crystallization kinetics for the star-shaped PLLAs, and the activation energies were found to vary from 146.86 kJ/mol for the linear PLLA EG-3 to 221.23 kJ/mol of

  10. Biodegradation of trichloroethylene and biomanipulation of aquifers. Technical report (Final)

    SciTech Connect

    Jaffe, P.R.; Taylor, S.W.; Baek, N.H.; Christopher, P.; Milly, D.

    1988-08-01

    Three distinct aspects of the biodegradation process in a porous media were addressed. The effect of the trichloroethylene(TCE) concentration on bacterial activity was investigated. The results showed that the dissolved-phase concentration directly affects the bacterial activity. For aerobic soils, LD50 for water concentrations ranged between 200-300 mg/l for CO/sub 2/ evolution, and 80 to 150 mg/l for dehydrogenase activity. The degradation of TCE and its intermediates by mixed cultures containing fermenters and methanogens was investigated. Results showed that fermenters play an important role in this process and that the degradation rate correlates with the methanogenic activity. It was shown that TCE can be degraded by these mixed cultures via 1,1-dichloroethylene to vinyl chloride, to chloroethane which is readily degradable. Kinetic rates were obtained for this degradation process and normalized with respect to the methane production. The effect of biomass production in porous media on the permeability and dispersivity was investigated. Experimental results showed that the permeability of a sandy media depends on the biomass if the biomass is less than 0.4 mg of organic carbon/cu cm, and becomes independent of the biomass for higher values. Changes in permeability and dispersivity as a function of the biofilm thickness were modeled successfully using a modified cut-and-random-rejoin-type model.

  11. 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.

  12. Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment.

    PubMed

    He, Xia; Zhang, Qian; Cooney, Michael J; Yan, Tao

    2015-07-01

    Fat, oil and, grease (FOG) deposits are one primary cause of sanitary sewer overflows (SSOs). While numerous studies have examined the formation of FOG deposits in sewer pipes, little is known about their biodegradation under sewer environments. In this study, FOG deposit biodegradation potential was determined by studying the biodegradation of calcium palmitate in laboratory under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Over 110 days of observation, calcium palmitate was biodegraded to CO2 under aerobic and nitrate-reducing conditions. An approximate 13 times higher CO2 production rate was observed under aerobic condition than under nitrate-reducing condition. Under sulfate-reducing condition, calcium palmitate was recalcitrant to biodegradation as evidenced by small reduction in sulfate. No evidence was found to support calcium palmitate degradation under methanogenic condition in the simulated sewer environment. Dominant microbial populations in the aerobic and nitrate-reducing microcosms were identified by Illumina seqeuncing, which may contain the capability to degrade calcium palmitate under both aerobic and nitrate-reducing conditions. Further study on these populations and their functional genes could shed more light on this microbial process and eventually help develop engineering solutions for SSOs control in the future. PMID:25715780

  13. Impact of metals on the biodegradation of organic pollutants.

    PubMed Central

    Sandrin, Todd R; Maier, Raina M

    2003-01-01

    Forty percent of hazardous waste sites in the United States are co-contaminated with organic and metal pollutants. Data from both aerobic and anaerobic systems demonstrate that biodegradation of the organic component can be reduced by metal toxicity. Metal bioavailability, determined primarily by medium composition/soil type and pH, governs the extent to which metals affect biodegradation. Failure to consider bioavailability rather than total metal likely accounts for much of the enormous variability among reports of inhibitory concentrations of metals. Metals appear to affect organic biodegradation through impacting both the physiology and ecology of organic degrading microorganisms. Recent approaches to increasing organic biodegradation in the presence of metals involve reduction of metal bioavailability and include the use of metal-resistant bacteria, treatment additives, and clay minerals. The addition of divalent cations and adjustment of pH are additional strategies currently under investigation. PMID:12826480

  14. Removal of oxytetracycline (OTC) in a synthetic pharmaceutical wastewater by a sequential anaerobic multichamber bed reactor (AMCBR)/completely stirred tank reactor (CSTR) system: biodegradation and inhibition kinetics.

    PubMed

    Sponza, Delia Teresa; Çelebi, Hakan

    2012-01-01

    An anaerobic multichamber bed reactor (AMCBR) was effective in removing both molasses-chemical oxygen demand (COD), and the antibiotic oxytetracycline (OTC). The maximum COD and OTC removals were 99% in sequential AMCBR/completely stirred tank reactor (CSTR) at an OTC concentration of 300 mg L(-1). 51%, 29% and 9% of the total volatile fatty acid (TVFA) was composed of acetic, propionic acid and butyric acids, respectively. The OTC loading rates at between 22.22 and 133.33 g OTC m(-3) d(-1) improved the hydrolysis of molasses-COD (k), the maximum specific utilization of molasses-COD (k(mh)) and the maximum specific utilization rate of TVFA (k(TVFA)). The direct effect of high OTC loadings (155.56 and -177.78 g OTC m(-3) d(-1)) on acidogens and methanogens were evaluated with Haldane inhibition kinetic. A significant decrease of the Haldane inhibition constant was indicative of increases in toxicity at increasing loading rates. PMID:22078970

  15. New Direction in Hydrogeochemical Transport Modeling: Incorporating Multiple Kinetic and Equilibrium Reaction Pathways

    SciTech Connect

    Steefel, C.I.

    2000-02-02

    At least two distinct kinds of hydrogeochemical models have evolved historically for use in analyzing contaminant transport, but each has important limitations. One kind, focusing on organic contaminants, treats biodegradation reactions as parts of relatively simple kinetic reaction networks with no or limited coupling to aqueous and surface complexation and mineral dissolution/precipitation reactions. A second kind, evolving out of the speciation and reaction path codes, is capable of handling a comprehensive suite of multicomponent complexation (aqueous and surface) and mineral precipitation and dissolution reactions, but has not been able to treat reaction networks characterized by partial redox disequilibrium and multiple kinetic pathways. More recently, various investigators have begun to consider biodegradation reactions in the context of comprehensive equilibrium and kinetic reaction networks (e.g. Hunter et al. 1998, Mayer 1999). Here we explore two examples of multiple equilibrium and kinetic reaction pathways using the reactive transport code GIMRT98 (Steefel, in prep.): (1) a computational example involving the generation of acid mine drainage due to oxidation of pyrite, and (2) a computational/field example where the rates of chlorinated VOC degradation are linked to the rates of major redox processes occurring in organic-rich wetland sediments overlying a contaminated aerobic aquifer.

  16. 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. PMID:27060247

  17. Management of aerobic vaginitis.

    PubMed

    Tempera, Gianna; Furneri, Pio Maria

    2010-01-01

    Aerobic vaginitis is a new nonclassifiable pathology that is neither specific vaginitis nor bacterial vaginosis. The diversity of this microbiological peculiarity could also explain several therapeutic failures when patients were treated for infections identified as bacterial vaginosis. The diagnosis 'aerobic vaginitis' is essentially based on microscopic examinations using a phase-contrast microscope (at ×400 magnification). The therapeutic choice for 'aerobic vaginitis' should take into consideration an antibiotic characterized by an intrinsic activity against the majority of bacteria of fecal origin, bactericidal effect and poor/absent interference with the vaginal microbiota. Regarding the therapy for aerobic vaginitis when antimicrobial agents are prescribed, not only the antimicrobial spectrum but also the presumed ecological disturbance on the anaerobic and aerobic vaginal and rectal microbiota should be taken into a consideration. Because of their very low impact on the vaginal microbiota, kanamycin or quinolones are to be considered a good choice for therapy. PMID:21051843

  18. Treatment of real industrial wastewater using the combined approach of advanced oxidation followed by aerobic oxidation.

    PubMed

    Ramteke, Lokeshkumar P; Gogate, Parag R

    2016-05-01

    Fenton oxidation and ultrasound-based pretreatment have been applied to improve the treatment of real industrial wastewater based on the use of biological oxidation. The effect of operating parameters such as Fe(2+) loading, contact time, initial pH, and hydrogen peroxide loading on the extent of chemical oxygen demand (COD) reduction and change in biochemical oxygen demand (BOD5)/COD ratio has been investigated. The optimum operating conditions established for the pretreatment were initial pH of 3.0, Fe(2+) loading of 2.0, and 2.5 g L(-1) for the US/Fenton/stirring and Fenton approach, respectively, and temperature of 25 °C with initial H2O2 loading of 1.5 g L(-1). The use of pretreatment resulted in a significant increase in the BOD5/COD ratio confirming the production of easily digestible intermediates. The effect of the type of sludge in the aerobic biodegradation was also investigated based on the use of primary activated sludge (PAS), modified activated sludge (MAS), and activated sludge (AS). Enhanced removal of the pollutants as well as higher biomass yield was observed for MAS as compared to PAS and AS. The use of US/Fenton/stirring pretreatment under the optimized conditions followed by biological oxidation using MAS resulted in maximum COD removal at 97.9 %. The required hydraulic retention time for the combined oxidation system was also significantly lower as compared to only biological oxidation operation. Kinetic studies revealed that the reduction in the COD followed a first-order kinetic model for advanced oxidation and pseudo first-order model for biodegradation. The study clearly established the utility of the combined technology for the effective treatment of real industrial wastewater. PMID:26846248

  19. Biodegradation of a mixture of chlorinated volatile organic compounds

    SciTech Connect

    Barnes, L.J.W.; Daniel, S.R.; Warner, J.B.

    1997-12-31

    A mixture of vinyl chloride, cis- and trans-1,2-dichloroethene (DCE), and 1,1-dichloroethane (DCA) was biodegraded at 20 C in static microcosms by a consortium of indigenous microorganisms from a Superfund site contaminated with a variety of halogenated compounds. Microcosms were set up with sand and groundwater from the site to model biodegradation under aquifer conditions and biodegradation with various amendments in batch cultures. Under aerobic conditions, vinyl chloride and cis- and trans-1,2-DCE biodegraded slowly, although there was no change in the concentration of 1,1-DCA. The biodegradation rates for all three chlorinated ethenes were greatly increased by enriching for methanotrophs in an aerobic environment, but this had little effect on the concentration of 1,1-DCA. DCA and the dichloroethene isomers decreased. The rate at which 1,1-DCA decreased from the VOC mixture correlated directly to the concentration of the chlorinated ethenes in that mixture. This relationship may be new in the literature and has important implications for the potential success for intrinsic bioremediation of sites contaminated with mixtures of chlorinated compounds.

  20. Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation.

    SciTech Connect

    Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

    1998-03-19

    Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems.

  1. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.C.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-04-01

    We have been able to accomplish the biodegradation of bituminous Illinois No. 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. We report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois No. 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite. 13 refs., 1 fig., 5 tabs.

  2. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... help to put toxic effects into perspective. (2) Definitions. (i) “Adaptation” is the process by which a... inoculum, including source, collection date, handling, storage and adaptation possibilities (i.e., that...

  3. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... help to put toxic effects into perspective. (2) Definitions. (i) “Adaptation” is the process by which a... inoculum, including source, collection date, handling, storage and adaptation possibilities (i.e., that...

  4. 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

  5. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface

    PubMed Central

    Kristensen, Andreas H.; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M.; Moldrup, Per

    2011-01-01

    Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O2 consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

  6. Teaching Aerobic Lifestyles: New Perspectives.

    ERIC Educational Resources Information Center

    Goodrick, G. Ken; Iammarino, Nicholas K.

    1982-01-01

    New approaches to teaching aerobic life-styles in secondary schools are suggested, focusing on three components: (1) the psychological benefits of aerobic activity; (2) alternative aerobic programs at nonschool locations; and (3) the development of an aerobics curriculum to help maintain an active life-style after graduation. (JN)

  7. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  8. Advances in our knowledge of biodegradation of hydrocarbons in reservoirs

    SciTech Connect

    Connan, J. )

    1993-09-01

    Biodegradation of hydrocarbons in reservoirs is a widespread phenomenon that is currently observed by petroleum organic geochemists in most sedimentary basins. This basic phenomenon is responsible for the occurrence of large, heavy oil deposits referred to as tar mats or tar belts. Biodegradation of crude oils takes place in reservoirs in which oil-eating bacteria may thrive. For this reason, effective and present biodegradation effects are not observed at subsurface temperatures higher than 70-80[degrees]C. Significant compositional changes, especially at a molecular level, still remain linked to the aerobic biodegradation of crude oils. Under favorable circumstances, both alkanes and aromatics are degraded, but when nutrients (N, P, O[sup 2]) are impoverished, aromatics seem to be preferentially removed. Biodegradation extends also to sulfur-bearing aromatics with a preferential removal of alkylated structures. Changes in molecular patterns are used to assess degrees of biodegradation in crude oils. The most bacterially resistant structures are polycyclic alkanes and aromatics. The in-reservoir biodegradation of hydrocarbons does not generate new hydrocarbons, e.g., 25-norhopanes as proposed by several authors. In fact, the selective removal of less resistant structures concentrates preexisting minor families that were not detected on the unaltered crude due to their low absolute concentration. Consequently, the molecular spectrum found in severely biodegraded oils may be considered as highly diagnostic of a part of the primary genetic spectrum of each oil. In outcrop samples, biodegradation is associated with other complementary phenomena such as photooxidation, oxidation, inspissation, evaporation, water washing, etc. Of particular importance are weathering effects linked to oxidation, which entail drastic compositional changes, with neogenesis of resins, asphaltenes, and even insoluble residue.

  9. Biodegradation of 4-chlorophenol by acclimated and unacclimated activated sludge-Evaluation of biokinetic coefficients

    SciTech Connect

    Sahinkaya, Erkan; Dilek, Filiz B. . E-mail: fdilek@metu.edu.tr

    2005-10-01

    Unacclimated and acclimated activated sludges were examined for their ability to degrade 4-CP (4-chlorophenol) in the presence and absence of a readily growing substrate using aerobic batch reactors. The effects of 4-CP on the {mu} (specific growth rate), COD removal efficiency, Y (yield coefficient), and q (specific substrate utilization rate) were investigated. It was observed that the toxicity of 4-CP on the culture decreased remarkably after acclimation. For example, the IC{sub 50} value on the basis of {mu} was found to increase from 130 to 218mg/L with the acclimation of the culture. Although an increase in 4-CP concentration up to 300mg/L has no adverse effect on the COD removal efficiency of the acclimated culture, a considerable decrease was observed in the case of an unacclimated culture. Although 4-CP removal was not observed with an unacclimated culture, almost complete removal was achieved with the acclimated culture, up to 300mg/L. The Haldane kinetic model adequately predicted the biodegradation of 4-CP and the kinetic constants obtained were q{sub m}=41.17mg/(gMLVSSh), K{sub s}=1.104mg/L, and K{sub i}=194.4mg/L. The degradation of 4-CP led to formation of 5-chloro-2-hydroxymuconic semialdehyde, which was further metabolized, indicating complete degradation of 4-CP via a meta-cleavage pathway.

  10. Long-term evolution of biodegradation and volatilization rates in a crude oil-contaminated aquifer

    USGS Publications Warehouse

    Chaplin, B.P.; Delin, G.N.; Baker, R.J.; Lahvis, M.A.

    2002-01-01

    Volatilization and subsequent biodegradation near the water Table make up a coupled natural attenuation pathway that results in significant mass loss of hydrocarbons. Rates of biodegradation and volatilization were documented twice 12 years apart at a crude-oil spill site near Bemidji, Minnesota. Biodegradation rates were determined by calibrating a gas transport model to O2, CO2, and CH4 gas-concentration data in the unsaturated zone. Reaction stoichiometry was assumed in converting O2 and CO2 gas-flux estimates to rates of aerobic biodegradation and CH4 gas-flux estimates to rates of methanogenesis. Model results indicate that the coupled pathway has resulted in significant hydrocarbon mass loss at the site, and it was estimated that approximately 10.52 kg/day were lost in 1985 and 1.99 kg/day in 1997. In 1985 3% of total volatile hydrocarbons diffusing from the floating oil were biodegraded in the lower 1 m of the unsaturated zone and increased to 52% by 1997. Rates of hydrocarbon biodegradation above the center of the floating oil were relatively stable from 1985 to 1997, as the primary metabolic pathway shifted from aerobic to methanogenic biodegradation. Model results indicate that in 1997 biodegradation under methanogenenic conditions represented approximately one-half of total hydrocarbon biodegradation in the lower 1 m of the unsaturated zone. Further downgradient, where substrate concentrations have greatly increased, total biodegradation rates increased by greater than an order of magnitude from 0.04 to 0.43 g/m2-day. It appears that volatilization is the primary mechanism for attenuation in early stages of plume evolution, while biodegradation dominates in later stages.

  11. Enhanced biodegradation by hydraulic heterogeneities in petroleum hydrocarbon plumes

    NASA Astrophysics Data System (ADS)

    Bauer, Robert D.; Rolle, Massimo; Bauer, Sebastian; Eberhardt, Christina; Grathwohl, Peter; Kolditz, Olaf; Meckenstock, Rainer U.; Griebler, Christian

    2009-02-01

    In case of dissolved electron donors and acceptors, natural attenuation of organic contaminant plumes in aquifers is governed by hydrodynamic mixing and microbial activity. Main objectives of this work were (i) to determine whether aerobic and anaerobic biodegradation in porous sediments is controlled by transverse dispersion, (ii) to elucidate the effect of sediment heterogeneity on mixing and biodegradation, and (iii) to search for degradation-limiting factors. Comparative experiments were conducted in two-dimensional sediment microcosms. Aerobic toluene and later ethylbenzene degradation by Pseudomonas putida strain F1 was initially followed in a plume developing from oxic to anoxic conditions and later under steady-state mixing-controlled conditions. Competitive anaerobic degradation was then initiated by introduction of the denitrifying strain Aromatoleum aromaticum EbN1. In homogeneous sand, aerobic toluene degradation was clearly controlled by dispersive mixing. Similarly, under denitrifying conditions, microbial activity was located at the plume's fringes. Sediment heterogeneity caused flow focusing and improved the mixing of reactants. Independent from the electron accepting process, net biodegradation was always higher in the heterogeneous setting with a calculated efficiency plus of 23-100% as compared to the homogeneous setup. Flow and reactive transport model simulations were performed in order to interpret and evaluate the experimental results.

  12. Biodegradation potential of photocatalyzed surfactant washwater.

    PubMed

    Maillacheruvu, K; Buck, L; Lee, E

    2001-01-01

    Enhanced release of hydrophobic compounds from a soil matrix can be achieved by use of soil-washing or soil-flushing using various surfactants. However, the surfactants used in achieving the desorption of organic contaminants may also cause a problem in subsequent removal/disposal of these contaminants. UV radiation in the presence of TiO2 as a pre-treatment step to achieve initial (or partial) breakdown of naphthalene and Sodium Dodecyl Sulfate (SDS) using batch experiments indicated that 56% to 88% naphthalene degradation occurred within 30 minutes to one hour. Preliminary results on the estimate of the batch aerobic biodegradation potential of photocatalyzed washwater containing naphthalene and SDS suggested that SDS was the major carbon and energy source for an activated sludge enrichment culture and an enrichment culture obtained from microorganisms at a contaminated site. Continuous-flow stirred tank reactors (CSTRs) with with a solids retention time (SRT) of 4 days were not effective, but an SRT of 8 days was successful in biodegrading the naphthalene and surfactant. These results indicated that photocatalytic treatment as a pre-treatment step followed by a biodegradation step may offer potential in cleaning up surfactant washwaters containing organic contaminants. PMID:11501312

  13. 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

  14. A coupling kinetics model for pollutant release and transport in the process of landfill settlement.

    PubMed

    Zhao, Ying; Xue, Qiang; Liu, Lei

    2012-10-01

    A coupling kinetics model is developed to simulate the release and transport of landfill leachate pollutants in a deformable municipal solid waste landfill by taking into account of landfill settlement, seepage of leachate water, hydrolyse of insoluble and degradable organic pollutants in solid phase, biodegradation of soluble and degradable organic pollutants in solid phase and aqueous one, growth of aerobic and anaerobic microorganism, and consumption of dissolved oxygen. The release and transport of organic pollutants and microorganisms in landfills in the process of landfill settlement was simulated by considering no hydraulic effect. Simulation results demonstrated that the interaction between landfill settlement and the release, transport and biodegradation of landfill leachate pollutants was significant. Porosity and saturated hydraulic conductivity were not constants because of the landfill settlement, which affected the release, transport and biodegradation of landfill leachate pollutants, and furthermore acted on the landfill settlement. The simulation results accorded with the practical situation, which preliminarily verified the reliability of the mathematical model and the numerical program in this paper. PMID:23202755

  15. A Coupling Kinetics Model for Pollutant Release and Transport in the Process of Landfill Settlement

    PubMed Central

    Zhao, Ying; Xue, Qiang; Liu, Lei

    2012-01-01

    A coupling kinetics model is developed to simulate the release and transport of landfill leachate pollutants in a deformable municipal solid waste landfill by taking into account of landfill settlement, seepage of leachate water, hydrolyse of insoluble and degradable organic pollutants in solid phase, biodegradation of soluble and degradable organic pollutants in solid phase and aqueous one, growth of aerobic and anaerobic microorganism, and consumption of dissolved oxygen. The release and transport of organic pollutants and microorganisms in landfills in the process of landfill settlement was simulated by considering no hydraulic effect. Simulation results demonstrated that the interaction between landfill settlement and the release, transport and biodegradation of landfill leachate pollutants was significant. Porosity and saturated hydraulic conductivity were not constants because of the landfill settlement, which affected the release, transport and biodegradation of landfill leachate pollutants, and furthermore acted on the landfill settlement. The simulation results accorded with the practical situation, which preliminarily verified the reliability of the mathematical model and the numerical program in this paper. PMID:23202755

  16. 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. PMID:24768259

  17. Anaerobic biodegradation of soybean biodiesel and diesel blends under sulfate-reducing conditions.

    PubMed

    Wu, Shuyun; Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

    2016-10-01

    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. PMID:27448319

  18. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.A.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-01-01

    Microbial degradation of coals to materials that are soluble in water has been a topic of intensive research for the last few years. The potential for economical recovery of low-grade coals, coupled with possibilities for further upgrading by microbial desulfurization or methanation has spurred intensive research at a number of laboratories. Until very recently, coal biodegradation has been accomplished using low-grade, naturally oxidized coals such as leonardiate, or coals subjected to pretreatment with oxidizing chemicals. The authors have been able to accomplish the biodegradation of bituminous Illinois 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. They report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite.

  19. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  20. IMPACTS OF IRON, NUTRIENTS, AND MINERAL FINES ON ANAEROBIC BIODEGRADATION OF CANOLA OIL IN FRESHWATER SEDIMENTS

    EPA Science Inventory

    Factors affecting anaerobic biodegradation kinetics of canola oil in freshwater sediments were investigated. An optimum dose of ferric hydroxide (10.5 g Fe(III)·kg-1 sediment) was found to stimulate anaerobic biodegradation of canola oil (18.6 g oil kg-1). ...

  1. Anaerobic biodegradation of surrogate naphthenic acids.

    PubMed

    Clothier, Lindsay N; Gieg, Lisa M

    2016-03-01

    Surface bitumen extraction from the Alberta's oil sands region generates large settling basins known as tailings ponds. The oil sands process-affected water (OSPW) stored in these ponds contain solid and residual bitumen-associated compounds including naphthenic acids (NAs) that can potentially be biodedgraded by indigenous tailings microorganisms. While the biodegradation of some NAs is known to occur under aerobic conditions, little is understood about anaerobic NA biodegradation even though tailings ponds are mainly anoxic. Here, we investigated the potential for anaerobic NA biodegradation by indigenous tailings microorganisms. Enrichment cultures were established from anoxic tailings that were amended with 5 single-ringed surrogate NAs or acid-extractable organics (AEO) from OSPW and incubated under nitrate-, sulfate-, iron-reducing, and methanogenic conditions. Surrogate NA depletion was observed under all anaerobic conditions tested to varying extents, correlating to losses in the respective electron acceptor (sulfate or nitrate) or the production of predicted products (Fe(II) or methane). Tailings-containing cultures incubated under the different electron-accepting conditions resulted in the enrichment and putative identification of microbial community members that may function in metabolizing surrogate NAs under the various anoxic conditions. In addition, more complex NAs (in the form of AEO) was observed to drive sulfate and iron reduction relative to controls. Overall, this study has shown that simple surrogate NAs can be biodegraded under a variety of anoxic conditions, a key first step in understanding the potential anaerobic metabolism of NAs in oil sands tailings ponds and other industrial wastewaters. PMID:26724449

  2. 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. PMID:17997031

  3. Characteristics of aerobic granulation at mesophilic temperatures in wastewater treatment.

    PubMed

    Cui, Fenghao; Park, Seyong; Kim, Moonil

    2014-01-01

    Compact and structurally stable aerobic granules were developed in a sequencing batch reactor (SBR) at mesophilic temperatures (35°C). The morphological, biological and chemical characteristics of the aerobic granulation were investigated and a theoretical granulation mechanism was proposed according to the results of the investigation. The mature aerobic granules had compact structure, small size (mean diameter of 0.24 mm), excellent settleability and diverse microbial structures, and were effective for the removal of organics and nitrification. The growth kinetics demonstrated that the biomass growth depended on coexistence and interactions between heterotrophs and autotrophs in the granules. The functions of heterotrophs and autotrophs created a compact and secure layer on the outside of the granules, protecting the inside sludge containing environmentally sensitive and slow growing microorganisms. The mechanism and the reactor performance may promise feasibility and efficiency for treating industry effluents at mesophilic temperatures using aerobic granulation. PMID:24211486

  4. 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...

  5. BIODEGRADATION OF METHYL TERT-BUTYL ETHER USING AN INNOVATIVE BIOMASS CONCENTRATOR REACTOR

    EPA Science Inventory

    The aerobic biodegradation of methyl tert-butyl ether (MTBE) was investigated using a pilot-scale Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d of Cincinnati dechlorinated tap water and an influent MTBE concentration o...

