Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

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

Sun, Jian; Shi, Jian; Murthy Konda, N. V. S. N.

Background Biomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration. Results We evaluated a commercially available PV system formore » IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C 2 C 1 Im][OAc] ) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that > 99.9 wt% [C 2 C 1 Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses. Conclusions These findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.« less

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

DOE PAGES

Sun, Jian; Shi, Jian; Murthy Konda, N. V. S. N.; ...

2017-06-15

Background Biomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration. Results We evaluated a commercially available PV system formore » IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C 2 C 1 Im][OAc] ) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that > 99.9 wt% [C 2 C 1 Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses. Conclusions These findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.« less

Enhanced Mixed Feedstock Processing Using Ionic Liquids

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

Simmons, Blake A

2016-10-22

Biomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before IL pretreatment technology becomes commercially viable. Once of the most significant challenges is the affordable and scalable recovery and recycle or the IL itself. Pervaporation is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration than traditional solvent extraction processes, as well as efficient and energetically more advantageousmore » than standard evaporative techniques. In this study we evaluated a commercially available pervaporation system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. We demonstrate that >99.9 wt% [C2C1Im][OAc] can be recovered from aqueous solution and recycled at least five times. A preliminary techno-economic analysis validated the promising role of pervaporation in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses. These findings establish the foundation for further development of pervaporation as an effective method of recovering and recycling ILs using a commercially viable process technology.« less

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

PubMed

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of pulsed electric fields and microwave pretreatments on some selected physicochemical properties of oil extracted from black cumin seed.

PubMed

Bakhshabadi, Hamid; Mirzaei, HabibOllah; Ghodsvali, Alireza; Jafari, Seid Mahdi; Ziaiifar, Aman Mohammad

2018-01-01

Application of novel technologies such as microwave and pulsed electric fields (PEF) might increase the speed and efficiency of oil extraction. In the present research, PEF (3.25 kV/cm electric field intensity and 30 pulse number) and microwave (540 W for 180 s) pretreatments were used to study the process of oil extraction from black cumin ( Nigella sativa ) seeds. After applying the selected pretreatments, the oil of seeds was extracted with the use of a screw press and the extraction efficiency, refractive index, oil density, color index, oxidative stability, and chemical components of oil and protein of meal were evaluated. The achieved results expressed that PEF and microwave pretreatments increased the oil extraction efficiency and its oxidative stability. Different pretreatments didn't have any significant influence on the refractive index of black cumin seed oil ( p >.05). When microwave and PEF were used, the oil density showed an enhancement as the following: 1.51% and 0.96%, respectively in comparison with the samples with no pretreatments. Evaluation of the extracted oils, using GC/MS analysis indicated that thymoquinone was the dominant phenolic component in the black cumin oil. Finally, the SEM analysis revealed that microwave and PEF can be useful in the extraction of oil from black cumin seeds since these treatments damaged cell walls and facilitated the oil extraction process.

A green and efficient technology for the degradation of cellulosic materials: structure changes and enhanced enzymatic hydrolysis of natural cellulose pretreated by synergistic interaction of mechanical activation and metal salt.

PubMed

Zhang, Yanjuan; Li, Qian; Su, Jianmei; Lin, Ye; Huang, Zuqiang; Lu, Yinghua; Sun, Guosong; Yang, Mei; Huang, Aimin; Hu, Huayu; Zhu, Yuanqin

2015-02-01

A new technology for the pretreatment of natural cellulose was developed, which combined mechanical activation (MA) and metal salt treatments in a stirring ball mill. Different valent metal nitrates were used to investigate the changes in degree of polymerization (DP) and crystallinity index (CrI) of cellulose after MA+metal salt (MAMS) pretreatment, and Al(NO3)3 showed better pretreatment effect than NaNO3 and Zn(NO3)2. The destruction of morphological structure of cellulose was mainly resulted from intense ball milling, and the comparative studies on the changes of DP and crystal structure of MA and MA+Al(NO3)3 pretreated cellulose samples showed a synergistic interaction of MA and Al(NO3)3 treatments with more effective changes of structural characteristics of MA+Al(NO3)3 pretreated cellulose and substantial increase of reducing sugar yield in enzymatic hydrolysis of cellulose. In addition, the results indicated that the presence of Al(NO3)3 had significant enhancement for the enzymatic hydrolysis of cellulose. Copyright © 2014 Elsevier Ltd. All rights reserved.

Waste Separations and Pretreatment Workshop report

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

Cruse, J.M.; Harrington, R.A.; Quadrel, M.J.

1994-01-01

This document provides the minutes from the Waste Separations and Pretreatment Workshop sponsored by the Underground Storage Tank-Integrated Demonstration in Salt Lake City, Utah, February 3--5, 1993. The Efficient Separations and Processing-Integrated Program and the Hanford Site Tank Waste Remediation System were joint participants. This document provides the detailed minutes, including responses to questions asked, an attendance list, reproductions of the workshop presentations, and a revised chart showing technology development activities.

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production.

PubMed

Kumar, Deepak; Murthy, Ganti S

2011-09-05

While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies.

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

PubMed Central

2011-01-01

Background While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Results Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Conclusions Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies. PMID:21892958

Diethylstilbestrol in fish tissue determined through subcritical fluid extraction and with GC-MS

NASA Astrophysics Data System (ADS)

Qiao, Qinghui; Shi, Nianrong; Feng, Xiaomei; Lu, Jie; Han, Yuqian; Xue, Changhu

2016-06-01

As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol (DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane (R134a) extraction in combination with gas chromatography-mass spectrometry (GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C18 and NH2 solid phase extraction (SPE). Finally, the analyte was derived by heptafluorobutyric anhydride (HFBA), followed by GC-MS analysis. Response surface methodology (RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26°C; amount of co-solvent volume, 4.7 mL. Under this condition, at a spiked level of 1, 5, 10 μg kg-1, the mean recovery of DES was more than 90% with relative standard deviations (RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.

Enhanced enzymatic hydrolysis and acetone-butanol-ethanol fermentation of sugarcane bagasse by combined diluted acid with oxidate ammonolysis pretreatment.

PubMed

Li, Hailong; Xiong, Lian; Chen, Xuefang; Wang, Can; Qi, Gaoxiang; Huang, Chao; Luo, Mutan; Chen, Xinde

2017-03-01

This study aims to propose a biorefinery pretreatment technology for the bioconversion of sugarcane bagasse (SB) into biofuels and N-fertilizers. Performance of diluted acid (DA), aqueous ammonia (AA), oxidate ammonolysis (OA) and the combined DA with AA or OA were compared in SB pretreatment by enzymatic hydrolysis, structural characterization and acetone-butanol-ethanol (ABE) fermentation. Results indicated that DA-OA pretreatment improves the digestibility of SB by sufficiently hydrolyzing hemicellulose into fermentable monosaccharides and oxidating lignin into soluble N-fertilizer with high nitrogen content (11.25%) and low C/N ratio (3.39). The enzymatic hydrolysates from DA-OA pretreated SB mainly composed of glucose was more suitable for the production of ABE solvents than the enzymatic hydrolysates from OA pretreated SB containing high ratio of xylose. The fermentation of enzymatic hydrolysates from DA-OA pretreated SB produced 12.12g/L ABE in 120h. These results suggested that SB could be utilized efficient, economic, and environmental by DA-OA pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laser Spot Center Detection and Comparison Test

NASA Astrophysics Data System (ADS)

Zhu, Jun; Xu, Zhengjie; Fu, Deli; Hu, Cong

2018-04-01

High efficiency and precision of the pot center detection are the foundations of avionics instrument navigation and optics measurement basis for many applications. It has noticeable impact on overall system performance. Among them, laser spot detection is very important in the optical measurement technology. In order to improve the low accuracy of the spot center position, the algorithm is improved on the basis of the circle fitting. The pretreatment is used by circle fitting, and the improved adaptive denoising filter for TV repair technology can effectively improves the accuracy of the spot center position. At the same time, the pretreatment and de-noising can effectively reduce the influence of Gaussian white noise, which enhances the anti-jamming capability.

Sodium Hydroxide Pretreatment of Switchgrass for Ethanol Production

USDA-ARS?s Scientific Manuscript database

Lignocellulose-to-ethanol conversion is a promising technology to supplement corn-based ethanol production. However, the recalcitrant structure of lignocellulosic material is a major obstacle to the efficient conversion. To improve the enzymatic digestibility of switchgrass for the fermentable sugar...

Enhanced methane production from microalgal biomass by anaerobic bio-pretreatment.

PubMed

He, Shuai; Fan, Xiaolei; Katukuri, Naveen Reddy; Yuan, Xianzheng; Wang, Fei; Guo, Rong-Bo

2016-03-01

Anaerobic digestion (AD) of microalgal biomass is one of the most energy efficient technologies to convert microalgae to biofuels. In order to improve the biogas productivity, breaking up the tough and rigid cell wall of microalgae by pretreatment is necessary. In this work, Bacillus licheniformis, a facultative anaerobic bacterial with hydrolytic and acidogenic activities, was adopted to pretreat Chlorella sp. In the established pretreatment process, pure bacterial culture (0%, 1%, 2%, 4%, 8%, v/v) were used to pretreat Chlorella sp. under anaerobic condition at 37°C for 60 h. The soluble chemical oxygen demands (SCOD) content was increased by 16.4-43.4%, while volatile fatty acids (VFAs) were improved by 17.3-44.2%. Furthermore, enhancement of methane production (9.2-22.7%) was also observed in subsequent AD. The results indicated that the more dosages of bacteria were used to pretreat the microalgal biomass in the range of 1-8%, the more methane was produced. Copyright © 2015 Elsevier Ltd. All rights reserved.

Force Projection Technology Overview

DTIC Science & Technology

2011-08-12

Technologies • Fuel Efficient Powertrain Lubricant • Nanotechnology for Fuels and Lubes • Water from Air • Water Reuse • In-line Water Monitoring...purification systems with new pretreatment, desalination and post treatment technologies. Payoff: • Reduces the logistical footprint associated with water...FY11 FY12 FY13 FY14 FY15 FY16 FY17 •Water From Air •Water Quality Monitoring •Water Reuse •Pre and Post Treatment • Desalination 6 5 5

A review on hydrothermal pre-treatment technologies and environmental profiles of algal biomass processing.

PubMed

Patel, Bhavish; Guo, Miao; Izadpanah, Arash; Shah, Nilay; Hellgardt, Klaus

2016-01-01

The need for efficient and clean biomass conversion technologies has propelled Hydrothermal (HT) processing as a promising treatment option for biofuel production. This manuscript discussed its application for pre-treatment of microalgae biomass to solid (biochar), liquid (biocrude and biodiesel) and gaseous (hydrogen and methane) products via Hydrothermal Carbonisation (HTC), Hydrothermal Liquefaction (HTL) and Supercritical Water Gasification (SCWG) as well as the utility of HT water as an extraction medium and HT Hydrotreatment (HDT) of algal biocrude. In addition, the Solar Energy Retained in Fuel (SERF) using HT technologies is calculated and compared with benchmark biofuel. Lastly, the Life Cycle Assessment (LCA) discusses the limitation of the current state of art as well as introduction to new potential input categories to obtain a detailed environmental profile. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prospective technologies for using biohydrogen in power installations on the basis of fuel cells (a review)

NASA Astrophysics Data System (ADS)

Dunikov, D. O.; Borzenko, V. I.; Malyshenko, S. P.; Blinov, D. V.; Kazakov, A. N.

2013-03-01

The present state of technology for obtaining hydrogen by biological methods and for purifying it is reviewed from the viewpoint of its possible use in kilowatt-class power installations. Hybrid membranesorption biohydrogen purification methods combining membrane-based pretreatment and sorption-based final treatment, also with the use of metal hydrides, should be regarded as the most efficient ones.

Exploring new strategies for cellulosic biofuels production

Treesearch

Paul Langan; S. Gnankaran; Kirk D. Rector; Norma Pawley; David T. Fox; Dae Won Cho; Kenneth E. Hammel

2011-01-01

A research program has been initiated to formulate new strategies for efficient low-cost lignocellulosic biomass processing technologies for the production of biofuels. This article reviews results from initial research into lignocellulosic biomass structure, recalcitrance, and pretreatment. In addition to contributing towards a comprehensive understanding of...

Ternary ionic liquid-water pretreatment systems of an agave bagasse and municipal solid waste blend.

PubMed

Perez-Pimienta, Jose A; Sathitsuksanoh, Noppadon; Thompson, Vicki S; Tran, Kim; Ponce-Noyola, Teresa; Stavila, Vitalie; Singh, Seema; Simmons, Blake A

2017-01-01

Pretreatment is necessary to reduce biomass recalcitrance and enhance the efficiency of enzymatic saccharification for biofuel production. Ionic liquid (IL) pretreatment has gained a significant interest as a pretreatment process that can reduce cellulose crystallinity and remove lignin, key factors that govern enzyme accessibility. There are several challenges that need to be addressed for IL pretreatment to become viable for commercialization, including IL cost and recyclability. In addition, it is unclear whether ILs can maintain process performance when utilizing low-cost, low-quality biomass feedstocks such as the paper fraction of municipal solid waste (MSW), which are readily available in high quantities. One approach to potentially reduce IL cost is to use a blend of ILs at different concentrations in aqueous mixtures. Herein, we describe 14 IL-water systems with mixtures of 1-ethyl-3-ethylimidazolium acetate ([C 2 C 1 Im][OAc]), 1-butyl-3-ethylimidazolium acetate ([C 4 C 1 Im][OAc]), and water that were used to pretreat MSW blended with agave bagasse (AGB). The detailed analysis of IL recycling in terms of sugar yields of pretreated biomass and IL stability was examined. Both biomass types (AGB and MSW) were efficiently disrupted by IL pretreatment. The pretreatment efficiency of [C 2 C 1 Im][OAc] and [C 4 C 1 Im][OAc] decreased when mixed with water above 40%. The AGB/MSW (1:1) blend demonstrated a glucan conversion of 94.1 and 83.0% using IL systems with ~10 and ~40% water content, respectively. Chemical structures of fresh ILs and recycle ILs presented strong similarities observed by FTIR and 1 H-NMR spectroscopy. The glucan and xylan hydrolysis yields obtained from recycled IL exhibited a slight decrease in pretreatment efficiency (less than 10% in terms of hydrolysis yields compared to that of fresh IL), and a decrease in cellulose crystallinity was observed. Our results demonstrated that mixing ILs such as [C 2 C 1 Im][OAc] and [C 4 C 1 Im][OAc] and blending the paper fraction of MSW with agricultural residues, such as AGB, may contribute to lower the production costs while maintaining high sugar yields. Recycled IL-water mixtures provided comparable results to that of fresh ILs. Both of these results offer the potential of reducing the production costs of sugars and biofuels at biorefineries as compared to more conventional IL conversion technologies.Graphical abstractSchematic of ionic liquid (IL) pretreatment of agave bagasse (AB) and paper-rich fraction of municipal solid waste (MSW).

Effects of pre-treatment technologies on dark fermentative biohydrogen production: A review.

PubMed

Bundhoo, M A Zumar; Mohee, Romeela; Hassan, M Ali

2015-07-01

Biohydrogen production from dark fermentation of lignocellulosic materials represents a huge potential in terms of renewable energy exploitation. However, the low hydrogen yield is currently hindering its development on industrial scale. This study reviewed various technologies that have been investigated for enhancing dark fermentative biohydrogen production. The pre-treatment technologies can be classified based on their applications as inoculum or substrates pre-treatment or they can be categorised into physical, chemical, physicochemical and biological based on the techniques used. From the different technologies reviewed, heat and acid pre-treatments are the most commonly studied technologies for both substrates and inoculum pre-treatment. Nevertheless, these two technologies need not necessarily be the most suitable since across different studies, a wide array of other emerging techniques as well as combined technologies have yielded positive findings. To date, there exists no perfect technology for either inoculum or substrate pre-treatment. Although the aim of inoculum pre-treatment is to suppress H2-consumers and enrich H2-producers, many sporulating H2-consumers survive the pre-treatment while some non-spore H2-producers are inhibited. Besides, several inoculum pre-treatment techniques are not effective in the long run and repeated pre-treatment may be required for continuous suppression of H2-consumers and sustained biohydrogen production. Furthermore, many technologies employed for substrates pre-treatment may yield inhibitory compounds that can eventually decrease biohydrogen production. Consequently, much research needs to be done to find out the best technology for both substrates and inoculum pre-treatment while also taking into consideration the energetic, economic and technical feasibility of implementing such a process on an industrial scale. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improvement of enzymatic hydrolysis and ethanol production from corn stalk by alkali and N-methylmorpholine-N-oxide pretreatments.

PubMed

Cai, Ling-Yan; Ma, Yu-Long; Ma, Xiao-Xia; Lv, Jun-Min

2016-07-01

A combinative technology of alkali and N-methylmorpholine-N-oxide (NMMO) was used to pretreat corn stalk (CS) for improving the efficiencies of subsequent enzymatic hydrolysis and ethanol fermentation. The results showed that this strategy could not only remove hemicellulose and lignin but also decrease the crystallinity of cellulose. About 98.0% of enzymatic hydrolysis yield was obtained from the pretreated CS as compared with 46.9% from the untreated sample. The yield for corresponding ethanol yield was 64.6% while untreated CS was only 18.8%. Besides, xylose yield obtained from the untreated CS was only 11.1%, while this value was 93.8% for alkali with NMMO pretreated sample. These results suggest that a combination of alkali with 50% (wt/wt) NMMO solution may be a promising alternative for pretreatment of lignocellulose, which can increase the productions of subsequent enzymatic hydrolysis and ethanol fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of Trace Pharmaceuticals from Water using coagulation and powdered activated carbon as pretreatment to ultrafiltration membrane system.

PubMed

Sheng, Chenguang; Nnanna, A G Agwu; Liu, Yanghe; Vargo, John D

2016-04-15

In this study, the efficacy of water treatment technologies: ultra-filtration (UF), powdered activated carbon (PAC), coagulation (COA) and a combination of these technologies (PAC/UF and COA/UF) to remove target pharmaceuticals (Acetaminophen, Bezafibrate, Caffeine, Carbamazepine, Cotinine, Diclofenac, Gemfibrozil, Ibuprofen, Metoprolol, Naproxen, Sulfadimethoxine, Sulfamethazine, Sulfamethoxazole, Sulfathiazole, Triclosan and Trimethoprim) was investigated. Samples of wastewater from municipal WWTPs were analyzed using direct aqueous injection High Performance Liquid Chromatography with Tandem Quadrupole Mass Spectrometric (LC/MS/MS) detection. On concentration basis, results showed an average removal efficiency of 29%, 50%, and 7%, respectively, for the UF, PAC dosage of 50ppm, and COA dosage of 10ppm. When PAC dosage of 100ppm was used as pretreatment to the combined PAC and UF in-line membrane system, a 90.3% removal efficiency was achieved. The removal efficiency of UF in tandem with COA was 33%, an increase of 4% compared with the single UF treatment. The adsorption effect of PAC combined with the physical separation process of UF revealed the best treatment strategy for removing pharmaceutical contaminant from water. Copyright © 2016 Elsevier B.V. All rights reserved.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

PubMed

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Evaluation of target efficiencies for solid-liquid separation steps in biofuels production.

PubMed

Kochergin, Vadim; Miller, Keith

2011-01-01

Development of liquid biofuels has entered a new phase of large scale pilot demonstration. A number of plants that are in operation or under construction face the task of addressing the engineering challenges of creating a viable plant design, scaling up and optimizing various unit operations. It is well-known that separation technologies account for 50-70% of both capital and operating cost. Additionally, reduction of environmental impact creates technological challenges that increase project cost without adding to the bottom line. Different technologies vary in terms of selection of unit operations; however, solid-liquid separations are likely to be a major contributor to the overall project cost. Despite the differences in pretreatment approaches, similar challenges arise for solid-liquid separation unit operations. A typical process for ethanol production from biomass includes several solid-liquid separation steps, depending on which particular stream is targeted for downstream processing. The nature of biomass-derived materials makes it either difficult or uneconomical to accomplish complete separation in a single step. Therefore, setting realistic efficiency targets for solid-liquid separations is an important task that influences overall process recovery and economics. Experimental data will be presented showing typical characteristics for pretreated cane bagasse at various stages of processing into cellulosic ethanol. Results of generic material balance calculations will be presented to illustrate the influence of separation target efficiencies on overall process recoveries and characteristics of waste streams.

Rice Husk Ash to Stabilize Heavy Metals Contained in Municipal Solid Waste Incineration Fly Ash: First Results by Applying New Pre-treatment Technology

PubMed Central

Benassi, Laura; Franchi, Federica; Catina, Daniele; Cioffi, Flavio; Rodella, Nicola; Borgese, Laura; Pasquali, Michela; Depero, Laura E.; Bontempi, Elza

2015-01-01

A new technology was recently developed for municipal solid waste incineration (MSWI) fly ash stabilization, based on the employment of all waste and byproduct materials. In particular, the proposed method is based on the use of amorphous silica contained in rice husk ash (RHA), an agricultural byproduct material (COSMOS-RICE project). The obtained final inert can be applied in several applications to produce “green composites”. In this work, for the first time, a process for pre-treatment of rice husk, before its use in the stabilization of heavy metals, based on the employment of Instant Pressure Drop technology (DIC) was tested. The aim of this work is to verify the influence of the pre-treatment on the efficiency on heavy metals stabilization in the COSMOS-RICE technology. DIC technique is based on a thermomechanical effect induced by an abrupt transition from high steam pressure to a vacuum, to produce changes in the material. Two different DIC pre-treatments were selected and thermal annealing at different temperatures were performed on rice husk. The resulting RHAs were employed to obtain COSMOS-RICE samples, and the stabilization procedure was tested on the MSWI fly ash. In the frame of this work, some thermal treatments were also realized in O2-limiting conditions, to test the effect of charcoal obtained from RHA on the stabilization procedure. The results of this work show that the application of DIC technology into existing treatment cycles of some waste materials should be investigated in more details to offer the possibility to stabilize and reuse waste. PMID:28793605

Ternary ionic liquid–water pretreatment systems of an agave bagasse and municipal solid waste blend

DOE PAGES

Perez-Pimienta, Jose A.; Sathitsuksanoh, Noppadon; Thompson, Vicki S.; ...

2017-03-21

Background: Pretreatment is necessary to reduce biomass recalcitrance and enhance the enzymatic saccharification for biofuel production. Ionic liquid (IL) pretreatment has gained a significant interest as a pretreatment process that can reduce biomass crystallinity, remove lignin, and thus obtain higher enzymatic saccharification yields. However, there are several challenges that need to be overcome for the IL pretreatment to become viable for commercialization, including IL cost and recyclability. In addition to maintain process performance by blending high quality (e.g. agave bagasse) and low cost biomass feedstocks such as municipal solid waste (MSW) which is readily available in high quantities. One approachmore » to potentially reduce IL cost is to use a blend of ILs at different concentrations in aqueous mixtures. Herein, we describe 14 IL-water systems with mixtures of 1-ethyl-3-ethylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-ethylimidazolium acetate ([C4C1Im][OAc]) used to pretreat MSW blended with agave bagasse (AGB). The detailed analysis of IL recycling in terms of sugar yields of pretreated biomass and IL stability was examined. Results: Both biomass types (AGB and MSW) were efficiently disrupted by IL pretreatment. The pretreatment efficiency of [C2C1Im][OAc] and [C4C1Im][OAc] decreased when mixed with water above 40%. The AGB/MSW (1:1) blend demonstrated a glucan conversion of 94.1% and 83.0% using IL systems with ~10% and ~40% water content, respectively. Chemical structures of fresh ILs and recycle ILs presented strong similarities observed by FTIR and 1H-NMR spectroscopy. The glucan and xylan hydrolysis yields obtained from recycled IL exhibited a slight decrease in pretreatment efficiency (less than 10% in terms of hydrolysis yields compared to that of fresh IL), and a decrease in cellulose crystallinity trend was observed. Conclusions: Our results demonstrated the mixing ILs such as [C2C1Im][OAc] and [C4C1Im][OAc] and blending MSW with agricultural residues, such as AGB, may help lower the production costs while maintaining high sugar yields. Recycled IL-water mixtures provided comparable results to that of fresh ILs. Both of these results offer the potential of reducing the production costs of sugars and biofuels at biorefineries as compared to more conventional IL conversion technologies.« less

Ternary ionic liquid–water pretreatment systems of an agave bagasse and municipal solid waste blend

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

Perez-Pimienta, Jose A.; Sathitsuksanoh, Noppadon; Thompson, Vicki S.

Background: Pretreatment is necessary to reduce biomass recalcitrance and enhance the enzymatic saccharification for biofuel production. Ionic liquid (IL) pretreatment has gained a significant interest as a pretreatment process that can reduce biomass crystallinity, remove lignin, and thus obtain higher enzymatic saccharification yields. However, there are several challenges that need to be overcome for the IL pretreatment to become viable for commercialization, including IL cost and recyclability. In addition to maintain process performance by blending high quality (e.g. agave bagasse) and low cost biomass feedstocks such as municipal solid waste (MSW) which is readily available in high quantities. One approachmore » to potentially reduce IL cost is to use a blend of ILs at different concentrations in aqueous mixtures. Herein, we describe 14 IL-water systems with mixtures of 1-ethyl-3-ethylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-ethylimidazolium acetate ([C4C1Im][OAc]) used to pretreat MSW blended with agave bagasse (AGB). The detailed analysis of IL recycling in terms of sugar yields of pretreated biomass and IL stability was examined. Results: Both biomass types (AGB and MSW) were efficiently disrupted by IL pretreatment. The pretreatment efficiency of [C2C1Im][OAc] and [C4C1Im][OAc] decreased when mixed with water above 40%. The AGB/MSW (1:1) blend demonstrated a glucan conversion of 94.1% and 83.0% using IL systems with ~10% and ~40% water content, respectively. Chemical structures of fresh ILs and recycle ILs presented strong similarities observed by FTIR and 1H-NMR spectroscopy. The glucan and xylan hydrolysis yields obtained from recycled IL exhibited a slight decrease in pretreatment efficiency (less than 10% in terms of hydrolysis yields compared to that of fresh IL), and a decrease in cellulose crystallinity trend was observed. Conclusions: Our results demonstrated the mixing ILs such as [C2C1Im][OAc] and [C4C1Im][OAc] and blending MSW with agricultural residues, such as AGB, may help lower the production costs while maintaining high sugar yields. Recycled IL-water mixtures provided comparable results to that of fresh ILs. Both of these results offer the potential of reducing the production costs of sugars and biofuels at biorefineries as compared to more conventional IL conversion technologies.« less

FLASH Technology: Full-Scale Hospital Waste Water Treatments Adopted in Aceh

NASA Astrophysics Data System (ADS)

Rame; Tridecima, Adeodata; Pranoto, Hadi; Moesliem; Miftahuddin

2018-02-01

A Hospital waste water contains a complex mixture of hazardous chemicals and harmful microbes, which can pose a threat to the environment and public health. Some efforts have been carried out in Nangroe Aceh Darussalam (Aceh), Indonesia with the objective of treating hospital waste water effluents on-site before its discharge. Flash technology uses physical and biological pre-treatment, followed by advanced oxidation process based on catalytic ozonation and followed by GAC and PAC filtration. Flash Full-Scale Hospital waste water Treatments in Aceh from different district have been adopted and investigated. Referring to the removal efficiency of macro-pollutants, the collected data demonstrate good removal efficiency of macro-pollutants using Flash technologies. In general, Flash technologies could be considered a solution to the problem of managing hospital waste water.

Electrochemical pretreatment of waste activated sludge: effect of process conditions on sludge disintegration degree and methane production.

PubMed

Ye, Caihong; Yuan, Haiping; Dai, Xiaohu; Lou, Ziyang; Zhu, Nanwen

2016-11-01

Waste activated sludge (WAS) requires a long digestion time because of a rate-limiting hydrolysis step - the first phase of anaerobic digestion (AD). Pretreatment can be used prior to AD to facilitate the hydrolysis step and improve the efficiency of WAS digestion. This study evaluated a novel application of electrochemical (EC) technology employed as the pretreatment method prior to AD of WAS, focusing on the effect of process conditions on sludge disintegration and subsequent AD process. A superior process condition of EC pretreatment was obtained by reaction time of 30 min, electrolysis voltage of 20 V, and electrode distance of 5 cm, under which the disintegration degree of WAS ranged between 9.02% and 9.72%. In the subsequent batch AD tests, 206 mL/g volatile solid (VS) methane production in EC pretreated sludge was obtained, which was 20.47% higher than that of unpretreated sludge. The AD time was 19 days shorter for EC pretreated sludge compared to the unpretreated sludge. Additionally, the EC + AD reactor achieved 41.84% of VS removal at the end of AD. The analysis of energy consumption showed that EC pretreatment could be effective in enhancing sludge AD with reduced energy consumption when compared to other pretreatment methods.

A comparative analysis of selected wastewater pretreatment processes in food industry

NASA Astrophysics Data System (ADS)

Jaszczyszyn, Katarzyna; Góra, Wojciech; Dymaczewski, Zbysław; Borowiak, Robert

2018-02-01

The article presents a comparative analysis of the classical coagulation with the iron sulphate and adsorption on bentonite for the pretreatment of wastewater in the food industry. As a result of the studies, chemical oxygen demand (COD) and total nitrogen (TN) reduction were found to be comparable in both technologies, and a 29% higher total phosphorus removal efficiency by the coagulation was observed. After the coagulation and adsorption processes, a significant difference between mineral and organic fraction in the sludge was found (49% and 51% for bentonite and 28% and 72% for iron sulphate, respectively).

Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose

PubMed Central

Socha, Aaron M.; Parthasarathi, Ramakrishnan; Shi, Jian; Pattathil, Sivakumar; Whyte, Dorian; Bergeron, Maxime; George, Anthe; Tran, Kim; Stavila, Vitalie; Venkatachalam, Sivasankari; Hahn, Michael G.; Simmons, Blake A.; Singh, Seema

2014-01-01

Ionic liquids (ILs), solvents composed entirely of paired ions, have been used in a variety of process chemistry and renewable energy applications. Imidazolium-based ILs effectively dissolve biomass and represent a remarkable platform for biomass pretreatment. Although efficient, imidazolium cations are expensive and thus limited in their large-scale industrial deployment. To replace imidazolium-based ILs with those derived from renewable sources, we synthesized a series of tertiary amine-based ILs from aromatic aldehydes derived from lignin and hemicellulose, the major by-products of lignocellulosic biofuel production. Compositional analysis of switchgrass pretreated with ILs derived from vanillin, p-anisaldehyde, and furfural confirmed their efficacy. Enzymatic hydrolysis of pretreated switchgrass allowed for direct comparison of sugar yields and lignin removal between biomass-derived ILs and 1-ethyl-3-methylimidazolium acetate. Although the rate of cellulose hydrolysis for switchgrass pretreated with biomass-derived ILs was slightly slower than that of 1-ethyl-3-methylimidazolium acetate, 90–95% glucose and 70–75% xylose yields were obtained for these samples after 72-h incubation. Molecular modeling was used to compare IL solvent parameters with experimentally obtained compositional analysis data. Effective pretreatment of lignocellulose was further investigated by powder X-ray diffraction and glycome profiling of switchgrass cell walls. These studies showed different cellulose structural changes and differences in hemicellulose epitopes between switchgrass pretreatments with the aforementioned ILs. Our concept of deriving ILs from lignocellulosic biomass shows significant potential for the realization of a “closed-loop” process for future lignocellulosic biorefineries and has far-reaching economic impacts for other IL-based process technology currently using ILs synthesized from petroleum sources. PMID:25136131

Current Pretreatment Technologies for the Development of Cellulosic Ethanol and Biorefineries.

PubMed

Silveira, Marcos Henrique Luciano; Morais, Ana Rita C; da Costa Lopes, Andre M; Olekszyszen, Drielly Nayara; Bogel-Łukasik, Rafał; Andreaus, Jürgen; Pereira Ramos, Luiz

2015-10-26

Lignocellulosic materials, such as forest, agriculture, and agroindustrial residues, are among the most important resources for biorefineries to provide fuels, chemicals, and materials in such a way to substitute for, at least in part, the role of petrochemistry in modern society. Most of these sustainable biorefinery products can be produced from plant polysaccharides (glucans, hemicelluloses, starch, and pectic materials) and lignin. In this scenario, cellulosic ethanol has been considered for decades as one of the most promising alternatives to mitigate fossil fuel dependence and carbon dioxide accumulation in the atmosphere. However, a pretreatment method is required to overcome the physical and chemical barriers that exist in the lignin-carbohydrate composite and to render most, if not all, of the plant cell wall components easily available for conversion into valuable products, including the fuel ethanol. Hence, pretreatment is a key step for an economically viable biorefinery. Successful pretreatment method must lead to partial or total separation of the lignocellulosic components, increasing the accessibility of holocellulose to enzymatic hydrolysis with the least inhibitory compounds being released for subsequent steps of enzymatic hydrolysis and fermentation. Each pretreatment technology has a different specificity against both carbohydrates and lignin and may or may not be efficient for different types of biomasses. Furthermore, it is also desirable to develop pretreatment methods with chemicals that are greener and effluent streams that have a lower impact on the environment. This paper provides an overview of the most important pretreatment methods available, including those that are based on the use of green solvents (supercritical fluids and ionic liquids). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of various pretreatment methods on anaerobic mixed microflora to enhance biohydrogen production utilizing dairy wastewater as substrate.

PubMed

Venkata Mohan, S; Lalit Babu, V; Sarma, P N

2008-01-01

Influence of different pretreatment methods applied on anaerobic mixed inoculum was evaluated for selectively enriching the hydrogen (H(2)) producing mixed culture using dairy wastewater as substrate. The experimental data showed the feasibility of molecular biohydrogen generation utilizing dairy wastewater as primary carbon source through metabolic participation. However, the efficiency of H(2) evolution and substrate removal efficiency were found to be dependent on the type of pretreatment procedure adopted on the parent inoculum. Among the studied pretreatment methods, chemical pretreatment (2-bromoethane sulphonic acid sodium salt (0.2 g/l); 24 h) procedure enabled higher H(2) yield along with concurrent substrate removal efficiency. On the contrary, heat-shock pretreatment (100 degrees C; 1 h) procedure resulted in relatively low H(2) yield. Compared to control experiments all the adopted pretreatment methods documented higher H(2) generation efficiency. In the case of combination experiments, integration of pH (pH 3; adjusted with ortho-phosphoric acid; 24 h) and chemical pretreatment evidenced higher H(2) production. Data envelopment analysis (DEA), a frontier analysis technique model was successfully applied to enumerate the relative efficiency of different pretreatment methods studied by considered pretreatment procedures as input and cumulative H(2) production rate and substrate degradation rate as corresponding two outputs.

Quantifying pretreatment degradation compounds in solution and accumulated by cells during solids and yeast recycling in the Rapid Bioconversion with Integrated recycling Technology process using AFEX™ corn stover.

PubMed

Sarks, Cory; Higbee, Alan; Piotrowski, Jeff; Xue, Saisi; Coon, Joshua J; Sato, Trey K; Jin, Mingjie; Balan, Venkatesh; Dale, Bruce E

2016-04-01

Effects of degradation products (low molecular weight compounds produced during pretreatment) on the microbes used in the RaBIT (Rapid Bioconversion with Integrated recycling Technology) process that reduces enzyme usage up to 40% by efficient enzyme recycling were studied. Chemical genomic profiling was performed, showing no yeast response differences in hydrolysates produced during RaBIT enzymatic hydrolysis. Concentrations of degradation products in solution were quantified after different enzymatic hydrolysis cycles and fermentation cycles. Intracellular degradation product concentrations were also measured following fermentation. Degradation product concentrations in hydrolysate did not change between RaBIT enzymatic hydrolysis cycles; the cell population retained its ability to oxidize/reduce (detoxify) aldehydes over five RaBIT fermentation cycles; and degradation products accumulated within or on the cells as RaBIT fermentation cycles increased. Synthetic hydrolysate was used to confirm that pretreatment degradation products are the sole cause of decreased xylose consumption during RaBIT fermentations. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Thermophilic Ionic Liquid-Tolerant Cellulase Cocktail for the Production of Cellulosic Biofuels

PubMed Central

Park, Joshua I.; Steen, Eric J.; Burd, Helcio; Evans, Sophia S.; Redding-Johnson, Alyssa M.; Batth, Tanveer; Benke, Peter I.; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L.; Keasling, Jay D.; Lee, Taek Soon; Petzold, Christopher J.; Mukhopadhyay, Aindrila; Singer, Steven W.; Simmons, Blake A.; Gladden, John M.

2012-01-01

Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels. PMID:22649505

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

Gabhane, Jagdish; William, S.P.M. Prince, E-mail: spmp_william@neeri.res.in; Vaidya, Atul N.

Highlights: • SAAP is an efficient and economic means of pretreatment. • SAAP was found to be efficient in lignin and hemicellulose removal. • SAAP enhanced the enzymatic hydrolysis. • FTIR, XRD and SEM provided vivid understanding about the mode of action of SAAP. • Mass balance closer of 98% for pretreated GB confirmed the reliability of SAAP. - Abstract: A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure andmore » functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment.« less

Augmented digestion of lignocellulose by steam explosion, acid and alkaline pretreatment methods: a review.

PubMed

Singh, Joginder; Suhag, Meenakshi; Dhaka, Anil

2015-03-06

Lignocellulosic materials can be explored as one of the sustainable substrates for bioethanol production through microbial intervention as they are abundant, cheap and renewable. But at the same time, their recalcitrant structure makes the conversion process more cumbersome owing to their chemical composition which adversely affects the efficiency of bioethanol production. Therefore, the technical approaches to overcome recalcitrance of biomass feedstock has been developed to remove the barriers with the help of pretreatment methods which make cellulose more accessible to the hydrolytic enzymes, secreted by the microorganisms, for its conversion to glucose. Pretreatment of lignocellulosic biomass in cost effective manner is a major challenge to bioethanol technology research and development. Hence, in this review, we have discussed various aspects of three commonly used pretreatment methods, viz., steam explosion, acid and alkaline, applied on various lignocellulosic biomasses to augment their digestibility alongwith the challenges associated with their processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of a new pulping technology for pre-treating source-separated organic household waste prior to anaerobic digestion.

PubMed

Naroznova, Irina; Møller, Jacob; Larsen, Bjarne; Scheutz, Charlotte

2016-04-01

A new technology for pre-treating source-separated organic household waste prior to anaerobic digestion was assessed, and its performance was compared to existing alternative pre-treatment technologies. This pre-treatment technology is based on waste pulping with water, using a specially developed screw mechanism. The pre-treatment technology rejects more than 95% (wet weight) of non-biodegradable impurities in waste collected from households and generates biopulp ready for anaerobic digestion. Overall, 84-99% of biodegradable material (on a dry weight basis) in the waste was recovered in the biopulp. The biochemical methane potential for the biopulp was 469 ± 7 mL CH4/g ash-free mass. Moreover, all Danish and European Union requirements regarding the content of hazardous substances in biomass intended for land application were fulfilled. Compared to other pre-treatment alternatives, the screw-pulping technology showed higher biodegradable material recovery, lower electricity consumption and comparable water consumption. The higher material recovery achieved with the technology was associated with greater transfer of nutrients (N and P), carbon (total and biogenic) but also heavy metals (except Pb) to the produced biomass. The data generated in this study could be used for the environmental assessment of the technology and thus help in selecting the best pre-treatment technology for source separated organic household waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biofiltration: Fundamentals, design and operations principles and applications

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

Swanson, W.J.; Loehr, R.C.

1997-06-01

Biofiltration is a biological air pollution control technology for volatile organic compounds (VOCs). This paper summarizes the fundamentals, design and operation, and application of the process. Biofiltration has been demonstrated to be an effective technology for VOCs from many industries. Large and full-scale systems are in use in Europe and the US. With proper design and operation, VOC removal efficiencies of 95--99% have been achieved. Important parameters for design and performance are empty-bed contact time, gas surface loading, mass loading, elimination capacity, and removal efficiency. Key design and operation factors include chemical and media properties, moisture, pH, temperature, nutrient availability,more » gas pretreatment, and variations in loading.« less

Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of three-dimensional catalytic electro-Fenton and membrane bioreactor.

PubMed

Jia, Shengyong; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng

2015-12-01

Laboratorial scale experiments were conducted to investigate a novel system three-dimensional catalytic electro-Fenton (3DCEF, catalyst of sewage sludge based activated carbon which loaded Fe3O4) integrating with membrane bioreactor (3DCEF-MBR) on advanced treatment of biologically pretreated coal gasification wastewater. The results indicated that 3DCEF-MBR represented high efficiencies in eliminating COD and total organic carbon, giving the maximum removal efficiencies of 80% and 75%, respectively. The integrated 3DCEF-MBR system significantly reduced the transmembrane pressure, giving 35% lower than conventional MBR after 30 days operation. The enhanced hydroxyl radical oxidation and bacteria self repair function were the mechanisms for 3DCEF-MBR performance. Therefore, the integrated 3DCEF-MBR was expected to be the promising technology for advanced treatment in engineering applications. Copyright © 2015. Published by Elsevier Ltd.

Helically agitated mixing in dry dilute acid pretreatment enhances the bioconversion of corn stover into ethanol

PubMed Central

2014-01-01

Background Dry dilute acid pretreatment at extremely high solids loading of lignocellulose materials demonstrated promising advantages of no waste water generation, less sugar loss, and low steam consumption while maintaining high hydrolysis yield. However, the routine pretreatment reactor without mixing apparatus was found not suitable for dry pretreatment operation because of poor mixing and mass transfer. In this study, helically agitated mixing was introduced into the dry dilute acid pretreatment of corn stover and its effect on pretreatment efficiency, inhibitor generation, sugar production, and bioconversion efficiency through simultaneous saccharification and ethanol fermentation (SSF) were evaluated. Results The overall cellulose conversion taking account of cellulose loss in pretreatment was used to evaluate the efficiency of pretreatment. The two-phase computational fluid dynamics (CFD) model on dry pretreatment was established and applied to analyze the mixing mechanism. The results showed that the pretreatment efficiency was significantly improved and the inhibitor generation was reduced by the helically agitated mixing, compared to the dry pretreatment without mixing: the ethanol titer and yield from cellulose in the SSF reached 56.20 g/L and 69.43% at the 30% solids loading and 15 FPU/DM cellulase dosage, respectively, corresponding to a 26.5% increase in ethanol titer and 17.2% increase in ethanol yield at the same fermentation conditions. Conclusions The advantage of helically agitated mixing may provide a prototype of dry dilute acid pretreatment processing for future commercial-scale production of cellulosic ethanol. PMID:24387051

Combining hot-compressed water and ball milling pretreatments to improve the efficiency of the enzymatic hydrolysis of eucalyptus

PubMed Central

Inoue, Hiroyuki; Yano, Shinichi; Endo, Takashi; Sakaki, Tsuyoshi; Sawayama, Shigeki

2008-01-01

Background Lignocellulosic biomass such as wood is an attractive material for fuel ethanol production. Pretreatment technologies that increase the digestibility of cellulose and hemicellulose in the lignocellulosic biomass have a major influence on the cost of the subsequent enzymatic hydrolysis and ethanol fermentation processes. Pretreatments without chemicals such as acids, bases or organic solvents are less effective for an enzymatic hydrolysis process than those with chemicals, but they have a less negative effect on the environment. Results The enzymatic digestibility of eucalyptus was examined following a combined pretreatment without chemicals comprising a ball milling (BM) and hot-compressed water (HCW) treatment. The BM treatment simultaneously improved the digestibility of both glucan and xylan, and was effective in lowering the enzyme loading compared with the HCW treatment. The combination of HCW and BM treatment reduced the BM time. The eucalyptus treated with HCW (160°C, 30 minutes) followed by BM (20 minutes) had an approximately 70% yield of total sugar with a cellulase loading of 4 FPU/g substrate. This yield was comparable to the yields from samples treated with HCW (200°C, 30 minutes) or BM (40 minutes) hydrolyzed with 40 FPU/g substrate. Conclusion The HCW treatment is useful in improving the milling efficiency. The combined HCW-BM treatment can save energy and enzyme loading. PMID:18471309

Pretreatment solution recycling and high-concentration output for economical production of bioethanol.

PubMed

Han, Minhee; Moon, Se-Kwon; Choi, Gi-Wook

2014-11-01

The purpose of this study was to enhance the economic efficiency of producing bioethanol. Pretreatment solution recycling is expected to increase economic efficiency by reducing the cost of pretreatment and the amount of wastewater. In addition, the production of high-concentration bioethanol could increase economic efficiency by reducing the energy cost of distillation. The pretreatment conditions were 95 °C, 0.72 M NaOH, 80 rpm twin-screw speed, and flow rate of 90 mL/min at 18 g/min of raw biomass feeding for pretreatment solution recycling. The pretreatment with NaOH solution recycling was conducted five times. All of the components and the pretreatment efficiency were similar, despite reuse. In addition, we developed a continuous biomass feeding system for production of high-concentration bioethanol. Using this reactor, the bioethanol productivity was investigated using various pretreated biomass feeding rates in a simultaneous saccharification and fermentation (SSF) process. The maximum ethanol concentration, yield, and productivity were 74.5 g/L, 89.5%, and 1.4 g/L h, respectively, at a pretreated biomass loading of approximately 25% (w/v) with an enzyme dosage of 30 FPU g/cellulose. The results presented here constitute an important contribution toward the production of bioethanol from Miscanthus.

Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

PubMed

Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

2016-03-01

Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological pretreatment of corn stover with ligninolytic enzyme for high efficient enzymatic hydrolysis.

PubMed

Wang, Feng-Qin; Xie, Hui; Chen, Wei; Wang, En-Tao; Du, Feng-Guang; Song, An-Dong

2013-09-01

Aiming at increasing the efficiency of transferring corn stover into sugars, a biological pretreatment was developed and investigated in this study. The protocol was characterized by the pretreatment with crude ligninolytic enzymes from Phanerochete chrysosporium and Coridus versicolor to break the lignin structure in corn stover, followed by a washing procedure to eliminate the inhibition of ligninolytic enzyme on cellulase. By a 2 d-pretreatment, sugar yield from corn stover hydrolysis could be increased by 50.2% (up to 323 mg/g) compared with that of the control. X-ray diffractometry and FT-IR analysis revealed that biological pretreatment could partially remove the lignin of corn stover, and consequently enhance the enzymatic hydrolysis efficiency of cellulose and hemeicellulose. In addition, the amount of microbial inhibitors, such as acetic acid and furfural, were much lower in biological pretreatment than that in acid pretreatment. This study provided a promising pretreatment method for biotransformation of corn stovers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose.

PubMed

Gabhane, Jagdish; William, S P M Prince; Vaidya, Atul N; Das, Sera; Wate, Satish R

2015-06-01

A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pre-treatment of thickened waste activated sludge (TWAS) for enhanced biogas production via the application of a novel radial horn sonication technology.