  6. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  7. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  8. Managing for Improved Aerobic Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic deterioration or spoilage of silage is the result of aerobic microorganisms metabolizing components of the silage using oxygen. In the almost 40 years over which these silage conferences have been held, we have come to recognize the typical pattern of aerobic microbial development by which s...

  9. KEY CONCEPTS IN BIODEGRADATION

    EPA Science Inventory

    This one hour segment of the course identifies the biological processes that degrade petroleum hydrocarbons and MTBE. It reviews the stoichiometry of hydrocarbon degradation by aerobic respiration, nitrate reduction, sulfate reduction, iron (III) reduction, and methanogenesis. ...

  10. DEVELOPMENT OF PREDICTIVE STRUCTURE-BIODEGRADATION RELATIONSHIP MODELS WITH THE USE OF RESPIROMETRICALLY GENERATED BIOKINETIC DATA

    EPA Science Inventory

    Biodegradation is an important mechanism determining the fate of chemicals is the aquatic environment. n this paper, experimental data, determined from electrolytic respirometry, for 27 compounds were analyzed using first order and Monod kinetics. dditional data from the literatu...

  11. DEVELOPMENT OF PREDICTIVE STRUCTURE-BIODEGRADATION RELATIONSHIP MODELS WITH THE USE OF RESPIROMETRICALLY GENERATED BIOKINETIC DATA

    EPA Science Inventory

    Biodegradation is an important mechanism determining the fate of chemicals in the aquatic environment. In this paper, experimental data, determined from electrolytic respirometry, for 27 compounds were analyzed using first order and Monod kinetics. Additional data from the lite...

  12. Mathematical models for biodegradation of chlorinated solvents. 1: Model framework

    SciTech Connect

    Zhang, X.; Banerji, S.; Bajpai, R.

    1996-12-31

    Complete mineralization of chlorinated solvents by microbial action has been demonstrated under aerobic as well as anaerobic conditions. In most of the cases, it is believed that the biodegradation is initiated by broad-specificity enzymes involved in metabolism of a primary substrate. Under aerobic conditions, some of the primary carbon and energy substrates are methane, propane, toluene, phenol, and ammonia; under anaerobic conditions, glucose, sucrose, acetate, propionate, isopropanol, methanol, and even natural organics act as the carbon source. Published biochemical studies suggest that the limiting step is often the initial part of the biodegradation pathway within the microbial system. For aerobic systems, the limiting step is thought to be the reaction catalyzed by mono- and dioxygenases which are induced by most primary substrates, although some constitutive strains have been reported. Other critical features of the biodegradative pathway include: (1) activity losses of critical enzyme(s) through the action of metabolic byproducts, (2) energetic needs of contaminant biodegradation which must be met by catabolism of the primary substrates, (3) changes in metabolic patterns in mixed cultures found in nature depending on the availability of electron acceptors, and (4) the associated accumulation and disappearance of metabolic intermediates. Often, the contaminant pool itself consists of several chlorinated solvents with separate and interactive biochemical needs. The existing models address some of the issues mentioned above. However, their ability to successfully predict biological fate of chlorinated solvents in nature is severely limited due to the existing mathematical models. Limiting step(s), inactivation of critical enzymes, recovery action, energetics, and a framework for multiple degradative pathways will be presented as a comprehensive model. 91 refs.

  13. Research approach to teaching groundwater biodegradation in karst aquifers

    USGS Publications Warehouse

    King, L.; Byl, T.; Painter, R.

    2006-01-01

    TSU in partnership with the USGS has conducted extensive research regarding biode??gradation of contaminants in karst aquifers. This research resulted in the development of a numerical approach to modeling biodegradation of contaminants in karst aquifers that is taught to environmental engineering students in several steps. First, environmental engineering students are taught chemical-reaction engineering principles relating to a wide variety of environmental fate and transport issues. Second, as part of TSU's engineering course curriculum, students use a non-ideal flow laboratory reactor system and run a tracer study to establish residence time distribution (RTD). Next, the students couple that formula to a first-order biodegradation rate and predict the removal of a biodegradable contaminant as a function of residence time. Following this, students are shown data collected from karst bedrock wells that suggest that karst aquifers are analogous to non-ideal flow reactors. The students are challenged to develop rates of biodegradation through lab studies and use their results to predict biodegradaton at an actual contaminated karst site. Field studies are also conducted to determine the accuracy of the students' predictions. This academic approach teaches biodegradation processes, rate-kinetic processes, hydraulic processes and numerical principles. The students are able to experience how chemical engineering principles can be applied to other situations, such as, modeling biodegradation of contaminants in karst aquifers. This paper provides background on the chemical engineering principles and karst issues used in the research-enhanced curriculum. ?? American Society for Engineering Education, 2006.

  14. [Biodegradation Coefficients of Typical Pollutants in the Plain Rivers Network].

    PubMed

    Feng, Shuai; Li, Xu-yongl; Deng, Jian-cai

    2016-05-15

    Biodegradation is a significant part of pollutant integrated degradation, the process rate of which is represented by the biodegradation coefficient. To investigate the biodegradation law of typical pollutants in the plain rivers network located in the upstream of the Lake Taihu, experiments were conducted in site in September 2015, one order kinetics model was used to measure the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus, and influencing factors of the biodegradation coefficients were also analyzed. The results showed that the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus were 0.008 3-0.126 4 d⁻¹, 0.002 1-0.213 8 d⁻¹, 0.002 1-0.090 5 d⁻¹ and 0.011 0- 0.152 8 d⁻¹, respectively. The influencing factors of the biodegradation coefficients for permanganate index were permanganate index and pH; those for ammonia were ammonia concentration and pH; those for total nitrogen were inorganic nitrogen concentration, total dissolved solid concentration and nitrite concentration; and those for total phosphorus were background concentration and pH. The research results were of important guiding significance for pollutants removal and ecological restoration of the plain rivers network located in the unstream of the Lake Taihu. PMID:27506025

  15. 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. PMID:15170523

  16. Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

    PubMed

    Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

    2016-02-15

    To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material. PMID:26790603

  17. Biodegradation of bisphenol-A in river sediment.

    PubMed

    Chang, Bea V; Yuan, Shaw Y; Chiou, Chung C

    2011-01-01

    This research investigated the aerobic and anaerobic degradation of bisphenol-A (BPA) in river sediment. With the addition of 250 μg g⁻¹ BPA, the percentages of BPA remaining in sediment from sites A, B, and C were 21.9 %, 3.5 % and 12.5 %, respectively, after 5 days of incubation under aerobic conditions; degradation was not significant after 140 days of incubation under anaerobic conditions. The aerobic degradation of BPA was enhanced by adding yeast extract (5 mg L⁻¹), sodium chloride (1 %), cellulose (0.96 mg L⁻¹), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L⁻¹), or surfactin (43 mg L⁻¹), with rhamnolipid yielding higher BPA degradation than the other additives. 2,4-bis (1,1-dimethyl ethyl) phenol, an intermediate product resulting from the aerobic degradation of BPA was accumulated in sediments. Of the bacterial strains isolated from the sediment, strains J1, J2, J3, and J4 expressed the best aerobic degrading ability. The highest BPA degradation rate was found in the sediment by the addition of strains J1, J2, J3, and J4 combined, whereas the sediment without the addition of the 4 strains had the lowest biodegradation rate. This research offers feasible methods for the removal of BPA in river sediment for bioremediation. PMID:21714622

  18. Aerobic degradation of olive mill wastewaters.

    PubMed

    Benitez, J; Beltran-Heredia, J; Torregrosa, J; Acero, J L; Cercas, V

    1997-02-01

    The degradation of olive mill wastewater by aerobic microorganisms has been investigated in a batch reactor, by conducting experiments where the initial concentration of organic matter, quantified by the chemical oxygen demand, and the initial biomass were varied. The evolution of the chemical oxygen demand, biomass and the total contents of phenolic and aromatic compounds were followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic constants are evaluated. This final predicted equation agrees well with all the experimental data. PMID:9077005

  19. 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. PMID:25721526

  20. Competitive substrate biodegradation during surfactant-enhanced remediation

    SciTech Connect

    Goudar, C.; Strevett, K.; Grego, J.

    1999-12-01

    The impact of synthetic surfactants on the aqueous phase biodegradation of benzene, toluene, and p-xylene (BTpX) was studied using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), and two nonionic surfactants, POE(20) sorbitan monooleate (T-maz-80) and octyl-phenolpoly(ethyleneoxy) ethanol (CA-620). Batch biodegradation experiments were performed to evaluate surfactant biodegradability using two different microbial cultures. Of the four surfactants used in this study, SDS and T-maz-80 were readily degraded by a microbial consortium obtained from an activated sludge treatment system, whereas only SDS was degraded by a microbial culture that was acclimated to BTpX. Biodegradation kinetic parameters associated with SDS and T-maz-80 degradation by the activated sludge consortium were estimated using respirometric data in conjunction with a nonlinear parameter estimation technique as {mu}{sub max} = 0.93 h{sup {minus}1}, K{sub s}= 96.18 mg/L and {mu}{sub max} = 0.41 h{sup {minus}1}, K{sub s} = 31.92 mg/L, respectively. When both BTpX and surfactant were present in the reactor along with BTpX-acclimated microorganisms, two distinct biodegradation patterns were seen. SDS was preferentially utilized inhibiting hydrocarbon biodegradation, whereas, the other three surfactants had no impact on BTpX biodegradation. None of the four surfactants were toxic to the microbial cultures used in this study. Readily biodegradable surfactants are not very effective for subsurface remediation applications as they are rapidly consumed, and also because of their potential inhibitory effects on intrinsic hydrocarbon biodegradation. This greatly increases treatment costs as surfactant recovery and reuse are adversely affected.

  1. Biodegradation of insecticide monocrotophos by Bacillus subtilis KPA-1, isolated from agriculture soils.

    PubMed

    Acharya, K P; Shilpkar, P; Shah, M C; Chellapandi, P

    2015-02-01

    Twenty bacterial strains, which are capable of degrading monocrotophos, were isolated from five soil samples collected from agriculture soils in India. The ability of the strains to mineralize monocrotophos was investigated under different culture conditions. A potential strain degrading monocrotophos was selected and named KPA-1. The strain was identified as a Bacillus subtilis on the basis of the results of its cellular morphology, physiological and chemotaxonomic characteristics, and phylogenetic conclusion of 16S ribosomal DNA (rDNA) gene sequences. Organophosphate hydrolase (opdA gene) involved in the initial biodegradation of monocrotophos in KPA-1 was quantitatively expressed, which was a constitutively expressed cytosolic enzyme. RT-qPCR data revealed that KPA-1 harboring opdA gene in an early stage was significantly downregulated from opdA gene in a degradation stage (1.5 fold more) with a p value of 0.0375 (p < 0.05). We have optimized culture conditions for the efficient degradation (94.2 %) of monocrotophos under aerobic conditions. Growth and degradation kinetic studies proved that KPA-1 was able to grow in minimal salt medium containing 1000 ppm monocrotophos as the only carbon source. Hence, KPA-1 culture has a great potential utility for the bioremediation of agriculture soils contaminated with organophosphorus pesticides, particularly monocrotophos. PMID:25424286

  2. Characterization and biodegradation of water-soluble biomarkers and organic carbon extracted from low temperature chars

    SciTech Connect

    Norwood, Matt J.; Louchouarn, Patrick; Kuo, Li-Jung; Harvey, Omar

    2013-03-16

    This study demonstrates that wildfires/biomass combustion may be an important source of labile pyrogenic water-soluble organic matter (Py-WSOM) to aquatic systems. Spectroscopic analysis (of the solid char and Py-WSOM) with Fourier transform infrared spectroscopy (FTIR) indicated that the Py-WSOM extracted from two low temperature chars (one wood, one grass) was dominated by polar moieties (-OH and C-O) derived from depolymerization and fragmentation of lignocellulose. Incubation experiments under aerobic conditions with unsterilized river water suggested that Py-WSOM and associated biomarkers may have turnover rates on the order of weeks to months, consistent with mixing and transport conditions of riverine systems. For example, pyrogenic dissolved organic carbon (Py-DOC) had a half-life of 30-40 days. Turnover rate for the combustion biomarkers was shorter, with levoglucosan and free lignin phenols having a half-life around 3-4 days and polymeric lignin components 13-14 days. The latter observations contradict earlier studies on the biodegradation of dissolved lignin and point to the need for re-assessment of lignin degradation kinetics in well-mixed riverine systems, particularly when such lignin components are derived from thermally altered plant material that may exist in a form more labile than that in highly processed riverine DOM.

  3. Performance characterization of a model bioreactor for the biodegradation of trichloroethylene by 'pseudomonas cepacia' g4

    SciTech Connect

    Folsom, B.R.; Chapman, P.J.

    1991-01-01

    Of the volatile organic chemicals present in common groundwater contaminants, trichloroethylene (TCE) is the one most commonly found. TCE has been shown to be biodegraded by axenic cultures of aerobic organisms. Pseudomonas cepacia G4 grown in chemostats with phenol demonstrated constant specific degradation rates for both phenol and trichloroethylene (TCE) over a range of dilution rates. Washout of cells from chemostats was evident at a dilution rate of 0.2/h at 28C. Increased phenol concentrations in the nutrient feed led to increased biomass production with constant specific degradation rates for both phenol and TCE. The addition of lactate to the phenol feed led to increased biomass production but lowered specific phenol and TCE degradation rates. The maximum potential for TCE degradation was about 1.1 g per day per g of cell protein. Cell growth and degradation kinetic parameters were used in the design of a recirculating bioreactor for TCE degradation. In the reactor, the total amount of TCE degraded increased as either reaction time or biomass was increased. TCE degradation was observed up to 300 microM TCE with no significant decreases in rates. On the average, the reactor was able to degrade 0.7 g of TCE per day per g of cell protein. The results demonstrate the feasibility of TCE bioremediation through the use of bioreactors. (Copyright (c) 1991, American Society for Microbiology.)

  4. Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

    PubMed

    Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

    2003-01-01

    This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates. PMID:12523845

  5. 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

  6. Editorial: Biodegradable Materials

    PubMed Central

    Schaschke, Carl; Audic, Jean-Luc

    2014-01-01

    This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment. PMID:25421242

  7. 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.

  8. Biodegradation of cresol isomers in anoxic aquifers.

    PubMed Central

    Smolenski, W J; Suflita, J M

    1987-01-01

    The biodegradation of o-, m-, and p-cresol was examined in material obtained from a shallow anaerobic alluvial sand aquifer. The cresol isomers were preferentially metabolized, with p-cresol being the most easily degraded. m-Cresol was more persistent than the para-isomer, and o-cresol persisted for over 90 days. Biodegradation of cresol isomers was favored under sulfate-reducing conditions (SRC) compared with that under methanogenic conditions (MC). Slurries that were acclimated to p-cresol metabolism transformed this substrate at 18 and 330 nmol/h per g (dry weight) for MC and SRC, respectively. Inhibition of electron flow to sulfate reduction with 2.0 mM molybdate reduced p-cresol metabolism in incubations containing sulfate. When methanogenesis was blocked with 5 mM bromoethanesulfonic acid in incubations lacking sulfate, p-cresol catabolism was retarded. Under SRC 3.4 mol of sulfate was consumed per mol of p-cresol metabolized. The addition of sulfate to methanogenic incubations stimulated p-cresol degradation. Simultaneous adaptation studies in combination with spectrophotometric and chromatographic analysis of metabolites indicated that p-cresol was oxidized under SRC to p-hydroxybenzoate via the corresponding alcohol and aldehyde. This series of reactions was inhibited under sulfate-limited or aerobic conditions. Therefore, the primary catabolic event for p-cresol decomposition under SRC appears to involve the hydroxylation of the aryl methyl group. PMID:3579279

  9. Biodegradation of glycol ethers in soil

    SciTech Connect

    Gonsior, S.J.; West, R.J.

    1995-08-01

    Because of the widespread use of glycol ethers in applications ranging from consumer products to use as chemical intermediates, there is a need to better understand the fate of these compounds in the environment. Soil biodegradation studies were conducted for three propylene glycol ethers: 1-methoxy-2-propanol, 1-phenoxy-2-propanol, and 1-methoxy-2-propanol acetate. The test compounds were labeled with carbon-14 at either the methoxy or phenoxy substituents. Biodegradation of the three compounds was observed in two sandy loam soils. The time required for disappearance of 50% of the test compounds ranged from < 1 d at 0.2 ppm (w/w) to <7 d at 107 ppm. Degradation rates were slower in a sandy soil, reflecting the lower concentration of microorganisms present. No significant accumulation of intermediate products was observed, and ultimate yields of {sup 14}CO{sub 2} were in the range of 40 to 65% of the initial concentration. Results indicated that the glycol ethers were degraded in a variety of soils under aerobic conditions.

  10. Morphological and biodegradability studies of Euphorbia latex modified polyester - Banana fiber composites

    NASA Astrophysics Data System (ADS)

    Rai, Bhuvneshwar; Kumar, Gulshan; Diwan, R. K.

    2016-05-01

    The composites of Banana fiber were prepared using polyester resin blended Euphorbia coagulum, morphology and the degree of rate of aerobic biodegradation of the prepared composites were studied. Polyester resin blended Euphorbia coagulum containing Banana fiber, Euphorbia coagulum and polyester resin taken in the ratio 40: 24: 36 was used for the study, which was the optimum composition of the composite reported in a previous study by the authors. In the biodegradability study cellulose has been used as positive reference material. Result shows that Euphorbia coagulum modified polyester - Banana fiber composites exhibited biodegradation to the extent of around 40%. The use of developed green composites may help in reducing the generation of non-biodegradable polymeric wastes.

  11. Biodegradable Materials for Nonwovens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Demand for nonwovens is increasing globally, particularly in the disposable products area. As the consumption of nonwoven products with short life increases, the burden on waste disposal also rises. In this context, biodegradable nonwovens become more important today and for the future. Several new ...

  12. Aerobic treatability of waste effluent from the leather finishing industry. Master's thesis

    SciTech Connect

    Vinger, J.A.

    1993-12-01

    The Seton Company supplies finished leather products exclusively for the automotive industry. In the process of finishing leather, two types of wastewaters are generated. The majority of the wastewater is composed of water-based paint residuals while the remainder is composed of solvent-based coating residuals. Aerobic treatability studies were conducted using water-based and solvent-based waste recirculatory waters from the Seton Company's Saxton, Pennsylvania processing plant. The specific objective was to determine the potential for using aerobic biological processes to biodegrade the industry's wastes and determine the potential for joint treatment at the local publicly owned treatment works (POTW). This study was accomplished in two phases. Phase I was conducted during the Spring Semester 1993 and consisted of aerobic respirometer tests of the raw wastes and mass balance analysis. The results of Phase I were published in a report to the Seton Company as Environmental Resources Research Institute project number 92C.II40R-1. Phase II was conducted during the Summer Semester 1993 and consisted of bench-scale reactor tests and additional aerobic respirometer tests. The aerobic respirometer batch tests and bench-scale reactor tests were used to assess the treatability of solvent-based and water-based wastewaters and determine the degree of biodegradability of the wastewaters. Mass balance calculations were made using measured characteristics.

  13. Effect and behaviour of different substrates in relation to the formation of aerobic granular sludge.

    PubMed

    Pronk, M; Abbas, B; Al-Zuhairy, S H K; Kraan, R; Kleerebezem, R; van Loosdrecht, M C M

    2015-06-01

    When aerobic granular sludge is applied for industrial wastewater treatment, different soluble substrates can be present. For stable granular sludge formation on volatile fatty acids (e.g. acetate), production of storage polymers under anaerobic feeding conditions has been shown to be important. This prevents direct aerobic growth on readily available chemical oxygen demand (COD), which is thought to result in unstable granule formation. Here, we investigate the impact of acetate, methanol, butanol, propanol, propionaldehyde, and valeraldehyde on granular sludge formation at 35 °C. Methanogenic archaea, growing on methanol, were present in the aerobic granular sludge system. Methanol was completely converted to methane and carbon dioxide by the methanogenic archaeum Methanomethylovorans uponensis during the 1-h anaerobic feeding period, despite the relative high dissolved oxygen concentration (3.5 mg O2 L(-1)) during the subsequent 2-h aeration period. Propionaldehyde and valeraldehyde were fully disproportionated anaerobically into their corresponding carboxylic acids and alcohols. The organic acids produced were converted to storage polymers, while the alcohols (produced and from influent) were absorbed onto the granular sludge matrix and converted aerobically. Our observations show that easy biodegradable substrates not converted anaerobically into storage polymers could lead to unstable granular sludge formation. However, when the easy biodegradable COD is absorbed in the granules and/or when the substrate is converted by relatively slow growing bacteria in the aerobic period, stable granulation can occur. PMID:25616527

  14. Influence of an aniline supplement on the stability of aerobic granular sludge.

    PubMed

    Dai, Yajie; Jiang, Yixin; Su, Haijia

    2015-10-01

    In order to evaluate the stability of aerobic granules in a toxic environment, this study discussed the influence of an aniline supplement on the properties and microbial community of aerobic granules. In the early stages of sequencing batch reactor (SBR) operation, an aniline supplement slightly affected the properties of the aerobic granules (strength, growth rate, SVI and so on). This effect was thereafter removed because of a change in the microbial community and the structure of aerobic granules: with the present of aniline, microbes with biodegradation ability appeared and gathered in the aerobic granules and the aerobic granules densified and settled faster as their SVI decreased to 35 mL/g and settling velocity increased to 41.56 m/h. When a synthetic waste water containing acetate as carbon source was used as influent, aniline (10-500 mg/L) could be degraded in 6 h, at a rate as high as 37.5 mg aniline/(L·h), with a removal rate in excess of 90%, while the effluent COD fell below 100 mg/L from the initial about 2000 mg/L. The aerobic granules cultured by acetate were compact, stable and resistant to aniline. PMID:26233584

  15. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  16. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  17. Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites.

    PubMed

    Silambarasan, Sivagnanam; Vangnai, Alisa S

    2016-01-25

    4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μmax, Ks and Ki, were determined to be 0.039 h(-1), 6.623 mg L(-1) and 25.57 mg L(-1), respectively using Haldane inhibition model, while the maximum biodegradation rate (Vmax) of 4-NA was at 0.541 mg L(-1) h(-1) and 0.551 mg L(-1) h(-1), following Michaelis-Menten and Hanes-Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment. PMID:26489917

  18. Anaerobic Biodegradation of Pristane by Nitrate Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Dawson, K. S.; Freeman, K. H.; Macalady, J. L.

    2007-12-01

    In recent sediments, microbial biodegradation provides a control on the long-term preservation of organic matter, through the preferential loss of certain biomolecules and the alteration and concentration of other more recalcitrant molecules. Biodegradation of hydrocarbons derived from membrane lipids, has been demonstrated by both aerobic and strictly anaerobic culturing experiments. The isoprenoid pristane, once considered stable under anaerobic conditions, is in fact degraded by a denitrifying microcosm (BREGNARD et al., 1997) and a methanogenic, sulphate-reducing enrichment culture (GROSSI, 2000). We recently demonstrated pristane biodegradation and accompanying loss of nitrate by an activated sludge isolate. The measured nitrate consumption accounts for a 7.1 +/- 0.4 mg loss of pristane, 4.74% of the initial substrate, in 181 days, assuming pristane conversion to CO2. We have characterized the microorganisms active in the biodegradation process, through the creation of a 16S rDNA clone library, as well as fluorescence in situ hybridization (FISH). Experiments are in progress to enrich cultures of sulfate reducing bacteria that utilize pristane as a sole carbon source and to characterize reaction mechanisms in pristane-oxidizing pathways.

  19. Biodegradation of oil refinery wastes under OPA and CERCLA

    SciTech Connect

    Gamblin, W.W.; Banipal, B.S.; Myers, J.M.

    1995-12-31

    Land treatment of oil refinery wastes has been used as a disposal method for decades. More recently, numerous laboratory studies have been performed attempting to quantify degradation rates of more toxic polycyclic aromatic hydrocarbon compounds (PAHs). This paper discusses the results of the fullscale aerobic biodegradation operations using land treatment at the Macmillan Ring-Free Oil refining facility. The tiered feasibility approach of evaluating biodegradation as a treatment method to achieve site-specific cleanup criteria, including pilot biodegradation operations, is discussed in an earlier paper. Analytical results of biodegradation indicate that degradation rates observed in the laboratory can be met and exceeded under field conditions and that site-specific cleanup criteria can be attained within a proposed project time. Also prevented are degradation rates and half-lives for PAHs for which cleanup criteria have been established. PAH degradation rates and half-life values are determined and compared with the laboratory degradation rates and half-life values which used similar oil refinery wastes by other in investigators (API 1987).

  20. Systematic approach for modeling tetrachloroethene biodegradation

    SciTech Connect

    Bagley, D.M.

    1998-11-01

    The anaerobic biodegradation of tetrachloroethene (PCE) is a reasonably well understood process. Specific organisms capable of using PCE as an electron acceptor for growth require the addition of an electron donor to remove PCE from contaminated ground waters. However, competition from other anaerobic microorganisms for added electron donor will influence the rate and completeness of PCE degradation. The approach developed here allows for the explicit modeling of PCE and byproduct biodegradation as a function of electron donor and byproduct concentrations, and the microbiological ecology of the system. The approach is general and can be easily modified for ready use with in situ ground-water models or ex situ reactor models. Simulations conducted with models developed from this approach show the sensitivity of PCE biodegradation to input parameter values, in particular initial biomass concentrations. Additionally, the dechlorination rate will be strongly influenced by the microbial ecology of the system. Finally, comparison with experimental acclimation results indicates that existing kinetic constants may not be generally applicable. Better techniques for measuring the biomass of specific organisms groups in mixed systems are required.