PubMed

Suhartini, Sri; Melville, Lynsey; Amato, Tony

2017-05-01

The efficacy of sonication as a pre-treatment to anaerobic digestion (AD) was assessed using thickened waste activated sludge (TWAS). Efficiency was measured in relation to solubilisation, dewaterability, and AD performance. Eighteen experimental conditions were evaluated at low frequency (20 kHz), duration (2-10 s), amplitude (∼8-12 μm) and applied pressure (0.5-3.0 barg), using a sonix™ patented titanium sonoprobe capable of delivering an instantaneous power of ∼6 kW provided by Doosan Enpure Ltd (DEL). An optimised experimental protocol was used as a pre-treatment for biochemical methane potential (BMP) testing and semi-continuous trials. Four digesters, with a 2-L working volume were operated mesophilically (37 ± 0.5 °C) over 22 days. The results showed that the sonix™ technology delivers effective sonication at very short retention times compared to conventional system. Results demonstrate that the technology effectively disrupts the floc structures and filaments within the TWAS, causing an increase in solubilisation and fine readily digestible material. Both BMP tests and semi-continuous trials demonstrated that sonicated TWAS gave higher biodegradability and methane potential compared to untreated TWAS. Partial-stream sonication (30:70 sonicated to untreated TWAS) resulted in a proportionate increase in biogas production illustrating the benefits of full-stream sonication.

Improving the enzymatic hydrolysis of thermo-mechanical fiber from Eucalyptus urophylla by a combination of hydrothermal pretreatment and alkali fractionation.

PubMed

Sun, Shaoni; Cao, Xuefei; Sun, Shaolong; Xu, Feng; Song, Xianliang; Sun, Run-Cang; Jones, Gwynn Lloyd

2014-01-01

The recalcitrance of lignocellulosic biomass is a major limitation for its conversion into biofuels by enzymatic hydrolysis. The use of a pretreatment technology is an essential step to diminish biomass recalcitrance for bioethanol production. In this study, a two-step pretreatment using hydrothermal pretreatment at various temperatures and alkali fractionation was performed on eucalyptus fiber. The detailed chemical composition, physicochemical characteristics, and morphology of the pretreated fibers in each of the fractions were evaluated to advance the performance of eucalyptus fiber in enzymatic digestibility. The hydrothermal pretreatment (100 to 220°C) significantly degraded hemicelluloses, resulting in an increased crystallinity of the pretreated fibers. However, as the pretreatment temperature reached 240°C, partial cellulose was degraded, resulting in a reduced crystallinity of cellulose. As compared to the hydrothermal pretreatment alone, a combination of hydrothermal and alkali treatments significantly removed hemicelluloses and lignin, resulting in an improved enzymatic hydrolysis of the cellulose-rich fractions. As compared with the raw fiber, the enzymatic hydrolysis rate increased 1.1 to 8.5 times as the hydrothermal pretreatment temperature increased from 100 to 240°C. Interestingly, after a combination of hydrothermal pretreatment and alkali fractionation, the enzymatic hydrolysis rate increased 3.7 to 9.2 times. Taking into consideration the consumption of energy and the production of xylo-oligosaccharides and lignin, an optimum pretreatment condition was found to be hydrothermal pretreatment at 180°C for 30 min and alkali fractionation with 2% NaOH at 90°C for 2.5 h, in which 66.3% cellulose was converted into glucose by enzymatic hydrolysis. The combination of hydrothermal pretreatment and alkali fractionation was a promising method to remove hemicelluloses and lignin as well as overcome the biomass recalcitrance for enzymatic hydrolysis from eucalyptus fiber. In addition, the various techniques applied in this work constituted an efficient approach to understand the underlying chemical and morphological changes of the cellulose-rich fractions.

Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

NASA Astrophysics Data System (ADS)

Corredor, Deisy Y.

The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis process. Up to 72% of hexose yield and 94% of pentose yield were obtained using "modified" steam explosion with 2% sulfuric acid at 140°C for 30 min and enzymatic hydrolysis with cellulase (15 FPU/g cellulose) and beta-glucosidase (50 CBU/g cellulose).

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol.

PubMed

Li, Jihong; Li, Shizhong; Han, Bing; Yu, Menghui; Li, Guangming; Jiang, Yan

2013-11-29

Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions.

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol

PubMed Central

2013-01-01

Background Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. Results An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. Conclusions A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions. PMID:24286508

Development of natural cellulase inhibitor mediated intensified biological pretreatment technology using Pleurotus florida for maximum recovery of cellulose from paddy straw under solid state condition.

PubMed

Naresh Kumar, Manickam; Ravikumar, Rajarathinam; Thenmozhi, Senniyappan; Kirupa Sankar, Muthuvelu

2017-11-01

Inhibitor mediated intensified bio-pretreatment (IMBP) technology using natural cellulase inhibitor (NCI) for maximum cellulose recovery from paddy straw was studied. Pretreatment was carried out under solid state condition. Supplementation of 8% NCI in pretreatment medium improves cellulose recovery and delignification by 1.2 and 1.5-fold respectively, compared to conventional bio-pretreatment due to inhibition of 61% of cellulase activity in IMBP. Further increase in NCI concentration showed negative effect on Pleurotus florida growth and suppress the laccase productivity by 1.1-fold. Laccase activity in IMBP was found to be 2.0U/mL on 19 th day, which is higher than (1.5U/mL) conventional bio-pretreatment. Physico-chemical modifications in paddy straw before and after pretreatment were analysed by SEM, ATR-FTIR, XRD and TGA. According to these findings, the IMBP technology can be a viable eco-friendly technology for sustainable production of bioethanol with maximum cellulose recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fermentation of undetoxified sugarcane bagasse hydrolyzates using a two stage hydrothermal and mechanical refining pretreatment

USDA-ARS?s Scientific Manuscript database

Economical and environmentally friendly pretreatment technologies are required for commercial conversion of lignocellulosic feedstocks to fermentable sugars for fermentation to biofuels. In this paper, a novel pretreatment technology was developed for conversion of sugarcane bagasse into ethanol usi...

Improving methane production from digested manure biofibers by mechanical and thermal alkaline pretreatment.

PubMed

Tsapekos, P; Kougias, Panagiotis G; Frison, A; Raga, R; Angelidaki, I

2016-09-01

Animal manure digestion is associated with limited methane production, due to the high content in fibers, which are hardly degradable lignocellulosic compounds. In this study, different mechanical and thermal alkaline pretreatment methods were applied to partially degradable fibers, separated from the effluent stream of biogas reactors. Batch and continuous experiments were conducted to evaluate the efficiency of these pretreatments. In batch experiments, the mechanical pretreatment improved the degradability up to 45%. Even higher efficiency was shown by applying thermal alkaline pretreatments, enhancing fibers degradability by more than 4-fold. In continuous experiments, the thermal alkaline pretreatment, using 6% NaOH at 55°C was proven to be the most efficient pretreatment method as the methane production was increased by 26%. The findings demonstrated that the methane production of the biogas plants can be increased by further exploiting the fraction of the digested manure fibers which are discarded in the post-storage tank. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of co-pretreatment of calcium hydroxide and steam explosion on anaerobic digestion efficiency with corn stover.

PubMed

Ji, Jinli; Zhang, Jiyu; Yang, Liutianyi; He, Yanfeng; Zhang, Ruihong; Liu, Guangqing; Chen, Chang

2017-06-01

Anaerobic digestion (AD) is an effective way to utilize the abundant resource of corn stover (CS). In this light, Ca(OH) 2 pretreatment alone, steam explosion (SE) pretreatment alone, and co-pretreatment of Ca(OH) 2 and SE were applied to improve the digestion efficiency of CS. Results showed that AD of co-pretreated CS with 1.0% Ca(OH) 2 and SE at 1.5 MPa achieved the highest cumulative methane yield of [Formula: see text], which was 61.54% significantly higher (p < .01) than untreated CS. The biodegradability value of CS after co-pretreatment enhanced from 43.03% to 69.52%. Methane yield could be well fitted by the first-order model and the modified Gompertz model. In addition, composition and structural changes of CS after pretreatment were analyzed by a fiber analyzer, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The validated results indicated that co-pretreatment of Ca(OH) 2 and SE was efficient to improve the digestion performance of CS and might be a suitable method for agricultural waste pretreatment in the future AD industry.

Effects of pre-fermentation and pulsed-electric-field treatment of primary sludge in microbial electrochemical cells.

PubMed

Ki, Dongwon; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, César I

2015-11-01

The aim of this study was to investigate the combination of two technologies - pulsed electric field (PEF) pre-treatment and semi-continuous pre-fermentation of primary sludge (PS) - to produce volatile fatty acids (VFAs) as the electron donor for microbial electrolysis cells (MECs). Pre-fermentation with a 3-day solids retention time (SRT) led to the maximum generation of VFAs, with or without pretreatment of the PS through pulsed-electric-fields (PEF). PEF treatment before fermentation enhanced the accumulation of the preferred VFA, acetate, by 2.6-fold. Correspondingly, MEC anodes fed with centrate from 3-day pre-fermentation of PEF-treated PS had a maximum current density ∼3.1 A/m(2), which was 2.4-fold greater than the control pre-fermented centrate. Over the full duration of batch MEC experiments, using pre-fermented centrate led to successful performance in terms of Coulombic efficiency (95%), Coulombic recovery (80%), and COD-removal efficiency (85%). Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous pretreatment and saccharification: green technology for enhanced sugar yields from biomass using a fungal consortium.

PubMed

Dhiman, Saurabh Sudha; Haw, Jung-Rim; Kalyani, Dayanand; Kalia, Vipin C; Kang, Yun Chan; Lee, Jung-Kul

2015-03-01

Two different biomasses were subjected to simultaneous pretreatment and saccharification (SPS) using a cocktail of hydrolytic and oxidizing enzymes. Application of a novel laccase as a detoxifying agent caused the removal of 49.8% and 32.6% of phenolic contents from the soaked rice straw and willow, respectively. Hydrolysis of soaked substrates using a newly developed fungal consortium resulted in saccharification yield of up to 74.2% and 63.6% for rice straw and willow, respectively. A high saccharification yield was obtained with soaked rice straw and willow without using any hazardous chemicals. The efficiency of each step related to SPS was confirmed by atomic force microscopy. The suitability of the developed SPS process was further confirmed by converting the hydrolysate from the process into bioethanol with 72.4% sugar conversion efficiency. To the best of our knowledge, this is the first report on the development of a less tedious, single-pot, and eco-friendly SPS methodology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Visible light photocatalytic disintegration of waste activated sludge for enhancing biogas production.

PubMed

Anjum, Muzammil; Al-Talhi, Hasan A; Mohamed, Saleh A; Kumar, Rajeev; Barakat, M A

2018-06-15

Biogas production using waste activated sludge (WAS) is one of the most demanding technologies for sludge treatment and generating energy in sustainable manner. The present study deals with the photocatalytic pretreatment of WAS using ZnO-ZnS@polyaniline (ZnO-ZnS@PANI) nanocomposite as means for increasing its degradability for improved biogas production by anaerobic digestion (AD). Photocatalysis accelerated the hydrolysis of WAS and increased the sCOD by 6.7 folds after 6 h and transform tCOD into bioavailable sCOD. After the AD of WAS, a removal of organic matter (60.6%) and tCOD (69.3%) was achieved in photocatalytic pretreated sludge. The biogas production was 1.6 folds higher in photocatalytic sludge with accumulative biogas up to 1645.1 ml L -1 vs after 45 days compared with the raw sludge (1022.4 ml L -1 VS ). Moreover, the photocatalysis decrease the onset of methanogenesis from 25 to 12 days while achieve the maximum conversion rate of reducing sugars into organic acids at that time. These results suggested that photocatalysis is an efficient pretreatment method and ZnO-ZnS@PANI can degrade sludge efficiently for enhance biogas production in anaerobic digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass.

PubMed

Matsakas, Leonidas; Nitsos, Christos; Raghavendran, Vijayendran; Yakimenko, Olga; Persson, Gustav; Olsson, Eva; Rova, Ulrika; Olsson, Lisbeth; Christakopoulos, Paul

2018-01-01

The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance saccharification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractionation into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas organosolv is excellent for delignification but offers poor biomass deconstruction. In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pretreatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) were evaluated. Pretreatment of birch at 200 °C with 60% v/v ethanol and 1% w/w biomass H 2 SO 4 was proven to be the most efficient pretreatment condition yielding pretreated solids with 77.9% w/w cellulose, 8.9% w/w hemicellulose, and 7.0 w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25% w/w, respectively, and ash to be < 0.17% w/w in all cases, making it suitable for various applications. The pretreated solids presented high saccharification yields, reaching 68% at low enzyme load (6 FPU/g) and complete saccharification at high enzyme load (22.5 FPU/g). Finally, simultaneous saccharification and fermentation (SSF) at 20% w/w solids yielded an ethanol titer of 80 g/L after 192 h, corresponding to 90% of the theoretical maximum. The novel hybrid method developed in this study allowed for the efficient fractionation of birch biomass and production of pretreated solids with high cellulose and low lignin contents. Moreover, the explosive discharge at the end of pretreatment had a positive effect on enzymatic saccharification, resulting in high hydrolyzability of the pretreated solids and elevated ethanol titers in the following high-gravity SSF. To the best of our knowledge, the ethanol concentration obtained with this method is the highest so far for birch biomass.

Recent developments in smart freezing technology applied to fresh foods.

PubMed

Xu, Ji-Cheng; Zhang, Min; Mujumdar, Arun S; Adhikari, Benu

2017-09-02

Due to the increased awareness of consumers in sensorial and nutritional quality of frozen foods, the freezing technology has to seek new and innovative technologies for better retaining the fresh like quality of foods. In this article, we review the recent developments in smart freezing technology applied to fresh foods. The application of these intelligent technologies and the associated underpinning concepts have greatly improved the quality of frozen foods and the freezing efficiency. These technologies are able to automatically collect the information in-line during freezing and help control the freezing process better. Smart freezing technology includes new and intelligent technologies and concepts applied to the pretreatment of the frozen product, freezing processes, cold chain logistics as well as warehouse management. These technologies enable real-time monitoring of quality during the freezing process and help improve product quality and freezing efficiency. We also provide a brief overview of several sensing technologies used to achieve automatic control of individual steps of freezing process. These sensing technologies include computer vision, electronic nose, electronic tongue, digital simulation, confocal laser, near infrared spectroscopy, nuclear magnetic resonance technology and ultrasound. Understanding of the mechanism of these new technologies will be helpful for applying them to improve the quality of frozen foods.

Improving the sludge disintegration efficiency of sonication by combining with alkalization and thermal pre-treatment methods.

PubMed

Şahinkaya, S; Sevimli, M F; Aygün, A

2012-01-01

One of the most serious problems encountered in biological wastewater treatment processes is the production of waste activated sludge (WAS). Sonication, which is an energy-intensive process, is the most powerful sludge pre-treatment method. Due to lack of information about the combined pre-treatment methods of sonication, the combined pre-treatment methods were investigated and it was aimed to improve the disintegration efficiency of sonication by combining sonication with alkalization and thermal pre-treatment methods in this study. The process performances were evaluated based on the quantities of increases in soluble chemical oxygen demand (COD), protein and carbohydrate. The releases of soluble COD, carbohydrate and protein by the combined methods were higher than those by sonication, alkalization and thermal pre-treatment alone. Degrees of sludge disintegration in various options of sonication were in the following descending order: sono-alkalization > sono-thermal pre-treatment > sonication. Therefore, it was determined that combining sonication with alkalization significantly improved the sludge disintegration and decreased the required energy to reach the same yield by sonication. In addition, effects on sludge settleability and dewaterability and kinetic mathematical modelling of pre-treatment performances of these methods were investigated. It was proven that the proposed model accurately predicted the efficiencies of ultrasonic pre-treatment methods.

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

NASA Astrophysics Data System (ADS)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Production of bioethanol from wheat straw: An overview on pretreatment, hydrolysis and fermentation.

PubMed

Talebnia, Farid; Karakashev, Dimitar; Angelidaki, Irini

2010-07-01

Wheat straw is an abundant agricultural residue with low commercial value. An attractive alternative is utilization of wheat straw for bioethanol production. However, production costs based on the current technology are still too high, preventing commercialization of the process. In recent years, progress has been made in developing more effective pretreatment and hydrolysis processes leading to higher yield of sugars. The focus of this paper is to review the most recent advances in pretreatment, hydrolysis and fermentation of wheat straw. Based on the type of pretreatment method applied, a sugar yield of 74-99.6% of maximum theoretical was achieved after enzymatic hydrolysis of wheat straw. Various bacteria, yeasts and fungi have been investigated with the ethanol yield ranging from 65% to 99% of theoretical value. So far, the best results with respect to ethanol yield, final ethanol concentration and productivity were obtained with the native non-adapted Saccharomyses cerevisiae. Some recombinant bacteria and yeasts have shown promising results and are being considered for commercial scale-up. Wheat straw biorefinery could be the near-term solution for clean, efficient and economically-feasible production of bioethanol as well as high value-added products. Copyright 2009 Elsevier Ltd. All rights reserved.

Systematic comparison of mechanical and thermal sludge disintegration technologies.

PubMed

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. Copyright 2009 Elsevier Ltd. All rights reserved.

Physical and chemical pretreatment of lignocellulosics in pineapple (Ananus comosus) peels dried for investment

NASA Astrophysics Data System (ADS)

Sukkaew, Adulsman; Boonsong, Panthip; Thongpradistha, Sriubol; Intan, Maimoon

2017-08-01

Pineapple (Ananus comosus) Peels, once known as waste from agricultural, can be a problem when we eliminate in agriculture and industry. The current technology can help preliminarily to solve this problem. The sustainable solution to this problem is lignocellulosics pretreatments for converted saccharide as a carbon source for ethanol production. The objective of this study is the investigation of pineapple peels pretreatment to produce fermentable sugar by drying and digesting 5% sulfuric acid (H2SO4). And study of cost economic passed selection for investment. The result found that the best investment of drying was 100 °C at 11 hours for the sulphuric acid which could be easily crushed into a fine powder. Moreover, digestion of pineapple peels gave the best total sugar 252.2 g/l by 5% H2SO4 incubated for 60 minutes at room temperature. The pineapple peels were digested by 5%H2SO4 concentration by incubating for 60 minutes at room temperature, finding to be the best condition and the lowest investment. Finally, the optimisation of investment and management for lignocellulosic pretreatment will improve efficiency of strategy for economic and energy development.

Strategies for merging microbial fuel cell technologies in water desalination processes: Start-up protocol and desalination efficiency assessment

NASA Astrophysics Data System (ADS)

Borjas, Zulema; Esteve-Núñez, Abraham; Ortiz, Juan Manuel

2017-07-01

Microbial Desalination Cells constitute an innovative technology where microbial fuel cell and electrodialysis merge in the same device for obtaining fresh water from saline water with no energy-associated cost for the user. In this work, an anodic biofilm of the electroactive bacteria Geobacter sulfurreducens was able to efficiently convert the acetate present in synthetic waste water into electric current (j = 0.32 mA cm-2) able to desalinate water. .Moreover, we implemented an efficient start-up protocol where desalination up to 90% occurred in a desalination cycle (water production:0.308 L m-2 h-1, initial salinity: 9 mS cm-1, final salinity: <1 mS cm-1) using a filter press-based MDC prototype without any energy supply (excluding peristaltic pump energy). This start-up protocol is not only optimized for time but also simplifies operational procedures making it a more feasible strategy for future scaling-up of MDCs either as a single process or as a pre-treatment method combined with other well established desalination technologies such as reverse osmosis (RO) or reverse electrodialysis.

Effects of treatment time and temperature on the DC corona pretreatment performance of waste activated sludge

NASA Astrophysics Data System (ADS)

Yu, GAO; Ning, ZHAO; Yongdi, DENG; Minghang, WANG; Boxue, DU

2018-02-01

In order to improve the anaerobic digestion efficiency of waste activated sludge (WAS), a pretreatment procedure should be carried out so as to disrupt the microbial cell structure, thus releasing intracellular organic matters. In this paper, a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures. The magnitude of the DC voltage was 4 kV at both negative and positive polarities. The changes in the soluble chemical oxygen demand, phosphorus and nitrogen content, and pH value within the WAS were utilized to estimate the pretreatment performance of the DC corona. It was found that with increasing treatment time, the pretreatment efficiency tends to be reduced. With increased temperature, the pretreatment efficiency appears to be better. It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure, which is dependent upon the treatment time and the temperature.

Multi-scale structural and chemical analysis of sugarcane bagasse in the process of sequential acid–base pretreatment and ethanol production by Scheffersomyces shehatae and Saccharomyces cerevisiae

PubMed Central

2014-01-01

Background Heavy usage of gasoline, burgeoning fuel prices, and environmental issues have paved the way for the exploration of cellulosic ethanol. Cellulosic ethanol production technologies are emerging and require continued technological advancements. One of the most challenging issues is the pretreatment of lignocellulosic biomass for the desired sugars yields after enzymatic hydrolysis. We hypothesized that consecutive dilute sulfuric acid-dilute sodium hydroxide pretreatment would overcome the native recalcitrance of sugarcane bagasse (SB) by enhancing cellulase accessibility of the embedded cellulosic microfibrils. Results SB hemicellulosic hydrolysate after concentration by vacuum evaporation and detoxification showed 30.89 g/l xylose along with other products (0.32 g/l glucose, 2.31 g/l arabinose, and 1.26 g/l acetic acid). The recovered cellulignin was subsequently delignified by sodium hydroxide mediated pretreatment. The acid–base pretreated material released 48.50 g/l total reducing sugars (0.91 g sugars/g cellulose amount in SB) after enzymatic hydrolysis. Ultra-structural mapping of acid–base pretreated and enzyme hydrolyzed SB by microscopic analysis (scanning electron microcopy (SEM), transmitted light microscopy (TLM), and spectroscopic analysis (X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy) elucidated the molecular changes in hemicellulose, cellulose, and lignin components of bagasse. The detoxified hemicellulosic hydrolysate was fermented by Scheffersomyces shehatae (syn. Candida shehatae UFMG HM 52.2) and resulted in 9.11 g/l ethanol production (yield 0.38 g/g) after 48 hours of fermentation. Enzymatic hydrolysate when fermented by Saccharomyces cerevisiae 174 revealed 8.13 g/l ethanol (yield 0.22 g/g) after 72 hours of fermentation. Conclusions Multi-scale structural studies of SB after sequential acid–base pretreatment and enzymatic hydrolysis showed marked changes in hemicellulose and lignin removal at molecular level. The cellulosic material showed high saccharification efficiency after enzymatic hydrolysis. Hemicellulosic and cellulosic hydrolysates revealed moderate ethanol production by S. shehatae and S. cerevisiae under batch fermentation conditions. PMID:24739736

A novel integration of three-dimensional electro-Fenton and biological activated carbon and its application in the advanced treatment of biologically pretreated Lurgi coal gasification wastewater.

PubMed

Hou, Baolin; Han, Hongjun; Zhuang, Haifeng; Xu, Peng; Jia, Shengyong; Li, Kun

2015-11-01

A novel integrated process with three-dimensional electro-Fenton (3D EF) and biological activated carbon (BAC) was employed in advanced treatment of biologically pretreated Lurgi coal gasification wastewater. SAC-Fe (sludge deserved activated carbon from sewage and iron sludge) and SAC (sludge deserved activated carbon) were used in 3D EF as catalytic particle electrodes (CPEs) and in BAC as carriers respectively. Results indicated that 3D EF with SAC-Fe as CPEs represented excellent pollutants and COLOR removals as well as biodegradability improvement. The efficiency enhancement attributed to generating more H2O2 and OH. The integrated process exhibited efficient performance of COD, BOD5, total phenols, TOC, TN and COLOR removals at a much shorter retention time, with the corresponding concentrations in effluent of 31.18, 6.69, 4.29, 17.82, 13.88mg/L and <20 times, allowing discharge criteria to be met. The integrated system was efficient, cost-effective and ecological sustainable and could be a promising technology for engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation energy efficiency of bioconversion knot rejects to ethanol in comparison to other thermochemically pretreated biomass

Treesearch

Zhaojiang Wang; Menghua Qin; J.Y. Zhu; Guoyu Tian; Zongquan Li

2013-01-01

Rejects from sulfite pulp mill that otherwise would be disposed of by incineration were converted to ethanol by a combined physical–biological process that was comprised of physical refining and simultaneous saccharification and fermentation (SSF). The energy efficiency was evaluated with comparison to thermochemically pretreated biomass, such as those pretreated by...

Pretreatment of Lignocellulosic Biomass with Ionic Liquids and Ionic Liquid-Based Solvent Systems.

PubMed

Hou, Qidong; Ju, Meiting; Li, Weizun; Liu, Le; Chen, Yu; Yang, Qian

2017-03-20

Pretreatment is very important for the efficient production of value-added products from lignocellulosic biomass. However, traditional pretreatment methods have several disadvantages, including low efficiency and high pollution. This article gives an overview on the applications of ionic liquids (ILs) and IL-based solvent systems in the pretreatment of lignocellulosic biomass. It is divided into three parts: the first deals with the dissolution of biomass in ILs and IL-based solvent systems; the second focuses on the fractionation of biomass using ILs and IL-based solvent systems as solvents; the third emphasizes the enzymatic saccharification of biomass after pretreatment with ILs and IL-based solvent systems.

Fuel ethanol production from corn stover under optimized dilute phosphoric acid pretreatment and enzymatic hydrolysis

USDA-ARS?s Scientific Manuscript database

Ethanol is a renewable oxygenated fuel. Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Generation of fermentable sugars from corn stover involves pretreatment and enzymatic saccharification. Pretreatment is crucial as nat...

Using high pressure processing (HPP) to pretreat sugarcane bagasse.

PubMed

Castañón-Rodríguez, J F; Torrestiana-Sánchez, B; Montero-Lagunes, M; Portilla-Arias, J; Ramírez de León, J A; Aguilar-Uscanga, M G

2013-10-15

High pressure processing (HPP) technology was used to modify the structural composition of sugarcane bagasse. The effect of pressure (0, 150 and 250 MPa), time (5 and 10 min) and temperature (25 and 50 °C) as well as the addition of phosphoric acid, sulfuric acid and NaOH during the HPP treatment were assessed in terms of compositional analysis of the lignocellulosic fraction, structural changes and crystallinity of the bagasse. The effect of HPP pretreatment on the bagasse structure was also evaluated on the efficiency of the enzymatic hydrolysis of bagasse. Results showed that 68.62 and 45.84% of the hemicellulose fraction was degraded by pretreating at 250 MPa with sulfuric and phosphoric acids, respectively. The removal of lignin (54.10%) was higher with the HPP-NaOH treatment. The compacted lignocellulosic structure of the raw bagasse was modified by the HPP treatments and showed few cracks, tiny holes and some fragments flaked off from the surface. Structural changes were higher at 250 MPa and 50 °C. The X ray diffraction (XRD) patterns of the raw bagasse showed a major diffraction peak of the cellulose crystallographic 2θ planes ranging between 22 and 23°. The distribution of the crystalline structure of cellulose was affected by increasing the pressure level. The HPP treatment combined with NaOH 2% led to the higher glucose yield (25 g/L) compared to the combination of HPP with water and acids (>5 g/L). Results from this work suggest that HPP technology may be used to pretreat sugarcane bagasse. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optimization of SHINE Process: Design and Verification of Plant-Scale AG 1 Anion-Exchange Concentration Column and Titania Sorbent Pretreatment

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

Stepinski, Dominique C.; Abdul, Momen; Youker, Amanda J.

2016-06-01

Argonne National Laboratory has developed a Mo-recovery and -purification system for the SHINE medical technologies process, which uses a uranyl sulfate solution for the accelerator-driven production of Mo-99. The objective of this effort is to reduce the processing time for the acidification of the Mo-99 product prior to loading onto a concentration column and concentration of the Mo-99 product solution. Two methods were investigated: (1) the replacement of the titania concentration column by an anion-exchange column to decrease processing time and increase the radioiodine-decontamination efficiency and (2) pretreatment of the titania sorbent to improve its effectiveness for the Mo-recovery andmore » -concentration columns. Promising results are reported for both methods.« less

Anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues for methane production.

PubMed

Li, Guixia; Zhong, Weizhang; Wang, Rui; Chen, Jiaqi; Li, Zaixing

2017-08-01

Optimum anaerobic conditions of cephalosporin bacterial residues after thermal-alkaline pretreatment were determined by orthogonal experiments. And through biochemical methane potential tests (BMPs) for cephalosporin bacterial residues, the ability for bacterial degradation of cephalosporin was also evaluated. The thermal-alkaline pretreatment with the optimum values of 6% NaOH at 105 °C for 15 min significantly improved digestion performance. With the thermal-alkaline pretreatment, the specific methane yield of the pretreated cephalosporin bacterial residue increased by 254.79% compared with that of the un-pretreated cephalosporin bacterial residue. The results showed that anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues could be one of the options for efficient methane production and waste treatment. This work investigates the thermal-alkaline pretreatment of cephalosporin bacterial residues, which can increase their methane yield by 254.79% compared with no pretreatment. The digestion performance is significantly improved under the condition of 6% NaOH at 105 °C for 15 min. The results show that anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues could be one of the options for efficient methane production and waste treatment.

Enhancing enzymolysis and fermentation efficiency of sugarcane bagasse by synergistic pretreatment of Fenton reaction and sodium hydroxide extraction.

PubMed

Zhang, Teng; Zhu, Ming-Jun

2016-08-01

A study on the synergistic pretreatment of sugarcane bagasse (SCB) using Fenton reaction and NaOH extraction was conducted. The optimized process conditions for Fenton pretreatment were 10% (w/w) of H2O2, 20mM of Fe(2+), pH 2.5, pretreatment time 6h, and pretreatment temperature 55°C. Sequential pretreatments were performed in combination with NaOH extraction (NaOH 1% (w/w), 80°C, 5% of solid loading, 1h). Among all the pretreatments, Fenton pretreatment followed by NaOH extraction had the highest efficiency of 64.7% and 108.3% for enzymolysis and simultaneous saccharification fermentation (SSF) with an ethanol concentration of 17.44g/L. The analyses by the scanning electron microscopy, X-ray diffraction and confocal laser scanning microscopy revealed that Fenton pretreatment disrupts the structure of SCB to facilitate the degradation of lignin by NaOH. The overall data suggest that this combinatorial strategy is a promising process for SCB pretreatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prewashing enhances the liquid hot water pretreatment efficiency of waste wheat straw with high free ash content.

PubMed

Huang, Chen; Wu, Xinxing; Huang, Yang; Lai, Chenhuan; Li, Xin; Yong, Qiang

2016-11-01

The effect of prewashing process prior to the liquid hot water (LHW) pretreatment of high free ash content waste wheat straw (WWS) was investigated. It was found that prewashing process decreased the ash content of WWS greatly, from 29.48% to 9.82%. This contributed to the lower pH value of prehydrolyzate and higher xylan removal in the following LHW pretreatment. More importantly, the prewashing process effectively increased the cellulose enzymatic hydrolysis efficiency of pretreated WWS, from 53.04% to 84.15%. The acid buffering capacity (ABC) and cation exchange capacity (CEC) of raw and prewashed WWS were examined. The majority of free ash removal from WWS by prewashing resulted in the decrease of the ABC of the WWS from 211.74 to 61.81mmol/pH-kg, and potentially enhancing the efficiency of the follow-up LHW pretreatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial pretreatment of cotton stalks by Phanerochaete chrysosporium for bioethanol production

NASA Astrophysics Data System (ADS)

Shi, Jian

Lignocellulosic biomass has been recognized as a widespread, potentially low cost renewable source of mixed sugars for fermentation to fuel ethanol. Pretreatment, as the first step towards conversion of lignocellulose to ethanol, remains one of the main barriers to technical and commercial success of the processing technology. Existing pretreatment methods have largely been developed on the basis of physiochemical technologies which are considered relatively expensive and usually involve adverse environmental impacts. In this study, an environmentally benign alternative, microbial pretreatment using Phanerochaete chrysosporium, was explored to degrade lignin in cotton stalks and facilitate their conversion into ethanol. Two submerged liquid pretreatment techniques (SmC), shallow stationary and agitated cultivation, at three inorganic salt concentrations (no salts, modified salts without Mn2+, modified salts with Mn2+) were compared by evaluating their pretreatment efficiencies. Shallow stationary cultivation with no salt was superior to other pretreatment conditions and gave 20.7% lignin degradation along with 76.3% solids recovery and 29.0% carbohydrate availability over a 14 day period. The influence of substrate moisture content (65%, 75% and 80% M.C. wet-basis), inorganic salt concentration (no salts, modified salts without Mn2+ , modified salts with Mn2+) and culture time (0-14 days) on pretreatment effectiveness in solid state (SSC) systems was also examined. It was shown that solid state cultivation at 75% M.C. without salts was the most preferable pretreatment resulting in 27.6% lignin degradation, 71.1% solids recovery and 41.6% carbohydrate availability over a period of 14 days. A study on hydrolysis and fermentation of cotton stalks treated microbially using the most promising SmC (shallow stationary, no salts) and SSC (75% moisture content, no salts) methods resulted in no increase in cellulose conversion with direct enzyme application (10.98% and 3.04% for SmC and SSC pretreated samples, respectively) compared with untreated cotton stalk samples (17.93%). Washing of pretreated cotton stalks alone caused no significant increase in cellulose conversion. However, a heat treatment (autoclaving) followed by washing remarkably improved (P<0.05) cellulose conversion to 14.94% and 17.81% for SmC and SSC pretreatment, respectively. Mathematical models describing holocellulose consumption, lignin degradation, cellulase and ligninolytic enzyme production, and oxygen uptake associated with the growth of P. chrysosporium during 14 days fungal pretreatment were developed. For SmC pretreatment, model parameters were estimated by nonlinear regression and validated using an independent set of experimental data. Models yielded sufficiently accurate predictions for holocellulose consumption (R2=0.9772 and 0.9837, 1d and 3d oxygen flushing, respectively), lignin degradation (R2=0.9879 and 0.8682) and ligninolytic enzyme production (R2=0.8135 and 0.9693) under both 1 and 3d oxygen flushing conditions. However, the prediction capabilities for fungal growth (1d and 3d), cellulase production (3d) and oxygen uptake (3d) were limited. For SSC, the models were established in three phases (I: day 0-4, II: day 4-7, III: day 7-14). After validation it was shown that the developed models can yield sufficiently accurate predictions for fungal growth (R 2=0.9724), holocellulose consumption (R2=0.9686), lignin degradation (R2=0.9309) and ligninolytic enzyme production (R2=0.9203); however predictions of cellulase production were fair (R2=0.6133). Although significant delignification occurred during fungal pretreatment indicating the presence of ligninolytic enzymes, common spectrophotometric enzyme assays failed to detect lignin peroxidase (LiP) and manganese peroxidase (MnP) activities in fungal pretreatment cultures. Efforts were made to overcome the drawbacks of standardized assays by performing protein gel electrophoresis and crude enzyme delignification studies. Results from this research are expected to be beneficial in the development of pretreatment technologies that are environment friendly and utilize naturally occurring microorganisms.

Postharvest Ultrasound-Assisted Freeze-Thaw Pretreatment Improves the Drying Efficiency, Physicochemical Properties, and Macamide Biosynthesis of Maca (Lepidium meyenii).

PubMed

Chen, Jin-Jin; Gong, Peng-Fei; Liu, Yi-Lan; Liu, Bo-Yan; Eggert, Dawn; Guo, Yuan-Heng; Zhao, Ming-Xia; Zhao, Qing-Sheng; Zhao, Bing

2018-04-01

A novel technique of ultrasound-assisted freeze-thaw pretreatment (UFP) was developed to improve the drying efficiency of maca and bioactive amide synthesis in maca. The optimal UFP conditions are ultrasonic processing 90 min at 30 °C with 6 freeze-thaw cycles. Samples with freeze-thaw pretreatment (FP), ultrasound pretreatment (UP), and UFP were prepared for further comparative study. A no pretreatment (NP) sample was included as a control. The results showed that UFP improved the drying efficiency of maca slices, showing the highest effective moisture diffusivity (1.75 × 10 -9 m 2 /s). This result was further supported by low-field nuclear magnetic resonance (LF-NMR) analysis and scanning electron microscopy (SEM). The rehydration capacity and protein content of maca slices were improved by UFP. More importantly, contents of bioactive macamides and their biosynthetic precursors were increased in 2.5- and 10-fold, respectively. In conclusion, UFP is an efficient technique to improve drying efficiency, physicochemical properties, and bioactive macamides of maca, which can be applied in the industrial manufacture of maca products. © 2018 Institute of Food Technologists®.

PROJECT W-551 INTERIM PRETREATMENT SYSTEM PRECONCEPTUAL CANDIDATE TECHNOLOGY DESCRIPTIONS

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

MAY TH

The Office of River Protection (ORP) has authorized a study to recommend and select options for interim pretreatment of tank waste and support Waste Treatment Plant (WTP) low activity waste (LAW) operations prior to startup of all the WTP facilities. The Interim Pretreatment System (IPS) is to be a moderately sized system which separates entrained solids and 137Cs from tank waste for an interim time period while WTP high level waste vitrification and pretreatment facilities are completed. This study's objective is to prepare pre-conceptual technology descriptions that expand the technical detail for selected solid and cesium separation technologies. This revisionmore » includes information on additional feed tanks.« less

Comparison of Ultrasonic and CO2 Laser Pretreatment Methods on Enzyme Digestibility of Corn Stover

PubMed Central

Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

2012-01-01

To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO2 laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO2 laser irradiation. The present work demonstrated that the CO2 laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO2 laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO2 laser pretreatment on corn stover to be more effective than ultrasonic pretreatment. PMID:22605970

Comparison of ultrasonic and CO₂laser pretreatment methods on enzyme digestibility of corn stover.

PubMed

Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

2012-01-01

To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO(2) laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO(2) laser irradiation. The present work demonstrated that the CO(2) laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO(2) laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO(2) laser pretreatment on corn stover to be more effective than ultrasonic pretreatment.

Effects of various pretreatments on biological sulfate reduction with waste activated sludge as electron donor and waste activated sludge diminution under biosulfidogenic condition.

PubMed

Sheng, Yuxing; Cao, Hongbin; Li, Yuping; Zhang, Yi

2010-07-15

The current study focused on the influences of various pretreatments, including alkaline, ultrasonic and thermal pretreatments on biological sulfate reduction with waste activated sludge (WAS) as sole electron donor. Our results showed that thermal and ultrasonic pretreatments increased the sulfate reduction percentage by 14.8% and 7.1%, respectively, compared with experiment with raw WAS, while alkaline pretreatment decreased the sulfate reduction percentage by 46%. By analyzing the WAS structure, particle size distribution, organic component, and enzyme activity after different pretreatments, we studied the effects of these pretreatments on WAS as well as on the mechanisms of how biological sulfate reduction was affected. The reduction of WAS and variation of WAS structure in the process of sulfate reduction were investigated. Our results showed that biosulfidogenesis was an efficient method of diminishing WAS, and various pretreatments could enhance the reduction efficiency of volatile solid in the WAS. 2010 Elsevier B.V. All rights reserved.

"Trojan Horse" strategy for deconstruction of biomass for biofuels production.

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

Sinclair, Michael B.; Hadi, Masood Z.; Timlin, Jerilyn Ann

2008-08-01

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multi-agency national priority. Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated 'energy crops' and agricultural waste are preferred long-term solutions for renewable, cheap, and globally available biofuels as they avoid some of the market pressures and secondary greenhouse gas emission challenges currently facing corn ethanol. These sources of lignocellulosic biomass are converted to fermentable sugars using a variety of chemical and thermochemical pretreatments, which disrupt cellulose and lignin cross-links, allowing exogenously added recombinant microbial enzymes to more efficiently hydrolyze themore » cellulose for 'deconstruction' into glucose. This process is plagued with inefficiencies, primarily due to the recalcitrance of cellulosic biomass, mass transfer issues during deconstruction, and low activity of recombinant deconstruction enzymes. Costs are also high due to the requirement for enzymes and reagents, and energy-intensive and cumbersome pretreatment steps. One potential solution to these problems is found in synthetic biology; they propose to engineer plants that self-produce a suite of cellulase enzymes targeted to the apoplast for cleaving the linkages between lignin and cellulosic fibers; the genes encoding the degradation enzymes, also known as cellulases, are obtained from extremophilic organisms that grow at high temperatures (60-100 C) and acidic pH levels (<5). These enzymes will remain inactive during the life cycle of the plant but become active during hydrothermal pretreatment i.e., elevated temperatures. Deconstruction can be integrated into a one-step process, thereby increasing efficiency (cellulose-cellulase mass-transfer rates) and reducing costs. The proposed disruptive technologies address biomass deconstruction processes by developing transgenic plants encoding a suite of enzymes used in cellulosic deconstruction. The unique aspects of this technology are the rationally engineered, highly productive extremophilic enzymes, targeted to specific cellular locations (apoplast) and their dormancy during normal plant proliferation, which become Trojan horses during pretreatment conditions. They have been leveraging established Sandia's enzyme-engineering and imaging capabilities. Their technical approach not only targets the recalcitrance and mass-transfer problem during biomass degradation but also eliminates the costs associated with industrial-scale production of microbial enzymes added during processing.« less

Evaluation of efficient glucose release using sodium hydroxide and phosphoric acid as pretreating agents from the biomass of Sesbania grandiflora (L.) Pers.: A fast growing tree legume.

PubMed

Mund, Nitesh K; Dash, Debabrata; Barik, Chitta R; Goud, Vaibhav V; Sahoo, Lingaraj; Mishra, Prasannajit; Nayak, Nihar R

2017-07-01

Sesbania grandiflora (L.) Pers. is one of the fast growing tree legumes having the efficiency to produce around 50tha -1 above ground dry matters in a year. In this study, biomass of 2years old S. grandiflora was selected for the chemical composition, pretreatments and enzymatic hydrolysis studies. The stem biomass with a wood density of 3.89±0.01gmcm -3 contains about 38% cellulose, 12% hemicellulose and 28% lignin. Enzymatic hydrolysis of pretreated biomass revealed that phosphoric acid (H 3 PO 4 ) pretreated samples even at lower cellulase loadings [1 Filter Paper Units (FPU)], could efficiently convert about 86% glucose, while, even at higher cellulase loadings (60FPU) alkali pretreated biomass could convert only about 58% glucose. The effectiveness of phosphoric acid pretreatment was also supported by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Co-digestion of sewage sludge from external small WWTP's in a large plant

NASA Astrophysics Data System (ADS)

Miodoński, Stanisław

2017-11-01

Improving energy efficiency of WWTPs (Waste Water Treatment Plants) is crucial action of modern wastewater treatment technology. Technological treatment process optimization is important but the main goal will not be achieved without increasing production of renewable energy from sewage sludge in anaerobic digestion process which is most often used as sludge stabilization method on large WWTP's. Usually, anaerobic digestion reactors used for sludge digestion were designed with reserve and most of them is oversized. In many cases that reserve is unused. On the other hand, smaller WWTPs have problem with management of sewage sludge due to lack of adequately developed infrastructure for sludge stabilization. Paper shows an analysis of using a technological reserve of anaerobic digestion reactors at large WWTP (1 million P.E.) for sludge stabilization collected from smaller WWTP in a co-digestion process. Over 30 small WWTPs from the same region as the large WWTP were considered in this study. Furthermore, performed analysis included also evaluation of potential sludge disintegration pre-treatment for co-digestion efficiency improvement.

Lignocellulose fractionation into furfural and glucose by AlCl3-catalyzed DES/MIBK biphasic pretreatment.

PubMed

Wang, Zhi-Kun; Shen, Xiao-Jun; Chen, Jun-Jie; Jiang, Ying-Qiu; Hu, Zhi-Yan; Wang, Xing; Liu, Li

2018-06-01

Herein, an efficient DES/MIBK biphasic pretreatment system for preparation of furfural and fermentable glucose from lignocellulose was developed with AlCl 3 as catalysis. The low-cost and renewable DES (Choline chloride-Oxalic acid) served not only as a Brønsted acid catalyst, but also as a pretreatment solvent in present work, and MIBK as an extracting reagent which can increase the yield of furfural in DES phase. The effects of this biphasic pretreatment on the furfural yield and saccharification of the lignocellulose before and after pretreatment were explored using HPLC, HAPEC, FT-IR, XRD and SEM. Under the best pretreatment condition (at 140 °C for 90 min), furfural could be obtained in 70.3% yield and 80.8% of the pretreated lignocellulose was saccharified, which was 8.4 times higher than that of the raw lignocellulose without pretreatment. In a word, this pretreatment system can be considered as a potential technique for efficient valorization of lignocellulose for production of furfural and fermentable glucose. Copyright © 2018. Published by Elsevier B.V.

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

McMillan, J.D.

This paper reviews existing and proposed pretreatment processes for biomass. The focus is on the mechanisms by which the various pretreatments act and the influence of biomass structure and composition on the efficacy of particular pretreatment techniques. This analysis is used to identify pretreatment technologies and issues that warrant further research.

Efficient Anaerobic Digestion of Microalgae Biomass: Proteins as a Key Macromolecule.

PubMed

Magdalena, Jose Antonio; Ballesteros, Mercedes; González-Fernandez, Cristina

2018-05-06

Biogas generation is the least complex technology to transform microalgae biomass into bioenergy. Since hydrolysis has been pointed out as the rate limiting stage of anaerobic digestion, the main challenge for an efficient biogas production is the optimization of cell wall disruption/hydrolysis. Among all tested pretreatments, enzymatic treatments were demonstrated not only very effective in disruption/hydrolysis but they also revealed the impact of microalgae macromolecular composition in the anaerobic process. Although carbohydrates have been traditionally recognized as the polymers responsible for the low microalgae digestibility, protease addition resulted in the highest organic matter solubilization and the highest methane production. However, protein solubilization during the pretreatment can result in anaerobic digestion inhibition due to the release of large amounts of ammonium nitrogen. The possible solutions to overcome these negative effects include the reduction of protein biomass levels by culturing the microalgae in low nitrogen media and the use of ammonia tolerant anaerobic inocula. Overall, this review is intended to evidence the relevance of microalgae proteins in different stages of anaerobic digestion, namely hydrolysis and methanogenesis.

Improved biomass and lipid production in Synechocystis sp. NN using industrial wastes and nano-catalyst coupled transesterification for biodiesel production.

PubMed

Jawaharraj, Kalimuthu; Karpagam, Rathinasamy; Ashokkumar, Balasubramaniem; Kathiresan, Shanmugam; Moorthy, Innasi Muthu Ganesh; Arumugam, Muthu; Varalakshmi, Perumal

2017-10-01

In this study, the improved biomass (1.6 folds) and lipid (1.3 folds) productivities in Synechocystis sp. NN using agro-industrial wastes supplementation through hybrid response surface methodology-genetic algorithm (RSM-GA) for cost-effective methodologies for biodiesel production was achieved. Besides, efficient harvesting in Synechocystis sp. NN was achieved by electroflocculation (flocculation efficiency 97.8±1.2%) in 10min when compared to other methods. Furthermore, different pretreatment methods were employed for lipid extraction and maximum lipid content of 19.3±0.2% by Synechocystis sp. NN was attained by ultrasonication than microwave and liquid nitrogen assisted pretreatment methods. The highest FAME (fatty acid methyl ester) conversion of 36.5±8.3mg FAME/g biomass was obtained using titanium oxide as heterogeneous nano-catalyst coupled whole-cell transesterification based method. Conclusively, Synechocystis sp. NN may be used as a biodiesel feedstock and its fuel production can be enriched by hybrid RSM-GA and nano-catalyst technologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pretreatment technologies for industrial effluents: Critical review on bioenergy production and environmental concerns.