  1. Biodegradability of activated sludge organics under anaerobic conditions.

    PubMed

    Ekama, G A; Sötemann, S W; Wentzel, M C

    2007-01-01

    From an experimental and theoretical investigation of the continuity of activated sludge organic (COD) compounds along the link between the fully aerobic or N removal activated sludge and anaerobic digestion unit operations, it was found that the unbiodegradable particulate organics (i) originating from the influent wastewater and (ii) generated by the activated sludge endogenous process, as determined from response of the activated sludge system, are also unbiodegradable under anaerobic digestion conditions. This means that the activated sludge biodegradable organics that can be anaerobically digested can be calculated from the active fraction of the waste activated sludge based on the widely accepted ordinary heterotrophic organism (OHO) endogenous respiration/death regeneration rates and unbiodegradable fraction. This research shows that the mass balances based steady state and dynamic simulation activated sludge, aerobic digestion and anaerobic digestion models provide internally consistent and externally compatible elements that can be coupled to produce plant wide steady state and dynamic simulation WWTP models. PMID:17045327

  2. Anaerobic Biodegradation of Ethylene Glycol within Hydraulic Fracturing Fluid

    NASA Astrophysics Data System (ADS)

    Heyob, K. M.; Mouser, P. J.

    2014-12-01

    Ethylene glycol (EG) is a commonly used organic additive in hydraulic fracturing fluids used for shale gas recovery. Under aerobic conditions, this compound readily biodegrades to acetate and CO2 or is oxidized through the glycerate pathway. In the absence of oxygen, organisms within genera Desulfovibrio, Acetobacterium, and others can transform EG to acetaldehyde, a flammable and suspected carcinogenic compound. Acetaldehyde can then be enzymatically degraded to ethanol or acetate and CO2. However, little is known on how EG degrades in the presence of other organic additives, particularly under anaerobic conditions representative of deep groundwater aquifers. To better understand the fate and attenuation of glycols within hydraulic fracturing fluids we are assessing their biodegradation potential and pathways in batch anaerobic microcosm treatments. Crushed Berea sandstone was inoculated with groundwater and incubated with either EG or a synthetic fracturing fluid (SFF) containing EG formulations. We tracked changes in dissolved organic carbon (DOC), EG, and its transformation products over several months. Approximately 41% of bulk DOC in SFF is degraded within 21 days, with 58% DOC still remaining after 63 days. By comparison, this same SFF degrades by 70% within 25 days when inoculated with sediment-groundwater microbial communities, suggesting that bulk DOC degradation occurs at a slower rate and to a lesser extent with bedrock. Aerobic biodegradation of EG occurs rapidly (3-7 days); however anaerobic degradation of EG is much slower, requiring several weeks for substantial DOC loss to be observed. Ongoing experiments are tracking the degradation pathways of EG alone and in the presence of SFF, with preliminary data showing incomplete glycol transformation within the complex hydraulic fracturing fluid mixture. This research will help to elucidate rates, processes, and pathways for EG biodegradation and identify key microbial taxa involved in its degradation.

  3. 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. PMID:26774779

  4. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1997-01-01

    Provides school counselors with information on aerobic exercise (specifically running) and the psychological, behavioral, and physical benefits children obtained by participating in fitness programs. Recommends collaboration between school counselors and physical education teachers and gives a preliminary discussion of aerobic running and its…

  5. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1992-01-01

    Provides school counselors with information regarding aerobic exercise (specifically running), and the psychological, behavioral, and physical benefits children obtain by participating in fitness programs. Presents methods of collaboration between school counselors and physical education teachers. Offers preliminary discussion of aerobic running…

  6. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  7. Biodegradation of chemicals in a standardized test and in environmental conditions.

    PubMed

    Ahtiainen, Jukka; Aalto, Miia; Pessala, Piia

    2003-05-01

    The estimation of biodegradation rates is an important source of uncertainty in chemical risk assessment. The existing OECD tests for ready biodegradability have been developed to devise screening methods to determine whether a chemical is potentially easily biodegradable, rather than to predict the actual rate, of biodegradation in the environment. However, risk assessment needs degradation rates. In practice these rates are often estimated (default values) from ready biodegradability tests. These tests have many compromising arbitrary features compared to the situation in the real environment. One important difference is the concentration of the chemical. In wastewater treatment or in the environment many chemicals are present at ng l(-1) to microg l(-1) levels whereas in the tests the concentrations exceed 10-400 mg carbon per litre. These different concentrations of the chemical will lead to different growth kinetics and hence different biodegradation rates. At high concentrations the chemical, if it is degradable, can serve as a primary substrate and competent microorganisms will grow exponentially, resulting in a sigmoid biodegradation curve. At low environmental concentrations the chemical does not serve as a primary substrate, and therefore does not support significant growth of the degraders, and the substrate has a linear biodegradation rate. In this study the biodegradation rates of two reference chemicals, aniline and 4-chloroaniline, were compared in a standard method and in more realistic conditions at low concentrations, using 14C-labelled substances and different sources of inocula. Biomass evolution during the tests was monitored by adenosine triphosphate measurement and also on the basis of the residual 14C-activity in the particulate matter. The results partly support the thesis that low concentrations lead to different biodegradation kinetics compared to the concentrations used in the standard tests. Furthermore the biodegradation rates of the

  8. Fungal biodegradation of pomegranate ellagitannins.

    PubMed

    Ascacio-Valdés, Juan A; Buenrostro, José J; De la Cruz, Reynaldo; Sepúlveda, Leonardo; Aguilera, Antonio F; Prado, Arely; Contreras, Juan C; Rodríguez, Raúl; Aguilar, Cristóbal N

    2014-01-01

    Ellagitannins (ETs) are phytochemicals derived from secondary metabolism associated to defense system, with complex chemical structures, which have high participation during all stages of protection against microbial infection. In this study, we report the fungal biodegradation of a bioactive ET, named punicaline which was recovered and purified from pomegranate peels and used as carbon source in solid-state culture (SSC) using polyurethane as solid support. SSC was kinetically monitored during 36 h of incubation time. ETs and glycosides consumption were spectrophotometrically determined. Ellagic acid (EA) accumulation was analyzed by HPLC. Several enzymatic activities were assayed (cellulase, xylanase, β-glucosydase, polyphenoloxidase, tannase, and ET hydrolyzing activities). The consumption levels of ETs and glycosides were 66 and 40%, while EA accumulation reached 42.02 mg g(-1). A differential pattern of enzymatic activities was found; evidence from our studies suggests that the ET hydrolyzing activity is directly associated to EA accumulation, and production of this enzyme may represent the most critical step to successfully develop a bioprocess for production of an important bioactive compound, the EA. PMID:23564673

  9. Safe biodegradable fluorescent particles

    DOEpatents

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  10. Rapid identification of microorganisms for biodegradation of alkylphenols and alkylphenol ethercarboxylates

    SciTech Connect

    Hemming, B.; Williams, J.B.

    1995-12-31

    Alkylphenols, especially nonylphenol and octylphenol, are used in a wide variety of applications. These compounds, and alkylphenol ethercarboxylates, are also believed to be formed during the biodegradation of alkylphenol ethoxylates in activated sludge wastewater treatment systems. Microbe Inotech Laboratories has developed a rapid assay to identify the microorganisms present in activated sludge wastewater treatment systems (GC-FAME) and a screening assay to measure the biodegradation of compounds. These assays were used to show that alkylphenols and their corresponding ethercarboxylates were degraded aerobically even when these compounds were the sole carbon source.

  11. Mechanism of aerobic biological destabilisation of wool scour effluent emulsions.

    PubMed

    Poole, Andrew J; Cord-Ruwisch, Ralf; William Jones, F

    2005-07-01

    Wool scouring effluent is a highly polluted industrial wastewater in which the main pollutant, wool wax, is held in a stable oil-in-water emulsion by non-ionic detergent. The use of microbial action to cause emulsion destabilisation has been proposed as a new treatment strategy for this effluent stream. This strategy aims at improving aerobic treatment performance by physically removing the high-COD, slowly bio-degradable wool wax from the system without bio-degradation. The mechanism by which an aerobic-mixed culture destabilises the wool scouring effluent emulsion was investigated. Our results show that destabilisation is due to partial bio-degradation of both the scouring detergent and the wool wax. Cleavage of the wool wax esters was the first stage in wax degradation, when 40-50% of wax was de-emulsified. Over the same period, detergent degradation was low, at 7-21%. With further incubation, detergent degradation increased, aiding further breakdown of the emulsion. The degradation of the detergent, a nonylphenol ethoxylate, resulted in both a reduction in molar concentration (of up to 82%) and a shortening of the ethoxylate chain length. The latter reduced the hydrophile-lipophile balance (HLB) from 12 to approximately 7, thereby reducing the ability of the residual detergent to stabilise the emulsion. Analysis of the emulsified and de-emulsified wax fractions could not identify a group of compounds that were preferentially de-emulsified based on molecular weight or polarity. These findings will assist in using a de-emulsification strategy in both existing and new treatment systems in order to save on aeration costs and treatment times for biological treatment of this highly polluted wastewater. PMID:15979119

  12. Biodegradation-tunable mesoporous silica nanorods for controlled drug delivery.

    PubMed

    Park, Sung Bum; Joo, Young-Ho; Kim, Hyunryung; Ryu, WonHyoung; Park, Yong-il

    2015-05-01

    Mesoporous silica in the forms of micro- or nanoparticles showed great potentials in the field of controlled drug delivery. However, for precision control of drug release from mesoporous silica-based delivery systems, it is critical to control the rate of biodegradation. Thus, in this study, we demonstrate a simple and robust method to fabricate "biodegradation-tunable" mesoporous silica nanorods based on capillary wetting of anodic aluminum oxide (AAO) template with an aqueous alkoxide precursor solution. The porosity and nanostructure of silica nanorods were conveniently controlled by adjusting the water/alkoxide molar ratio of precursor solutions, heat-treatment temperature, and Na addition. The porosity and biodegradation kinetics of the fabricated mesoporous nanorods were analyzed using N2 adsorption/desorption isotherm, TGA, DTA, and XRD. Finally, the performance of the mesoporous silica nanorods as drug delivery carrier was demonstrated with initial burst and subsequent "zero-order" release of anti-cancer drug, doxorubicin. PMID:25746247

  13. Relative quantitative PCR to assess bacterial community dynamics during biodegradation of diesel and biodiesel fuels under various aeration conditions.

    PubMed

    Cyplik, Paweł; Schmidt, Marcin; Szulc, Alicja; Marecik, Roman; Lisiecki, Piotr; Heipieper, Hermann J; Owsianiak, Mikołaj; Vainshtein, Mikhail; Chrzanowski, Łukasz

    2011-03-01

    The degradation of diesel fuel, B20 blend and biodiesel in liquid cultures by a seven-member bacterial consortium was compared under conditions with full aeration or with limited aeration with nitrate added as main electron acceptor. Community dynamics was assessed employing real-time PCR and the ddCt method for relative quantification. Biodegradation rates increased with increasing biodiesel content, but were significantly reduced under conditions with nitrate. Despite large variations in biodegradation rates, magnitude changes in population numbers were typically observed only from zero to one order, regardless the type of fuel and electron acceptor. Only Comamonadaceae and Variovorax sp. distinctly preferred aerobic conditions, and during aerobic growth showed suppression as fuel contained more biodiesel. Thus, the consortium is relatively stable and most of the degraders can shift their metabolism from hydrocarbons to biodiesel. The stability of the consortium is of interest in the context of biodiesel-mediated biodegradation of petroleum hydrocarbons. PMID:21239170

  14. Soil aeration to achieve co-metabolic biodegradation of chlorinated solvents in the presence of inducer compounds

    SciTech Connect

    Eisenbeis, J.J.; Bourquin, A.W.

    1995-12-31

    A chemical distribution facility in Denver has been found to have soil and ground water contaminated with a wide variety of organic compounds, primarily toluene and chlorinated solvents, and their breakdown products. Since toluene and chlorobenzenes (both present at the site) have been shown to be inducers for an aerobic enzyme pathway that can degrade trichloroethene (TCE), 1,2-dichloroethene (DCE) and vinyl chloride, field and laboratory studies are being conducted to determine if cometabolic aerobic biodegradation of these and other compounds is occurring in soils that have been aerated with soil vapor extraction (SVE). Studies summarized in this paper include in situ respiration tests to estimate overall biodegradation rate in aerated soils within the influence of a SVE system, sampling to determine if in situ biodegradation of chlorinated volatile organic compounds in ground water has occurred, and a laboratory column study simulating bioventing of unremediated soils.

  15. Biodegradation of rhamnolipids in liquid cultures: effect of biosurfactant dissipation on diesel fuel/B20 blend biodegradation efficiency and bacterial community composition.

    PubMed

    Chrzanowski, Łukasz; Dziadas, Mariusz; Ławniczak, Łukasz; Cyplik, Paweł; Białas, Wojciech; Szulc, Alicja; Lisiecki, Piotr; Jeleń, Henryk

    2012-05-01

    Bacterial utilization of rhamnolipids during biosurfactant-supplemented biodegradation of diesel and B20 (20% biodiesel and 80% diesel v/v) fuels was evaluated under conditions with full aeration or with nitrate and nitrite as electron acceptors. Rhamnolipid-induced changes in community dynamics were assessed by employing real-time PCR and the ddCt method for relative quantification. The experiments with rhamnolipids at 150 mg/l, approx. double critical micelle concentration (CMC) and diesel oil confirmed that rhamnolipids were readily degraded by a soil-isolated consortium of hydrocarbon degraders in all samples, under both aerobic and nitrate-reducing conditions. The presence of rhamnolipids increased the dissipation rates for B20 constituents under aerobic conditions, but did not influence the biodegradation rate of pure diesel. No effect was observed under nitrate-reducing conditions. The biodegradation of rhamnolipids did not favor the growth of any specific consortium member, which proved that the employed biosurfactant did not interfere with the microbial equilibrium during diesel/biodiesel biodegradation. PMID:22366606

  16. Biodegradable Polymers for the Environment

    NASA Astrophysics Data System (ADS)

    Gross, Richard A.; Kalra, Bhanu

    2002-08-01

    Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Extraordinary progress has been made in the development of practical processes and products from polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products. In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet.

  17. Interaction of Polybrominated Diphenyl Ethers and Aerobic Granular Sludge: Biosorption and Microbial Degradation

    PubMed Central

    Ni, Shou-Qing; Cui, Qingjie; Zheng, Zhen

    2014-01-01

    As a new category of persistent organic pollutants, polybrominated diphenyl ethers (PBDEs) have become ubiquitous global environmental contaminants. No literature is available on the aerobic biotransformation of decabromodiphenyl ether (BDE-209). Herein, we investigated the interaction of PBDEs with aerobic granular sludge. The results show that the removal of BDE-209 from wastewater is mainly via biosorption onto aerobic granular sludge. The uptake capacity increased when temperature, contact time, and sludge dosage increased or solution pH dropped. Ionic strength had a negative influence on BDE-209 adsorption. The modified pseudo first-order kinetic model was appropriate to describe the adsorption kinetics. Microbial debromination of BDE-209 did not occur during the first 30 days of operation. Further study found that aerobic microbial degradation of 4,4′-dibromodiphenyl ether happened with the production of lower BDE congeners. PMID:25009812

  18. Evaluation of an aerobic treatment for olive mill wastewater detoxification.

    PubMed

    El Hajjouji, Houda; El Fels, Loubna; Pinelli, Eric; Barje, Farid; El Asli, Abdelghani; Merlina, Georges; Hafidi, Mohamed

    2014-01-01

    Olive mill wastewater (OMWW) is a by-product of the olive oil extraction industry. Its dumping creates severe environmental problems in the Mediterranean countries. The phytoxicity of OMWW is due to the phenolic substances and is evaluated through a genotoxicity method. An aerobic treatment of OMWW was conducted during 45 days. Different concentrations of raw and treated OMWW were tested using the Vicia faba micronuclei test. Results showed that raw OMWW induced significant micronuclei formation at 10% of OMWW dilution. At 20% of dilution, no mitosis was recorded. The 45 days aerobic treatment OMWW showed an important decrease in the genotoxicity and also in the toxicity that was observed at 10% and 20% OMWW dilution. This could be correlated with the biodegradation of 76% of the total phenols. Indeed, qualitative analysis by high performance liquid chromatography shows the disappearance of the majority of phenolic compounds after 45 days of treatment. This study was completed by an agricultural test with V. faba plant. Data showed significant growth yield of 36.3% and 29.9% after being irrigated with 5 and 10 t/ha, respectively. These results supported the positive role of aerobic treatment on OMWW and their capacity to ameliorate the agronomic potential of these effluents. PMID:25244133

  19. Partial nitritation and o-cresol removal with aerobic granular biomass in a continuous airlift reactor.

    PubMed

    Jemaat, Zulkifly; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián

    2014-01-01

    Several chemical industries produce wastewaters containing both, ammonium and phenolic compounds. As an alternative to treat this kind of complex industrial wastewaters, this study presents the simultaneous partial nitritation and o-cresol biodegradation in a continuous airlift reactor using aerobic granular biomass. An aerobic granular sludge was developed in the airlift reactor for treating a high-strength ammonium wastewater containing 950 ± 25 mg N-NH4(+) L(-1). Then, the airlift reactor was bioaugmented with a p-nitrophenol-degrading activated sludge and o-cresol was added progressively to the ammonium feed to achieve 100 mg L(-1). The results showed that stable partial nitritation and full biodegradation of o-cresol were simultaneously maintained obtaining a suitable effluent for a subsequent anammox reactor. Moreover, two o-cresol shock-load events with concentrations of 300 and 1000 mg L(-1) were applied to assess the capabilities of the system. Despite these shock load events, the partial nitritation process was kept stable and o-cresol was totally biodegraded. Fluorescence in situ hybridization technique was used to identify the heterotrophic bacteria related to o-cresol biodegradation and the ammonia oxidising bacteria along the granules. PMID:24140352

  20. Monitoring biodegradation of hydrocarbons by stable isotope fractionation

    NASA Astrophysics Data System (ADS)

    Dorer, Conrad; Fischer, Anko; Herrmann, Steffi; Richnow, Hans-Hermann; Vogt, Carsten

    2010-05-01

    In the last decade, several studies have demonstrated that stable isotope tools are highly applicable for monitoring anaerobic biodegradation processes. An important methodological approach is to characterize distinct degradation pathways with respect to the specific mechanism of C-H-bond cleavage and to quantify the extent of biodegradation by compound specific isotope analysis (CSIA). Here, enrichment factors (ɛbulk) needed for a CSIA field site approach must be determined in laboratory reference experiments. Recent research results from different laboratories have shown that single ɛbulk values for similar degradation pathways can be highly variable; thus, the use of two-dimensional compound specific isotope analysis (2D-CSIA) has been encouraged for characterizing biodegradation pathways more precisely. 2D-CSIA for hydrocarbons can be expressed by the slope of the linear regression for hydrogen versus carbon discrimination known as lambda ≈ ɛHbulk/ɛCbulk. We determined the carbon and hydrogen isotope fractionation for the biodegradation of benzene, toluene and xylenes by various reference cultures. Specific enzymatic reactions initiating different biodegradation pathways could be distinguished by 2D-CSIA. For the aerobic di- and monohydroxylation of the benzene ring, lambda values always lower than 9 were observed. Enrichment cultures degrading benzene anaerobically produced significant different values: lambda values between 8-19 were oberved for nitrate-reducing consortia, whereas sulfate-reducing and methanogenic consortia showed always lambda values greater than 20 [1,2]. The observed variations suggest that (i) aerobic benzene biodegradation can be distinguished from anaerobic biodegradation, and (ii) that more than a single mechanism seems to exist for the activation of benzene under anoxic conditions. lambda values for anaerobic toluene degradation initiated by the enzyme benzylsuccinate synthase (BSS) ranged from 4 to 41, tested with strains using

  1. Ozone/UV treatment to enhance biodegradation of surfactants in industrial wastewater. CRADA final report

    SciTech Connect

    Cline, J.E.; Sullivan, P.F.; Lovejoy, M.A.; Collier, J.; Adams, C.D.

    1996-10-01

    The new owners of a surfactant manufacturing plant wanted to triple production but were limited by the plant`s wastewater treatment capacity. Mass balance calculations indicated that little aerobic biodegradation was occurring in the plant`s wastewater treatment system. Literature reviews and laboratory tests confirmed that as much as 60% of the plant`s products might resist aerobic biodegradation. Overall chemical losses, both solid and aqueous, were estimated at 3.8% of theoretical. Organic loadings to the wastewater treatment system were 170 kg/d of which 50 kg/d reached the biological treatment system. Pollution prevention measures have allowed a > 20% increase in production levels with a > 30% decrease in effluent volume and no increase in discharge of chemical oxygen demand (COD). A new dissolved air flotation (DAF) system removes 70% of the organic loading. Sludge volumes are lower by an order of magnitude than with the clarifier/drum-filter process it replaced.

  2. Biodegradable polyoxalate and copolyoxalate particles for drug-delivery applications.

    PubMed

    Hong, Donghyun; Song, Byungjoo; Kim, Hyungmin; Kwon, Jungil; Khang, Gilson; Lee, Dongwon

    2011-11-01

    Polyoxalate and copolyoxalate were developed in the 1970s and have been used for biomedical applications such as suture coating purposes, owing to their biocompatibility and biodegradability. They are known to degrade into diols and oxalic acid, which are considered biocompatible. One of the advantages of oxalate-based polymer is the ease of control of physicochemical properties, such as biodegradability, crystallinity and mechanical strength. The composition and hydrophobicity of diols greatly influenced their hydrolytic stability and mechanical properties. Oxalate-based polymers have faster hydrolytic-degradation kinetics than the commercial biodegradable polymers, poly(lactide-co-glycolide) and poly(caprolactone). Recently, our group has developed fully biodegradable polymer drug carriers based on oxalate-based polymers that are composed of various diols. The hydrophobicity of the oxalate-based polymers allowed them to be formulated into nano- or micro-particles, which are suitable for targeting macrophages in inflammatory diseases. The nano- or micro-particles exhibited excellent cytotoxicity profiles and fast drug-release kinetics, suggesting great potential as drug-delivery systems for the treatment of acute inflammatory diseases. In this article, we discuss the synthesis and physicochemical properties of oxalate-based polymers which can be used as a drug-delivery vehicle for the treatment of inflammatory diseases. PMID:22826873

  3. Sequential anaerobic-aerobic degradation of indigenous PCBs in a contaminated soil matrix

    SciTech Connect

    Klasson, K.T.; Reeves, M.E.; Evans, B.S.; Dudley, C.A.

    1994-12-31

    Many industrial locations, including the US Department of Energy`s, have identified needs for treatment of polychlorinated biphenyl (PCB) wastes and remediation of PCB-contaminated sites. Biodegradation of PCBs is a potentially effective technology for the treatment of PCB-contaminated soils and sludges; however, a practicable remediation technology has not yet been demonstrated. A biological treatment technology is likely to consist of an anaerobic fermentation step in which PCB dechlorination takes place producing PCBs with fewer chlorines. These products are then more susceptible to aerobic mineralization. In laboratory experiments, soil slurry bioreactors inoculated with microorganisms extracted from PCB-contaminated sediments from the Hudson River and Woods Pond have been used to obtain anaerobic dechlorination of PCBs in soil slurry reactors. The anaerobic dechlorination was followed by qualitative estimation of the effect of aerobic fermentation of the dechlorination products based on literature data. The sequential anaerobic-(simulated) aerobic treatment constituted an improvement compared anaerobic treatment alone.

  4. Xenobiotic benzotriazoles--biodegradation under meso- and oligotrophic conditions as well as denitrifying, sulfate-reducing, and anaerobic conditions.