PubMed

Prabakar, Desika; Suvetha K, Subha; Manimudi, Varshini T; Mathimani, Thangavel; Kumar, Gopalakrishnan; Rene, Eldon R; Pugazhendhi, Arivalagan

2018-07-15

The implementation of different pretreatment techniques and technologies prior to effluent discharge is a direct result of the inefficiency of several existing wastewater treatment methods. A majority of the industrial sectors have known to cause severe negative effects on the environment. The five major polluting industries are the paper and pulp mills, coal manufacturing facilities, petrochemical, textile and the pharmaceutical sectors. Pretreatment methods have been widely used in order to lower the toxicity levels of effluents and comply with environmental standards. In this review, the possible environmental benefits and concerns of adopting different pretreatment technologies for renewable energy production and product/resource recovery has been reviewed and discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

PROJECT W-551 DETERMINATION DATA FOR EARLY LAW INTERIM PRETREATMENT SYSTEM SELECTION

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

TEDESCHI AR

This report provides the detailed assessment forms and data for selection of the solids separation and cesium separation technology for project W-551, Interim Pretreatment System. This project will provide early pretreated low activity waste feed to the Waste Treatment Plant to allow Waste Treatment Plan Low Activity Waste facility operation prior to construction completion of the Pretreatment and High Level Waste facilities. The candidate solids separations technologies are rotary microfiltration and crossflow filtration, and the candidate cesium separation technologies are fractional crystallization, caustic-side solvent extraction, and ion-exchange using spherical resorcinol-formaldehyde resin. This data was used to prepare a cross-cutting technologymore » summary, reported in RPP-RPT-37740.« less

Conversion of lignocellulosic agave residues into liquid biofuels using an AFEX™-based biorefinery.

PubMed

Flores-Gómez, Carlos A; Escamilla Silva, Eleazar M; Zhong, Cheng; Dale, Bruce E; da Costa Sousa, Leonardo; Balan, Venkatesh

2018-01-01

Agave-based alcoholic beverage companies generate thousands of tons of solid residues per year in Mexico. These agave residues might be used for biofuel production due to their abundance and favorable sustainability characteristics. In this work, agave leaf and bagasse residues from species Agave tequilana and Agave salmiana were subjected to pretreatment using the ammonia fiber expansion (AFEX) process. The pretreatment conditions were optimized using a response surface design methodology. We also identified commercial enzyme mixtures that maximize sugar yields for AFEX-pretreated agave bagasse and leaf matter, at ~ 6% glucan (w/w) loading enzymatic hydrolysis. Finally, the pretreated agave hydrolysates (at a total solids loading of ~ 20%) were used for ethanol fermentation using the glucose- and xylose-consuming strain Saccharomyces cerevisiae 424A (LNH-ST), to determine ethanol yields at industrially relevant conditions. Low-severity AFEX pretreatment conditions are required (100-120 °C) to enable efficient enzymatic deconstruction of the agave cell wall. These studies showed that AFEX-pretreated A. tequilana bagasse, A. tequilana leaf fiber, and A. salmiana bagasse gave ~ 85% sugar conversion during enzyme hydrolysis and over 90% metabolic yields of ethanol during fermentation without any washing step or nutrient supplementation. On the other hand, although lignocellulosic A. salmiana leaf gave high sugar conversions, the hydrolysate could not be fermented at high solids loadings, apparently due to the presence of natural inhibitory compounds. These results show that AFEX-pretreated agave residues can be effectively hydrolyzed at high solids loading using an optimized commercial enzyme cocktail (at 25 mg protein/g glucan) producing > 85% sugar conversions and over 40 g/L bioethanol titers. These results show that AFEX technology has considerable potential to convert lignocellulosic agave residues to bio-based fuels and chemicals in a biorefinery.

Evaluation energy efficiency of bioconversion knot rejects to ethanol in comparison to other thermochemically pretreated biomass.

PubMed

Wang, Zhaojiang; Qin, Menghua; Zhu, J Y; Tian, Guoyu; Li, Zongquan

2013-02-01

Rejects from sulfite pulp mill that otherwise would be disposed of by incineration were converted to ethanol by a combined physical-biological process that was comprised of physical refining and simultaneous saccharification and fermentation (SSF). The energy efficiency was evaluated with comparison to thermochemically pretreated biomass, such as those pretreated by dilute acid (DA) and sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL). It was observed that the structure deconstruction of rejects by physical refining was indispensable to effective bioconversion but more energy intensive than that of thermochemically pretreated biomass. Fortunately, the energy consumption was compensated by the reduced enzyme dosage and the elevated ethanol yield. Furthermore, adjustment of disk-plates gap led to reduction in energy consumption with negligible influence on ethanol yield. In this context, energy efficiency up to 717.7% was achieved for rejects, much higher than that of SPORL sample (283.7%) and DA sample (152.8%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Fermentative hydrogen production using pretreated microalgal biomass as feedstock.

PubMed

Wang, Jianlong; Yin, Yanan

2018-02-14

Microalgae are simple chlorophyll containing organisms, they have high photosynthetic efficiency and can synthesize and accumulate large quantities of carbohydrate biomass. They can be cultivated in fresh water, seawater and wastewater. They have been used as feedstock for producing biodiesel, bioethanol and biogas. The production of these biofuels can be integrated with CO 2 mitigation, wastewater treatment, and the production of high-value chemicals. Biohydrogen from microalgae is renewable. Microalgae have several advantages compared to terrestrial plants, such as higher growth rate with superior CO 2 fixation capacity; they do not need arable land to grow; they do not contain lignin. In this review, the biology of microalgae and the chemical composition of microalgae were briefly introduced, the advantages and disadvantages of hydrogen production from microalgae were discussed, and the pretreatment of microalgal biomass and the fermentative hydrogen production from microalgal biomass pretreated by different methods (including physical, chemical, biological and combined methods) were summarized and evaluated. For the production of biohydrogen from microalgae, the economic feasibility remains the most important aspect to consider. Several technological and economic issues must be addressed to achieve success on a commercial scale.

Chemical and physical pretreatments of fruits and vegetables: Effects on drying characteristics and quality attributes - a comprehensive review.

PubMed

Deng, Li-Zhen; Mujumdar, Arun S; Zhang, Qian; Yang, Xu-Hai; Wang, Jun; Zheng, Zhi-An; Gao, Zhen-Jiang; Xiao, Hong-Wei

2017-12-20

Pretreatment is widely used before drying of agro-products to inactivate enzymes, enhance drying process and improve quality of dried products. In current work, the influence of various pretreatments on drying characteristics and quality attributes of fruits and vegetables is summarized. They include chemical solution (hyperosmotic, alkali, sulfite and acid, etc.) and gas (sulfur dioxide, carbon dioxide and ozone) treatments, thermal blanching (hot water, steam, super heated steam impingement, ohmic and microwave heating, etc), and non-thermal process (ultrasound, freezing, pulsed electric field, and high hydrostatic pressure, etc). Chemical pretreatments effectively enhance drying kinetics, meanwhile, it causes soluble nutrients losing, trigger food safety issues by chemical residual. Conventional hot water blanching has significant effect on inactivating various undesirable enzymatic reactions, destroying microorganisms, and softening the texture, as well as facilitating drying rate. However, it induces undesirable quality of products, e.g., loss of texture, soluble nutrients, pigment and aroma. Novel blanching treatments, such as high-humidity hot air impingement blanching, microwave and ohmic heat blanching can reduce the nutrition loss and are more efficient. Non-thermal technologies can be a better alternative to thermal blanching to overcome these drawbacks, and more fundamental researches are needed for better design and scale up.

The effect of porous lead iodide precursor film on perovskite film formation and its photovoltaic property after an effective pretreatment

NASA Astrophysics Data System (ADS)

Yan, Jian-Jun; Li, Yan; Chang, Yin; Jiang, Pan; Wang, Cheng-Wei

2016-06-01

An effective solvent sealed natural drying (SND) pretreatment was introduced for forming a satisfactory crystalline porous iodide (PbI2) precursor film, which could help to generate excellent CH3NH3PbI3 perovskite films for high performance of planar heterojunction perovskite solar cells. And the influence of SND pretreated time on the device performance was investigated in detail. We found that the PbI2 precursor film after 10 min pretreatment could make the perovskite device achieve the optimal power conversion efficiency (PCE) of 8.6%, significantly increased up to 95.5% and 28.4% compared to without pretreatment or traditional treatment. The results show that the time of SND pretreatment is critical to forming large grain size and good crystallinity for PbI2 precursor film, which would markedly improve the efficiency of planar heterojunction perovskite solar cells.

Ultrasound assisted biogas production from co-digestion of wastewater sludges and agricultural wastes: Comparison with microwave pre-treatment.

PubMed

Aylin Alagöz, B; Yenigün, Orhan; Erdinçler, Ayşen

2018-01-01

This study investigates the effect of ultrasonication and microwave sludge disintegration/pre-treatment techniques on the anaerobic co-digestion efficiency of wastewater sludges with olive and grape pomaces. The effects of both co-digestion and sludge pre-treatment techniques were evaluated in terms of the organic removal efficiency and the biogas production. The "co-digestion" of wastewater sludge with both types of pomaces was revealed to be a much more efficient way for the biogas production compared to the single (mono) sludge digestion. The ultrasonication and microwave pre-treatments applied to the sludge samples caused to a further increase in biogas and methane yields. Based on applied specific energies, ultrasonication pre-treatment was found much more effective than microwave irradiation. The specific energy applied in microwave pre-treatment (87,000kj/kgTS) was almost 9 times higher than that of used in ultrasonication (10,000kj/kgTS), resulting only 10-15% increases in biogas/methane yield. Co-digestion of winery and olive industry residues with pre-treated wastewater sludges appears to be a suitable technique for waste management and energy production. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of dilute acid pre-treatment process in bioethanol production from durian (Durio zibethinus) seeds waste

NASA Astrophysics Data System (ADS)

Ghazali, K. A.; Salleh, S. F.; Riayatsyah, T. M. I.; Aditiya, H. B.; Mahlia, T. M. I.

2016-03-01

Lignocellulosic biomass is one of the promising feedstocks for bioethanol production. The process starts from pre-treatment, hydrolysis, fermentation, distillation and finally obtaining the final product, ethanol. The efficiency of enzymatic hydrolysis of cellulosic biomass depends heavily on the effectiveness of the pre-treatment step which main function is to break the lignin structure of the biomass. This work aims to investigate the effects of dilute acid pre-treatment on the enzymatic hydrolysis of durian seeds waste to glucose and the subsequent bioethanol fermentation process. The yield of glucose from dilute acid pre-treated sample using 0.6% H2SO4 and 5% substrate concentration shows significant value of 23.4951 g/L. Combination of dilute acid pre-treatment and enzymatic hydrolysis using 150U of enzyme able to yield 50.0944 g/L of glucose content higher compared to normal pre-treated sample of 8.1093 g/L. Dilute acid pre-treatment sample also shows stable and efficient yeast activity during fermentation process with lowest glucose content at 2.9636 g/L compared to 14.7583g/L for normal pre-treated sample. Based on the result, it can be concluded that dilute acid pre-treatment increase the yield of ethanol from bioethanol production process.

Determination of optimal biomass pretreatment strategies for biofuel production: investigation of relationships between surface-exposed polysaccharides and their enzymatic conversion using carbohydrate-binding modules.

PubMed

Khatri, Vinay; Meddeb-Mouelhi, Fatma; Adjallé, Kokou; Barnabé, Simon; Beauregard, Marc

2018-01-01

Pretreatment of lignocellulosic biomass (LCB) is a key step for its efficient bioconversion into ethanol. Determining the best pretreatment and its parameters requires monitoring its impacts on the biomass material. Here, we used fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay to study the relationship between surface-exposed polysaccharides and enzymatic hydrolysis of LCB. Our results indicated that alkali extrusion pretreatment led to the highest hydrolysis rates for alfalfa stover, cattail stems and flax shives, despite its lower lignin removal efficiency compared to alkali pretreatment. Corn crop residues were more sensitive to alkali pretreatments, leading to higher hydrolysis rates. A clear relationship was consistently observed between total surface-exposed cellulose detected by the FTCM-depletion assay and biomass enzymatic hydrolysis. Comparison of bioconversion yield and total composition analysis (by NREL/TP-510-42618) of LCB prior to or after pretreatments did not show any close relationship. Lignin removal efficiency and total cellulose content (by NREL/TP-510-42618) led to an unreliable prediction of enzymatic polysaccharide hydrolysis. Fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay provided direct evidence that cellulose exposure is the key determinant of hydrolysis yield. The clear and robust relationships that were observed between the cellulose accessibility by FTCM probes and enzymatic hydrolysis rates change could be evolved into a powerful prediction tool that might help develop optimal biomass pretreatment strategies for biofuel production.

Supercritical fluids as a green technology for the pretreatment of lignocellulosic biomass.

PubMed

Daza Serna, L V; Orrego Alzate, C E; Cardona Alzate, C A

2016-01-01

One of the main drawbacks for using lignocellulosic biomass is related to its recalcitrance. The pretreatment of lignocellulosic biomass plays an important role for delignification and crystallinity reduction purposes. In this work rice husk (RH) was submitted to supercritical pretreatment at 80°C and 270 bar with the aim to determine the effect on lignin content, crystallinity as well as enzymatic digestibility. The yields obtained were compared with dilute sulfuric acid pretreatment as base case. Additionally a techno-economic and environmental comparison of the both pretreatment technologies was performed. The results show a lignin content reduction up to 90.6% for the sample with 75% moisture content using a water-ethanol mixture. The results for crystallinity and enzymatic digestibility demonstrated that no reductions were reached. Supercritical pretreatment presents the best economical and environmental performance considering the solvents and carbon dioxide recycling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coordinated development of leading biomass pretreatment technologies.

PubMed

Wyman, Charles E; Dale, Bruce E; Elander, Richard T; Holtzapple, Mark; Ladisch, Michael R; Lee, Y Y

2005-12-01

For the first time, a single source of cellulosic biomass was pretreated by leading technologies using identical analytical methods to provide comparative performance data. In particular, ammonia explosion, aqueous ammonia recycle, controlled pH, dilute acid, flowthrough, and lime approaches were applied to prepare corn stover for subsequent biological conversion to sugars through a Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) among Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, and Texas A&M University. An Agricultural and Industrial Advisory Board provided guidance to the project. Pretreatment conditions were selected based on the extensive experience of the team with each of the technologies, and the resulting fluid and solid streams were characterized using standard methods. The data were used to close material balances, and energy balances were estimated for all processes. The digestibilities of the solids by a controlled supply of cellulase enzyme and the fermentability of the liquids were also assessed and used to guide selection of optimum pretreatment conditions. Economic assessments were applied based on the performance data to estimate each pretreatment cost on a consistent basis. Through this approach, comparative data were developed on sugar recovery from hemicellulose and cellulose by the combined pretreatment and enzymatic hydrolysis operations when applied to corn stover. This paper introduces the project and summarizes the shared methods for papers reporting results of this research in this special edition of Bioresource Technology.

Chemical and morphological characterization of sugarcane bagasse submitted to a delignification process for enhanced enzymatic digestibility

PubMed Central

2011-01-01

Background In recent years, biorefining of lignocellulosic biomass to produce multi-products such as ethanol and other biomaterials has become a dynamic research area. Pretreatment technologies that fractionate sugarcane bagasse are essential for the successful use of this feedstock in ethanol production. In this paper, we investigate modifications in the morphology and chemical composition of sugarcane bagasse submitted to a two-step treatment, using diluted acid followed by a delignification process with increasing sodium hydroxide concentrations. Detailed chemical and morphological characterization of the samples after each pretreatment condition, studied by high performance liquid chromatography, solid-state nuclear magnetic resonance, diffuse reflectance Fourier transformed infrared spectroscopy and scanning electron microscopy, is reported, together with sample crystallinity and enzymatic digestibility. Results Chemical composition analysis performed on samples obtained after different pretreatment conditions showed that up to 96% and 85% of hemicellulose and lignin fractions, respectively, were removed by this two-step method when sodium hydroxide concentrations of 1% (m/v) or higher were used. The efficient lignin removal resulted in an enhanced hydrolysis yield reaching values around 100%. Considering the cellulose loss due to the pretreatment (maximum of 30%, depending on the process), the total cellulose conversion increases significantly from 22.0% (value for the untreated bagasse) to 72.4%. The delignification process, with consequent increase in the cellulose to lignin ratio, is also clearly observed by nuclear magnetic resonance and diffuse reflectance Fourier transformed infrared spectroscopy experiments. We also demonstrated that the morphological changes contributing to this remarkable improvement occur as a consequence of lignin removal from the sample. Bagasse unstructuring is favored by the loss of cohesion between neighboring cell walls, as well as by changes in the inner cell wall structure, such as damaging, hole formation and loss of mechanical resistance, facilitating liquid and enzyme access to crystalline cellulose. Conclusions The results presented herewith show the efficiency of the proposed method for improving the enzymatic digestibility of sugarcane bagasse and provide understanding of the pretreatment action mechanism. Combining the different techniques applied in this work warranted thorough information about the undergoing morphological and chemical changes and was an efficient approach to understand the morphological effects resulting from sample delignification and its influence on the enhanced hydrolysis results. PMID:22122978

Evaluation of High Solids Alkaline Pretreatment of Rice Straw

PubMed Central

Cheng, Yu-Shen; Zheng, Yi; Yu, Chao Wei; Dooley, Todd M.; Jenkins, Bryan M.

2010-01-01

Fresh-harvested, air-dried rice straw was pretreated at a water content of 5 g H2O/g straw using sodium hydroxide (NaOH) and compared to pretreatment at 10 g H2O/g straw by hydrated lime (Ca(OH)2). Full factorial experiments including parallel wash-only treatments were completed with both sources of alkali. The experiments were designed to measure the effects of alkaline loading and pretreatment time on delignification and sugar yield upon enzymatic hydrolysis. Reaction temperature was held constant at 95°C for lime pretreatment and 55°C for NaOH pretreatment. The range of delignification was 13.1% to 27.0% for lime pretreatments and was 8.6% to 23.1% for NaOH pretreatments. Both alkaline loading and reaction time had significant positive effects (p < 0.001) on delignification under the design conditions, but only alkaline loading had a significant positive effect on enzymatic hydrolysis. Treatment at higher temperature also improved delignification; delignification with water alone ranged from 9.9% to 14.5% for pretreatment at 95°C, but there was little effect observed at 55°C. Post-pretreatment washing of biomass was not necessary for subsequent enzymatic hydrolysis. Maximum glucose yields were 176.3 mg/g dried biomass (48.5% conversion efficiency of total glucose) in lime-pretreated and unwashed biomass and were 142.3 mg/g dried biomass (39.2% conversion efficiency of total glucose) in NaOH-pretreated and unwashed biomass. PMID:20440580

Excess sludge reduction using pilot-scale lysis-cryptic growth system integrated ultrasonic/alkaline disintegration and hydrolysis/acidogenesis pretreatment.

PubMed

Ma, Huaji; Zhang, Shuting; Lu, Xuebin; Xi, Bo; Guo, Xingli; Wang, Han; Duan, Jingxiao

2012-07-01

A pilot-scale lysis-cryptic growth system was built and operated continuously for excess sludge reduction. Combined ultrasonic/alkaline disintegration and hydrolysis/acidogenesis were integrated into its sludge pretreatment system. Continuous operation showed that the observed biomass yield and the sludge reduction efficiency of the lysis-cryptic growth system were 0.27 kg VSS/kg COD consumed and 56.5%, respectively. The water quality of its effluent was satisfactory. The sludge pretreatment system performed well and its TCOD removal efficiency was 7.9% which contributed a sludge reduction efficiency of 2.1%. The SCOD, VFA, TN, NH(4)(+)-N, TP and pH in the supernatant of pretreated sludge were 1790 mg/L, 1530 mg COD/L, 261.1mg/L, 114.0mg/L, 93.1mg/L and 8.69, respectively. The total operation cost of the lysis-cryptic growth system was $ 0.186/m(3) wastewater, which was 11.4% less than that of conventional activated sludge (CAS) system without excess sludge pretreatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Promoting anaerobic biogasification of corn stover through biological pretreatment by liquid fraction of digestate (LFD).

PubMed

Hu, Yun; Pang, Yunzhi; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Chufo, Wachemo Akiber; Jaffar, Muhammad; Li, Xiujin

2015-01-01

A new biological pretreatment method by using liquid fraction of digestate (LFD) was advanced for promoting anaerobic biogasification efficiency of corn stover. 17.6% TS content and ambient temperature was appropriate for pretreatment. The results showed that C/N ratio decreased to about 30, while total lignin, cellulose, and hemicellulose (LCH) contents were reduced by 8.1-19.4% after pretreatment. 3-days pretreatment was considered to be optimal, resulting in 70.4% more biogas production, 66.3% more biomethane yield and 41.7% shorter technical digestion time compared with the untreated stover. The reductions on VS, cellulose, and hemicellulose were increased by 22.1-35.9%, 22.3-35.4%, and 19.8-27.2% for LFD-treated stovers. The promoted anaerobic biogasification efficiency was mainly attributed to the improved biodegradability due to the pre-decomposition role of the bacteria in LFD. The method proved to be an efficient and low cost approach for producing bioenergy from corn stover, meanwhile, reducing LFD discharge and minimizing its potential pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

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

Johnson, Amanda M.; Kim, Hoon; Ralph, John

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

DOE PAGES

Johnson, Amanda M.; Kim, Hoon; Ralph, John; ...

2017-02-23

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of catalytic ultrasound oxidation and membrane bioreactor.

PubMed

Jia, Shengyong; Han, Hongjun; Zhuang, Haifeng; Xu, Peng; Hou, Baolin

2015-01-01

Laboratorial scale experiments were conducted to investigate a novel system integrating catalytic ultrasound oxidation (CUO) with membrane bioreactor (CUO-MBR) on advanced treatment of biologically pretreated coal gasification wastewater. Results indicated that CUO with catalyst of FeOx/SBAC (sewage sludge based activated carbon (SBAC) which loaded Fe oxides) represented high efficiencies in eliminating TOC as well as improving the biodegradability. The integrated CUO-MBR system with low energy intensity and high frequency was more effective in eliminating COD, BOD5, TOC and reducing transmembrane pressure than either conventional MBR or ultrasound oxidation integrated MBR. The enhanced hydroxyl radical oxidation, facilitation of substrate diffusion and improvement of cell enzyme secretion were the mechanisms for CUO-MBR performance. Therefore, the integrated CUO-MBR was the promising technology for advanced treatment in engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dilute sulfuric acid pretreatment of corn stover for enzymatic hydrolysis and efficient ethanol production by recombinant Escherichia coli FBR5 without detoxification

USDA-ARS?s Scientific Manuscript database

A pretreatment strategy for dilute H2SO4 pretreatment of corn stover was developed for the purpose of reducing the generation of inhibitory substances during pretreatment so that a detoxification step is not required prior to fermentation while maximizing the sugar yield. We have optimized dilute su...

Efficient removal of lignin with the maintenance of hemicellulose from kenaf by two-stage pretreatment process.

PubMed

Wan Azelee, Nur Izyan; Md Jahim, Jamaliah; Rabu, Amir; Abdul Murad, Abdul Munir; Abu Bakar, Farah Diba; Md Illias, Rosli

2014-01-01

The enhancement of lignocellulose hydrolysis using enzyme complexes requires an efficient pretreatment process to obtain susceptible conditions for the enzyme attack. This study focuses on removing a major part of the lignin layer from kenaf (Hibiscus cannabinus) while simultaneously maintaining most of the hemicellulose. A two-stage pretreatment process is adopted using calcium hydroxide, Ca(OH)₂, and peracetic acid, PPA, to break the recalcitrant lignin layer from other structural polysaccharides. An experimental screening of several pretreatment chemicals, concentrations, temperatures and solid-liquid ratios enabled the production of an optimally designed pretreatment process for kenaf. Our results showed that the pretreatment process has provide 59.25% lignin removal while maintaining 87.72% and 96.17% hemicellulose and cellulose, respectively, using 1g of Ca(OH)₂/L and a 8:1 (mL:g) ratio of liquid-Ca(OH)₂ at 50 °C for 1.5 h followed by 20% peracetic acid pretreatment at 75 °C for 2 h. These results validate this mild approach for aiding future enzymatic hydrolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhancing the functional and economical efficiency of a novel combined thermo chemical disperser disintegration of waste activated sludge for biogas production.

PubMed

Kavitha, S; Jayashree, C; Adish Kumar, S; Kaliappan, S; Rajesh Banu, J

2014-12-01

In this investigation, an effort was made to pretreat surplus waste activated sludge (WAS) inexpensively by a novel combined process involving thermo chemical disperser pretreatment. This pretreatment was found to be efficient at a specific energy (SE) consumption of 3360.94 kJ/kg TS, with the chemical oxygen demand (COD) solubilization of 20%. This was comparatively higher than thermo chemically treated sludge where the solubilization was found to be 15.5% at a specific energy consumption of 10,330 kJ/kg TS respectively. Higher production of volatile fatty acids (VFA) (675 mg/L) in anaerobic fermentation of pretreated WAS indicates better hydrolysis performance. The biogas production potential of sludge pretreated through this combined technique was found to be 0.455 (L/gVS) and comparatively higher than thermo chemically pretreated sludge. Economic investigation provides 90% net energy savings in this combined pretreatment. Therefore, this combined process was considered to be potentially effective and economical in sludge disintegration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of curcumin and ursolic acid on the mitochondrial coupling efficiency and hydrogen peroxide emission of intact skeletal myoblasts.

PubMed

Tueller, Daniel J; Harley, Jackson S; Hancock, Chad R

2017-10-21

Curcumin may improve blood glucose management, but the mechanism is not fully established. We demonstrated that curcumin (40 μM) reduced the mitochondrial coupling efficiency (percentage of oxygen consumption coupled to ATP synthesis) of intact skeletal muscle cells. A 30-minute pretreatment with curcumin reduced mitochondrial coupling efficiency by 17.0 ± 0.4% relative to vehicle (p < 0.008). Curcumin pretreatment also decreased the rate of hydrogen peroxide emission by 43 ± 13% compared to vehicle (p < 0.05). Analysis of cell respiration in the presence of curcumin revealed a 40 ± 4% increase in the rate of oxygen consumption upon curcumin administration (p < 0.05 compared to vehicle). No difference in mitochondrial coupling efficiency was observed between vehicle- and curcumin-pretreated cells after permeabilization of cell membranes (p > 0.7). The interaction between curcumin and ursolic acid, another natural compound that may improve blood glucose management, was also examined. Pretreatment with ursolic acid (0.12 μM) increased the mitochondrial coupling efficiency of intact cells by 4.1 ± 1.1% relative to vehicle (p < 0.008) and attenuated the effect of curcumin when the two compounds were used in combination. The observed changes to mitochondrial coupling efficiency and hydrogen peroxide emission were consistent with the established effects of curcumin on blood glucose control. Our findings also show that changes to mitochondrial coupling efficiency after curcumin pretreatment may go undetected unless cells are assessed in the intact condition. Copyright © 2017 Elsevier Inc. All rights reserved.

Breakdown of cell wall nanostructure in dilute acid pretreated biomass.

PubMed

Pingali, Sai Venkatesh; Urban, Volker S; Heller, William T; McGaughey, Joseph; O'Neill, Hugh; Foston, Marcus; Myles, Dean A; Ragauskas, Arthur; Evans, Barbara R

2010-09-13

The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient way. Here we use small-angle neutron scattering (SANS) to characterize morphological changes in switchgrass lignocellulose across molecular to submicrometer length scales resulting from the industrially relevant dilute acid pretreatment method. Our results demonstrate that dilute acid pretreatment increases the cross-sectional radius of the crystalline cellulose fibril. This change is accompanied by removal of hemicellulose and the formation of R(g) ∼ 135 A lignin aggregates. The structural signature of smooth cell wall surfaces is observed at length scales larger than 1000 A, and it remains remarkably invariable during pretreatment. This study elucidates the interplay of the different biomolecular components in the breakdown process of switchgrass by dilute acid pretreatment. The results are important for the development of efficient strategies of biomass to biofuel conversion.

Enhancing biogas production of corn stover by fast pyrolysis pretreatment.

PubMed

Wang, Fang; Zhang, Deli; Wu, Houkai; Yi, Weiming; Fu, Peng; Li, Yongjun; Li, Zhihe

2016-10-01

A new thermo-chemical pretreatment by a lower temperature fast pyrolysis (LTFP) was applied to promote anaerobic digestion (AD) efficiency of corn stover (CS). The pretreatment experiment was performed by a fluidized bed pyrolysis reactor at 180, 200 and 220°C with a carrier gas flow rate of 4 and 3m(3)/h. The components characteristics, Scanning Electron Microscope (SEM) images and Crystal Intensity (CrI) of the pretreated CS were tested to explore effectiveness of the pretreatment. The results showed that the cumulative methane production at 180°C for 4 and 3m(3)/h were 199.8 and 200.3mL/g TS, respectively. As compared to the untreated CS, the LTFP pretreatment significantly (a<0.05) increased the methane production by 18.07% and 18.33%, respectively. Methane production was well fitted by the Gompertz models, and the maximum methane potential and AD efficiency was obtained at 180°C for 3m(3)/h. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recent developments in novel freezing and thawing technologies applied to foods.

PubMed

Wu, Xiao-Fei; Zhang, Min; Adhikari, Benu; Sun, Jincai

2017-11-22

This article reviews the recent developments in novel freezing and thawing technologies applied to foods. These novel technologies improve the quality of frozen and thawed foods and are energy efficient. The novel technologies applied to freezing include pulsed electric field pre-treatment, ultra-low temperature, ultra-rapid freezing, ultra-high pressure and ultrasound. The novel technologies applied to thawing include ultra-high pressure, ultrasound, high voltage electrostatic field (HVEF), and radio frequency. Ultra-low temperature and ultra-rapid freezing promote the formation and uniform distribution of small ice crystals throughout frozen foods. Ultra-high pressure and ultrasound assisted freezing are non-thermal methods and shorten the freezing time and improve product quality. Ultra-high pressure and HVEF thawing generate high heat transfer rates and accelerate the thawing process. Ultrasound and radio frequency thawing can facilitate thawing process by volumetrically generating heat within frozen foods. It is anticipated that these novel technologies will be increasingly used in food industries in the future.

Anaerobic digestion of thermal pre-treated emulsified slaughterhouse wastes (TESW): Effect of trace element limitation on process efficiency and sludge metabolic properties.

PubMed

Eftaxias, Alexandros; Diamantis, Vasileios; Aivasidis, Alexandros

2018-06-01

Slaughterhouse solid wastes, characterized by a high lipid content, are considered a valuable resource for energy production by means of anaerobic digestion technologies. Aim of this study was to examine the effect of trace element limitation on the mesophilic anaerobic digestion of thermally pre-treated emulsified slaughterhouse wastes (TESW). Under two distinct experimental periods (Period I - low and Period II - high trace element dosage respectively) a CSTR with sludge recirculation was operated at increasing organic loading rate (OLR) from 1.5 to 10 g L -1  d -1 . Under optimum conditions, COD removal was higher than 96%, biogas yield equal to 0.53 L g -1  COD feed and the biogas methane content 77%. Trace element limitation however, resulted in a dramatic decline in process efficiency, with VFA accumulation and events of extreme sludge flotation, despite that the soluble concentration of Ni, Co and Mo were between 12 and 28 μg L -1 . This is indicative of mass transfer limitations caused by lipids adsorption onto the anaerobic biomass. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electrokinetic remediation of manganese and ammonia nitrogen from electrolytic manganese residue.

PubMed

Shu, Jiancheng; Liu, Renlong; Liu, Zuohua; Du, Jun; Tao, Changyuan

2015-10-01

Electrolytic manganese residue (EMR) is a solid waste found in filters after sulphuric acid leaching of manganese carbonate ore, which mainly contains manganese and ammonia nitrogen and seriously damages the ecological environment. This work demonstrated the use of electrokinetic (EK) remediation to remove ammonia nitrogen and manganese from EMR. The transport behavior of manganese and ammonia nitrogen from EMR during electrokinetics, Mn fractionation before and after EK treatment, the relationship between Mn fractionation and transport behavior, as well as the effects of electrolyte and pretreatment solutions on removal efficiency and energy consumption were investigated. The results indicated that the use of H2SO4 and Na2SO4 as electrolytes and pretreatment of EMR with citric acid and KCl can reduce energy consumption, and the removal efficiencies of manganese and ammonia nitrogen were 27.5 and 94.1 %, respectively. In these systems, electromigration and electroosmosis were the main mechanisms of manganese and ammonia nitrogen transport. Moreover, ammonia nitrogen in EMR reached the regulated level, and the concentration of manganese in EMR could be reduced from 455 to 37 mg/L. In general, the electrokinetic remediation of EMR is a promising technology in the future.

Integrated anaerobic/aerobic biological treatment for intensive swine production.

PubMed

Bortone, Giuseppe

2009-11-01

Manure processing could help farmers to effectively manage nitrogen (N) surplus load. Many pig farms have to treat wastewater. Piggery wastewater treatment is a complex challenge, due to the high COD and N concentrations and low C/N ratio. Anaerobic digestion (AD) could be a convenient pre-treatment, particularly from the energetic view point and farm income, but this causes further reduction of C/N ratio and makes denitrification difficult. N removal can only be obtained integrating anaerobic/aerobic treatment by taking into account the best use of electron donors. Experiences gained in Italy during development of integrated biological treatment approaches for swine manure, from bench to full scale, are reported in this paper. Solid/liquid separation as pre-treatment of raw manure is an efficient strategy to facilitate liquid fraction treatment without significantly lowering C/N ratio. In Italy, two full scale SBRs showed excellent efficiency and reliability. Current renewable energy policy and incentives makes economically attractive the application of AD to the separated solid fraction using high solid anaerobic digester (HSAD) technology. Economic evaluation showed that energy production can reduce costs up to 60%, making sustainable the overall treatment.

Technospheric Mining of Rare Earth Elements from Bauxite Residue (Red Mud): Process Optimization, Kinetic Investigation, and Microwave Pretreatment.

PubMed

Reid, Sable; Tam, Jason; Yang, Mingfan; Azimi, Gisele

2017-11-10

Some rare earth elements (REEs) are classified under critical materials, i.e., essential in use and subject to supply risk, due to their increasing demand, monopolistic supply, and environmentally unsustainable and expensive mining practices. To tackle the REE supply challenge, new initiatives have been started focusing on their extraction from alternative secondary resources. This study puts the emphasis on technospheric mining of REEs from bauxite residue (red mud) produced by the aluminum industry. Characterization results showed the bauxite residue sample contains about 0.03 wt% REEs. Systematic leaching experiments showed that concentrated HNO 3 is the most effective lixiviant. However, because of the process complexities, H 2 SO 4 was selected as the lixiviant. To further enhance the leaching efficiency, a novel process based on microwave pretreatment was employed. Results indicated that microwave pretreatment creates cracks and pores in the particles, enabling the lixiviant to diffuse further into the particles, bringing more REEs into solution, yielding of 64.2% and 78.7% for Sc and Nd, respectively, which are higher than the maximum obtained when HNO 3 was used. This novel process of "H 2 SO 4 leaching-coupled with-microwave pretreatment" proves to be a promising technique that can help realize the technological potential of REE recovery from secondary resources, particularly bauxite residue.

Application of Magnetic Nanoparticles in Pretreatment Device for POPs Analysis in Water

NASA Astrophysics Data System (ADS)

Chu, Dongzhi; Kong, Xiangfeng; Wu, Bingwei; Fan, Pingping; Cao, Xuan; Zhang, Ting

2018-01-01

In order to reduce process time and labour force of POPs pretreatment, and solve the problem that extraction column was easily clogged, the paper proposed a new technology of extraction and enrichment which used magnetic nanoparticles. Automatic pretreatment system had automatic sampling unit, extraction enrichment unit and elution enrichment unit. The paper briefly introduced the preparation technology of magnetic nanoparticles, and detailly introduced the structure and control system of automatic pretreatment system. The result of magnetic nanoparticles mass recovery experiments showed that the system had POPs analysis preprocessing capability, and the recovery rate of magnetic nanoparticles were over 70%. In conclusion, the author proposed three points optimization recommendation.

Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol

USDA-ARS?s Scientific Manuscript database

Elimination of inhibitory compounds released during pretreatment of lignocellulose is critical for efficient cellulose conversion and ethanol fermentation. This study examined the effect of bioabated liquor from pretreated corn stover on enzyme hydrolysis of Solka Floc or pretreated corn stover soli...

Understanding the impact of ionic liquid pretreatment on eucalyptus

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

Centikol, Ozgul; Dibble, Dean; Cheng, Gang

2010-01-01

The development of cost-competitive biofuels necessitates the realization of advanced biomass pretreatment technologies. Ionic liquids provide a basis for one of the most promising pretreatment technologies and are known to allow effective processing of cellulose and some biomass species. Here, we demonstrate that the ionic liquid 1-ethyl-3-methyl imidazolium acetate, [C2mim][OAc], induces structural changes at the molecular level in the cell wall of Eucalyptus globulus. Deacetylation of xylan, acetylation of the lignin units, selective removal of guaiacyl units (increasing the syringyl:guaiacyl ratio) and decreased {beta}-ether content were the most prominent changes observed. Scanning electron microscopy images of the plant cell wallmore » sections reveal extensive swelling during [C2mim][OAc] pretreatment. X-ray diffraction measurements indicate a change in cellulose crystal structure from cellulose I to cellulose II after [C2mim][OAc] pretreatment. Enzymatic saccharification of the pretreated material produced increased sugar yields and improved hydrolysis kinetics after [C2mim][OAc] pretreatment. These results provide new insight into the mechanism of ionic liquid pretreatment and reaffirm that this approach may be promising for the production of cellulosic biofuels from woody biomass.« less

Size effects on acid bisulfite pretreatment efficiency: multiple product yields in spent liquor and enzymatic digestibility of pretreated solids

Treesearch

Yalan Liu; Jinwu Wang; Michael P. Wolcott

2017-01-01

Currently, feedstock size effects on chemical pretreatment performance were not clear due to the complexity of the pretreatment process and multiple evaluation standards such as the sugar recovery in spent liquor or enzymatic digestibility. In this study, we evaluated the size effects by various ways: the sugar recovery and coproduct yields in spent liquor, the...

Dilute acid pretreatment of corncob for efficient sugar production

Treesearch

G.S. Wang; Jae-Won Lee; Junyong Zhu; Thomas W. Jeffries

2011-01-01

Aqueous dilute acid pretreatments of corncob were conducted using cylindrical pressure vessels in an oil bath. Pretreatments were conducted in a temperature range of 160–190 °C with acid-solution-to-solid-corncob ratio of 2. The acid concentration (v/v) in the pretreatment solution was varied from 0% to 0.7%, depending on temperature. This gives acid charge on ovendry-...

The potential value of the seaweed Ceylon moss (Gelidium amansii) as an alternative bioenergy resource.

PubMed

Wi, Seung Gon; Kim, Hyun Joo; Mahadevan, Shobana Arumugam; Yang, Duck-Joo; Bae, Hyeun-Jong

2009-12-01

Sea weed (Ceylon moss) possesses comparable bioenergy production potential to that of land plants. Ceylon moss has high content of carbohydrates, typically galactose (23%) and glucose (20%). We have explored the possibility of sodium chlorite in Ceylon moss pretreatment that can ultimately increase the efficiency of enzymatic saccharification. In an acidic medium, chlorite generates ClO(2) molecules that transform lignin into soluble compounds without any significant loss of carbohydrate content and this procedure is widely used as an analytical method for holocellulose determination. Sodium chlorite-pretreated samples resulted in glucose yield up to 70% with contrast of only 5% was obtained from non-pretreated samples. The efficiency of enzymatic hydrolysis is significantly improved by sodium chlorite pretreatment, and thus sodium chlorite pretreatment is potentially a very useful tool in the utilisation of Ceylon moss biomass for ethanol production or bioenergy purposes.

Thermochemical pretreatments for enhancing succinic acid production from industrial hemp (Cannabis sativa L.).

PubMed

Gunnarsson, Ingólfur B; Kuglarz, Mariusz; Karakashev, Dimitar; Angelidaki, Irini

2015-04-01

The aim of this study was to develop an efficient thermochemical method for treatment of industrial hemp biomass, in order to increase its bioconversion to succinic acid. Industrial hemp was subjected to various thermochemical pretreatments using 0-3% H2SO4, NaOH or H2O2 at 121-180°C prior to enzymatic hydrolysis. The influence of the different pretreatments on hydrolysis and succinic acid production by Actinobacillus succinogenes 130Z was investigated in batch mode, using anaerobic bottles and bioreactors. Enzymatic hydrolysis and fermentation of hemp material pretreated with 3% H2O2 resulted in the highest overall sugar yield (73.5%), maximum succinic acid titer (21.9 g L(-1)), as well as the highest succinic acid yield (83%). Results obtained clearly demonstrated the impact of different pretreatments on the bioconversion efficiency of industrial hemp into succinic acid. Copyright © 2015. Published by Elsevier Ltd.

Ozonation and alkaline-peroxide pretreatment of wheat straw for Cryptococcus curvatus fermentation

NASA Technical Reports Server (NTRS)

Greenwalt, C. J.; Hunter, J. B.; Lin, S.; McKenzie, S.; Denvir, A.

2000-01-01

Crop residues in an Advanced Life Support System (ALS) contain many valuable components that could be recovered and used. Wheat is 60% inedible, with approximately 90% of the total sugars in the residue cellulose and hemicellulose. To release these sugars requires pretreatment followed by enzymatic hydrolysis. Cryptococcus curvatus, an oleaginous yeast, uses the sugars in cellulose and hemicellulose for growth and production of storage triglycerides. In this investigation, alkaline-peroxide and ozonation pretreatment methods were compared for their efficiency to release glucose and xylose to be used in the cultivation of C. curvatus. Leaching the biomass with water at 65 degrees C for 4 h prior to pretreatment facilitated saccharification. Alkaline-peroxide and ozone pretreatment were almost 100% and 80% saccharification efficient, respectively. The sugars derived from the hydrolysis of alkaline-peroxide-treated wheat straw supported the growth of C. curvatus and the production of edible single-cell oil.

Study on loading coefficient in steam explosion process of corn stalk.

PubMed

Sui, Wenjie; Chen, Hongzhang

2015-03-01

The object of this work was to evaluate the effect of loading coefficient on steam explosion process and efficacy of corn stalk. Loading coefficient's relation with loading pattern and material property was first revealed, then its effect on transfer process and pretreatment efficacy of steam explosion was assessed by established models and enzymatic hydrolysis tests, respectively, in order to propose its optimization strategy for improving the process economy. Results showed that loading coefficient was mainly determined by loading pattern, moisture content and chip size. Both compact loading pattern and low moisture content improved the energy efficiency of steam explosion pretreatment and overall sugar yield of pretreated materials, indicating that they are desirable to improve the process economy. Pretreatment of small chip size showed opposite effects in pretreatment energy efficiency and enzymatic hydrolysis performance, thus its optimization should be balanced in investigated aspects according to further techno-economical evaluation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of hydraulic fracturing wastewater by wet air oxidation.

PubMed

Wang, Wei; Yan, Xiuyi; Zhou, Jinghui; Ma, Jiuli

2016-01-01

Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard.

Laccase applications in biofuels production: current status and future prospects.

PubMed

Kudanga, Tukayi; Le Roes-Hill, Marilize

2014-08-01

The desire to reduce dependence on the ever diminishing fossil fuel reserves coupled with the impetus towards green energy has seen increased research in biofuels as alternative sources of energy. Lignocellulose materials are one of the most promising feedstocks for advanced biofuels production. However, their utilisation is dependent on the efficient hydrolysis of polysaccharides, which in part is dependent on cost-effective and benign pretreatment of biomass to remove or modify lignin and release or expose sugars to hydrolytic enzymes. Laccase is one of the enzymes that are being investigated not only for potential use as pretreatment agents in biofuel production, mainly as a delignifying enzyme, but also as a biotechnological tool for removal of inhibitors (mainly phenolic) of subsequent enzymatic processes. The current review discusses the major advances in the application of laccase as a potential pretreatment strategy, the underlying principles as well as directions for future research in the search for better enzyme-based technologies for biofuel production. Future perspectives could include synergy between enzymes that may be required for optimal results and the adoption of the biorefinery concept in line with the move towards the global implementation of the bioeconomy strategy.

A novel free ammonia based pretreatment technology to enhance anaerobic methane production from primary sludge.

PubMed

Wei, Wei; Zhou, Xu; Xie, Guo-Jun; Duan, Haoran; Wang, Qilin

2017-10-01

This study proposed a novel free ammonia (FA, i.e., NH 3 ) pretreatment technology to enhance anaerobic methane production from primary sludge for the first time. The solubilization of primary sludge was substantially enhanced following 24 h FA pretreatment (250-680 mg NH 3 -N/L), by which the release of soluble chemical oxygen demand (SCOD) (i.e., 0.4 mg SCOD/mg VS added; VS: volatile solids) was approximately 10 times as much as that without pretreatment (i.e., 0.03 mg SCOD/mg VS added). Then, biochemical methane potential (BMP) tests demonstrated that FA pretreatment of 250-680 mg NH 3 -N/L was capable of enhancing anaerobic methane production while the digestion time was more than 7 days. Model based analysis indicated that the improved anaerobic methane production was due to an increased biochemical methane potential (B 0 ) of 8-17% (i.e., from 331 to 357-387 L CH 4 /kg VS added), with the highest B 0 achieved at 420 mg NH 3 -N/L pretreatment. However, FA pretreatment of 250-680 mg NH 3 -N/L decreased hydrolysis rate (k) by 24-38% compared with control (i.e., from 0.29 d -1 to 0.18-0.22 d -1 ), which explained the lower methane production over the first 7 days' digestion period. Economic analysis and environmental evaluation demonstrated that FA pretreatment technology was environmentally friendly and economically favorable. Biotechnol. Bioeng. 2017;114: 2245-2252. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

40 CFR Table 2 to Part 455 - Organic Pesticide Active Ingredient Effluent Limitations Best Available Technology Economically...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Organic Pesticide Active Ingredient Effluent Limitations Best Available Technology Economically Achievable (BAT) and Pretreatment Standards for... Economically Achievable (BAT) and Pretreatment Standards for Existing Sources (PSES) Pesticide kg/kkg (lb/1,000...

Evaluation of lime and hydrothermal pretreatments for efficient enzymatic hydrolysis of raw sugarcane bagasse.