    PubMed

    Herzog, Bastian; Lemmer, Hilde; Huber, Bettina; Horn, Harald; Müller, Elisabeth

    2014-02-01

    The intensive use of benzotriazoles as corrosion inhibitors for various applications and their application in dishwasher detergents result in an almost omnipresence of benzotriazole (BTri), 4-methyl- and 5-methyl-benzotriazole (4-TTri and 5-TTri, respectively) in aquatic systems. This study aims on the evaluation of the biodegradation potential of activated sludge communities (ASCs) toward the three benzotriazoles regarding aerobic, anoxic, and anaerobic conditions and different nutrients. ASCs were taken from three wastewater treatment plants with different technologies, namely, a membrane bioreactor (MBR-MH), a conventional activated sludge plant CAS-E (intermittent nitrification/denitrification), and CAS-M (two-stage activated sludge treatment) and used for inoculation of biodegradation setups. All ASCs eliminated up to 30 mg L(-1) 5-TTri and BTri under aerobic conditions within 2-7 and 21-49 days, respectively, but not under anoxic or anaerobic conditions. 4-TTri was refractory at all conditions tested. Significant differences were observed for BTri biodegradation with non-acclimated ASCs from MBR-MH with 21 days, CAS-E with 41 days, and CAS-M with 49 days. Acclimated ASCs removed BTri within 7 days. Furthermore, different carbon and nitrogen concentrations revealed that nitrogen was implicitly required for biodegradation while carbon showed no such effect. The fastest biodegradation occurred for 5-TTri with no need for acclimatization, followed by BTri. BTri showed sludge-specific biodegradation patterns, but, after sludge acclimation, was removed with the same pattern, regardless of the sludge used. Under anaerobic conditions in the presence of different electron acceptors, none of the three compounds showed biological removal. Thus, presumably, aerobic biodegradation is the major removal mechanism in aquatic systems. PMID:24136576

  5. Biodegradation of phenol at high initial concentration by Alcaligenes faecalis.

    PubMed

    Jiang, Yan; Wen, Jianping; Bai, Jing; Jia, Xiaoqiang; Hu, Zongding

    2007-08-17

    Strain Alcaligenes faecalis was isolated and identified as a member of the genus Alcaligenes by using BIOLOG and 16S rDNA sequence analysis. The phenol biodegradation tests showed that the phenol-degrading potential of A. faecalis related greatly to the different physiological phases of inoculum. The maximum phenol degradation occurred at the late phase of the exponential growth stages, where 1600 mg L(-1) phenol was completely degraded within 76 h. A. faecalis secreted and accumulated a vast quantity of phenol hydroxylase in this physiological phase, which ensured that the cells could quickly utilize phenol as a sole carbon and energy source. In addition, the kinetic behavior of A. faecalis in batch cultures was also investigated over a wide range of initial phenol concentrations (0-1600 mg L(-1)) by using Haldane model. It was clear that the Haldane kinetic model adequately described the dynamic behavior of the phenol biodegradation by the strain of A. faecalis. PMID:17597295

  6. Biodegradable pectin/clay aerogels.

    PubMed

    Chen, Hong-Bing; Chiou, Bor-Sen; Wang, Yu-Zhong; Schiraldi, David A

    2013-03-13

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. The addition of multivalent cations (Ca(2+) and Al(3+)) resulted in apparent cross-linking of the polymer and enhancement of aerogel properties. The compressive properties increased as the solid contents (both pectin and clay) increased; moduli in the range of 0.04-114 MPa were obtained for materials with bulk densities ranging from 0.03 g/cm(3) to 0.19 g/cm(3), accompanied by microstructural changes from a lamellar structure to a cellular structure. Biodegradability of the aerogels was investigated by detecting CO2 release for 4 weeks in compost media. The results revealed that pectin aerogels possess higher biodegradation rates than wheat starch, which is often used as a standard for effective biodegradation. The addition of clay and multivalent cations surprisingly increased the biodegradation rates. PMID:23406325

  7. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    PubMed

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. PMID:26529301

  8. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    NASA Astrophysics Data System (ADS)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  9. Methods for Assessment of Biodegradability of Plastic Films in Soil †

    PubMed Central

    Yabannavar, Asha V.; Bartha, Richard

    1994-01-01

    Traditional and novel techniques were tested and compared for their usefulness in evaluating biodegrad-ability claims made for newly formulated “degradable” plastic film products. Photosensitized polyethylene (PE), starch-PE, extensively plasticized polyvinyl chloride (PVC), and polypropylene (PP) films were incorporated into aerobic soil. Biodegradation was measured for 3 months under generally favorable conditions. Carbon dioxide evolution, residual weight recovery, and loss of tensile strength measurements were supplemented, for some films, by gas chromatographic measurements of plasticizer loss and gel permeation chromatographic (GPC) measurement of polymer molecular size distribution. Six- and 12-week sunlight exposures of photosensitized PE films resulted in extensive photochemical damage that failed to promote subsequent mineralization in soil. An 8% starch-PE film and the plasticized PVC film evolved significant amounts of CO2 in biodegradation tests and lost residual weight and tensile strength, but GPC measurements demonstrated that all these changes were confined to the additives and the PE and PVC polymers were not degraded. Carbon dioxide evolution was found to be a useful screening tool for plastic film biodegradation, but for films with additives, polymer biodegradation needs to be confirmed by GPC. Photochemical cross-linking of polymer strands reduces solubility and may interfere with GPC measurements of polymer degradation. PMID:16349408

  10. Aerobic bioremediation of 1,2 dichloroethane and vinyl chloride at field scale

    NASA Astrophysics Data System (ADS)

    Davis, Gregory B.; Patterson, Bradley M.; Johnston, Colin D.

    2009-06-01

    Aerobic bioremediation of 1,2 dichloroethane (1,2 DCA) and vinyl chloride (VC) was evaluated at field scale in a layered, silty and fine-sand anaerobic aquifer. Maximum concentrations of 1,2 DCA (2 g/L) and VC (0.75 g/L) in groundwater were within 25% and 70% of pure compound solubility, respectively. Aerobic conditions were induced by injecting air into sparging wells screened 20.5-21.5 m below ground (17-18 m below the water table). Using a cycle of 23 h of air injection followed by three days of no air injection, fifty days of air injection were accumulated over a 12 month period which included some longer periods of operational shutdown. Oxygen and volatile organic compound probes, and multilevel samplers were used to determine changes of the primary contaminants and the associated inorganic chemistry at multiple locations and depths. Air (oxygen) was distributed laterally up to 25 m from the sparge points, with oxygen partial pressures up to 0.7 atmospheres (28-35 mg/L in groundwater) near to the sparge points. The dissolved mass of 1,2 DCA and VC was reduced by greater than 99% over the 590 m 2 trial plot. Significantly, pH declined from nearly 11 to less than 9, and sulfate concentrations increased dramatically, suggesting the occurrence of mineral sulfide (e.g., pyrite) oxidation. Chloride and bicarbonate (aerobic biodegradation by-products) concentration increases were used to estimate that 300-1000 kg of chlorinated hydrocarbons were biodegraded, although the ratio of 1,2 DCA to VC that was biodegraded remained uncertain. The mass biodegraded was comparable but less than the 400-1400 kg of chlorinated compounds removed from the aqueous phase within a 10,000 m 3 volume of the aquifer. Due to the likely presence of non-aqueous phase liquid, the relative proportion of volatilisation compared to biodegradation could not be determined. The aerobic biodegradation rates were greater than those previously estimated from laboratory-based studies.

  11. Multi-Isotope Analysis as a Natural Reaction Probe of Biodegradation Mechanisms of 1,2- Dichloroethane

    NASA Astrophysics Data System (ADS)

    Hirschorn, S. K.; Dinglasan-Panlilio, M.; Edwards, E. A.; Lacrampe-Couloume, G.; Sherwood Lollar, B.

    2006-12-01

    1,2-Dichloroethane (1,2-DCA), a chlorinated aliphatic hydrocarbon, is an EPA priority pollutant and a widespread groundwater contaminant. Stable isotope fractionation during biodegradation of 1,2-DCA occurs due to differences in the reaction rates of heavy versus light atoms present at a reacting bond in the 1,2-DCA molecule. In general, light isotopic bonds react more quickly, producing a relative enrichment in the heavy isotope in the remaining contaminant pool. Compound specific isotope analysis has the potential to demonstrate the occurrence and extent of biodegradation at chlorinated solvent contaminated groundwater sites. In this study, stable carbon isotope fractionation was used as a novel reaction probe to provide information about the mechanism of 1,2-DCA biodegradation. Isotopic fractionation was measured during 1,2-DCA degradation by a microbial culture capable of degrading 1,2-DCA under O2-reducing and NO3-reducing conditions. The microbial culture produced isotopic enrichment values that are not only large and reproducible, but are the same whether O2 or NO3 was used as an electron acceptor. The mean isotopic enrichment value of -25.8 permil measured for the microbial culture during 1,2-DCA degradation under both O2 and NO3- reducing conditions can be converted into a kinetic isotope effect (KIE) value to relate the observed isotopic fractionation to the mechanism of degradation. This KIE value (1.05) is consistent with degradation via a hydrolysis (SN2) reaction under both electron-accepting conditions. Isotope analysis was able to provide a first line of evidence for the reaction mechanism of 1,2-DCA biodegradation by the microbial culture. Using a multi-isotope approach incorporating both carbon and hydrogen isotopic data, compound specific isotope analysis also has the potential to determine degradation mechanisms for 1,2-DCA under aerobic conditions where 1,2-DCA is known to be degraded by two distinct enzymatic pathways. Biodegradation of 1

  12. Preparation of a biodegradable oil absorber and its biodegradation.

    PubMed

    Yoo, Su-Yong; Daud, Wan Mohd Ashri Wan; Lee, Min-Gyu

    2012-01-01

    The biodegradable oil absorption resin (B-PEHA) was prepared by suspension polymerization, and its preparation was confirmed by Fourier transform infrared analysis. The oil absorption capacities of the prepared B-PEHA were: chloroform 30.88, toluene 19.75, xylene, 18.78, THF 15.96, octane 11.43, hexane 9.5, diesel oil 12.80, and kerosene 13.79 g/g. The biodegradation of the prepared B-PEHA was also investigated by determination of reduced sugar produced after enzymatic hydrolysis, thermogravimetric analysis, and incubation with Aspergillus niger. The biodegradation of B-PEHA was ~18%. PMID:21909668

  13. Laboratory evidence of MTBE biodegradation in Borden aquifer material

    NASA Astrophysics Data System (ADS)

    Schirmer, Mario; Butler, Barbara J.; Church, Clinton D.; Barker, James F.; Nadarajah, Nalina

    2003-02-01

    Mainly due to intrinsic biodegradation, monitored natural attenuation can be an effective and inexpensive remediation strategy at petroleum release sites. However, gasoline additives such as methyl tert-butyl ether (MTBE) can jeopardize this strategy because these compounds often degrade, if at all, at a slower rate than the collectively benzene, toluene, ethylbenzene and the xylene (BTEX) compounds. Investigation of whether a compound degrades under certain conditions, and at what rate, is therefore important to the assessment of the intrinsic remediation potential of aquifers. A natural gradient experiment with dissolved MTBE-containing gasoline in the shallow, aerobic sand aquifer at Canadian Forces Base (CFB) Borden (Ontario, Canada) from 1988 to 1996 suggested that biodegradation was the main cause of attenuation for MTBE within the aquifer. This laboratory study demonstrates biologically catalyzed MTBE degradation in Borden aquifer-like environments, and so supports the idea that attenuation due to biodegradation may have occurred in the natural gradient experiment. In an experiment with batch microcosms of aquifer material, three of the microcosms ultimately degraded MTBE to below detection, although this required more than 189 days (or >300 days in one case). Failure to detect the daughter product tert-butyl alcohol (TBA) in the field and the batch experiments could be because TBA was more readily degradable than MTBE under Borden conditions.

  14. Isolation and characterization of luminescent bacterium for sludge biodegradation.

    PubMed

    Zahaba, Maryam; Halmi, Mohd Izuan Effendi; Ahmad, Siti Aqlima; Shukor, Mohd Yunus; Syed, Mohd Arif

    2015-11-01

    Microtox is based on the inhibition of luminescence of the bacterium Vibrio fischeri by the toxicants. This technique has been accepted by the USEPA (United States Environmental Protection Agency) as a biomonitoring tool for remediation of toxicants such as hydrocarbon sludge. In the present study, a luminescent bacterium was isolated from yellow striped scad (Selaroides leptolepis) and was tentatively identified as Vibrio sp. isolate MZ. This aerobic isolate showed high luminescence activity in a broad range of temperature from 25 to 35 °C. In addition, optimal conditions for high bioluminescence activity in range of pH 7.5 to 8.5 and 10 gl(-1) of sodium chloride, 10 gl(-1) of peptone and 10 gl(-1) of sucrose as carbon source. Bench scale biodegradation 1% sludge (w/v) was set up and degradation was determined using gas chromatography with flame ionised detector (GC-FID). In this study, Rhodococcus sp. strain AQ5NOL2 was used to degrade the sludge. Based on the preliminary results obtained, Vibrio sp. isolate MZwas able to monitor the biodegradation of sludge. Therefore, Vibrio sp. isolate MZ has the potential to be used as a biomonitoring agent for biomonitoring of sludge biodegradation particularly in the tropical ranged environment. PMID:26688958

  15. The influence of iron on the biodegradation of benzene in soil microcosms

    SciTech Connect

    Poor, N.D.; Wheeler, E.; Novak, J.T.

    1996-12-31

    Iron was positively-correlated with benzene biodegradation rate in a statistically-significant multiple linear regression model of rates measured in aerobic soil microcosm experiments regressed with corresponding soil nitrate, phosphorus, iron, organic matter and sand content for 10 different previously uncontaminated Virginia subsurface soils. The addition of ferric chloride or ferric hydroxide to soil microcosms prepared with Alaga series sand and spiked with 10 mg/L initial benzene significantly increased the biodegradation rate in unamended experiments, but had no observable influence on biodegradation rates in experiments amended with ammonium phosphate and potassium phosphate. Unamended soil microcosms degraded 10 mg/L initial benzene in 10 days, iron-amended in 5 days, and nutrient-amended in 2 days.

  16. Internal loop photo-biodegradation reactor used for accelerated quinoline degradation and mineralization.

    PubMed

    Chang, Ling; Zhang, Yongming; Gan, Lu; Xu, Hua; Yan, Ning; Liu, Rui; Rittmann, Bruce E

    2014-07-01

    Biofilm biodegradation was coupled with ultra-violet photolysis using the internal loop photobiodegradation reactor for degradation of quinoline. Three protocols-photolysis alone (P), biodegradation alone (B), and intimately coupled photolysis and biodegradation (P&B)-were used for degradation of quinoline in batch and continuous-flow experiments. For a 1,000 mg/L initial quinoline concentration, the volumetric removal rate for quinoline was 38 % higher with P&B than with B in batch experiments, and the P&B kinetics were the sum of kinetics from the P and B experiments. Continuous-flow experiments with an influent quinoline concentration of 1,000 mg/L also gave significantly greater quinoline removal in P&B, and the quinoline-removal kinetics for P&B were approximately equal to the sum of the removal kinetics for P and B. P&B similarly increased the rate and extent of quinoline mineralization, for which the kinetics for P&B were nearly equal to the sum of kinetics for P and B. These findings support that the rate-limiting step for mineralization was transformation of quinoline, which was accelerated by the simultaneous action of photolysis and biodegradation. PMID:24488551

  17. Biodegradation of Polypropylene Nonwovens

    NASA Astrophysics Data System (ADS)

    Keene, Brandi Nechelle

    The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma

  18. Laboratory and field verification of a method to estimate the extent of petroleum biodegradation in soil.

    PubMed

    Douglas, Gregory S; Hardenstine, Jeffery H; Liu, Bo; Uhler, Allen D

    2012-08-01

    We describe a new and rapid quantitative approach to assess the extent of aerobic biodegradation of volatile and semivolatile hydrocarbons in crude oil, using Shushufindi oil from Ecuador as an example. Volatile hydrocarbon biodegradation was both rapid and complete-100% of the benzene, toluene, xylenes (BTEX) and 98% of the gasoline-range organics (GRO) were biodegraded in less than 2 days. Severe biodegradation of the semivolatile hydrocarbons occurred in the inoculated samples with 67% and 87% loss of the diesel-range hydrocarbons (DRO) in 3 and 20 weeks, respectively. One-hundred percent of the naphthalene, fluorene, and phenanthrene, and 46% of the chrysene in the oil were biodegraded within 3 weeks. Percent depletion estimates based on C(30) 17α,21β(H)-hopane (hopane) underestimated the diesel-range organics (DRO) and USEPA 16 priority pollutant PAH losses in the most severely biodegraded samples. The C(28) 20S-triaromatic steroid (TAS) was found to yield more accurate depletion estimates, and a new hopane stability ratio (HSR = hopane/(hopane + TAS)) was developed to monitor hopane degradation in field samples. Oil degradation within field soil samples impacted with Shushufindi crude oil was 83% and 98% for DRO and PAH, respectively. The gas chromatograms and percent depletion estimates indicated that similar levels of petroleum degradation occurred in both the field and laboratory samples, but hopane degradation was substantially less in the field samples. We conclude that cometabolism of hopane may be a factor during rapid biodegradation of petroleum in the laboratory and may not occur to a great extent during biodegradation in the field. We recommend that the hopane stability ratio be monitored in future field studies. If hopane degradation is observed, then the TAS percent depletion estimate should be computed to correct for any bias that may result in petroleum depletion estimates based on hopane. PMID:22694180

  19. Biodegradation of PCBs

    SciTech Connect

    Kopec, R.I.

    1992-01-01

    PCBs were examined for biodegradability by a strain of Pseudomonas sp. designated E1, by a strain of Pseudomonas aeruginosa designated E2, and by a strain of Pseudomonas putida designated E3. The PCBs included Aroclor mixes from Aroclor 1221 to Aroclor 1268, and pure congeners ranging from monochlorobiphenyl to decachlorobiphenyl. These congeners represented all structural classes. Pure culture studies revealed that cells of E1 grew well on all structural classes of PCB congeners up to heptachlorobiphenyl, and all Aroclor mixes up to Aroclor 1260. Gas chromotographic analysis revealed that biphenyl/acetate grown resting cells of E1 degraded congeners up to octachlorobiphenyl. The degradative patterns for E2 and E3 were assessed using gas chromatographic techniques. E2 was found to be markedly inferior to E1, degrading only the mono-, di-, and tri-chlorobiphenyl tested. Pseudomonas putida strain E3 could not degrade any PCB congener. Mutations in both E2 and E3 that enabled them to utilize more highly chlorinated congeners of PCBs were obtained in nutritionally depleted environments. Such mutants could not be obtained by direct selection using minimal media and appear to be [open quotes]Cairnsian[close quotes] mutations. The Pseudomonas sp. strain E1 was tested in 15 prior or current National Priority List soil microcosms to assess its biodegradative ability in situ. E1 was able to completely degrade the 2,3,4,2[prime],3[prime],4[prime]-2,4,5,2[prime],4[prime],5[prime]-hexachlorobiphenyl congener in seven of the microcosms within two months as well.

  20. Decomposition of organic waste products under aerobic and anaerobic conditions

    SciTech Connect

    Gale, P.M.

    1988-01-01

    The objectives of this research were to determine the kinetics of C and N mineralization under aerobic and anaerobic conditions. These parameters were then used to verify the simulation model, DECOMPOSITION, for the anaerobic system. Incubation experiments were conducted to compare the aerobic and anaerobic decomposition of alfalfa (Medicago sativa L.), a substrate with a low C:N ratio. Under anaerobic conditions the net mineralization of N occurred more rapidly than that under aerobic conditions. However, the rate of C mineralization as measured by CO{sub 2} evolution was much lower. For the anaerobic decomposition of alfalfa, C mineralization was best described as the sum of the CO{sub 2} and CH{sub 4} evolved plus the water soluble organic C formed. The kinetics of C mineralization, as determined by this approach, were used to successfully predict the rate and amount of N mineralization from alfalfa undergoing anaerobic decomposition. The decomposition of paper mill sludge, a high C:N ratio substrate, was also evaluated.

  1. Poplar lignin decomposition by gram-negative aerobic bacteria

    SciTech Connect

    Odier, E.; Janin, G.; Monties, B.

    1981-02-01

    Eleven gram-negative aerobic bacteria (Pseudomonadaceae and Neisseriaceae) out of 122 soil isolates were selected for their ability to assimilate poplar dioxane lignin without a cosubstrate. Dioxane lignin and milled wood lignin degradation rates ranged between 20 and 40% of initial content after 7 days in mineral medium, as determined by a loss of absorbance at 280 nm; 10 strains could degrade in situ lignin, as evidenced by the decrease of the acetyl bromide lignin content of microtome wood sections. No degradation of wood polysaccharides was detected. Lignin biodegradation by Pseudomonas 106 was confirmed by 14CO2 release from labeled poplar wood, although in lower yields compared with results obtained through chemical analysis based on acetyl bromide residual lignin determination. (Refs. 31).

  2. Characterization of pure cultures isolated from sulfamethoxazole-acclimated activated sludge with respect to taxonomic identification and sulfamethoxazole biodegradation potential

    PubMed Central

    2013-01-01

    Background Sulfamethoxazole (SMX, sulfonamide antibiotic) biodegradation by activated sludge communities (ASC) is still only partly understood. The present work is focusing on nine different bacteria species capable of SMX biodegradation that were isolated from SMX-acclimated ASC. Results Initially 110 pure cultures, isolated from activated sludge, were screened by UV-absorbance measurements (UV-AM) for their SMX biodegradation potential. Identification via almost complete 16S rRNA gene sequencing revealed five Pseudomonas spp., one Brevundimonas sp., one Variovorax sp. and two Microbacterium spp.. Thus seven species belonged to the phylum Proteobacteria and two to Actinobacteria. These cultures were subsequently incubated in media containing 10 mg L-1 SMX and different concentrations of carbon (sodium-acetate) and nitrogen (ammonium-nitrate). Different biodegradation patterns were revealed with respect to media composition and bacterial species. Biodegradation, validated by LC-UV measurements to verify UV-AM, occurred very fast with 2.5 mg L-1 d-1 SMX being biodegraded in all pure cultures in, for UV-AM modified, R2A-UV medium under aerobic conditions and room temperature. However, reduced and different biodegradation rates were observed for setups with SMX provided as co-substrate together with a carbon/nitrogen source at a ratio of DOC:N – 33:1 with rates ranging from 1.25 to 2.5 mg L-1 d-1. Conclusions Media containing only SMX as carbon and nitrogen source proved the organisms’ ability to use SMX as sole nutrient source where biodegradation rates decreased to 1.0 – 1.7 mg L-1 d-1. The different taxonomically identified species showed specific biodegradation rates and behaviours at various nutrient conditions. Readily degradable energy sources seem to be crucial for efficient SMX biodegradation. PMID:24289789

  3. FOSSIL FUEL BIODEGRADATION: LABORATORY STUDIES

    EPA Science Inventory

    Natural processes of biodegradation, that return carbon from its various organic forms to the inorganic state, are increasingly screened for bioremediation applications. ariety of microbial systems capable of degrading synthetic organic chemicals, from pesticides to polychlorinat...

  4. Phenanthrene Biodegradation in Freshwater Environments

    PubMed Central

    Sherrill, T. W.; Sayler, G. S.

    1980-01-01

    Phenanthrene, a low-molecular-weight polycyclic aromatic hydrocarbon, was incubated with water samples from various reservoir systems in Tennessee to evaluate the potential for significant polycyclic aromatic hydrocarbon degradation by the indigenous microbial populations. Biodegradation was assessed by comparison of total polycyclic aromatic hydrocarbon substrate recovery in degradation flasks relative to sterile control flasks. During 1977 field studies, the mean phenanthrene biodegradation was approximately 80% after a 4-week incubation. Within a given habitat, 45% of the total variability in phenanthrene biodegradation was attributable to the physical, chemical, and microbiological site characteristics examined. Polycyclic aromatic hydrocarbon degradation was directly related to the historical environmental pollution of the sampling sites examined, the length of biodegradation assessment, temperature, and the molecular size of the polycyclic aromatic hydrocarbon substrate. PMID:16345487

  5. THERMOPHILIC ANAEROBIC BIODEGRADATION OF PHENOLICS

    EPA Science Inventory

    The report gives results of a series of anaerobic microbial acclimation and treatment performance tests with synthetic phenolic substrates. The research is a feasibility level assessment of substituting anaerobic biodegradation of phenolics for solvent extraction. The tests showe...

  6. Biodegradation at Dynamic Plume Fringes: Mixing Versus Reaction Control

    NASA Astrophysics Data System (ADS)

    Cirpka, O. A.; Eckert, D.; Griebler, C.; Haberer, C.; Kürzinger, P.; Bauer, R.; Mellage, A.

    2014-12-01

    Biodegradation of continuously emitted plumes is known to be most pronounced at the plume fringe, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. Under steady-state conditions, physical mixing of contaminant and electron acceptor by transverse dispersion was shown to be the major bottleneck for biodegradation, with plume lengths scaling inversely with the bulk transverse dispersivity in quasi two-dimensional settings. Under these conditions, the presence of suitable microbes is essential but the biokinetic parameters do not play an important role. When the location of the plume shifts (caused, e.g., by a fluctuating groundwater table), however, the bacteria are no more situated at the plume fringe and biomass growth, decay, activation and deactivation determine the time lag until the fringe-controlled steady state is approached again. During this time lag, degradation is incomplete. The objective of the presented study was to analyze to which extent flow and transport dynamics diminish effectiveness of fringe-controlled biodegradation and which microbial processes and related biokinetic parameters determine the system response in overall degradation to hydraulic fluctuations. We performed experiments in quasi-two-dimensional flow through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth and maintenance (often subsumed as "biomass decay") microbial dormancy (that is, change into a metabolically inactive state) and

  7. Biodegradability of pentachlorophenol in the environment: A literature review

    SciTech Connect

    Nakles, D. )

    1993-04-01

    Pentachlorophenol has been widely used as a wood preserving agent for over 50 years to treat millions of electrical utility poles and crossarms. Treatment of poles with pentachlorophenol has in some cases resulted in contamination of soils, groundwater, and surface water. Environmental releases are a concern because of the potential toxicity of pentachlorophenol and its stringent regulation. Microbiological degradation of pentachlorophenol in environmental media has been demonstrated in numerous cases. The potential for pentachlorophenol to be biologically degraded is of interest to the electrical utility industry for two reasons. First, it is a factor in understanding the probable fate of pentachlorophenol where it has been released into the environment, and second, its biodegradability can potentially result in effective and economical treatment strategies for soils, water, and subsurface environments. The objective of this literature review is to collect a baseline of information on the biodegradability of pentachlorophenol in soils, surface water, and groundwater for the electric utility industry. The focus of the electric utility industry's interest in the environmental management and control of pentachlorophenol is primarily in the management of environmental media, particularly soils, that may have become incidentally contaminated with pentachlorophenol in association with the treatment, storage, or use of utility poles and crossarms. The review of the literature has found that [open quotes]unassisted[close quotes] biodegradation of pentachlorophenol in aquatic, soil, and subsurface environments may occur, presumably if there is an acclimated microbial population of sufficient density. Aerobic conditions appear to be most conducive to biodegradation in these cases. Several studies have shown that with an acclimated, mixed culture and conventional wastewater treatment approaches, pentachlorophenol can be effectively treated in water.

  8. Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties.

    PubMed

    Garcia, M Teresa; Kaczerewska, Olga; Ribosa, Isabel; Brycki, Bogumił; Materna, Paulina; Drgas, Małgorzata

    2016-07-01

    Aerobic biodegradability and aquatic toxicity of five types of quaternary ammonium-based gemini surfactants have been examined. The effect of the spacer structure and the head group polarity on the ecological properties of a series of dimeric dodecyl ammonium surfactants has been investigated. Standard tests for ready biodegradability assessment (OECD 310) were conducted for C12 alkyl chain gemini surfactants containing oxygen, nitrogen or a benzene ring in the spacer linkage and/or a hydroxyethyl group attached to the nitrogen atom of the head groups. According to the results obtained, the gemini surfactants examined cannot be considered as readily biodegradable compounds. The negligible biotransformation of the gemini surfactants under the standard biodegradation test conditions was found to be due to their toxic effects on the microbial population responsible for aerobic biodegradation. Aquatic toxicity of gemini surfactants was evaluated against Daphnia magna. The acute toxicity values to Daphnia magna, IC50 at 48 h exposure, ranged from 0.6 to 1 mg/L. On the basis of these values, the gemini surfactants tested should be classified as toxic or very toxic to the aquatic environment. However, the dimeric quaternary ammonium-based surfactants examined result to be less toxic than their corresponding monomeric analogs. Nevertheless the aquatic toxicity of these gemini surfactants can be reduced by increasing the molecule hydrophilicity by adding a heteroatom to the spacer or a hydroxyethyl group to the polar head groups. PMID:27045632

  9. Biodegradation of partially hydrolyzed polyacrylamide by bacteria isolated from production water after polymer flooding in an oil field.

    PubMed

    Bao, Mutai; Chen, Qingguo; Li, Yiming; Jiang, Guancheng

    2010-12-15

    Partially hydrolyzed polyacrylamide (HPAM) in production water after polymer flooding in oil filed causes environmental problems, such as increases the difficulty in oil-water separation, degrades naturally to produce toxic acrylamide and endanger local ecosystem. Biodegradation of HPAM may be an efficient way to solve these problems. The biodegradability of HPAM in an aerobic environment was studied. Two HPAM-degrading bacterial strains, named PM-2 and PM-3, were isolated from the produced water of polymer flooding. They were subsequently identified as Bacillus cereus and Bacillus sp., respectively. The utilization of HPAM by the two strains was explored. The amide group of HPAM could serve as a nitrogen source for the two microorganisms, the carbon backbone of these polymers could be partly utilized by microorganisms. The HPAM samples before and after bacterial biodegradation were analyzed by the infrared spectrum, high performance liquid chromatography and scanning electronic microscope. The results indicated that the amide group of HPAM in the biodegradation products had been converted to a carboxyl group, and no acrylamide monomer was found. The HPAM carbon backbone was metabolized by the bacteria during the course of its growth. Further more, the hypothesis about the biodegradation of HPAM in aerobic bacterial culture is proposed. PMID:20813455

  10. 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

  11. ANALYSIS OF AN AEROBIC FLUIDIZED BED REACTOR DEGRADING MTBE AND BTEX AT REDUCED EBCTS

    EPA Science Inventory

    The purpose of this study was to investigate the biodegradation of MTBE and BTEX using a fluidized bed reactor (FBR) with granular activated carbon (GAC) as a biological attachment medium. Batch experiments were run to analyze the MTBE and TBA degradation kinetics of the culture ...

  12. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  13. Biodegradation of atrazine by Rhodococcus sp. BCH2 to N-isopropylammelide with subsequent assessment of toxicity of biodegraded metabolites.

    PubMed

    Kolekar, Parag D; Phugare, Swapnil S; Jadhav, Jyoti P

    2014-02-01

    Atrazine is a persistent organic pollutant in the environment which affects not only terrestrial and aquatic biota but also human health. Since its removal from the environment is needed, atrazine biodegradation is achieved in the present study using the bacterium Rhodococcus sp. BCH2 isolated from soil, long-term treated with atrazine. The bacterium was capable of degrading about 75 % atrazine in liquid medium having pH 7 under aerobic and dark condition within 7 days. The degradation ability of the bacterium at various temperatures (20-60 °C), pH (range 3-11), carbon (glucose, fructose, sucrose, starch, lactose, and maltose), and nitrogen (ammonium molybdate, sodium nitrate, potassium nitrate, and urea) sources were studied for triumph optimum atrazine degradation. The results indicate that atrazine degradation at higher concentrations (100 ppm) was pH and temperature dependent. However, glucose and potassium nitrate were optimum carbon and nitrogen source, respectively. Atrazine biodegradation analysis was carried out by using high-performance thin-layer chromatography (HPTLC), Fourier transform infrared spectroscopy (FTIR), and liquid chromatography quadrupole time-of-flight (LC/Q-TOF-MS) techniques. LC/Q-TOF-MS analysis revealed formation of various intermediate metabolites including hydroxyatrazine, N-isopropylammelide, deisopropylhydroxyatrazine, deethylatrazine, deisopropylatrazine, and deisopropyldeethylatrazine which was helpful to propose biochemical degradation pathway of atrazine. Furthermore, the toxicological studies of atrazine and its biodegraded metabolites were executed on earthworm Eisenia foetida as a model organism with respect to enzymatic (SOD and Catalase) antioxidant defense mechanism and lipid peroxidation studies. These results suggest innocuous degradation of atrazine by Rhodococcus sp. BCH2 in nontoxic form. Therefore the Rhodococcus sp.BCH2 could prove a valuable source for the eco-friendly biodegradation of atrazine pesticide. PMID

  14. Bioresorbable vascular scaffolds: Biodegradation, drug delivery and vascular remodeling.

    PubMed

    Tesfamariam, Belay

    2016-05-01

    The metallic stents with durable polymers have been effective in reducing the need for revascularization, but the permanent presence of the metal and polymer have been associated with persistent inflammation, hypersensitivity reactions and incidence of thrombosis. Recent innovations of bioresorbable polymers are in development which could serve as temporary scaffolds that degrade into molecules and eventually resorb overtime, and leave the artery free of any permanent prosthetic constraints. The transient scaffolding has the advantages of restoring blood vessel to natural state, improve vasomotor tone and increase lumen enlargement because of expansive remodeling following completion of polymer resorption. The success of bioresorbable vascular scaffolds will depend on the degradation timeline, such that the elastic recoil of the blood vessel and negative remodeling which could potentially lead to restenosis are prevented. Bioresorbable scaffolds with bulky backbone and thick struts could lead to prolonged biodegradation, alter blood flow dynamics and increase thrombogenicity. The development of bioresorbable scaffolds is challenging because of the complexity of finding an ideal balance of polymer biodegradation and controlled drug release over time, such that the fractional drug released achieves optimal inhibitory concentration until the blood vessel remodels to a stable set point. This review discusses the various types of biodegradable materials, factors affecting biodegradation, drug release kinetics, vascular biocompatibility, adaptive vascular remodeling, and challenges in the development of bioresorbable scaffolds to treat vascular restenosis. PMID:27001225

  15. [Application of Micro-aerobic Hydrolysis Acidification in the Pretreatment of Petrochemical Wastewater].

    PubMed

    Zhu, Chen; Wu, Chang-yong; Zhou, Yue-xi; Fu, Xiao-yong; Chen, Xue-min; Qiu, Yan-bo; Wu, Xiao-feng

    2015-10-01

    Micro-aerobic hydrolysis acidification technology was applied in the reconstruction of ananaerobic hydrolysis acidification tank in a north petrochemical wastewater treatment plant. After put into operation, the monitoring results showed that the average removal rate of COD was 11.7% when influent COD was 490.3-673.2 mg x L(-1), hydraulic retention time (HRT) was 24 and the dissolved oxygen (DO) was 0.2-0.35 mg x L(-1). In addition, the BOD5/COD value was increased by 12.4%, the UV254 removal rate reached 11.2%, and the VFA concentration was increased by 23.0%. The relative molecular weight distribution (MWD) results showed that the small molecule organic matter (< 1 x 10(3)) percentage was increased from 59.5% to 82.1% and the high molecular organic matter ( > 100 x 10(3)) percentage was decreased from 31.8% to 14.0% after micro-aerobic hydrolysis acidification. The aerobic biodegradation batch test showed that the degradation of petrochemical wastewater was significantly improved by the pretreatment of micro-aerobic hydrolysis acidification. The COD of influent can be degraded to 102.2 mg x L(-1) by 48h aerobic treatment while the micro-aerobic hydrolysis acidification effluent COD can be degraded to 71.5 mg x L(-1) on the same condition. The effluent sulfate concentration of micro-aerobic hydrolysis acidification tank [(930.7 ± 60.1) mg x L(-1)] was higher than that of the influent [(854.3 ± 41.5) mg x L(-1)], indicating that sulfate reducing bacteria (SRB) was inhibited. The toxic and malodorous gases generation was reduced with the improvement of environment. PMID:26841606

  16. Comparison of Leachate Quality from Aerobic and Anaerobic Municipal Solid Waste Bioreactors

    NASA Astrophysics Data System (ADS)

    Borglin, S. E.; Hazen, T. C.; Oldenburg, C. M.

    2002-12-01

    Municipal solid waste landfills are becoming a drain on the resources of local municipalities as the requirements for stabilization and containment become increasingly stringent. Current regulations limit the moisture in the landfill to minimize leachate production and lower the potential for release of leachate to the environment. Recent research has shown that addition and recycling of moisture in the waste optimizes the biodegradation of stabilization and also provides a means for leachate treatment. This study compares the characteristics of leachate produced from aerobic and anaerobic laboratory bioreactors, and leachate collected from a full-scale anaerobic bioreactor. The laboratory reactors consisted of 200-liter tanks filled with fresh waste materials with the following conditions: (a) aerobic (air injection with leachate recirculation), (b) anaerobic (leachate recirculation). The leachate from the reactors was monitored for metals, nutrients, organic carbon, and microbiological activity for up to 500 days. Leachate from the aerobic tank had significantly lower concentrations of all potential contaminants, both organic and metal, after only a few weeks of operation. Metals leaching was low throughout the test period for the aerobic tanks, and decreased over time for the anaerobic tanks. Organic carbon as measured by BOD, COD, TOC, and COD were an order of magnitude higher in the leachate from the anaerobic system. Microbiological assessment by lipid analysis, enzyme activity assays, and cell counts showed high biomass and diversity in both the aerobic and anaerobic bioreactors, with higher activity in the anaerobic leachate. Results from the full-scale anaerobic bioreactor were not significantly different from those of the laboratory anaerobic bioreactor. The reduction in noxious odors was a significant advantage of the aerobic system. These results suggest that aerobic management of landfills could reduce or eliminate the need for leachate treatment

  17. Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

    PubMed

    Tomei, M Concetta; Mosca Angelucci, Domenica; Levantesi, Caterina

    2016-03-01

    Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion. PMID:26760266

  18. Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB.

    PubMed

    Torlapati, Jagadish; Boufadel, Michel C

    2014-01-01

    We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al., 2010). In that study, samples were collected from three different islands: Eleanor Island (EL107), Knight Island (KN114A), and Smith Island (SM006B), and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA). The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with that of the overall polycyclic aromatic hydrocarbons

  19. Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB

    PubMed Central

    Torlapati, Jagadish; Boufadel, Michel C.

    2014-01-01

    We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al., 2010). In that study, samples were collected from three different islands: Eleanor Island (EL107), Knight Island (KN114A), and Smith Island (SM006B), and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA). The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with that of the overall polycyclic aromatic hydrocarbons

  20. "Aerobic" Writing: A Writing Practice Model.

    ERIC Educational Resources Information Center

    Crisp, Sally Chandler

    "Aerobic writing" is a writing center strategy designed to keep students in writing "shape." Like aerobic exercise, aerobic writing is sustained for a certain length of time and done on a regular basis at prescribed time intervals. The program requires students to write at least two times a week for approximately an hour each time. Students write,…

  1. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  2. Ecotoxicity by the biodegradation of alkylphenol polyethoxylates depends on the effect of trace elements.

    PubMed

    Hotta, Yudai; Hosoda, Akifumi; Sano, Fumihiko; Wakayama, Manabu; Niwa, Katsuki; Yoshikawa, Hiromichi; Tamura, Hiroto

    2010-01-27

    The bacteria Sphingomonas sp. strain BSN22, isolated from bean fields, degraded octylphenol polyethoxylates (OPEO(n)) to octylphenol (OP) under aerobic conditions. This biodegradation mechanism proceeded by the following two-step degradation process: (1) degradation of OPEO(n) to octylphenol triethoxylate (OPEO(3)), (2) degradation from OPEO(3) to OP via octylphenoxy acetic acid (OPEC(1)). The chemical structure of OPEC(1) was confirmed by analysis using (18)O-labeled water. Quantitative studies revealed that magnesium (Mg(2+)) and calcium (Ca(2+)) ions were essential for the biodegradation of OPEO(n). Furthermore, the rate of biodegradation was especially accelerated by ferric ions (Fe(3+)), and the accumulated amounts of endocrine active chemicals, such as OP, OPEO(1), and OPEC(1), significantly increased to the concentration of 22.8, 221.7, and 961.1 microM in the presence of 37.0 microM Fe(3+), respectively. This suggests that environmental elements significantly influence the resultant ecotoxicity as well as the rate of their biodegradation in the environment. This study on the mechanism of OPEO(n) biodegradation may play an important role in understanding and managing environmental safety, including drinking water safety. PMID:20025273

  3. Biodegradation of radioactive animals

    SciTech Connect

    Party, N.; Party, E.; Wilkerson, A.

    1995-06-01

    The two most common disposal alternatives for animals contaminated with radioactive materials are incineration and burial. For most of the country burial has entailed shipping the carcasses to a commercial disposal facility at Barnwell, South Carolina, where it was landfilled along with other solid radioactive waste. Unfortunately, since 30 June 1994, this facility accepts waste generated by the states of the Southeast Compact only. Therefore, burial is no longer an option for most of the country`s generators and incineration is an option only for those institutions which have, or have access to, an incinerator that is permitted to burn radioactive materials and that accepts animal carcasses with de minimis levels of radioactive contaminants. Many institutions, especially those in congested urban areas where the public does not support incineration, do not have viable outlets for radioactive animal carcasses. Interim, on-site storage poses problems of its own. Biodegradation of animal carcasses with dermestid beetles is an inexpensive approach to this waste management problem. 7 refs., 3 figs., 1 tab.

  4. 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. PMID:25812103

  5. Process Improvements: Aerobic Food Waste Composting at ISF Academy

    NASA Astrophysics Data System (ADS)

    Lau, Y. K.

    2015-12-01

    ISF Academy, a school with 1500 students in Hong Kong, installed an aerobic food waste composting system in November of 2013. The system has been operational for over seven months; we will be making improvements to the system to ensure the continued operational viability and quality of the compost. As a school we are committed to reducing our carbon footprint and the amount of waste we send to the local landfill. Over an academic year we produce approximately 27 metric tons of food waste. Our system processes the food waste to compost in 14 days and the compost is used by our primary school students in a organic farming project.There are two areas of improvement: a) if the composting system becomes anaerobic, there is an odor problem that is noticed by the school community; we will be testing the use of a bio-filter to eliminate the odor problem and, b) we will be working with an equipment vendor from Australia to install an improved grease trap system. The grease and oil that is collected will be sold to a local company here in Hong Kong that processes used cooking oil for making biofuels. This system will include a two stage filtration system and a heated vessel for separating the oil from the waste water.The third project will be to evaluate biodegradable cutlery for the compositing in the system. Currently, we use a significant quantity of non-biodegradable cutlery that is then thrown away after one use. Several local HK companies are selling biodegradable cutlery, but we need to evaluate the different products to determine which ones will work with our composting system. The food waste composting project at ISF Academy demonstrates the commitment of the school community to a greener environment for HK, the above listed projects will improve the operation of the system.

  6. Injectable and biodegradable hydrogels: gelation, biodegradation and biomedical applications.

    PubMed

    Li, Yulin; Rodrigues, João; Tomás, Helena

    2012-03-21

    Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found a variety of biomedical applications, such as drug delivery, cell encapsulation, and tissue engineering. This critical review systematically summarizes the recent progresses on biodegradable and injectable hydrogels fabricated from natural polymers (chitosan, hyaluronic acid, alginates, gelatin, heparin, chondroitin sulfate, etc.) and biodegradable synthetic polymers (polypeptides, polyesters, polyphosphazenes, etc.). The review includes the novel naturally based hydrogels with high potential for biomedical applications developed in the past five years which integrate the excellent biocompatibility of natural polymers/synthetic polypeptides with structural controllability via chemical modification. The gelation and biodegradation which are two key factors to affect the cell fate or drug delivery are highlighted. A brief outlook on the future of injectable and biodegradable hydrogels is also presented (326 references). PMID:22116474

  7. Effects of the Biodegradation on Biodegradable Polymer Blends and Polypropylene

    NASA Astrophysics Data System (ADS)

    Pereira, R. C. T.; Franchetti, S. M. M.; Agnelli, J. A. M.; Mattoso, L. H. C.

    2008-08-01

    The large use of plastics in the world generates a large amount of waste which persists around 200 years in the environment. To minimize this effect is important to search some new polymer materials: the blends of biodegradable polymers with synthetic polymers. It is a large area that needs an intensive research to investigate the blends properties and its behavior face to the different treatments to aim at the biodegradation. The blends used in this work are: some biodegradable polymers such as: poly(hydroxybutyrate) (PHB) and poly(ɛ-polycaprolactone) (PCL) with a synthetic polymer, polypropylene (PP), in lower concentration. These blends were prepared using an internal mixer (Torque Rheometer), and pressed. These films were submitted to fungus biotreatment. The films analyses will be carried out by Fourier Transform Infrared (FTIR), UV-Vis absorption (UV-Vis), Scanning Electronic Microscopy (SEM), DSC and TGA.

  8. Biodegradation of news inks

    SciTech Connect

    Erhan, S.Z.; Bagby, M.O.

    1995-12-01

    Printing ink vehicles that require no petroleum components were prepared by modifying vegetable oil. Physical properties of inks formulated with these vehicles meet or exceed the industry standards for lithographic and letterpress newsprint applications. Elimination of petroleum-based resin and reduced pigment requirements, due to the light vehicle color, provide a competitively priced alternative to petroleum-based inks of equal quality. These ink vehicles, made exclusively from soybean oil, were subjected to biodegradation, and the results were compared with those obtained with commercial vehicles. Results show that they degrade faster and more completely than commercial hybrid (partial) soy or mineral oil based vehicles. Fermentations were allowed to proceed for 5, 12, and 25 days. Both mono-and mixed cultures of microorganisms commonly found in soil were used. In 25 days, commercial mineral oil based vehicles degraded 17-27%, while commercial hybrid soy oil based vehicles degraded 58-68% and our 100% soy oil based vehicles degrade 82-92%. Similar studies were conducted with commercial news inks consisting of soy or mineral oil with petroleum resins along with the four colored pigments and USDA`s 100% soy oil based ink consisting of modified soybean oil and pigment. Results show that pigment slowed the degradation of ink vehicles; however, neither time nor type of pigment played a significant role. Also these inks were degraded by using {open_quotes}Modified Sturm Test{close_quotes} (Organization for Economic Cooperation and Development). In this method, test organisms were obtained from activated sludge, and the extent of degradation was determined by measuring carbon dioxide evolution. In all cases USDA`s ink degraded faster and more completely (for all four colors) than either hybrid soy oil based or petroleum based inks.

  9. Release of biodegradable dissolved organic matter from ancient sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Schillawski, Sarah; Petsch, Steven

    2008-09-01

    Sedimentary rocks contain the largest mass of organic carbon on Earth, yet these reservoirs are not well integrated into modern carbon budgets. Here we describe the release of dissolved organic matter (DOM) from OM-rich sedimentary rocks under simulated weathering conditions. Results from column experiments demonstrate slow, sustained release of DOM from ancient sedimentary rocks under simulated weathering conditions. 1H-NMR analysis of shale-derived DOM reveals a highly aliphatic, carbohydrate-poor material distinct from other natural DOM pools. Shale-derived DOM is rapidly assimilated and biodegraded by aerobic heterotrophic bacteria. Consequently, no compositional signature of shale-derived DOM other than 14C-depletion is likely to persist in rivers or other surface reservoirs. Combined, these efforts show that dissolution provides a mechanism for the conversion of refractory kerogen into labile biomass, linking rock weathering with sedimentary OM oxidation and the delivery of aged OM to rivers and ocean margins.

  10. Initial Transformations in the Biodegradation of Benzothiazoles by Rhodococcus Isolates

    PubMed Central

    De Wever, Helene; Vereecken, Karen; Stolz, Andreas; Verachtert, Hubert

    1998-01-01

    Benzothiazole-2-sulfonate (BTSO3) is one of the side products occurring in 2-mercaptobenzothiazole (MBT) production wastewater. We are the first to isolate an axenic culture capable of BTSO3 degradation. The isolate was identified as a Rhodococcus erythropolis strain and also degraded 2-hydroxybenzothiazole (OBT) and benzothiazole (BT), but not MBT, which was found to inhibit the biodegradation of OBT, BT, and BTSO3. In anaerobic resting cell assays, BTSO3 was transformed into OBT in stoichiometric amounts. Under aerobic conditions, OBT was observed as an intermediate in BT breakdown and an unknown compound transiently accumulated in several assays. This product was identified as a dihydroxybenzothiazole. Benzothiazole degradation pathways seem to converge into OBT, which is then transformed further into the dihydroxy derivative. PMID:9726870

  11. Biodegradation Rates Assessment For An In Situ Bioremediation Process

    NASA Astrophysics Data System (ADS)

    Troquet, J.; Poutier, F.

    Bioremediation methods seem a promising way of dealing with soil and subsoil con- tamination by organic substances. The biodegradation process is supported by micro- organisms which use the organic carbon from the pollutants as energy source and cells building blocks. However, bioremediation is not yet universally understood and its success is still an intensively debated issue because all soils and groundwater are not able to sustain biological growth and, then, cannot be successfully bioremediated. The outcome of each degradation process depends on several factors, which, such as oxygen transfer and pollutant bio-availability, can be controlled and are therefore key variables of such bioremediation processes. Then, it is essential to carry out a fea- sibility study based on pilot-testing before starting a remediation project in order to determine the best formulation of nutrients and bacteria to use for the specific condi- tions encountered. The scope of this work is to study the main parameters of the process and its physi- cal limiting steps in order to determine the biodegradation rates in a specific case of contamination. Several ground samples from an actual petroleum hydrocarbon con- taminated site have been laboratory tested. Five fixed bed column reactors, enabling the study of the influence of the different op- erating variables on the biodegradation kinetics, are used. The stoichiometric equation for bacteria growth and pollutant degradation has been established, allowing the de- termination of mass balances. Biodegradation monitoring is achieved by continuously measuring the emissions of carbon dioxide production and intermittently by analysing residual hydrocarbons. Results lead to the knowledge of biodegradation rates which allow to determine the treatment duration and cost.

  12. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    PubMed

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong

    2015-04-28

    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. PMID:25661171

  13. EFFECTS OF MICROCOSM PREPARATION ON RATES OF TOLUENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS

    EPA Science Inventory

    Microcosms were prepared with subsurface material from two aquifers to examine the effects of preparation methods on rates of toluene biodegradation under denitrifying conditions. In both cases, the data fit a zero-order kinetics plot. However, rates of removal were generally pro...

  14. Developments in metallic biodegradable stents.

    PubMed

    Hermawan, H; Dubé, D; Mantovani, D

    2010-05-01

    Interest in metallic degradable biomaterials research has been growing in the last decade. Both scientific journals and patent databases record a high increase in publications in this area. Biomedical implants with temporary function, such as coronary stents, are the targeted applications for this novel class of biomaterials. It is expected that stents made of degradable biomaterials, named biodegradable stents, will provide a temporary opening into a narrowed arterial vessel until the vessel remodels and will progressively disappear thereafter. Biodegradable stents made of metal have recently been progressed into preclinical tests in humans after their first introduction in early 2000s. By referring to patents and journal publications, this paper reviews the developments in biodegradable stents, with emphasis on those made of metals, starting from the first design ideas to validation testing. PMID:19815097

  15. Simultaneous nitritation and p-nitrophenol removal using aerobic granular biomass in a continuous airlift reactor.

    PubMed

    Jemaat, Zulkifly; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián

    2013-12-01

    The chemical and petrochemical industries produce wastewaters containing ammonium and phenolic compounds. Biological treatment of these wastewaters could be problematic due to the possible inhibitory effects exerted by phenolic compounds. The feasibility of performing simultaneous nitritation and p-nitrophenol (PNP) biodegradation using a continuous aerobic granular reactor was evaluated. A nitrifying granular sludge was bioaugmented with a PNP-degrading floccular sludge, while PNP was progressively added to the feed containing a high ammonium concentration. Nitritation was sustained throughout the operational period with ca. 85% of ammonium oxidation and less than 0.3% of nitrate in the effluent. PNP biodegradation was unstable and the oxygen limiting condition was found to be the main explanation for this unsteadiness. An increase in dissolved oxygen concentration from 2.0 to 4.5 mg O2 L(-1) significantly enhanced PNP removal, achieving total elimination. Acinetobacter genus and ammonia-oxidising bacteria were the predominant bacteria species in the granular biomass. PMID:24177164

  16. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  17. Petroleum biodegradation in marine environments.