PubMed

Grimaldi, Maira Prearo; Marques, Marina Paganini; Laluce, Cecília; Cilli, Eduardo Maffud; Sponchiado, Sandra Regina Pombeiro

2015-01-01

Ethanol production from sugarcane bagasse requires a pretreatment step to disrupt the cellulose-hemicellulose-lignin complex and to increase biomass digestibility, thus allowing the obtaining of high yields of fermentable sugars for the subsequent fermentation. Hydrothermal and lime pretreatments have emerged as effective methods in preparing the lignocellulosic biomass for bioconversion. These pretreatments are advantageous because they can be performed under mild temperature and pressure conditions, resulting in less sugar degradation compared with other pretreatments, and also are cost-effective and environmentally sustainable. In this study, we evaluated the effect of these pretreatments on the efficiency of enzymatic hydrolysis of raw sugarcane bagasse obtained directly from mill without prior screening. In addition, we evaluated the structure and composition modifications of this bagasse after lime and hydrothermal pretreatments. The highest cellulose hydrolysis rate (70 % digestion) was obtained for raw sugarcane bagasse pretreated with lime [0.1 g Ca(OH)2/g raw] for 60 min at 120 °C compared with hydrothermally pretreated bagasse (21 % digestion) under the same time and temperature conditions. Chemical composition analyses showed that the lime pretreatment of bagasse promoted high solubilization of lignin (30 %) and hemicellulose (5 %) accompanied by a cellulose accumulation (11 %). Analysis of pretreated bagasse structure revealed that lime pretreatment caused considerable damage to the bagasse fibers, including rupture of the cell wall, exposing the cellulose-rich areas to enzymatic action. We showed that lime pretreatment is effective in improving enzymatic digestibility of raw sugarcane bagasse, even at low lime loading and over a short pretreatment period. It was also demonstrated that this pretreatment caused alterations in the structure and composition of raw bagasse, which had a pronounced effect on the enzymes accessibility to the substrate, resulting in an increase of cellulose hydrolysis rate. These results indicate that the use of raw sugarcane bagasse (without prior screening) pretreated with lime (cheaper and environmentally friendly reagent) may represent a cost reduction in the cellulosic ethanol production.

The Use of Clay-Polymer Nanocomposites in Wastewater Pretreatment

PubMed Central

Rytwo, Giora

2012-01-01

Some agricultural effluents are unsuitable for discharge into standard sewage-treatment plants: their pretreatment is necessary to avoid clogging of the filtering devices by colloidal matter. The colloidal stability of the effluents is mainly due to mutual repulsive forces that keep charged particles in suspension. Pretreatment processes are based on two separate stages: (a) neutralization of the charges (“coagulation”) and (b) bridging between several small particles to form larger aggregates that sink, leaving clarified effluent (“flocculation”). The consequent destabilization of the colloidal suspension lowers total suspended solids (TSSs), turbidity, and other environmental quality parameters, making the treatments that follow more efficient. Clay-based materials have been widely used for effluent pretreatment and pollutant removal. This study presents the use of nanocomposites, comprised of an anchoring particle and a polymer, as “coagoflocculants” for the efficient and rapid reduction of TSS and turbidity in wastewater with a high organic load. The use of such particles combines the advantages of coagulant and flocculant by neutralizing the charge of the suspended particles while bridging between them and anchoring them to a denser particle (the clay mineral), enhancing their precipitation. Very rapid and efficient pretreatment is achieved in one single treatment step. PMID:22454607

Comparison of ozone and thermal hydrolysis combined with anaerobic digestion for municipal and pharmaceutical waste sludge with tetracycline resistance genes.

PubMed

Pei, Jin; Yao, Hong; Wang, Hui; Ren, Jia; Yu, Xiaohua

2016-08-01

Biosolids from wastewater treatment plant (WWTP) are environmental reservoirs of antibiotic resistance genes, which attract great concerns on their efficient treatments. Anaerobic digestion (AD) is widely used for sewage sludge treatment but its effectiveness is limited due to the slow hydrolysis. Ozone and thermal hydrolysis pre-treatment were employed to improve AD efficiency and reduce antibiotic-resistant genes in municipal and pharmaceutical waste sludge (MWS and PWS, respectively) in this study. Sludge solubilization achieved 15.75-25.09% and 14.85-33.92% after ozone and thermal hydrolysis, respectively. Both pre-treatments improved cumulative methane production and the enhancements were greater on PWS than MWS. Five tetracycline-resistant genes (tet(A), tet(G), tet(Q), tet(W), tet(X)) and one mobile element (intI1) were qPCR to assess pre-treatments. AD of pre-treated sludge reduced more tet genes than raw sludge for both ozonation and thermal hydrolysis in PWS and MWS. Thermal hydrolysis pre-treatment was more efficient than ozone for reduction after AD. Results of this study help support management options for reducing the spread of antibiotic resistance from biosolids. Copyright © 2016. Published by Elsevier Ltd.

Chemical composition, pretreatments and saccharification of Senna siamea (Lam.) H.S. Irwin & Barneby: An efficient biomass producing tree legume.

PubMed

Mund, Nitesh K; Dash, Debabrata; Barik, Chitta R; Goud, Vaibhav V; Sahoo, Lingaraj; Mishra, Prasannajit; Nayak, Nihar R

2016-05-01

Protocols were developed for efficient release of glucose from the biomass of Senna siamea, one of the highly efficient biomass producing tree legumes. Composition of mature, 1year and 2years coppice biomass were analysed. For the hydrolysis of the glucan, two pretreatments, cellulose solvent- and organic solvent-based lignocellulose fractionation (COSLIF) and alkali (sodium hydroxide) were used; COSLIF (85% phosphoric acid, 45min incubation at 50°C) pretreated mature biomass exhibited best result in which 88.90% glucose released after 72h of incubation with the use of 5 filter paper units (FPU) of cellulase and 10 international units (IU) of β-glucosidase per gram of glucan. Of the biomass of different particle sizes (40-200mesh) used for saccharification, 40-60mesh shown the maximum glucose release. COSLIF pretreated mature, 1year and 2years coppice biomass showed equivalent glucose release profiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficient conversion of pretreated brewer's spent grain and wheat bran by submerged cultivation of Hericium erinaceus.

PubMed

Wolters, Niklas; Schabronath, Christoph; Schembecker, Gerhard; Merz, Juliane

2016-12-01

Brewer's spent grain (BSG) and wheat bran (WB) are industrial byproducts that accumulate in millions of tons per year and are typically applied as animal feed. Since both byproducts show a great potential as substrates for fermentation, the approach developed in this study consists of utilizing these lignocellulosic byproducts for biomass production of the medicinal fungus Hericium erinaceus through submerged cultivation. To increase the biological efficiency of the bioconversion, acidic pretreatment was applied yielding a bioconversion of 38.6% for pretreated BSG and 34.8% for pretreated WB. This study shows that the complete degradation of (hemi)cellulose into monosaccharides was not required for an efficient bioconversion. The produced fungal biomass was applied in a second fermentation step to induce the secondary metabolite erinacine C production. Thus, biomass was produced as a functional food ingredient with erinacine C contents of 174.8mg/g for BSG and 99.3mg/g for WB based bioconversions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of pretreatment on simultaneous saccharification and fermentation of hardwood into acetone/butanol

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

Shah, M.M.; Song, S.K.; Lee, Y.Y.

1991-12-31

The effectiveness of pretreatments on hardwood substrate was investigated in connection with its subsequent conversion by simultaneous saccharification and fermentation (SSF), using Clostridium acetobutylicum. The main objectives of the pretreatment were to achieve efficient separation of lignin from carbohydrates, and to obtain maximum sugar yield on enzymatic hydrolysis of pretreated wood. Two methods have given promising results: (1) supercritical CO{sub 2}-SO{sub 2} treatment, and (2) monoethanolamine (MEA) treatment. The MEA pretreatment removed above 90% of hardwood lignin while retaining 83% of carbohydrates. With CO{sub 2}-SO{sub 2} pretreatment, the degree of lignin separation was lower. Under the scheme of SSF, themore » pretreated hardwood was converted to acetone, butanol, and ethanol (ABE) via single stage processing by cellulose enzyme system and C. acetobutylicum cells. The product yield in the process was such that 15 g of ABE/100 g of dry aspen wood was produced. In the overall process of SSF, the enzymatic hydrolysis was found to be the rate-limiting step. The ability of C. acetobutylicum to metabolize various 6-carbon and 5-carbon sugars resulted in efficient utilization of all available sugars from hardwood.« less

Biomass torrefaction: A promising pretreatment technology for biomass utilization

NASA Astrophysics Data System (ADS)

Chen, ZhiWen; Wang, Mingfeng; Ren, Yongzhi; Jiang, Enchen; Jiang, Yang; Li, Weizhen

2018-02-01

Torrefaction is an emerging technology also called mild pyrolysis, which has been explored for the pretreatment of biomass to make the biomass more favorable for further utilization. Dry torrefaction (DT) is a pretreatment of biomass in the absence of oxygen under atmospheric pressure and in a temperature range of 200-300 degrees C, while wet torrrefaction (WT) is a method in hydrothermal or hot and high pressure water at the tempertures within 180-260 degrees C. Torrrefied biomass is hydrophobic, with lower moisture contents, increased energy density and higher heating value, which are more comparable to the characteristics of coal. With the improvement in the properties, torrefied biomass mainly has three potential applications: combustion or co-firing, pelletization and gasification. Generally, the torrefaction technology can accelerate the development of biomass utilization technology and finally realize the maximum applications of biomass energy.

Life cycle assessment of sewage sludge co-incineration in a coal-based power station.

PubMed

Hong, Jingmin; Xu, Changqing; Hong, Jinglan; Tan, Xianfeng; Chen, Wei

2013-09-01

A life cycle assessment was conducted to evaluate the environmental and economic effects of sewage sludge co-incineration in a coal-fired power plant. The general approach employed by a coal-fired power plant was also assessed as control. Sewage sludge co-incineration technology causes greater environmental burden than does coal-based energy production technology because of the additional electricity consumption and wastewater treatment required for the pretreatment of sewage sludge, direct emissions from sludge incineration, and incinerated ash disposal processes. However, sewage sludge co-incineration presents higher economic benefits because of electricity subsidies and the income generating potential of sludge. Environmental assessment results indicate that sewage sludge co-incineration is unsuitable for mitigating the increasing pressure brought on by sewage sludge pollution. Reducing the overall environmental effect of sludge co-incineration power stations necessitates increasing net coal consumption efficiency, incinerated ash reuse rate, dedust system efficiency, and sludge water content rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover

PubMed Central

2014-01-01

Background In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation. PMID:24917886

Lignocellulosic ethanol: Technology design and its impact on process efficiency.

PubMed

Paulova, Leona; Patakova, Petra; Branska, Barbora; Rychtera, Mojmir; Melzoch, Karel

2015-11-01

This review provides current information on the production of ethanol from lignocellulosic biomass, with the main focus on relationships between process design and efficiency, expressed as ethanol concentration, yield and productivity. In spite of unquestionable advantages of lignocellulosic biomass as a feedstock for ethanol production (availability, price, non-competitiveness with food, waste material), many technological bottlenecks hinder its wide industrial application and competitiveness with 1st generation ethanol production. Among the main technological challenges are the recalcitrant structure of the material, and thus the need for extensive pretreatment (usually physico-chemical followed by enzymatic hydrolysis) to yield fermentable sugars, and a relatively low concentration of monosaccharides in the medium that hinder the achievement of ethanol concentrations comparable with those obtained using 1st generation feedstocks (e.g. corn or molasses). The presence of both pentose and hexose sugars in the fermentation broth, the price of cellulolytic enzymes, and the presence of toxic compounds that can inhibit cellulolytic enzymes and microbial producers of ethanol are major issues. In this review, different process configurations of the main technological steps (enzymatic hydrolysis, fermentation of hexose/and or pentose sugars) are discussed and their efficiencies are compared. The main features, benefits and drawbacks of simultaneous saccharification and fermentation (SSF), simultaneous saccharification and fermentation with delayed inoculation (dSSF), consolidated bioprocesses (CBP) combining production of cellulolytic enzymes, hydrolysis of biomass and fermentation into one step, together with an approach combining utilization of both pentose and hexose sugars are discussed and compared with separate hydrolysis and fermentation (SHF) processes. The impact of individual technological steps on final process efficiency is emphasized and the potential for use of immobilized biocatalysts is considered. Copyright © 2014 Elsevier Inc. All rights reserved.

Application of Freezing and Thawing in Apple (Malus domestica) Juice Extraction.

PubMed

Nadulski, Rafał; Kobus, Zbigniew; Wilczyński, Kamil; Zawiślak, Kazimierz; Grochowicz, Józef; Guz, Tomasz

2016-09-28

The paper presents the results of the research on the impact of enzymatic liquefaction, freezing and thawing on the efficiency of juice pressure extraction from apple pulp and quality of the obtained juices. The research was conducted using three types of pretreatment prior the pressing: crushing and enzymatic liquefaction in temperature of 25 °C, crushing and enzymatic liquefaction in temperature of 45 °C and crushing followed by freezing and thawing of the pulp. The study included three varieties of apples. The juice was obtained using a laboratory basket press. It was determined that the pretreatment of the pulp as well as the varietal characteristics of the fruits have a significant impact on the efficiency of the pressure extraction process. The enzymatic treatment of the pulp, irrespective of the temperature at which it was conducted, significantly increased the efficiency of the process. No effect of the temperature (25 or 45 °C) of enzymatic treatment on the efficiency of the pressure extraction process was found. Pretreatment of the pulp based on freezing and thawing contributes to the increase of efficiency of pressing in the case of two apple cultivars, that is, Idared and Red Delicious. It was showed that total phenolic content, antioxidant activity, the soluble solids content and juice acidity (pH) depend on the pretreatment of the pulp and the varietal characteristics of apples. Following the application of pretreatment of the pulp, an increase was observed in the content of polyphenols and in the antioxidant activity of the juices obtained. © 2016 Institute of Food Technologists®

Pretreatment of microbial sludges

DOEpatents

Rivard, Christopher J.; Nagle, Nicholas J.

1995-01-01

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Biological pretreatment of corn stover with Phlebia brevispora NRRL-13108 for enhanced enzymatic hydrolysis and efficient ethanol production

USDA-ARS?s Scientific Manuscript database

Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical, or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. In this work, solid state cultivation of corn stover with Phlebia bre...

Pretreatment of microbial sludges

DOEpatents

Rivard, C.J.; Nagle, N.J.

1995-01-10

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Sulfite pretreatment (SPORL) for robust enzymatic saccharification of spruce and red pine

Treesearch

J.Y. Zhu; X.J. Pan; G.S. Wang; R. Gleisner

2009-01-01

This study established a novel process using sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust and efficient bioconversion of softwoods. The process consists of sulfite treatment of wood chips under acidic conditions followed by mechanical size reduction using disk refining. The results indicated that after the SPORL pretreatment of...

Robust and efficient enzymatic saccharification of softwoods by SPORL

Treesearch

J.Y. Zhu; X.J. Pan; W. Zhu; G.S. Wang; R. Gleisner

2009-01-01

This study demonstrated Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose (SPORL) for robust conversion of softwood through enzymatic hydrolysis. At a sodium bisulfite charge around 9%, over 90% cellulose conversion could be achieved when spruce wood chips were pretreated at 180°C with pH near 2. For lodgepole pine, pretreatment liquor initial...

Effect of sonically induced deflocculation on the efficiency of ozone mediated partial sludge disintegration for improved production of biogas.

PubMed

Sowmya Packyam, G; Kavitha, S; Adish Kumar, S; Kaliappan, S; Yeom, Ick Tae; Rajesh Banu, J

2015-09-01

In this study, ultrasonication was used for sludge deflocculation, followed by cell disintegration using ozone. The effect of this phase separated sono-ozone pretreatment is evaluated based on extra polymeric substances release, deoxyribonucleic acid (DNA) in the medium, solubilization of intra cellular components and suspended solids (SS) reduction. Ultrasonically induced deflocculation was optimized at an energy dosage of 76.4(log 1.88)kJ/kg TS. During cell disintegration (ozone dosage 0.0011 mgO3/mgSS), chemical oxygen demand solubilization (COD) and SS reduction of sonic mediated ozone pretreated sludge were 25.4% and 17.8% comparatively higher than ozone pretreated sludge, respectively. Further, biogas production potential of control (raw), flocculated (ozone pretreated), and deflocculated (sonic mediated ozone pretreated) sludges were observed to be 0.202, 0.535 and 0.637 L/(gVS), respectively. Thus, the phase separated pretreatment at lower ultrasonic specific energy and low dose ozone proved to enhance the anaerobic biodegradability efficiently. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous saccharification and fermentation (SSF) of Jatropha curcas shells: utilization of co-products from the biodiesel production process.

PubMed

Visser, Evan Michael; Oliveira Filho, Delly; Tótola, Marcos Rogério; Martins, Marcio Arêdes; Guimarães, Valéria Monteze

2012-06-01

Jatropha curcas has great potential as an oil crop for use in biodiesel applications, and the outer shell is rich in lignocellulose that may be converted to ethanol, giving rise to the concept of a biorefinery. In this study, two dilute pretreatments of 0.5% H(2)SO(4) and 1.0% NaOH were performed on Jatropha shells with subsequent simultaneous saccharification and fermentation (SSF) of the pretreated water-insoluble solids (WIS) to evaluate the effect of inhibitors in the pretreatment slurry. A cellulase loading of 15 FPU/g WIS, complimented with an excess of cellobiase (19.25 U/g), was used for SSF of either the washed WIS or the original slurry to determine the effect of inhibitors. Ethanol and glucose were monitored during SSF of 20 g of pretreated biomass. The unwashed slurry showed to have a positive effect on SSF efficiency for the NaOH-pretreated biomass. Maximum efficiencies of glucan conversion to ethanol in the WIS were 40.43% and 41.03% for the H(2)SO(4)- and NaOH-pretreated biomasses, respectively.

Evaluation and Demonstration of Non-Hexavalent Chromium Pretreatments and Sealers for Steel Substrates

DTIC Science & Technology

2009-09-01

Commercially available Alternative Technologies Steel Pretreatments – Non chromium – Henkel NT-1 – Trivalent chromium – Surtec 650 TCP – Non- chromium ...UNCLASSIFIED: Approved for public release; distribution unlimited. Evaluation and Demonstration of Non-Hexavalent Chromium Pretreatments and...Hexavalent Chromium Pretreatments and Sealers for Steel Substrates 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d

Testing of alkaline and enzymatic hydrolysis pretreatments for fat particles in slaughterhouse wastewater.

PubMed

Masse, L; Kennedy, K J; Chou, S

2001-04-01

Four pretreatments to hydrolyse and/or reduce the size of fat particles in slaughterhouse wastewater (SHW) were tested: sodium hydroxide and three lipases of plant, bacterial and animal (pancreatic) origin. Hydrolysing agents and SHW containing between 2.5 and 3 g/l of fat particles were mixed at room temperature for 4 h. Additions of 5-400 meq NaOH/l did not increase soluble COD (SCOD) in SHW, but the average particle size was reduced to 73% +/- 7% of the initial average particle size (D(in)) at NaOH concentrations ranging from 150 to 300 meq/l. Pretreatment with pancreatic lipase PL-250 reduced the average particle size to a maximum of 60% +/- 3% of D(in). As D(in) was decreased from 359 to 68 microns, the enzyme concentration required to obtain the maximum particle size reduction increased from 200 to 1000 mg/l. A 4-h pretreatment with PL-250 also increased the free long-chain fatty acid (LCFA) concentration to a maximum of 15.5 mg/l, indicating some solubilization of the pork fat particles in SHW. SCOD was not significantly increased by the pretreatment, but SCOD was not found to be a good indicator of enzymatic lipolysis because of enzyme adsorption on the fat particle surface. Pancreatic lipase appeared more efficient with beef fat than pork fat, possibly because beef fat contains less polyunsaturated fatty acids than pork fat. The bacterial lipase LG-1000 was also efficient in reducing average fat particle size, but high doses (> 1000 mg/l) were required to obtain a significant reduction after 4 h of pretreatment. SCOD was not increased by pretreatment with LG-1000. No particle size reduction or changes in SCOD were noted after 4 h of pretreatment with the plant lipase EcoSystem Plus. It was concluded that PL-250 was the best pretreatment to hydrolyse fat particles in SHW. However, its impact on the efficiency of a downstream anaerobic digestion process remains to be tested.

Redox-sensitive shell-crosslinked polypeptide-block-polysaccharide micelles for efficient intracellular anticancer drug delivery.

PubMed

Zhang, Aiping; Zhang, Zhe; Shi, Fenghua; Xiao, Chunsheng; Ding, Jianxun; Zhuang, Xiuli; He, Chaoliang; Chen, Li; Chen, Xuesi

2013-09-01

Redox-responsive SCMs based on amphiphilic PBLG-b-dextran with good biocompatibility are synthesized and used for efficient intracellular drug delivery. The molecular structures and SCMs characteristics are characterized by (1) H NMR, FT-IR, TEM, and DLS. The hydrodynamic radius of SCMs increases gradually in PBS due to the cleavage of disulfide bond in micellar shell caused by the presence of GSH. The encapsulation efficiency and release kinetics of DOX are investigated. The fastest DOX release is observed under intracellular-mimicking reductive environments. An MTT assay demonstrates that DOX-loaded SCMs show higher cellular proliferation inhibition against GSH-OEt pretreated HeLa and HepG2 than that of the non-pretreated and BSO-pretreated ones. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood.

PubMed

Katsimpouras, Constantinos; Kalogiannis, Konstantinos G; Kalogianni, Aggeliki; Lappas, Angelos A; Topakas, Evangelos

2017-01-01

Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pretreatment method for removing lignin while producing less degradation products. The remaining enriched cellulose fraction has the potential to be utilized under high gravity enzymatic saccharification and fermentation processes for the cost-competing production of bioethanol. Beech wood residual biomass was pretreated following an acetone/water oxidation process aiming at the production of high concentration of cellulosic ethanol. The effect of pressure, reaction time, temperature, and acetone-to-water ratio on the final composition of the pretreated samples was studied for the efficient utilization of the lignocellulosic feedstock. The optimal conditions were acetone/water ratio 1:1, 40 atm initial pressure of 40 vol% O 2 gas, and 64 atm at reaction temperature of 175 °C for 2 h incubation. The pretreated beech wood underwent an optimization step studying the effect of enzyme loading and solids content on the enzymatic liquefaction/saccharification prior to fermentation. In a custom designed free-fall mixer at 50 °C for either 6 or 12 h of prehydrolysis using an enzyme loading of 9 mg/g dry matter at 20 wt% initial solids content, high ethanol concentration of 75.9 g/L was obtained. The optimization of the pretreatment process allowed the efficient utilization of beech wood residual biomass for the production of high concentrations of cellulosic ethanol, while obtaining lignin that can be upgraded towards high-added-value chemicals. The threshold of 4 wt% ethanol concentration that is required for the sustainable bioethanol production was surpassed almost twofold, underpinning the efficient conversion of biomass to ethanol and bio-based chemicals on behalf of the biorefinery concept.