    PubMed

    Harayama, S; Kishira, H; Kasai, Y; Shutsubo, K

    1999-08-01

    Petroleum-based products are the major source of energy for industry and daily life. Petroleum is also the raw material for many chemical products such as plastics, paints, and cosmetics. The transport of petroleum across the world is frequent, and the amounts of petroleum stocks in developed countries are enormous. Consequently, the potential for oil spills is significant, and research on the fate of petroleum in a marine environment is important to evaluate the environmental threat of oil spills, and to develop biotechnology to cope with them. Crude oil is constituted from thousands of components which are separated into saturates, aromatics, resins and asphaltenes. Upon discharge into the sea, crude oil is subjected to weathering, the process caused by the combined effects of physical, chemical and biological modification. Saturates, especially those of smaller molecular weight, are readily biodegraded in marine environments. Aromatics with one, two or three aromatic rings are also efficiently biodegraded; however, those with four or more aromatic ring are quite resistant to biodegradation. The asphaltene and resin fractions contain higher molecular weight compounds whose chemical structures have not yet been resolved. The biodegradability of these compounds is not yet known. It is known that the concentrations of available nitrogen and phosphorus in seawater limit the growth and activities of hydrocarbon-degrading microorganisms in a marine environment. In other words, the addition of nitrogen and phosphorus fertilizers to an oil-contaminated marine environment can stimulate the biodegradation of spilled oil. This notion was confirmed in the large-scale operation for bioremediation after the oil spill from the Exxon Valdez in Alaska. Many microorganisms capable of degrading petroleum components have been isolated. However, few of them seem to be important for petroleum biodegradation in natural environments. One group of bacteria belonging to the genus

  18. Utilization of Triton X-100 and polyethylene glycols during surfactant-mediated biodegradation of diesel fuel.

    PubMed

    Wyrwas, Bogdan; Chrzanowski, Łukasz; Ławniczak, Łukasz; Szulc, Alicja; Cyplik, Paweł; Białas, Wojciech; Szymański, Andrzej; Hołderna-Odachowska, Aleksandra

    2011-12-15

    The hypothesis regarding preferential biodegradation of surfactants applied for enhancement of microbial hydrocarbons degradation was studied. At first the microbial degradation of sole Triton X-100 by soil isolated hydrocarbon degrading bacterial consortium was confirmed under both full and limited aeration with nitrate as an electron acceptor. Triton X-100 (600 mg/l) was utilized twice as fast for aerobic conditions (t(1/2)=10.3h), compared to anaerobic conditions (t(1/2)=21.8h). HPLC/ESI-MS analysis revealed the preferential biodegradation trends in both components classes of commercial Triton X-100 (alkylphenol ethoxylates) as well as polyethylene glycols. The obtained results suggest that the observed changes in the degree of ethoxylation for polyethylene glycol homologues occurred as a consequence of the 'central fission' mechanism during Triton X-100 biodegradation. Subsequent experiments with Triton X-100 at approx. CMC concentration (150 mg/l) and diesel oil supported our initial hypothesis that the surfactant would become the preferred carbon source even for hydrocarbon degrading bacteria. Regardless of aeration regimes Triton X-100 was utilized within 48-72 h. Efficiency of diesel oil degradation was decreased in the presence of surfactant for aerobic conditions by approx. 25% reaching 60 instead of 80% noted for experiments without surfactant. No surfactant influence was observed for anaerobic conditions. PMID:21996621

  19. Biodegradation of chlorinated ethenes at a karst site in middle Tennessee

    USGS Publications Warehouse

    Byl, Thomas Duane; Williams, Shannon D.

    2000-01-01

    This report presents results of field and laboratory investigations examining the biodegradation of chlorinated ethenes in a karst aquifer contaminated with trichloroethylene (TCE). The study site, located in Middle Tennessee, was selected because of the presence of TCE degradation byproducts in the karst aquifer and available site hydrologic and chlorinated-ethene information. Additional chemical, biological, and hydrologic data were gathered to evaluate whether the occurrence of TCE degradation byproducts in the karst aquifer was the result of biodegradation within the aquifer or simply transport into the aquifer. Geochemical analysis established that sulfate-reducing conditions, essential for reductive dechlorination of chlorinated solvents, existed in parts of the contaminated karst aquifer. Other areas of the aquifer fluctuated between anaerobic and aerobic conditions and contained compounds associated with cometabolism, such as ethane, methane, ammonia, and dissolved oxygen. A large, diverse bacteria population inhabits the contaminated aquifer. Bacteria known to biodegrade TCE and other chlorinated solvents, such as sulfate-reducers, methanotrophs, and ammonia-oxidizers, were identified from karst-aquifer water using the RNA-hybridization technique. Results from microcosms using raw karst-aquifer water found that aerobic cometabolism and anaerobic reductive-dechlorination degradation processes were possible when appropriate conditions were established in the microcosms. These chemical and biological results provide circumstantial evidence that several biodegradation processes are active in the aquifer. Additional site hydrologic information was developed to determine if appropriate conditions persist long enough in the karst aquifer for these biodegradation processes to be significant. Continuous monitoring devices placed in four wells during the spring of 1998 indicated that pH, specific conductance, dissolved oxygen, and oxidation-reduction potentials

  20. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  1. Biodegradation and bioaccumulation of phthalates

    SciTech Connect

    Scholz, N.; Diefenbach, R.

    1995-12-31

    Phthalate esters very often are considered as persistent in the environment. This view is supported by an assumed lack of biodegradability, the high log K{sub ow} values and the assumed high bioaccumulation potential. Results are presented which show phthalates esters to be readily biodegradable even with a non-adapted inoculum. Combined with a lack of relevant bioaccumulation in aquatic organisms, a reconsideration of the environmental impact of these substances is necessary. Special prerequisites for testing poorly water soluble substances are also discussed.

  2. Integrated biological (anaerobic-aerobic) and physico-chemical treatment of baker's yeast wastewater.

    PubMed

    Kalyuzhnyi, S; Gladchenko, M; Starostina, E; Shcherbakov, S; Versprille, B

    2005-01-01

    The UASB reactor (35 degrees C) was quite efficient for removal of bulk COD (52-74%) from simulated (on the basis of cultivation medium from the first separation process) general effluent of baker's yeast production (the average organic loading rates varied from 8.1 to 16 g COD/l/d). The aerobic-anoxic biofilter (19-23 degrees C) can be used for removal of remaining BOD and ammonia from anaerobic effluents; however, it suffered from COD-deficiency to fulfil denitrification requirements. To balance COD/N ratio, some bypass (approximately 10%) of anaerobically untreated general effluent should be added to the biofilter feed. The application of iron (III)-, aluminium- or calcium-induced coagulation for post-treatment of aerobic-anoxic effluents can fulfil the limits for discharge to sewerage (even for colour mainly exerted by hardly biodegradable melanoidins), however, the required amounts of coagulants were relatively high. PMID:16459801

  3. Organic micropollutants in aerobic and anaerobic membrane bioreactors: Changes in microbial communities and gene expression.

    PubMed

    Harb, Moustapha; Wei, Chun-Hai; Wang, Nan; Amy, Gary; Hong, Pei-Ying

    2016-10-01

    Organic micro-pollutants (OMPs) are contaminants of emerging concern in wastewater treatment due to the risk of their proliferation into the environment, but their impact on the biological treatment process is not well understood. The purpose of this study is to examine the effects of the presence of OMPs on the core microbial populations of wastewater treatment. Two nanofiltration-coupled membrane bioreactors (aerobic and anaerobic) were subjected to the same operating conditions while treating synthetic municipal wastewater spiked with OMPs. Microbial community dynamics, gene expression levels, and antibiotic resistance genes were analyzed using molecular-based approaches. Results showed that presence of OMPs in the wastewater feed had a clear effect on keystone bacterial populations in both the aerobic and anaerobic sludge while also significantly impacting biodegradation-associated gene expression levels. Finally, multiple antibiotic-type OMPs were found to have higher removal rates in the anaerobic MBR, while associated antibiotic resistance genes were lower. PMID:27441825

  4. Metagenomics of Hydrocarbon Resource Environments Indicates Aerobic Taxa and Genes to be Unexpectedly Common

    PubMed Central

    2013-01-01

    Oil in subsurface reservoirs is biodegraded by resident microbial communities. Water-mediated, anaerobic conversion of hydrocarbons to methane and CO2, catalyzed by syntrophic bacteria and methanogenic archaea, is thought to be one of the dominant processes. We compared 160 microbial community compositions in ten hydrocarbon resource environments (HREs) and sequenced twelve metagenomes to characterize their metabolic potential. Although anaerobic communities were common, cores from oil sands and coal beds had unexpectedly high proportions of aerobic hydrocarbon-degrading bacteria. Likewise, most metagenomes had high proportions of genes for enzymes involved in aerobic hydrocarbon metabolism. Hence, although HREs may have been strictly anaerobic and typically methanogenic for much of their history, this may not hold today for coal beds and for the Alberta oil sands, one of the largest remaining oil reservoirs in the world. This finding may influence strategies to recover energy or chemicals from these HREs by in situ microbial processes. PMID:23889694

  5. Ecotoxicity and biodegradability of antielectrostatic dicephalic cationic surfactants.

    PubMed

    Piętka-Ottlik, Magdalena; Frąckowiak, Renata; Maliszewska, Irena; Kołwzan, Barbara; Wilk, Kazimiera A

    2012-11-01

    Four series of dicephalic cationic surfactants, considered as new antielectrostatic agents have been investigated in order to establish their toxicity and biodegradability. Among them N,N-bis[3,3'-(dimethylamine)propyl]alkylamides, N,N-bis[3,3'-(dimethylamine)propyl]alkylamide dihydrochlorides, N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dibromides and N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dimethylsulphates with different hydrophobic chain length (n-C(9)H(19) to n-C(15)H(31)) and type of counterion (chloride, bromide and methylsulfate) have been studied. The inhibitory effect against microorganisms has been examined using model gram-positive and gram-negative bacteria, and yeasts. None of the tested surfactants have shown antimicrobial activity against gram-negative bacteria (Escherichia coli, Pseudomonas putida) and yeasts (Saccharomyces cerevisiae, Rhodotorula glutinis) at a concentration below 1000 μg mL(-1), however some of them were moderately active against gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis). The Microtox® test was successfully applied to measure EC(50) values of the studied dicephalic cationic surfactants. Their toxicity to Vibrio fischeri depended upon the alkanoyl chain length with the EC(50) values in a range of 2.6-980 mg L(-1). N,N-bis[3,3'-(dimethylamine)propyl]alkylamide dihydrochlorides 2a-b and N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dibromides 3a-b comprising n-decanoyl and n-dodecanoyl hydrophobic tails appeared to be the least toxic. Furthermore, the biodegradability under aerobic conditions of 2a-b, 3a-b was evaluated using OECD Method 301F. According to the obtained results 2a, 3a-3b can be considered as almost readily biodegradable and they are not expected to be persistent in the environment. Additionally, partial biodegradation was observed for 2b, indicating its possible biodegradation in wastewater treatment systems. PMID:22743183

  6. BIODEGRADATION OF TRICHLOROETHYLENE AND INVOLVEMENT OF AN AROMATIC BIODEGRADATIVE PATHWAY

    EPA Science Inventory

    Biodegradation of trichloroethylene (TCE) by the bacterial isolate 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 ...

  7. Methods to determine aerobic endurance.

    PubMed

    Bosquet, Laurent; Léger, Luc; Legros, Patrick

    2002-01-01

    Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate

  8. Biodegradability and toxicity assessment of bleach plant effluents treated anaerobically.

    PubMed

    Chaparro, T R; Botta, C M; Pires, E C

    2010-01-01

    As part of an experimental project on the treatment of bleach plant effluents the results of biodegradability and toxicity assessment of effluents from a bench-scale horizontal anaerobic immobilized bioreactor (HAIB) are discussed in this paper. The biodegradability of the bleach plant effluents from a Kraft pulp mill treated in the HAIB was evaluated using the modified Zahn-Wellens test. The inoculum came from a pulp mill wastewater treatment plant and the dissolved organic carbon (DOC) was used as the indicator of organic matter removal. The acute and chronic toxicity removal during the anaerobic treatment was estimated using Daphnia similis and Ceriodaphnia silvestrii respectively. Moreover, the evaluation of chromosome aberrations (CA), micronucleus frequencies (MN) and mitotic index (IM) in Allium cepa cells were used as genotoxicity indicators. The results indicate that the effluents from the anaerobic reactor are amenable to aerobic polishing. Acute and chronic toxicity were reduced by 90 and 81%, respectively. The largest CA and MN incidence in the meristematic cells of A. cepa were observed after exposure to the raw bleach plant effluent. The HAIB was able to reduce the acute and chronic toxicity as well as chromosome aberrations and the occurrence of micronucleus. PMID:20861545

  9. Biodegradation of the phthalates and their esters by bacteria.

    PubMed Central

    Keyser, P; Pujar, B G; Eaton, R W; Ribbons, D W

    1976-01-01

    Recent studies on the biodegradation phthalate esters in natural ecosystems, sewage, and laboratory cultures are reviewed. There is ample evidence to demonstrate that bacteria are major elements in the biodegradative processes and that in most situations complete oxidation of the aromatic ring occurs; much less is known about the catabolism of the alcoholic moiety, e.g., 2-ethylhexanol. Evidence is presented to support catabolic pathways in pseudomonads and micrococci that are initiated by successive hydrolyses of the diesters to give the phthalate anion. Thereafter a dioxygenase catalyzes the formation of 4,5-dihydro-4,5-dihydroxyphthalate, which is oxidized by an NAD-dependent dehydrogenase to give 4,5-dihydroxyphthalate, Protocatechuate, formed by decarboxylation of 4,5-dihydroxyphthalate, is the substrate for ring cleavage enzymes. Whereas flurorescent pseudomonads use the beta-ketoadipate pathway, the nonfluorescent strains and micrococci examined use of meta-cleavage (4,5-) route. All the intermediates proposed have been accumulated by enzymes purified from Pseudomonas fluorescens. Isophthalate and terephthalate (anions) are readily used as carbon sources by aerobic bacteria, and preliminary evidence is consistent with catabolic routes for these isomers converging at the ring-cleavage substrate protocatechuate. Some possible effects and interactions of synthetic organic chemicals with the natural microflora, and the influence of other vectors, is discussed in relation to the maintenance of the carbon cycle and environmental pollution. PMID:829485

  10. Biodegradation of microbial and synthetic polyesters by fungi.

    PubMed

    Kim, D Y; Rhee, Y H

    2003-05-01

    A variety of biodegradable polyesters have been developed in order to obtain useful biomaterials and to reduce the impact of environmental pollution caused by the large-scale accumulation of non-degradable waste plastics. Polyhydroxyalkanoates, poly(epsilon-caprolactone), poly( l-lactide), and both aliphatic and aromatic polyalkylene dicarboxylic acids are examples of biodegradable polyesters. In general, most aliphatic polyesters are readily mineralized by a number of aerobic and anaerobic microorganisms that are widely distributed in nature. However, aromatic polyesters are more resistant to microbial attack than aliphatic polyesters. The fungal biomass in soils generally exceeds the bacterial biomass and thus it is likely that fungi may play a considerable role in degrading polyesters, just as they predominantly perform the decomposition of organic matter in the soil ecosystem. However, in contrast to bacterial polyester degradation, which has been extensively investigated, the microbiological and environmental aspects of fungal degradation of polyesters are unclear. This review reports recent advances in our knowledge of the fungal degradation of microbial and synthetic polyesters and discusses the ecological importance and contribution of fungi in the biological recycling of waste polymeric materials in the biosphere. PMID:12743758

  11. Natural and enhanced biodegradation of propylene glycol in airport soil.

    PubMed

    Toscano, Giuseppe; Colarieti, M Letizia; Anton, Attila; Greco, Guido; Biró, Borbála

    2014-01-01

    Aircraft de-icing fluids (ADF) are a source of water and soil pollution in airport sites. Propylene glycol (PG) is a main component in several commercial formulations of ADFs. Even though PG is biodegradable in soil, seasonal overloads may result in occasional groundwater contamination. Feasibility studies for the biostimulation of PG degradation in soil have been carried out in soil slurries, soil microcosms and enrichment cultures with and without the addition of nutrients (N and P sources, oligoelements), alternative electron acceptors (nitrate, oxygen releasing compounds) and adsorbents (activated carbon). Soil samples have been taken from the contaminated area of Gardermoen Airport Oslo. Under aerobic conditions and in the absence of added nutrients, no or scarce biomass growth is observed and PG degradation occurs by maintenance metabolism at constant removal rate by the original population of PG degraders. With the addition of nutrient, biomass exponential growth enhances aerobic PG degradation also at low temperatures (4 ° C) that occur at the high season of snowmelt. Anaerobic PG degradation without added nutrients still proceeds at constant rate (i.e. no biomass growth) and gives rise to reduced fermentation product (propionic acid, reduced Fe and Mn, methane). The addition of nitrate does not promote biomass growth but allows full PG mineralization without reduced by-products. Further exploitation on the field is necessary to fully evaluate the effect of oxygen releasing compounds and adsorbents. PMID:23828729

  12. Biodegradation of petroleum hydrocarbons in an immobilized cell airlift bioreactor.

    PubMed

    Kermanshahi pour, A; Karamanev, D; Margaritis, A

    2005-09-01

    An "immobilized cell airlift bioreactor", was used for the aerobic bioremediation of simulated diesel fuel contaminated groundwater and tested with p-xylene and naphthalene in batch and continuous regimes. The innovative design of the experiments consists of two stages. At the first stage "immobilized soil bioreactor" (ISBR) was used to develop an efficient microbial consortium from the indigenous microorganisms, which exist in diesel fuel contaminated soil. The concept of ISBR relies on the entrapment of the soil particles into the pores of a semi-permeable membrane, which divides the bioreactor into two aerated and non-aerated portions. The second stage involves inoculating the "immobilized cell air lift bioreactor" with the cultivated microbial consortia of the first stage. Immobilized cell airlift bioreactor has the same configuration as ISBR except that in this bioreactor instead of soil, microorganisms were immobilized on the fibers of the membrane. The performance of a 0.83 L immobilized cell airlift bioreactor was investigated at various retention time (0.5-6 h) and concentrations of p-xylene (15, 40 and 77 mg/L) and naphthalene (8, 15 and 22 mg/L) in the continuous operation. In the batch regime, 0.9L bioreactor was operated at various biodegradation times (15-135 min) and concentrations of p-xylene (13.6, 44.9 and 67.5 mg/L) and naphthalene (1.5 and 3.8 mg/L). Under the conditions of the complete biodegradation of p-xylene and naphthalene, the obtained volumetric biodegradation rates at biomass density of 720 mg/L were 15 and 16 mg/L h, respectively. PMID:16095655

  13. Transformation and utilization of slowly biodegradable organic matters in biological sewage treatment of anaerobic anoxic oxic systems.

    PubMed

    Zhang, Q H; Jin, P K; Ngo, H H; Shi, X; Guo, W S; Yang, S J; Wang, X C; Wang, X; Dzakpasu, M; Yang, W N; Yang, L

    2016-10-01

    This study examined the distribution of carbon sources in two anaerobic anoxic oxic (AAO) sewage treatment plants in Xi'an and investigated the transformation characteristics and utilization potential of slowly biodegradable organic matters (SBOM). Results indicated under anaerobic and aerobic conditions, SBOM could be transformed at a rate of 65% in 8h into more readily biologically utilizable substrates such as volatile fatty acids (VFAs), polysaccharides and proteins. Additionally, non-biodegradable humus-type substances which are difficult to biodegrade and readily accumulate, were also generated. These products could be further hydrolyzed to aldehyde and ketone compounds and then transformed into substances with significant oxygen-containing functional groups and utilized subsequently. The molecular weights of proteinoid substances had a wide distribution and tended to decrease over time. Long hours of microbial reaction increased the proportion of micromolecular substances. This particular increase generated significant bioavailability, which can greatly improve the efficiency of nitrogen removal. PMID:27347798

  14. BIODEGRADATION STUDIES OF CARBOXYMETHYL TARTRONATE

    EPA Science Inventory

    Carboxymethyl tartronate (CMT) was shown to be biodegradable in bench-scale activated sludge reactors. After initial exposure to CMT in continuous flow systems an acclimation period of 14 weeks was necessary before efficient degradation occurred. Once acclimated to CMT the biomas...

  15. Biodegradable Pectin/clay Aerogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  16. Fate and effect of xenobiotics on biodegradation processes: basis for respirometric appraisal.

    PubMed

    Orhon, Derin; Sözen, Seval

    2012-01-01

    The paper mainly focused on illustrating the merit of respirometric analysis in assessing the inhibitory/toxic impact of xenobiotics on substrate biodegradation. It also evaluated biodegradation characteristics of these chemicals at continuous exposure through acclimation ofthe microbial culture. The nature and role ofoxygen uptake rate (OUR) profiles were discussed in conjunction with appropriate modelling, which should incorporate dissolved oxygen as an indispensable component for respirometric evaluation. Emphasis was placed upon differentiating acute effects from chronic impact, which may be totally different as it involves biodegradation of the chemical due biomass acclimation. Three case studies, each involving OUR measurements and process modelling, were presented for this purpose. The first one related to the inhibitory action of pharmaceutical effluent when mixed with plain-settled tannery wastewater. The second investigated the fate of H-acid, a commercially important naphthalene sulfonate, which exerted no adverse effect on substrate biodegradation, while remaining intact before and after a long acclimation period. The third one involved 2,6-dihydroxybenzoic acid, a naturally occurring organic compound in olive oil wastewater, which became biodegradable after acclimation by the development ofa specific microbial biomass fraction, while it heavily inhibited substrate biodegradation at first exposure. Model evaluation of the experimental data could provide related information on process stoichiometry and kinetics in all studies. PMID:22988610

  17. Biodegradation of oxo-alcohol ethoxylates in the continuous flow activated sludge simulation test.

    PubMed

    Szymanski, Andrzej; Wyrwas, Bogdan; Bubien, Ewa; Kurosz, Tatiana; Hreczuch, Wieslaw; Zembrzuski, Wlodzimierz; Lukaszewski, Zenon

    2002-07-01

    Biodegradation of two alpha-methyl branched oxo-alcohol ethoxylates (OAE) of different polydispersity: LIAL 125/14 BRD (LIALB) (broad M.W. distribution) and LIAL 125/14 NRD (LIALN) (narrow M.W. distribution), both having an average of 14 oxyethylene subunits (EO) and a C(12-15) alkyl moiety were tested under the continuous flow activated sludge conditions of the classical Husmann plant. Primary biodegradation and concentration of metabolites: free oxo-alcohol fraction (FOA) and poly(ethylene glycols) (PEG), were measured. PEG were divided into two fractions: short-chained PEG (PEGshch) (1-4 EO) and long-chained PEG (PEGlch) (>4 EO). The indirect tensammetric technique combined with an adequate separation was used for analysis. Central fission was found to be a highly dominating pathway, as is the case with fatty alcohol ethoxylates. OAE are highly primarily biodegraded (above 95%). High concentrations of FOA and PEG are formed. Once formed the PEGlch are further fragmented into the PEGshch. Free alcohol fraction compounds are biodegraded sooner when alkyl moiety is shorter. OAE polydispersity has an influence on the kinetics of biodegradation; PEG formed from LIALN are biodegraded slower and to a lower degree than those from LIALB. PMID:12188138

  18. Aerobic granular processes: Current research trends.

    PubMed

    Zhang, Quanguo; Hu, Jianjun; Lee, Duu-Jong

    2016-06-01

    Aerobic granules are large biological aggregates with compact interiors that can be used in efficient wastewater treatment. This mini-review presents new researches on the development of aerobic granular processes, extended treatments for complicated pollutants, granulation mechanisms and enhancements of granule stability in long-term operation or storage, and the reuse of waste biomass as renewable resources. A discussion on the challenges of, and prospects for, the commercialization of aerobic granular process is provided. PMID:26873285

  19. Biodegradation and interaction of quinoline and glucose in dual substrates system.

    PubMed

    Xu, Peng; Ma, Wencheng; Han, Hongjun; Hou, Baolin; Jia, Shengyong

    2015-03-01

    An indigenous mixed culture of microorganisms, isolated from a full-scale coal gasification wastewater treatment plant, was used in degrading quinoline in presence of glucose as an alternative carbon source. The results showed that biodegradation kinetics of both quinoline and glucose could be described by first-order reaction kinetics model. It was also found that the biodegradation rate of quinoline was accelerated by the presence of glucose, while glucose degradation was inhibited by the presence of quinoline. Both the biomass yield coefficient and specific growth rate were increased with the increasing of the glucose concentrations in the dual substrates system. A sum kinetics model was used to describe the relative effects of the two substrates on their individual uptakes. The interaction parameter values indicated that quinoline exhibits stronger inhibition on glucose degradation. But for glucose, its effect on quinoline utilization was stimulative. Furthermore, the stimulation was positively correlated with the concentration of glucose in the system. PMID:25283366

  20. Biodegradation of 17β-estradiol, estrone and testosterone in stream sediments

    USGS Publications Warehouse

    Bradley, Paul M.; Barber, Larry B.; Chapelle, Francis H.; Gray, James L.; Kolpin, Dana W.; McMahon, Peter B.

    2009-01-01

    Biodegradation of 17β-estradiol (E2), estrone (E1), and testosterone (T) was investigated in three wastewater treatment plant (WWTP) affected streams in the United States. Relative differences in the mineralization of [4-14C] substrates were assessed in oxic microcosms containing saturated sediment or water-only from locations upstream and downstream of the WWTP outfall in each system. Upstream sediment demonstrated significant mineralization of the “A” ring of E2, E1, and T, with biodegradation of T consistently greater than that of E2 and no systematic difference in E2 and E1 biodegradation. “A” ring mineralization also was observed in downstream sediment, with E1 and T mineralization being substantially depressed relative to upstream samples. In marked contrast, E2 mineralization in sediment immediately downstream from the WWTP outfalls was more than double that in upstream sediment. E2 mineralization was observed in water, albeit at insufficient rate to prevent substantial downstream transport. The results indicate that, in combination with sediment sorption processes which effectively scavenge hydrophobic contaminants from the water column and immobilize them in the vicinity of the WWTP outfall, aerobic biodegradation of reproductive hormones can be an environmentally important mechanism for nonconservative (destructive) attenuation of hormonal endocrine disruptors in effluent-affected streams.

  1. Biobased and biodegradable polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Qiu, Kaiyan

    In this dissertation, various noncrosslinked and crosslinked biobased and biodegradable polymer nanocomposites were fabricated and characterized. The properties of these polymer nanocomposites, and their relating mechanisms and corresponding applications were studied and discussed in depth. Chapter 1 introduces the research background and objectives of the current research. Chapter 2 presents the development of a novel low cost carbon source for bacterial cellulose (BC) production and fabrication and characterization of biobased polymer nanocomposites using produced BC and soy protein based resins. The carbon source, soy flour extract (SFE), was obtained from defatted soy flour (SF) and BC yield achieved using SFE medium was high. The results of this study showed that SFE consists of five sugars and Acetobacter xylinum metabolized sugars in a specific order. Chapter 3 discusses the fabrication and characterization of biodegradable polymer nanocomposites using BC and polyvinyl alcohol (PVA). These polymer nanocomposites had excellent tensile and thermal properties. Crosslinking of PVA using glutaraldehyde (GA) not only increased the mechanical and thermal properties but the water-resistance. Chapter 4 describes the development and characterization of microfibrillated cellulose (MFC) based biodegradable polymer nanocomposites by blending MFC suspension with PVA. Chemical crosslinking of the polymer nanocomposites was carried out using glyoxal to increase the mechanical and thermal properties as well as to make the PVA partially water-insoluble. Chapter 5 reports the development and characterization of halloysite nanotube (HNT) reinforced biodegradable polymer nanocomposites utilizing HNT dispersion and PVA. Several separation techniques were used to obtain individualized HNT dispersion. The results indicated uniform dispersion of HNTs in both PVA and malonic acid (MA) crosslinked PVA resulted in excellent mechanical and thermal properties of the materials, especially

  2. UV photolysis for accelerating pyridine biodegradation.

    PubMed

    Zhang, Yongming; Chang, Ling; Yan, Ning; Tang, Yingxia; Liu, Rui; Rittmann, Bruce E

    2014-01-01

    Pyridine, a nitrogen-containing heterocyclic compound, is slowly biodegradable, and coupling biodegradation with UV photolysis is a potential means to accelerate its biotransformation and mineralization. The initial steps of pyridine biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. We employed an internal circulation baffled biofilm reactor for pyridine biodegradation following three protocols: direct biodegradation (B), biodegradation after photolysis (P+B), and biodegradation with succinic acid added (B+S). Succinic acid was the main UV-photolysis product from pyridine, and its catabolic oxidation generates internal electron carriers that may accelerate the initial steps of pyridine biodegradation. Compared with direct biodegradation of pyridine (B), the removal rate for the same concentration of photolyzed pyridine (P+B) was higher by 15 to 43%, depending on the initial pyridine concentrations (increasing through the range of 130 to 310 mg/L). Adding succinic acid alone (B+S) gave results similar to P+B, which supports that succinic acid was the main agent for accelerating the pyridine biodegradation rate. In addition, protocols P+B and B+S were similar in terms of increasing pyridine mineralization over 10 h: 84% and 87%, respectively, which were higher than with protocol B (72%). The positive impact of succinic acid-whether added directly or produced via UV photolysis-confirms that its catabolism, which produced intracellular electron carriers, accelerated the initial steps of pyridine biotransformation. PMID:24364496

  3. Treatment of phenolics, aromatic hydrocarbons, and cyanide-bearing wastewater in individual and combined anaerobic, aerobic, and anoxic bioreactors.

    PubMed

    Sharma, Naresh K; Philip, Ligy

    2015-01-01

    Studies were conducted on a mixture of pollutants commonly found in coke oven wastewater (CWW) to evaluate the biodegradation of various pollutants under anaerobic, aerobic, and anoxic conditions. The removal of the pollutants was monitored during individual bioreactor operation and using a combination of bioreactors operating in anaerobic-aerobic-anoxic sequence. While studying the performance of individual reactors, it was observed that cyanide removal (83.3 %) was predominant in the aerobic bioreactor, while much of the chemical oxygen demand (COD) (69 %) was consumed in the anoxic bioreactor. With the addition of cyanide, the COD removal efficiency was affected in all the bioreactors, and several intermediates were detected. While treating synthetic CWW using the combined bioreactor system, the overall COD removal efficiency was 86.79 % at an OLR of 2.4 g COD/L/day and an HRT of 96 h. The removal efficiency of 3,5-xylenol and cyanide, with inlet concentration of 150 and 10 mg/L, was found to be 91.8 and 93.6 % respectively. It was found that the impact of xylenol on the performance of the bioreactors was less than cyanide toxicity. Molecular analysis using T-RFLP revealed the dominance of strictly aerobic, mesophilic proteobacterium, Bosea minatitlanensis, in the aerobic bioreactor. The anoxic bioreactor was dominant with Rhodococcus pyridinivorans, known for its remarkable aromatic decomposing activity, while an unclassified Myxococcales bacterium was identified as the predominant bacterial species in the anaerobic bioreactor. PMID:25267355

  4. Novel degradation pathway and kinetic analysis for buprofezin removal by newly isolated Bacillus sp.

    PubMed

    Wang, Guangli; Xu, Dayong; Xiong, Minghua; Zhang, Hui; Li, Feng; Liu, Yuan

    2016-09-15

    Given the intensive and widespread application of the pesticide, buprofezin, its environmental residues potentially pose a problem; yet little is known about buprofezin's kinetic and metabolic behaviors. In this study, a novel gram-positive strain, designated BF-5, isolated from aerobic activated sludge, was found to be capable of metabolizing buprofezin as its sole energy, carbon, and nitrogen source. Based on its physiological and biochemical characteristics, other aspects of its phenotype, and a phylogenetic analysis, strain BF-5 was identified as Bacillus sp. This study investigated the effect of culture conditions on bacterial growth and substrate degradation, such as pH, temperature, initial concentration, different nitrogen source, and additional nitrogen sources as co-substrates. The degradation rate parameters, qmax, Ks, Ki and Sm were determined to be 0.6918 h(-1), 105.4 mg L(-1), 210.5 mg L(-1), and 148.95 mg L(-1) respectively. The capture of unpublished potential metabolites by gas chromatography-mass spectrometry (GC-MS) analysis has led to the proposal of a novel degradation pathway. Taken together, our results clarify buprofezin's biodegradation pathway(s) and highlight the promising potential of strain BF-5 in bioremediation of buprofezin-contaminated environments. PMID:27208995

  5. Removal of oxytetracycline and determining its biosorption properties on aerobic granular sludge.

    PubMed

    Mihciokur, Hamdi; Oguz, Merve

    2016-09-01

    This study investigates biosorption of Oxytetracycline, a broad-spectrum antibiotic, using aerobic granular sludge as an adsorbent in aqueous solutions. A sequencing batch reactor fed by a synthetic wastewater was operated to create aerobic granular sludge. Primarily, the pore structure and surface area of granular sludge, the chemical structure and the molecular sizes of the pharmaceutical, operating conditions, such as pH, stirring rate, initial concentration of Oxytetracycline, during adsorption process was verified. Subsequently, thermodynamic and kinetic aspects of the adsorption were examined and adsorption isotherm studies were carried out. It was shown that the aerobic granular sludge was a good alternative for biosorption of this pharmaceutical. The pharmaceutical was adsorbed better at pH values of 6-8. The adsorption efficiency increased with rising ionic strength. Also, it was seen that the adsorption process was an exothermic process in terms of thermodynamics. The adsorption can be well explained by Langmuir isotherm model. PMID:27485178

  6. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    PubMed

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene. PMID:26054614

  7. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  8. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  9. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  10. Aerobic Dancing--A Rhythmic Sport.

    ERIC Educational Resources Information Center

    Sorensen, Jacki

    Fitness programs now and in the future must offer built-in cardiovascular conditioning, variety, novelty, and change to meet the physical, mental, and emotional needs of our society. Aerobic dancing (dancing designed to train and strengthen the heart, lungs, and vascular system) is one of the first indoor group Aerobic exercise programs designed…

  11. Anaerobic/aerobic treatment of selected azo dyes in wastewater

    SciTech Connect

    Seshadri, S.; Bishop, P.L. . Dept. of Civil and Environmental Engineering); Agha, A.M. . Faculty of Civil Engineering)

    1994-01-01

    Azo dyes represent the largest class of dyes in use today. Current environmental concern with these dyes revolves around the potential carcinogenic health risk presented by these dyes or their intermediate biodegradation products when exposed to microflora in the human digestive tract. These dyes may build up in the environment, since many wastewater treatment plants allow these dyes to pass through the system virtually untreated. The initial step in the degradation of these dyes is the cleavage of the Azo bond. This cleavage is often impossible under aerobic conditions, but has been readily demonstrated under anaerobic conditions. The focus of the study was to determine the feasibility of using an anaerobic fluidized-bed reactor to accomplish this cleavage. The effects of typical process variables such as hydraulic retention time (HRT), influent dye concentration levels, and degree of bed fluidization on removal efficiencies were also studied. The four dyes selected for this study were Acid-Orange 7, Acid-Orange 8, Acid-Orange 10, and Acid-Red 14. The effectiveness of using a bench-scale-activated sludge reactor as a sequenced second stage was also examined. Results indicate that nearly complete cleavage of the Azo bond is easily accomplished for each of the four dyes under hydraulic retention times of either 12 or 24 h. Initial results indicate, though, that aromatic amine by-products remain. The sequenced second stage was able to remove the remaining Chemical Oxygen Demand (COD) load to acceptable levels. Work is presently underway to determine the face of the anaerobic by-products in the aerobic second stage.

  12. Biodegradable microspheres for parenteral delivery.

    PubMed

    Sinha, V R; Trehan, A

    2005-01-01

    Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery. PMID:16566705

  13. Recalcitrance of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) to cometabolic degradation by pure cultures of aerobic and anaerobic bacteria.

    PubMed

    Megharaj, M; Jovcic, A; Boul, H L; Thiele, J H

    1997-08-01

    Pure cultures of aerobic and anaerobic bacteria capable of oxidation and reductive dehalogenation of chloroethylenes, and aerobic bacteria involved in biodegradation of polychlorinated biphenyls (PCBs) were screened for their ability to cometabolize the persistent pollutant 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE). Bacterial cultures expressing methane monooxygenase (Methylosinus trichosporium), propane monooxygenase (Mycobacterium vaccae) and biphenyl 2,3-dioxygenase enzymes (Pseudomonas fluorescens and Rhodococcus globerulus), as well as bacteria reductively dechlorinating chloroethylenes (Acetobacterium woodii and Clostridium butyricum) could not degrade DDE. Cell-free extracts of M. trichosporium, M. vaccae, P. fluorescens and R. globerulus were also unable to transform DDE, indicating that cell wall and membrane diffusion barriers were not biodegradation limiting. These studies suggest that these bacteria can not degrade DDE, even when provided with cosubstrates that induce chlorophenyl- and dichloroethylene-group transforming enzymes. PMID:9294241

  14. Biodegradation of dimethylsilanediol in soils.

    PubMed Central

    Sabourin, C L; Carpenter, J C; Leib, T K; Spivack, J L

    1996-01-01

    The biodegradation potential of [14C]dimethylsilanediol, the monomer unit of polydimethylsiloxane, in soils was investigated. Dimethylsilanediol was found to be biodegraded in all of the tested soils, as monitored by the production of 14CO2. When 2-propanol was added to the soil as a carbon source in addition to [14C]dimethylsilanediol, the production of 14CO2 increased. A method for the selection of primary substrates that support cometabolic degradation of a target compound was developed. By this method, the activity observed in the soils was successfully transferred to liquid culture. A fungus, Fusarium oxysporum Schlechtendahl, and a bacterium, an Arthrobacter species, were isolated from two different soils, and both microorganisms were able to cometabolize [14C]dimethylsilanediol to 14CO2 in liquid culture. In addition, the Arthrobacter sp. that was isolated grew on dimethylsulfone, and we believe that this is the first reported instance of a microorganism using dimethylsulfone as its primary carbon source. Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer, dimethylsilanediol. Now, biodegradation of dimethylsilanediol in soil has been demonstrated. PMID:8953708

  15. Engineering Flame Retardant Biodegradable Nanocomposites

    NASA Astrophysics Data System (ADS)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  16. Solubilization, solution equilibria, and biodegradation of PAH's under thermophilic conditions.

    PubMed

    Viamajala, Sridhar; Peyton, Brent M; Richards, Lee A; Petersen, James N

    2007-01-01

    Biodegradation rates of PAHs are typically low at mesophilic conditions and it is believed that the kinetics of degradation is controlled by PAH solubility and mass transfer rates. Solubility tests were performed on phenanthrene, fluorene and fluoranthene at 20 degrees C, 40 degrees C and 60 degrees C and, as expected, a significant increase in the equilibrium solubility concentration and of the rate of dissolution of these polycyclic aromatic hydrocarbons (PAHs) was observed with increasing temperature. A first-order model was used to describe the PAH dissolution kinetics and the thermodynamic property changes associated with the dissolution process (enthalpy, entropy and Gibb's free energy of solution) were evaluated. Further, other relevant thermodynamic properties for these PAHs, including the activity coefficients at infinite dilution, Henry's law constants and octanol-water partition coefficients, were calculated in the temperature range 20-60 degrees C. In parallel with the dissolution studies, three thermophilic Geobacilli were isolated from compost that grew on phenanthrene at 60 degrees C and degraded the PAH more rapidly than other reported mesophiles. Our results show that while solubilization rates of PAHs are significantly enhanced at elevated temperatures, the biodegradation of PAHs under thermophilic conditions is likely mass transfer limited due to enhanced degradation rates. PMID:16934313

  17. Solubilization, Solution Equilibria, and Biodegradation of PAH's under Thermophilic Conditions

    SciTech Connect

    Viamajala, S.; Peyton, B. M.; Richards, L. A.; Petersen, J. N.

    2007-01-01

    Biodegradation rates of PAHs are typically low at mesophilic conditions and it is believed that the kinetics of degradation is controlled by PAH solubility and mass transfer rates. Solubility tests were performed on phenanthrene, fluorene and fluoranthene at 20 C, 40 C and 60 C and, as expected, a significant increase in the equilibrium solubility concentration and of the rate of dissolution of these polycyclic aromatic hydrocarbons (PAHs) was observed with increasing temperature. A first-order model was used to describe the PAH dissolution kinetics and the thermodynamic property changes associated with the dissolution process (enthalpy, entropy and Gibb's free energy of solution) were evaluated. Further, other relevant thermodynamic properties for these PAHs, including the activity coefficients at infinite dilution, Henry's law constants and octanol-water partition coefficients, were calculated in the temperature range 20-60 C. In parallel with the dissolution studies, three thermophilic Geobacilli were isolated from compost that grew on phenanthrene at 60 C and degraded the PAH more rapidly than other reported mesophiles. Our results show that while solubilization rates of PAHs are significantly enhanced at elevated temperatures, the biodegradation of PAHs under thermophilic conditions is likely mass transfer limited due to enhanced degradation rates.

  18. Drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy.

    PubMed

    Floyd, J Alaina; Galperin, Anna; Ratner, Buddy D

    2016-02-01

    The grim prognosis for patients diagnosed with malignant gliomas necessitates the development of new therapeutic strategies for localized and sustained drug delivery to combat tumor drug resistance and regrowth. Here we introduce drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy (DREAM BIG therapy). DREAM BIG therapy is envisioned to deliver three chemotherapeutics, temporally staged over one year, via a bioadhesive, biodegradable spray directly to the brain surgical site after tumor excision. In this proof-of-principle article exploring key components of the DREAM BIG therapy prototype, rhodamine B (RB) encapsulated poly(lactic-co-glycolic acid) and immunoglobulin G (IgG) encapsulated poly(lactic acid) microspheres were formulated and characterized. The encapsulation efficiency of RB and IgG and the release kinetics of the model drugs from the microspheres were elucidated in addition to the release kinetics of RB from poly(lactic-co-glycolic acid) microspheres formulated in a degradable poly(N-isopropylacrylamide) solution. The successful aerosolized application onto brain tissue ex-vivo demonstrated the conformal adhesion of the RB encapsulated poly(lactic-co-glycolic acid) microspheres to the convoluted brain surface mediated by the thermoresponsive carrier, poly(N-isopropylacrylamide). These preliminary results suggest the potential of the DREAM BIG therapy for future use with multiple chemotherapeutics and microsphere types to combat gliomas at a localized site. PMID:26238392

  19. Kinetic Demonstration.

    ERIC Educational Resources Information Center

    Burgardt, Erik D.; Ryan, Hank

    1996-01-01

    Presents a unit on chemical reaction kinetics that consists of a predemonstration activity, the demonstration, and a set of postdemonstration activities that help students transfer the concepts to actual chemical reactions. Simulates various aspects of chemical reaction kinetics. (JRH)

  20. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  1. Determination of rate constants and half-lives for the simultaneous biodegradation of several cyanobacterial metabolites in Australian source waters.

    PubMed

    Ho, Lionel; Tang, Tim; Hoefel, Daniel; Vigneswaran, Bala

    2012-11-01

    The fate of five cyanobacterial metabolites was assessed in water sourced from Lake Burragorang (Warragamba Dam) in New South Wales, Australia. All of the studied metabolites were shown to be biodegradable in this water source. For some metabolites, biodegradation was influenced by factors, including temperature, location (within the water body) and seasonal variations. The biodegradation of the metabolites was shown to follow pseudo-first-order kinetics with rate constants ranging from 8.0 × 10(-4) to 1.3 × 10(-2) h(-1). Half-lives of the metabolites were also estimated and ranged from 2.2 to 36.1 d. The order of ease of biodegradability in this water source followed the trend: microcystin-LR ≥ cylindrospermopsin > saxitoxins > geosmin ≥ 2-methylisoborneol. The lack of detection of the mlrA gene during microcystin biodegradation suggests that these toxins may be degraded via a different pathway. While no metabolite-degrading organisms were isolated in this study, the inoculation of previously isolated geosmin- and microcystin-degrading bacteria into Lake Burragorang water resulted in efficient biodegradation of the respective metabolites. For example, microcystin-degrading isolate TT25 was able to degrade three microcystin variants to concentrations below analytical detection within 24 h, suggesting that inoculation of such bacteria has the potential to enhance biodegradation in Lake Burragorang. PMID:22921397

  2. Fringe-controlled biodegradation under dynamic conditions: Quasi 2-D flow-through experiments and reactive-transport modeling

    NASA Astrophysics Data System (ADS)

    Eckert, Dominik; Kürzinger, Petra; Bauer, Robert; Griebler, Christian; Cirpka, Olaf A.

    2015-01-01

    Biodegradation in contaminated aquifers has been shown to be most pronounced at the fringe of contaminant plumes, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. While physical mixing of contaminant and electron acceptor by transverse dispersion has been shown to be the major bottleneck for biodegradation in steady-state plumes, so far little is known on the effect of flow and transport dynamics (caused, e.g., by a seasonally fluctuating groundwater table) on biodegradation in these systems. Towards this end we performed experiments in quasi-two-dimensional flow-through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth, also maintenance and dormancy are important processes that affect biodegradation performance under transient environmental conditions and therefore deserve increased consideration in future reactive-transport modeling.

  3. Incomplete aerobic degradation of the antidiabetic drug Metformin and identification of the bacterial dead-end transformation product Guanylurea.

    PubMed

    Trautwein, Christoph; Kümmerer, Klaus

    2011-10-01

    Active pharmaceutical ingredients as well as personal care products are detected in increasing prevalence in different environmental compartments such as surface water, groundwater and soil. Still little is known about the environmental fate of these substances. The type II antidiabetic drug Metformin has already been detected in different surface waters worldwide, but concentrations were significantly lower than the corresponding predicted environmental concentration (PEC). In human and mammal metabolism so far no metabolites of Metformin have been identified, so the expected environmental concentrations should be very high. To assess the aerobic biodegradability of Metformin and the possible formation of degradation products, three Organisation of Economic Cooperation and Development (OECD) test series were performed in the present study. In the Closed Bottle test (OECD 301 D), a screening test that simulates the conditions of an environmental surface water compartment, Metformin was classified as not readily biodegradable (no biodegradation). In the Manometric Respiratory test (OEDC 301 F) working with high bacterial density, Metformin was biodegraded in one of three test bottles to 48.7% and in the toxicity control bottle to 57.5%. In the Zahn-Wellens test (OECD 302 B) using activated sludge, Metformin was biodegraded in both test vessels to an extent of 51.3% and 49.9%, respectively. Analysis of test samples by high performance liquid chromatography coupled to multiple stage mass spectrometry (HPLC-MS(n)) showed in the tests vessels were biodegradation was observed full elimination of Metformin and revealed Guanylurea (Amidinourea, Dicyandiamidine) as single and stable aerobic bacterial degradation product. In another Manometric Respiratory test Guanylurea showed no more transformation. Photodegradation of Guanylurea was also negative. A first screening in one of the greatest sewage treatment plant in southern Germany found Metformin with high concentrations

  4. [Biodegradability of the components of natural hydrocarbon mixtures previously submitted to landfarming].

    PubMed

    Pucci, G N; Pucci, O H

    2003-01-01

    The complex composition of the crude oil and the hydrocarbons that integrate the waste of the different stages of the oil industry turn this product a mixture that presents different difficulties for its elimination by biological methods. The objective of this paper was to study the biodegradation potential of autochthonous bacterial communities on hydrocarbons obtained from four polluted places and subjected to landfarming biorremediation system during a decade. The results showed a marked difference in biodegradability of the three main fractions of crude oil, aliphatic, aromatic, and polar fractions, obtained by column chromatography. All fractions were used as carbon source and energy. There were variations in the production of biomass among the different fractions as well as in the kinetics of biodegradation, according to the composition of each fraction. PMID:12920985

  5. Independent prediction of naphthalene transport and biodegradation in soil with a mathematical model

    SciTech Connect

    Ahn, I.S.; Ghiorse, W.C.; Lion, L.W.; Shuler, M.L.

    1999-10-05

    Experiments were performed to test the ability of a mathematical model to predict naphthalene transport and biodegradation. Pseudomonas putida G7, a model bacterial strain capable of degrading naphthalene, was added to a column packed with the soil that had been pre-equilibrated with naphthalene. Model prediction for transport and degradation were based on predetermined parameters that described naphthalene desorption kinetics and the utilization of naphthalene by the test bacterium. However, initial prediction for naphthalene biodegradation was high, and the formation of cell aggregates is advances as a plausible explanation. Access of substrate to cells in the interior of an aggregate would be restricted. When the numerical simulation was conducted with a factor to account for cell aggregation, it successfully described the experimental data. Thus, with a single adjustable parameter (an average effectiveness factor), the model predicted macroscopic responses of naphthalene in soil-columns where naphthalene was subject to transport and biodegradation.

  6. Toxicity and biodegradability of olive mill wastewaters in batch anaerobic digestion

    SciTech Connect

    Hamdi, M. Universite de Provence, Marseille )

    1992-11-01

    The anaerobic biodegradability and toxicity of olive mill wastewaters (OMW) were studied in batch anaerobic digestion experiments. Anaerobic digestion of OMW or the supernatant of its centrifugation, the methane production was achieved at up to 5-15% (V/V) dilution corresponding to only 5-20 g/L COD. The washed suspended solids of OMW were toxic at up to 80 g/L COD; however, the kinetic of biodegradability of OMW or the supernatant was faster than for suspended solids, which are constituted mealy of cellulose and lignin. The darkly colored polyphenols induce the problem of biodegradation of OMW, whereas the long chain fatty acids (LCFA), tannins and simple phenolic compounds are responsible for its toxicity for methanogenic bacteria. 26 refs., 4 figs., 1 tab.

  7. Inverse modeling of BTEX dissolution and biodegradation at the Bemidji, MN crude-oil spill site

    USGS Publications Warehouse

    Essaid, H.I.; Cozzarelli, I.M.; Eganhouse, R.P.; Herkelrath, W.N.; Bekins, B.A.; Delin, G.N.

    2003-01-01

    The U.S. Geological Survey (USGS) solute transport and biodegradation code BIOMOC was used in conjunction with the USGS universal inverse modeling code UCODE to quantify field-scale hydrocarbon dissolution and biodegradation at the USGS Toxic Substances Hydrology Program crude-oil spill research site located near Bemidji, MN. This inverse modeling effort used the extensive historical data compiled at the Bemidji site from 1986 to 1997 and incorporated a multicomponent transport and biodegradation model. Inverse modeling was successful when coupled transport and degradation processes were incorporated into the model and a single dissolution rate coefficient was used for all BTEX components. Assuming a stationary oil body, we simulated benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene (BTEX) concentrations in the oil and ground water, respectively, as well as dissolved oxygen. Dissolution from the oil phase and aerobic and anaerobic degradation processes were represented. The parameters estimated were the recharge rate, hydraulic conductivity, dissolution rate coefficient, individual first-order BTEX anaerobic degradation rates, and transverse dispersivity. Results were similar for simulations obtained using several alternative conceptual models of the hydrologic system and biodegradation processes. The dissolved BTEX concentration data were not sufficient to discriminate between these conceptual models. The calibrated simulations reproduced the general large-scale evolution of the plume, but did not reproduce the observed small-scale spatial and temporal variability in concentrations. The estimated anaerobic biodegradation rates for toluene and o-xylene were greater than the dissolution rate coefficient. However, the estimated anaerobic biodegradation rates for benzene, ethylbenzene, and m,p-xylene were less than the dissolution rate coefficient. The calibrated model was used to determine the BTEX mass balance in the oil body and groundwater plume

  8. Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Moe, Owen; Cornelius, Richard

    1988-01-01

    Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

  9. Biodegradation of high molecular weight polylactic acid

    NASA Astrophysics Data System (ADS)

    Stloukal, Petr; Koutny, Marek; Sedlarik, Vladimir; Kucharczyk, Pavel

    2012-07-01

    Polylactid acid seems to be an appropriate replacement of conventional non-biodegradable synthetic polymer primarily due to comparable mechanical, thermal and processing properties in its high molecular weight form. Biodegradation of high molecular PLA was studied in compost for various forms differing in their specific surface area. The material proved its good biodegradability under composting conditions and all investigated forms showed to be acceptable for industrial composting. Despite expectations, no significant differences in resulting mineralizations were observed for fiber, film and powder sample forms with different specific surface areas. The clearly faster biodegradation was detected only for the thin coating on porous material with high specific surface area.

  10. Inverse modeling of the biodegradation of emerging organic contaminants in the soil-plant system.

    PubMed

    Hurtado, Carlos; Trapp, Stefan; Bayona, Josep M

    2016-08-01

    Understanding the processes involved in the uptake and accumulation of organic contaminants into plants is very important to assess the possible human risk associated with. Biodegradation of emerging contaminants in plants has been observed, but kinetical studies are rare. In this study, we analyse experimental data on the uptake of emerging organic contaminants into lettuce derived in a greenhouse experiment. Measured soil, root and leaf concentrations from four contaminants were selected within the applicability domain of a steady-state two-compartment standard plant uptake model: bisphenol A (BPA), carbamazepine (CBZ), triclosan (TCS) and caffeine (CAF). The model overestimated concentrations in most cases, when no degradation rates in plants were entered. Subsequently, biodegradation rates were fitted so that the measured concentrations were met. Obtained degradation kinetics are in the order, BPA < CAF ≈ TCS < CBZ in roots, and BPA ≈ TCS < CBZ < CAF in leaves. Kinetics determined by inverse modeling are, despite the inherent uncertainty, indicative of the dissipation rates. The advantage of the procedure that is additional knowledge can be gained from existing experimental data. Dissipation kinetics found via inverse modeling is not a conclusive proof for biodegradation and confirmation by experimental studies is needed. PMID:27179241

  11. Biodegradation of paint stripper solvents in a modified gas lift loop bioreactor

    SciTech Connect

    Vanderberg-Twary, L.; Steenhoudt, K.; Travis, B.J.; Hanners, J.L.; Foreman, T.M.; Brainard, J.R.

    1997-07-05

    Paint stripping wastes generated during the decontamination and decommissioning of former nuclear facilities contain paint stripping organics (dichloromethane, 2-propanol, and methanol) and bulk materials containing paint pigments. It is desirable to degrade the organic residues as part of an integrated chemical-biological treatment system. The authors have developed a modified gas lift loop bioreactor employing a defined consortium of Thodococcus rhodochrous strain OFS and Hyphomicrobium sp. DM-2 that degrades paint stripper organics. Mass transfer coefficients and kinetic constants for biodegradation in the system were determined. It was found that transfer of organic substrates from surrogate waste into the air and further into the liquid medium in the bioreactor were rapid processes, occurring within minutes. Monod kinetics was employed to model the biodegradation of paint stripping organics. Analysis of the bioreactor process was accomplished with BIOLAB, a mathematical code that simulates coupled mass transfer and biodegradation processes. This code was used to fit experimental data to monod kinetics and to determine kinetic parameters. The BIOLAB code was also employed to compare activities in the bioreactor of individual microbial cultures to the activities of combined cultures in the bioreactor. This code is of benefit for further optimization and scale-up of the bioreactor for treatment of paint stripping and other volatile organic wastes in bulk materials.

  12. Degradation of Polycyclic Aromatic Hydrocarbons at Low Temperature under Aerobic and Nitrate-Reducing Conditions in Enrichment Cultures from Northern Soils

    PubMed Central

    Eriksson, Mikael; Sodersten, Erik; Yu, Zhongtang; Dalhammar, Gunnel; Mohn, William W.

    2003-01-01

    The potential for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at low temperature and under anaerobic conditions is not well understood, but such biodegradation would be very useful for remediation of polluted sites. Biodegradation of a mixture of 11 different PAHs with two to five aromatic rings, each at a concentration of 10 μg/ml, was studied in enrichment cultures inoculated with samples of four northern soils. Under aerobic conditions, low temperature severely limited PAH biodegradation. After 90 days, aerobic cultures at 20°C removed 52 to 88% of the PAHs. The most extensive PAH degradation under aerobic conditions at 7°C, 53% removal, occurred in a culture from creosote-contaminated soil. Low temperature did not substantially limit PAH biodegradation under nitrate-reducing conditions. Under nitrate-reducing conditions, naphthalene, 2-methylnaphthalene, fluorene, and phenanthrene were degraded. The most extensive PAH degradation under nitrate-reducing conditions at 7°C, 39% removal, occurred in a culture from fuel-contaminated Arctic soil. In separate transfer cultures from the above Arctic soil, incubated anaerobically at 7°C, removal of 2-methylnaphthalene and fluorene was stoichiometrically coupled to nitrate removal. Ribosomal intergenic spacer analysis suggested that enrichment resulted in a few predominant bacterial populations, including members of the genera Acidovorax, Bordetella, Pseudomonas, Sphingomonas, and Variovorax. Predominant populations from different soils often included phylotypes with nearly identical partial 16S rRNA gene sequences (i.e., same genus) but never included phylotypes with identical ribosomal intergenic spacers (i.e., different species or subspecies). The composition of the enriched communities appeared to be more affected by presence of oxygen, than by temperature or source of the inoculum. PMID:12514005

  13. Developmental hazard assessment with FETAX: Aerobic metabolites in bacterial transformation of naphthalene

    SciTech Connect

    Schultz, T.W.; Dawson, D.A.

    1995-05-01

    The underlying principle of bioremediation is the capability of microorganisms to biodegrade pollutants. When a contaminated site is biotreated, it is usually assumed that the disappearance of the pollutant means a reduction in the toxic effects of the contaminants. However, pollutants can undergo partial biodegradation or biotransformation. Microbial-mediated transformations play a critical role in the toxic effects of pollutants, as any alteration in structure can result in a change in physicochemical properties which influence toxicity. Therefore, a relevant question is; what is the toxicity of accumulative metabolites relative to the parent chemical? One class of chemicals that consistently appears at Superfund hazard waste sites is aromatic hydrocarbons. Studies of the aerobic bacterial metabolism of representative compounds, including benzene, naphthalene, and phenanthrene, have revealed similar oxidative pathways. Bacterial degradation of these aromatic hydrocarbons was initiated by the addition of two molecules of oxygen via a dioxygenase enzyme, with the resulting intermediate being converted to a catechol-like compound. From a biotransformation standpoint, one of the more thoroughly studied aromatic hydrocarbons has been naphthalene. Cerniglia (1984) has identified five major intermediates, 1,2-dihydroxynaphthalene, salicylaldehyde, salicylic acid, gentisic acid and catechol in the aerobic bacterial degradation of naphthalene. In vitro test systems such as the Frog Embryo Teratogenesis Assay - Xenopus (FETAX) provide a time- and resource-effective means for assessing developmental toxicity on a preliminary basis. FETAX is a 96-hr static-renewal system that uses early embryos of the frog Xenopus laevis. The purpose of this investigation was to determine the developmental hazard, using FETAX, of exposure to the model aromatic hydrocarbon, naphthalene, and it`s known major aerobic metabolites from bacterial transformation. 18 refs., 2 tabs.

  14. THE INFLUENCE OF THE GASOLINE OXYGENATE ETHANOL ON AEROBIC AND ANAEROBIC BTX BIODEGRADATION. (R823420)

    EPA Science Inventory

    Ethanol is frequently found along with benzene, toluene, and xylenes (BTX) in groundwater contaminated with gasoline. Yet, little is known about its effect on bioremediation of the toxic BTX contaminants. Aquifer microcosms were used to investigate the effect of ethanol on microb...

  15. Aerobic biodegradation of 2,4,6-trinitrotoluene (TNT) by Bacillus cereus isolated from contaminated soil.

    PubMed

    Mercimek, H Aysun; Dincer, Sadık; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih

    2013-10-01

    In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site. PMID:23715804

  16. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA: AEROBIC BIODEGRADATION REMEDY SCREENING

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (KU FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation, and L...

  17. Co-treatment of landfill leachate and domestic wastewater using a submerged aerobic biofilter.

    PubMed

    Ferraz, F M; Povinelli, J; Pozzi, E; Vieira, E M; Trofino, J C

    2014-08-01

    This study used a pilot-scale submerged aerobic biofilter (SAB) to evaluate the co-treatment of domestic wastewater and landfill leachate that was pre-treated by air stripping. The leachate tested volumetric ratios were 0, 2, and 5%. At a hydraulic retention time of 24 h, the SAB was best operated with a volumetric ratio of 2% and removed 98% of the biochemical oxygen demand (BOD), 80% of the chemical oxygen demand (COD) and dissolved organic carbon (DOC), and 90% of the total suspended solids (TSS). A proposed method, which we called the "equivalent in humic acid" (Eq.HA) approach, indicated that the hardly biodegradable organic matter in leachate was removed by partial degradation (71% of DOC Eq.HA removal). Adding leachate at a volumetric ratio of 5%, the concentration of the hardly biodegradable organic matter was decreased primarily as a result of dilution rather than biodegradation, which was confirmed by Fourier transform infrared (FTIR) spectroscopy. The total ammoniacal nitrogen (TAN) was mostly removed (90%) by nitrification, and the SAB performances at the volumetric ratios of 0 and 2% were equal. For the three tested volumetric ratios of leachate (0, 2, and 5%), the concentrations of heavy metals in the treated samples were below the local limits. PMID:24762568

  18. 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. PMID:24287305

  19. Fit women are not able to use the whole aerobic capacity during aerobic dance.

    PubMed

    Edvardsen, Elisabeth; Ingjer, Frank; Bø, Kari

    2011-12-01

    Edvardsen, E, Ingjer, F, and Bø, K. Fit women are not able to use the whole aerobic capacity during aerobic dance. J Strength Cond Res 25(12): 3479-3485, 2011-This study compared the aerobic capacity during maximal aerobic dance and treadmill running in fit women. Thirteen well-trained female aerobic dance instructors aged 30 ± 8.17 years (mean ± SD) exercised to exhaustion by running on a treadmill for measurement of maximal oxygen uptake (VO(2)max) and peak heart rate (HRpeak). Additionally, all subjects performed aerobic dancing until exhaustion after a choreographed videotaped routine trying to reach the same HRpeak as during maximal running. The p value for statistical significance between running and aerobic dance was set to ≤0.05. The results (mean ± SD) showed a lower VO(2)max in aerobic dance (52.2 ± 4.02 ml·kg·min) compared with treadmill running (55.9 ± 5.03 ml·kg·min) (p = 0.0003). Further, the mean ± SD HRpeak was 182 ± 9.15 b·min in aerobic dance and 192 ± 9.62 b·min in treadmill running, giving no difference in oxygen pulse between the 2 exercise forms (p = 0.32). There was no difference in peak ventilation (aerobic dance: 108 ± 10.81 L·min vs. running: 113 ± 11.49 L·min). In conclusion, aerobic dance does not seem to be able to use the whole aerobic capacity as in running. For well endurance-trained women, this may result in a lower total workload at maximal intensities. Aerobic dance may therefore not be as suitable as running during maximal intensities in well-trained females. PMID:22080322

  20. A 12 week aerobic exercise program improves fitness, hepatic insulin sensitivity and glucose metabolism in obese Hispanic adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rise in obesity related morbidity in children and adolescents requires urgent prevention and treatment strategies. Strictly controlled exercise programs might be useful tools to improve insulin sensitivity and glucose kinetics. Our objective was to test the hypothesis that a 12-wk aerobic exerci...

  1. 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. PMID:21882567

  2. 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. PMID:26774960

  3. Stable isotope fractionation analysis as a tool to monitor biodegradation in contaminated acquifers

    NASA Astrophysics Data System (ADS)

    Meckenstock, Rainer U.; Morasch, Barbara; Griebler, Christian; Richnow, Hans H.

    2004-12-01

    The assessment of biodegradation in contaminated aquifers has become an issue of increasing importance in the recent years. To some extent, this can be related to the acceptance of intrinsic bioremediation or monitored natural attenuation as a means to manage contaminated sites. Among the few existing methods to detect biodegradation in the subsurface, stable isotope fractionation analysis (SIFA) is one of the most promising approaches which is pronounced by the drastically increasing number of applications. This review covers the recent laboratory and field studies assessing biodegradation of contaminants via stable isotope analysis. Stable isotope enrichment factors have been found that vary from no fractionation for dioxygenase reactions converting aromatic hydrocarbons over moderate fractionation by monooxygenase reactions ( ɛ=-3‰) and some anaerobic studies on microbial degradation of aromatic hydrocarbons ( ɛ=-1.7‰) to larger fractionations by anaerobic dehalogenation reactions of chlorinated solvents ( ɛ=between -5‰ and -30‰). The different isotope enrichment factors can be related to the respective biochemical reactions. Based on that knowledge, we discuss under what circumstances SIFA can be used for a qualitative or even a quantitative assessment of biodegradation in the environment. In a steadily increasing number of cases, it was possible to explain biodegradation processes in the field based on isotope enrichment factors obtained from laboratory experiments with pure cultures and measured isotope values from the field. The review will focus on the aerobic and anaerobic degradation of aromatic hydrocarbons and chlorinated solvents as the major contaminants of groundwater. Advances in the instrumental development for stable isotope analysis are only mentioned if it is important for the understanding of the application.

  4. Biodegradation of 17β-Estradiol, Estrone and Testosterone in Stream Sediments

    NASA Astrophysics Data System (ADS)

    Bradley, P. M.; Chapelle, F. H.; Barber, L. B.; McMahon, P. B.; Gray, J. L.; Kolpin, D. W.

    2009-12-01

    The potentials for in situ biodegradation of 17β-estradiol (E2), estrone (E1), and testosterone (T) were investigated in three, hydrologically-distinct, WWTP-impacted streams in the United States. Relative differences in the mineralization of [4-14C] substrates were assessed in oxic microcosms containing sediment or water-only from locations upstream and downstream of the WWTP outfall in each system. Upstream samples provided insight into the biodegradative potential of sediment microbial communities that were not under the immediate impact of WWTP effluent. Upstream sediment from all three systems demonstrated significant mineralization of the “A” ring of E2, E1 and T, with the potential of T biodegradation consistently greater than of E2 and no systematic difference in the potentials of E2 and E1. Downstream samples provided insight into the impacts of effluent on reproductive hormone biodegradation. Significant “A” ring mineralization was also observed in downstream sediment, with the potentials for E1 and T mineralization being substantially depressed relative to upstream samples. In marked contrast, the potentials for E2 mineralization immediately downstream of the WWTP outfalls were more than double that of upstream samples. E2 mineralization was also observed in water, albeit at insufficient rate to prevent substantial downstream transport in the water column. The results of this study indicate that, in combination with sediment sorption processes which effectively scavenge hydrophobic contaminants from the water column and immobilize them in the vicinity of the WWTP outfall, aerobic biodegradation of reproductive hormones can be an environmentally important mechanism for non-conservative (destructive) attenuation of hormonal endocrine disruptors in effluent-impacted streams.

  5. Removal of naphthalene and phenanthrene using aerobic membrane bioreactor.

    PubMed

    Mijaylova Nacheva, Petia; Esquivel Sotelo, Alberto

    2016-06-01

    The removal of polycyclic aromatic hydrocarbons by membrane bioreactor (MBR) under aerobic conditions had been studied using naphthalene (NAP) and phenanthrene (PHE) as model compounds. Three MBRs with submerged ultra-filtration hollow fiber membranes were operated applying different operational conditions during 6.5 months. Complete NAP and PHE removal was obtained applying loads of 7 gNAP kgTSS(-1) day(-1) and 0.5 gPHE kgTSS(-1) day(-1), while the organic loading rate was adjusted to 0.26 kgCOD kgTSS(-1) day(-1), with the biomass concentration being 6000 mgTSS L(-1), the hydraulic retention time (HRT) 8 h and the solids retention time (SRT) 30 days. Load increases, as well as HRT and SRT reductions, affected the NAP and PHE removals. Biodegradation was found to be the major NAP and PHE removal mechanism. There was no NAP accumulation in the biomass. Low PHE quantities remain sorbed in the biomass and the contribution of the sorption in the removal of this compound was estimated to be less than 0.01 %. The volatilization does not contribute to the PHE removal in MBRs, but the contribution of NAP volatilization can reach up to 0.6 % when HRT of 8 h is applied. PMID:26895256

  6. Evaluation of an aerobic submerged filter packed with volcanic scoria.

    PubMed

    Morgan-Sagastume, J M; Noyola, A

    2008-05-01

    An aerobic submerged filter (ASF) using volcanic scoria stones as packing media was evaluated. The wastewater used was a mixture of sewage with sugar to obtain organic matter concentrations between 28 and 3230 mg CODt/L, hydraulic rates up to 2.88 m3/m2 d and organic loading rates between 0.45 and 9.4 kg CODt/m3 d. The system removed 80% of CODt as average for organic loading rates between 0.45 and 3 kg CODt/m3 d and 54% at the higher rate (9.4 kg CODt/m3 d). It was not necessary to backwash the filters, a negligible pressure drop and a good biomass attachment in the volcanic scoria stones was observed. Nitrification and organic matter biodegradation were carried out simultaneously with a nitrate production of 90% up to 1.7kgCODt/m3 d. Tracer studies revealed a completed mixed hydraulic pattern which was not affected by the presence of biomass. PMID:17590330

  7. Sorption and degradation of bisphenol A by aerobic activated sludge.

    PubMed

    Zhao, Junming; Li, Yongmei; Zhang, Chaojie; Zeng, Qingling; Zhou, Qi

    2008-06-30

    Laboratory-scale batch experiments were conducted to investigate the sorption and degradation of bisphenol A (BPA) at microg/L range in an aerobic activated sludge system. The sorption isotherms and thermodynamics indicated that the sorption of BPA on sludge was mainly a physical process in which partitioning played a dominating role. The values of sorption coefficient Koc were between 621 and 736 L/kg in the temperature range of 10-30 degrees C. Both mixed liquor suspended solid (MLSS) and temperature influenced BPA sorption on sludge. The degradation of BPA by acclimated activated sludge could be described by first-order reaction equation with the first-order degradation rate constant of 0.80 h(-1) at 20 degrees C. The decrease of initial COD concentration and the increase of MLSS concentration and temperature enhanced BPA degradation rate. The removal of BPA in the activated sludge system was characterized by a quick sorption on the activated sludge and subsequent biodegradation. PMID:18179868

  8. Combined biologic (anaerobic-aerobic) and chemical treatment of starch industry wastewater.

    PubMed

    Sklyar, Vladimir; Epov, Andrey; Gladchenko, Marina; Danilovich, Dmitrii; Kalyuzhnyi, Sergey

    2003-01-01

    A combined biologic and chemical treatment of high-strength (total chemical oxygen demand [CODtot] up to 20 g/L), strong nitrogenous (total N up to 1 g/L), and phosphoric (total P up to 0.4 g/L) starch industry wastewater was investigated at laboratory-scale level. As a principal step for COD elimination, upflow anaerobic sludge bed reactor performance was investigated at 30 degrees C. Under hydraulic retention times (HRTs) of about 1 d, when the organic loading rates were higher than 15 g of COD/(L.d), the CODtot removal varied between 77 and 93%, giving effluents with a COD/N ratio of 4-5:1, approaching the requirements of subsequent denitrification. The activated sludge reactor operating in aerobic-anoxic regime (HRT of about 4 d, duration of aerobic and anoxic phases of 30 min each) was able to remove up to 90% of total nitrogen and up to 64% of COD tot from the anaerobic effluents under 17-20 degrees C. The coagulation experiments with Fe(III) showed that 1.4 mg of resting hardly biodegradable COD and 0.5 mg of phosphate (as P) could be removed from the aerobic effluents by each milligram of iron added. PMID:12794298

  9. Biodegradation of Used Motor Oil in Soil Using Organic Waste Amendments

    PubMed Central

    Abioye, O. P.; Agamuthu, P.; Abdul Aziz, A. R.

    2012-01-01

    Soil and surface water contamination by used lubricating oil is a common occurrence in most developing countries. This has been shown to have harmful effects on the environment and human beings at large. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 15% (w/w) used lubricating oil and amended with 10% brewery spent grain (BSG), banana skin (BS), and spent mushroom compost (SMC) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (92%) was recorded in soil contaminated with 5% used lubricating oil and amended with BSG, while only 55% of oil biodegradation was recorded in soil contaminated with 15% used lubricating oil and amended with BSG. Results of first-order kinetic model to determine the rate of biodegradation of used lubricating oil revealed that soil amended with BSG recorded the highest rate of oil biodegradation (0.4361 day−1) in 5% oil pollution, while BS amended soil recorded the highest rate of oil biodegradation (0.0556 day−1) in 15% oil pollution. The results of this study demonstrated the potential of BSG as a good substrate for enhanced remediation of hydrocarbon contaminated soil at low pollution concentration. PMID:22919502

  10. Biodegradation of used motor oil in soil using organic waste amendments.

    PubMed

    Abioye, O P; Agamuthu, P; Abdul Aziz, A R

    2012-01-01

    Soil and surface water contamination by used lubricating oil is a common occurrence in most developing countries. This has been shown to have harmful effects on the environment and human beings at large. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 15% (w/w) used lubricating oil and amended with 10% brewery spent grain (BSG), banana skin (BS), and spent mushroom compost (SMC) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (92%) was recorded in soil contaminated with 5% used lubricating oil and amended with BSG, while only 55% of oil biodegradation was recorded in soil contaminated with 15% used lubricating oil and amended with BSG. Results of first-order kinetic model to determine the rate of biodegradation of used lubricating oil revealed that soil amended with BSG recorded the highest rate of oil biodegradation (0.4361 day(-1)) in 5% oil pollution, while BS amended soil recorded the highest rate of oil biodegradation (0.0556 day(-1)) in 15% oil pollution. The results of this study demonstrated the potential of BSG as a good substrate for enhanced remediation of hydrocarbon contaminated soil at low pollution concentration. PMID:22919502

  11. Influence of nitrifying conditions on the biodegradation and sorption of emerging micropollutants.

    PubMed

    Fernandez-Fontaina, E; Omil, F; Lema, J M; Carballa, M

    2012-10-15

    High biodegradation efficiencies of different emerging micropollutants were obtained with nitrifying activated sludge (NAS) working at high nitrogen loading rates (NLR), that boosted the development of biomass with high nitrifying activities (>1 g N-NH(4)(+)/g VSS d). Come-tabolic biodegradation seemed to be responsible for the removal of most compounds due to the action of the ammonium monooxygenase enzyme. NAS showed a different affinity for each compound, probably due to steric hindrance, activation energy limitations or the presence of specific functional groups. Increasing loading rates of micropollutants were removed at shorter hydraulic retention times, although the biodegradation efficiencies of compounds with slow/intermediate kinetics, such as fluoxetine, erythromycin, roxithromycin and trimethoprim, diminished due to kinetic and/or stoichiometric limitations. Solids retention time, always above the minimum to avoid the washout of nitrifiers, did not enhance the biodegradation of any of the selected compounds, with the exception of diclofenac. Regarding sorption, the solid-liquid distribution coefficients (K(d)) obtained in NAS were very similar to those found in conventional activated sludge by other authors. No correlation between K(d) values and any of the operational parameters was found for the selected substances. PMID:22877882

  12. Biodegradable stents in gastrointestinal endoscopy

    PubMed Central

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-01-01

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complication rate and modest clinical efficacy has to be carefully considered in individual patients prior to placement of BDSs. Otherwise, the price of these stents therefore it is nowadays an important limitation. PMID:24605020

  13. Biodegradable fixation of rabbit osteotomies.

    PubMed

    Vainionpää, S; Vihtonen, K; Mero, M; Pätiälä, H; Rokkanen, P; Kilpikari, J; Törmälä, P

    1986-06-01

    Osteotomies of the tibial diaphysis were operatively fixed with biodegradable implants in 44 rabbits. Polyglycolic acid (PGA)/polylactic acid (PLA) copolymer implants reinforced with 7 per cent carbon fibre and overlaid with gold were used in 24 rabbits. Poly-beta-hydroxy butyric acid (PHBA) with carbon fibre reinforcement and gold surfacing were used in 20 rabbits. No external support was used. Unsatisfactory results were achieved with the PGA/PLA copolymer implants. Better results were achieved in 15 out of 20 rabbits whose osteotomies were fixed with carbon fibre-reinforced PHBA implants. PMID:3739665

  14. Nylon biodegradation by lignin-degrading fungi.

    PubMed Central

    Deguchi, T; Kakezawa, M; Nishida, T

    1997-01-01

    The biodegradation of nylon by lignin-degrading fungi was investigated. The fungus IZU-154 significantly degraded nylon-66 membrane under ligninolytic conditions. Nuclear magnetic resonance analysis showed that four end groups, CHO, NHCHO, CH3, and CONH2, were formed in the biodegraded nylon-66 membranes, suggesting that nylon-66 was degraded oxidatively. PMID:8979361

  15. ANAEROBIC BIODEGRADABILITY OF NON-PETROLEUM OILS.

    EPA Science Inventory

    Research has demonstrated that vegetable oils are amenable to anaerobic biodegradation. This is in contrast to petroleum oils. Vegetable oils are already oxygenated because they are composed of fatty acids and glycerols, which contribute to the biodegradability. A strategy has be...

  16. Biological treatment of thin-film transistor liquid crystal display (TFT-LCD) wastewater using aerobic and anoxic/oxic sequencing batch reactors.

    PubMed

    Lei, Chin-Nan; Whang, Liang-Ming; Chen, Po-Chun

    2010-09-01

    The amount of pollutants produced during manufacturing processes of thin-film transistor liquid crystal display (TFT-LCD) substantially increases due to an increasing production of the opto-electronic industry in Taiwan. This study presents the treatment performance of one aerobic and one anoxic/oxic (A/O) sequencing batch reactors (SBRs) treating synthetic TFT-LCD wastewater containing dimethyl sulfoxide (DMSO), monoethanolamine (MEA), and tetra-methyl ammonium hydroxide (TMAH). The long-term monitoring results for the aerobic and A/O SBRs demonstrate that stable biodegradation of DMSO, MEA, and TMAH can be achieved without any considerably adverse impacts. The ammonium released during MEA and TMAH degradation can also be completely oxidized to nitrate through nitrification in both SBRs. Batch studies on biodegradation rates for DMSO, MEA, and TMAH under anaerobic, anoxic, and aerobic conditions indicate that effective MEA degradation can be easily achieved under all three conditions examined, while efficient DMSO and TMAH degradation can be attained only under anaerobic and aerobic conditions, respectively. The potential odor problem caused by the formation of malodorous dimethyl sulfide from DMSO degradation under anaerobic conditions, however, requires insightful consideration in treating DMSO-containing wastewater. PMID:20705321

  17. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part B--Nitrogen-, Sulfur-, and Oxygen-Containing Heterocyclic Aromatic Compounds.