Mapping the lignin distribution in pretreated sugarcane bagasse by confocal and fluorescence lifetime imaging microscopy

PubMed Central

2013-01-01

Background Delignification pretreatments of biomass and methods to assess their efficacy are crucial for biomass-to-biofuels research and technology. Here, we applied confocal and fluorescence lifetime imaging microscopy (FLIM) using one- and two-photon excitation to map the lignin distribution within bagasse fibers pretreated with acid and alkali. The evaluated spectra and decay times are correlated with previously calculated lignin fractions. We have also investigated the influence of the pretreatment on the lignin distribution in the cell wall by analyzing the changes in the fluorescence characteristics using two-photon excitation. Eucalyptus fibers were also analyzed for comparison. Results Fluorescence spectra and variations of the decay time correlate well with the delignification yield and the lignin distribution. The decay dependences are considered two-exponential, one with a rapid (τ1) and the other with a slow (τ2) decay time. The fastest decay is associated to concentrated lignin in the bagasse and has a low sensitivity to the treatment. The fluorescence decay time became longer with the increase of the alkali concentration used in the treatment, which corresponds to lignin emission in a less concentrated environment. In addition, the two-photon fluorescence spectrum is very sensitive to lignin content and accumulation in the cell wall, broadening with the acid pretreatment and narrowing with the alkali one. Heterogeneity of the pretreated cell wall was observed. Conclusions Our results reveal lignin domains with different concentration levels. The acid pretreatment caused a disorder in the arrangement of lignin and its accumulation in the external border of the cell wall. The alkali pretreatment efficiently removed lignin from the middle of the bagasse fibers, but was less effective in its removal from their surfaces. Our results evidenced a strong correlation between the decay times of the lignin fluorescence and its distribution within the cell wall. A new variety of lignin fluorescence states were accessed by two-photon excitation, which allowed an even broader, but complementary, optical characterization of lignocellulosic materials. These results suggest that the lignin arrangement in untreated bagasse fiber is based on a well-organized nanoenvironment that favors a very low level of interaction between the molecules. PMID:23548159

Technologies for reducing sludge production in wastewater treatment plants: State of the art.

PubMed

Wang, Qilin; Wei, Wei; Gong, Yanyan; Yu, Qiming; Li, Qin; Sun, Jing; Yuan, Zhiguo

2017-06-01

This review presents the state-of-the-art sludge reduction technologies applied in both wastewater and sludge treatment lines. They include chemical, mechanical, thermal, electrical treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater treatment line, and physical, chemical and biological pretreatment in sludge treatment line. Emphasis was put on their effect on sludge reduction performance, with 10% sludge reduction to zero sludge production in wastewater treatment line and enhanced TS (total solids) or volatile solids removal of 5-40% in sludge treatment line. Free nitrous acid (FNA) technology seems good in wastewater treatment line but it is only under the lab-scale trial. In sludge treatment line, thermal, ultrasonic (<4400kJ/kg TS), FNA pretreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal pretreatment and TPAD are superior to other pretreatment technologies when pathogen inactivation is required. The new wastewater treatment processes including SANI®, high-rate activated sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce sludge production. In the future, an effort should be put on the effect of sludge reduction technologies on the removal of organic micropollutants and heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Wei, Xiaoliang; Xia, Gordon; Kirby, Brent W.

Aiming to explore low-cost redox flow battery systems, a novel iron-polysulfide (Fe/S) flow battery has been demonstrated in a laboratory cell. This system employs alkali metal ferri/ferrocyanide and alkali metal polysulfides as the redox electrolytes. When proper electrodes, such as pretreated graphite felts, are used, 78% energy efficiency and 99% columbic efficiency are achieved. The remarkable advantages of this system over current state-of-the-art redox flow batteries include: 1) less corrosive and relatively environmentally benign redox solutions used; 2) excellent energy and utilization efficiencies; 3) low cost for redox electrolytes and cell components. These attributes can lead to significantly reduced capitalmore » cost and make the Fe/S flow battery system a promising low-cost energy storage technology. The major drawbacks of the present cell design are relatively low power density and possible sulfur species crossover. Further work is underway to address these concerns.« less

Evaluation of electricity generation from ultrasonic and heat/alkaline pretreatment of different sludge types using microbial fuel cells.

PubMed

Oh, Sang-Eun; Yoon, Joung Yee; Gurung, Anup; Kim, Dong-Jin

2014-08-01

This study investigated the effects of different sludge pretreatment methods (ultrasonic vs. combined heat/alkali) with varied sources of municipal sewage sludge (primary sludge (PS), secondary excess sludge (ES), anaerobic digestion sludge (ADS)) on electricity generation in microbial fuel cells (MFCs). Introduction of ultrasonically pretreated sludge (PS, ES, ADS) to MFCs generated maximum power densities of 13.59, 9.78 and 12.67mW/m(2) and soluble COD (SCOD) removal efficiencies of 87%, 90% and 57%, respectively. The sludge pretreated by combined heat/alkali (0.04N NaOH at 120°C for 1h) produced maximum power densities of 10.03, 5.21 and 12.53mW/m(2) and SCOD removal efficiencies of 83%, 75% and 74% with PS, ES and ADS samples, respectively. Higher SCOD by sludge pretreatment enhanced performance of the MFCs and the electricity generation was linearly proportional to the SCOD removal, especially for ES. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of microwave-assisted pretreatment of lignocellulosic biomass immersed in alkaline glycerol for fermentable sugars production.

PubMed

Diaz, Ana Belen; Moretti, Marcia Maria de Souza; Bezerra-Bussoli, Carolina; Carreira Nunes, Christiane da Costa; Blandino, Ana; da Silva, Roberto; Gomes, Eleni

2015-06-01

A pretreatment with microwave irradiation was applied to enhance enzyme hydrolysis of corn straw and rice husk immersed in water, aqueous glycerol or alkaline glycerol. Native and pretreated solids underwent enzyme hydrolysis using the extract obtained from the fermentation of Myceliophthora heterothallica, comparing its efficiency with that of the commercial cellulose cocktail Celluclast®. The highest saccharification yields, for both corn straw and rice husk, were attained when biomass was pretreated in alkaline glycerol, method that has not been previously reported in literature. Moreover, FTIR, TG and SEM analysis revealed a more significant modification in the structure of corn straw subjected to this pretreatment. Highest global yields were attained with the crude enzyme extract, which might be the result of its content in a great variety of hydrolytic enzymes, as revealed zymogram analysis. Moreover, its hydrolysis efficiency can be improved by its supplementation with commercial β-glucosidase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of pretreatment, enzymatic hydrolysis and fermentation for more efficient ethanol production by Jerusalem artichoke stalk.

PubMed

Li, Kai; Qin, Jin-Cheng; Liu, Chen-Guang; Bai, Feng-Wu

2016-12-01

Jerusalem artichoke (JA) is a potential energy crop for biorefinery due to its unique agronomic traits such as resistance to environmental stresses and high biomass yield in marginal lands. Although JA tubers have been explored for inulin extraction and biofuels production, there is little concern on its stalk (JAS). In this article, the pretreatment of JAS by alkaline hydrogen peroxide was optimized using the response surface methodology to improve sugars yield and reduce chemicals usage. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the structures of the pretreated JAS to evaluate the effectiveness of the pretreatment. Furthermore, the feeding of the pretreated JAS and cellulase was performed for high solid uploading (up to 30%) to increase ethanol titer, and simultaneous saccharification and fermentation with 55.6g/L ethanol produced, 36.5% more than that produced through separate hydrolysis and fermentation, was validated to be more efficient. Copyright © 2016 Elsevier Ltd. All rights reserved.

Low-Activity Waste Pretreatment System Additional Engineering-Scale Integrated Test Report

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

Landon, Matt R.; Wilson, Robert A.

Washington River Protections Solutions, LLC’s (WRPS) Low Activity Waste Pretreatment System (LAWPS) Project provides for the early production of immobilized low-activity waste (ILAW) by feeding LAW directly from Tank Farms to the Waste Treatment and Immobilization Plant (WTP) LAW Facility, bypassing the WTP Pretreatment Facility. Prior to the transfer of feed to the WTP LAW Vitrification Facility, tank supernatant waste will be pretreated in the LAWPS to meet the WTP LAW waste acceptance criteria (WAC). Full-scale and engineering-scale testing of critical technology elements, as part of the technology maturation process, are components of the overall LAWPS Project. WRPS awarded themore » engineering-scale integrated testing scope to AECOM via WRPS Subcontract 58349. This report is deliverable MSR-008 of the subcontract.« less

Comparative evaluation of acid and alkaline sulfite pretreatments for enzymatic saccharification of bagasses from three different sugarcane hybrids.

PubMed

Monte, Joseana R; Laurito-Friend, Debora F; Ferraz, André; Milagres, Adriane M F

2018-04-26

Sugarcane bagasses from three experimental sugarcane hybrids and a mill-reference sample were used to compare the efficiency and mode of action of acid and alkaline sulfite pretreatment processes. Varied chemical loads and reaction temperatures were used to prepare samples with distinguished characteristics regarding xylan and lignin removals, as well as sulfonation levels of residual lignins. The pretreatment with low sulfite loads (5%) under acidic conditions (pH 2) provided maximum glucose yield of 70% during enzymatic hydrolysis with cellulases (10 FPU/g) and β-glucosidases (20 UI/g bagasse). In this case, glucan enzymatic conversion from pretreated materials was mostly associated with extensive xylan removal (70-100%) and partial delignification occurred during the pretreatment. The use of low sulfite loads under acidic conditions required pretreatment temperatures of 160°C. In contrast, at a lower pretreatment temperature (120°C), alkaline sulfite process achieved similar glucan digestibility, but required a higher sulfite load (7.5%). Residual xylans from acid pretreated materials were almost completely hydrolysed by commercial enzymes, contrasting with relatively lower xylan to xylose conversions observed in alkaline pretreated samples. Efficient xylan removal during acid sulfite pretreatment and also during enzymatic digestion can be useful to enhance glucan accessibility and digestibility by cellulases. Alkaline sulfite process also provided substrates with high glucan digestibility, mainly associated with delignification and sulfonation of residual lignins. The results demonstrate that temperature, pH and sulfite can be combined for reducing lignocellulose recalcitrance and achieve similar glucan conversion rates in the alkaline and acid sulfite pretreated bagasses. This article is protected by copyright. All rights reserved. © 2018 American Institute of Chemical Engineers.

Effects and mechanism of ultrasound pretreatment on rapeseed protein enzymolysis.

PubMed

Jin, Jian; Ma, Haile; Wang, Weiwei; Luo, Min; Wang, Bei; Qu, Wenjuan; He, Ronghai; Owusu, John; Li, Yunliang

2016-03-15

The disadvantages which stem from the use of traditional enzymolysis of protein has necessitated the need to employ sweeping frequency and pulsed ultrasound (SFPU) in the pretreatment of rapeseed protein prior to proteolysis in order to bring about improvement in enzymolysis efficiency. Further, in order to determine the mechanism of ultrasound-accelerated enzymolysis of RP, the effects of SFPU on the kinetics, thermodynamics, molecular conformation and microstructure of RP were investigated. Kinetic studies showed that SFPU pretreatment on RP improved enzymolysis by decreasing the apparent constant KM significantly (P < 0.05) by 32.8% and reducing the thermodynamic parameters Ea , ΔH and ΔS by 16.6%, 17.7% and 9.2% respectively. Fluorescence spectra revealed that SFPU pretreatment induced molecular unfolding, causing more hydrophobic groups and regions inside the molecules to be exposed to the outside. Circular dichroism analysis indicated that SFPU pretreatment decreased the α-helix content by 16.1% and increased the random coil content by 3.6%. In addition, scanning electron microscopy showed that SFPU pretreatment increased the specific surface area of RP. Ultrasound pretreatment is an efficient method in RP proteolysis to produce peptides through its impact on the molecular conformation and microstructure of proteins. © 2015 Society of Chemical Industry.

Synergistic effect of UV pretreated Fe-ZSM-5 catalysts for heterogeneous catalytic complete oxidation of VOC: A technology development for sustainable use.

PubMed

Aziz, Abdul; Kim, Kwang Soo

2017-10-15

In this work, the performance of benzene, toluene, ethylbenzene, and xylene (BTEX) removal and degradation from gas, air streams on UV pretreated Fe-ZSM-5 in a batch reactor at room temperature were studied. The Fe-ZSM-5 zeolite catalyst was prepared by hydrothermal reaction method. The influence of UV pre-irradiation time on the removal of BTEX were assessed by varying the time, ranging from 15min to 60smin. Then, sustainability of the activation of the catalyst resulted by UV pretreatment was studied by the four-cycle experiment with one time UV irradiation and after each cycle irradiation followed by BTEX removal after every cycle respectively. The results of BTEX removal depicted that 30min of UV pretreatment was sufficient for complete organics removal. The UV pretreatment effect on the catalytic oxidation and the stability of the catalyst were studied by modern instrumental techniques. The novelty of the process was the sustainable reuse of catalyst with persistent VOC removal, which works on the -adsorption-oxidation-regeneration-adsorption- cycle, which was confirmed by the characterization studies of the catalyst after four runs. The results revealed that the change in the structure, stability, morphology, and removal efficiency of the catalyst during the experiments was negligible. The VOC degradation mechanism studies showed that the oxidation occurs due to the formation of free radicals as well as hydroxyl ions, so named it heterogeneous photo-Fenton oxidation. The residual materials analysis showed the complete mineralization of VOC except small amount of acetone as oxidation product. Lastly, the kinetics of the VOC removal was studied. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of microwave and conduction-convection heating autohydrolysis pretreatment for bioethanol production.

PubMed

Aguilar-Reynosa, Alejandra; Romaní, Aloia; Rodríguez-Jasso, Rosa M; Aguilar, Cristóbal N; Garrote, Gil; Ruiz, Héctor A

2017-11-01

This work describes the application of two forms of heating for autohydrolysis pretreatment on isothermal regimen: conduction-convection heating and microwave heating processing using corn stover as raw material for bioethanol production. Pretreatments were performed using different operational conditions: residence time (10-50 min) and temperature (160-200°C) for both pretreatments. Subsequently, the susceptibility of pretreated solids was studied using low enzyme loads, and high substrate loads. The highest conversion was 95.1% for microwave pretreated solids. Also solids pretreated by microwave heating processing showed better ethanol conversion in simultaneous saccharification and fermentation process (92% corresponding to 33.8g/L). Therefore, microwave heating processing is a promising technology in the pretreatment of lignocellulosic materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of different pre-treatment methods for the removal of limonene in citrus waste and their effect on methane potential and methane production rate.

PubMed

Ruiz, Begoña; de Benito, Amparo; Rivera, José Daniel; Flotats, Xavier

2016-12-01

The objective of this study was to assess the limonene removal efficiency of three pre-treatment methods when applied to citrus waste and to evaluate their effects on the biochemical methane potential and the methane production rate using batch anaerobic tests. The methods tested were based on removal (biological pretreatment by fungi) or recovery (steam distillation and ethanol extraction) of limonene. All the treatments decreased the concentration of limonene in orange peel, with average efficiencies of 22%, 44% and 100% for the biological treatment, steam distillation and ethanol extraction, respectively. By-products from limonene biodegradation by fungi exhibited an inhibitory effect also, not making interesting the biological pretreatment. The methane potential and production rate of the treated orange peel increased significantly after applying the recovery strategies, which separated and recovered simultaneously other inhibitory components of the citrus essential oil. Apart from the high recovery efficiency of the ethanol extraction process, it presented a favourable energy balance. © The Author(s) 2016.

Conversion Characteristics and Production Evaluation of Styrene/o-Xylene Mixtures Removed by DBD Pretreatment

PubMed Central

Jiang, Liying; Zhu, Runye; Mao, Yubo; Chen, Jianmeng; Zhang, Liang

2015-01-01

The combination of chemical oxidation methods with biotechnology to removal recalcitrant VOCs is a promising technology. In this paper, the aim was to identify the role of key process parameters and biodegradability of the degradation products using a dielectric barrier discharge (DBD) reactor, which provided the fundamental data to evaluate the possibilities of the combined system. Effects of various technologic parameters like initial concentration of mixtures, residence time and relative humidity on the decomposition and the degradation products were examined and discussed. It was found that the removal efficiency of mixed VOCs decreased with increasing initial concentration. The removal efficiency reached the maximum value as relative humidity was approximately 40%–60%. Increasing the residence time resulted in increasing the removal efficiency and the order of destruction efficiency of VOCs followed the order styrene > o-xylene. Compared with the single compounds, the removal efficiency of styrene and o-xylene in the mixtures of VOCs decreased significantly and o-xylene decreased more rapidly. The degradation products were analyzed by gas chromatography and gas chromatography-mass spectrometry, and the main compounds detected were O3, COx and benzene ring derivatives. The biodegradability of mixed VOCs was improved and the products had positive effect on biomass during plasma application, and furthermore typical results indicated that the biodegradability and biotoxicity of gaseous pollutant were quite depending on the specific input energy (SIE). PMID:25629961

Megasonic cleaning strategy for sub-10nm photomasks

NASA Astrophysics Data System (ADS)

Hsu, Jyh-Wei; Samayoa, Martin; Dress, Peter; Dietze, Uwe; Ma, Ai-Jay; Lin, Chia-Shih; Lai, Rick; Chang, Peter; Tuo, Laurent

2016-10-01

One of the main challenges in photomask cleaning is balancing particle removal efficiency (PRE) with pattern damage control. To overcome this challenge, a high frequency megasonic cleaning strategy is implemented. Apart from megasonic frequency and power, photomask surface conditioning also influences cleaning performance. With improved wettability, cleanliness is enhanced while pattern damage risk is simultaneously reduced. Therefore, a particle removal process based on higher megasonic frequencies, combined with proper surface pre-treatment, provides improved cleanliness without the unintended side effects of pattern damage, thus supporting the extension of megasonic cleaning technology into 10nm half pitch (hp) device node and beyond.

Removal of enzymatic and fermentation inhibitory compounds from biomass slurries for enhanced biorefinery process efficiencies.

PubMed

Gurram, Raghu N; Datta, Saurav; Lin, Yupo J; Snyder, Seth W; Menkhaus, Todd J

2011-09-01

Within the biorefinery paradigm, many non-monomeric sugar compounds have been shown to be inhibitory to enzymes and microbial organisms that are used for hydrolysis and fermentation. Here, two novel separation technologies, polyelectrolyte polymer adsorption and resin-wafer electrodeionization (RW-EDI), have been evaluated to detoxify a dilute acid pretreated biomass slurry. Results showed that detoxification of a dilute acid pretreated ponderosa pine slurry by sequential polyelectrolyte and RW-EDI treatments was very promising, with significant removal of acetic acid, 5-hydroxymethyl furfural, and furfural (up to 77%, 60%, and 74% removed, respectively) along with >97% removal of sulfuric acid. Removal of these compounds increased the cellulose conversion to 94% and elevated the hydrolysis rate to 0.69 g glucose/L/h. When using Saccharomyces cerevisiae D(5)A for fermentation of detoxified slurry, the process achieved 99% of the maximum theoretical ethanol yield and an ethanol production rate nearly five-times faster than untreated slurry. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

NASA Astrophysics Data System (ADS)

Duarte, C. L.; Ribeiro, M. A.; Oikawa, H.; Mori, M. N.; Napolitano, C. M.; Galvão, C. A.

2012-08-01

The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH.

Impact of physical pre-treatment of source-sorted organic fraction of municipal solid waste on greenhouse-gas emissions and the economy in a Swedish anaerobic digestion system.

PubMed

Carlsson, My; Holmström, David; Bohn, Irene; Bisaillon, Mattias; Morgan-Sagastume, Fernando; Lagerkvist, Anders

2015-04-01

Several methods for physical pre-treatments of source sorted organic fraction of municipal solid waste (SSOFMSW) before for anaerobic digestion (AD) are available, with the common feature that they generate a homogeneous slurry for AD and a dry refuse fraction for incineration. The selection of efficient methods relies on improved understanding of how the pre-treatment impacts on the separation and on the slurry's AD. The aim of this study was to evaluate the impact of the performance of physical pre-treatment of SSOFMSW on greenhouse-gas (GHG) emissions and on the economy of an AD system including a biogas plant with supplementary systems for heat and power production in Sweden. Based on the performance of selected Swedish facilities, as well as chemical analyses and BMP tests of slurry and refuse, the computer-based evaluation tool ORWARE was improved as to accurately describe mass flows through the physical pre-treatment and anaerobic degradation. The environmental and economic performance of the evaluated system was influenced by the TS concentration in the slurry, as well as the distribution of incoming solids between slurry and refuse. The focus to improve the efficiency of these systems should primarily be directed towards minimising the water addition in the pre-treatment provided that this slurry can still be efficiently digested. Second, the amount of refuse should be minimised, while keeping a good quality of the slurry. Electricity use/generation has high impact on GHG emissions and the results of the study are sensitive to assumptions of marginal electricity and of electricity use in the pre-treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Pilot-scale cultivation of Spirulina plantensis with digested piggery wastewater ].

PubMed

Guo, Qing-qing; Liu, Rui; Luo, Jin-fei; Wang, Gen-rong; Chen, Lii-jun; Liu, Xiao

2014-09-01

The swine waste pretreated with coagulation sedimentation was used for the outdoor pilot-scale cultivation of Spirulina platensis isolated from digested piggery wastewater (DPW) in a raceway pond. The growth of S. platensis and removal of nitrogen/ phosphorus were studied, moreover, the conversion efficiency of total nitrogen (TN) or total phosphorus (TP) from DPW to S. platensis was calculated. On this basis, the existing problems and countermeasures during outdoor pilot-scale culture were analyzed and summarized combined with the laboratory research. We conducted 6 batches culture experiments, only 3 of which could reach the S. platensis harvest requirements (D560 >0. 8). Meanwhile, the 3 successful batches achieved removal of COD, ammonia nitrogen, TN, TP with corresponding 28. 6% -48. 5% , 0.4% -48. 5% , 41. 8% -48. 6% , 14. 3% -94. 5% , and the conversion efficiency of TN or TP from DPW to S. platensis reached 12. 1% -98. 5% , 21.2% -83.7% , respectively. High concentration of ammonia nitrogen and insect attack of remaining egg hatching in the pretreated swine waste were the main factors to cause the slow-growing of the 3 batches of S. platensis. Therefore, it is highly necessary for the removal of ammonia nitrogen with biological treatment technology and insect eggs with membrane to achieve a stable high productivity.

Enhancing the ecological and operational characteristics of water treatment units at TPPs based on baromembrane technologies

NASA Astrophysics Data System (ADS)

Chichirova, N. D.; Chichirov, A. A.; Filimonova, A. A.; Saitov, S. R.

2017-12-01

The innovative baromembrane technologies for water demineralization were introduced at Russian TPPs more than 25 years ago. While being used in the power engineering industry of Russia, these technologies demonstrated certain advantages over the traditional ion-exchange and thermal technologies of makeup water treatment for steam boilers. Water treatment units based on the baromembrane technology are compact, easy to operate, and highly automated. The experience gained from the use of these units shows that their reliability depends directly on preliminary water treatment. The popular water pretreatment technology with coagulation by aluminum oxychloride proved to be inefficient during the seasonal changes of source water quality that occurs at some stations. The use of aluminum coagulant at pH 8 and higher does not ensure the stable and qualitative pretreatment regime: soluble aluminum forms slip on membranes of the ultrafiltration unit, thereby causing pollution and intoxication as well as leading to structural damages or worsening of mechanical properties of the membranes. The problem of increased pH and seasonal changes of the source water quality can be solved by substitution of the traditional coagulant into a new one. To find the most successful coagulant for water pretreatment, experiments have been performed on both qualitative and quantitative analysis of the content of natural organic matters in the Volga water and their structure. We have developed a software program and measured the concentrations of soluble aluminum and iron salts at different pH values of the source water. The analysis of the obtained results has indicated that iron sulfate at pH 6.0-10.2, in contrast to aluminum oxychloride, is not characterized by increased solubility. Thus, the basic process diagrams of water pretreatment based on baromembrane technologies with pretreatment through coagulation by iron salts and wastewater amount reducing from 60-40 to 5-2% have been introduced for thermal power stations.

Study on methenamine detection in starch products through SERS technology

NASA Astrophysics Data System (ADS)

Cui, Yu; Qu, Zhou

2016-01-01

Using silver sol as a strengthened base, this paper concludes that l0ppb-0.1ppb methenamine aqueous solution has a better signal in 1052cm-1 Raman feature. And the lower limit of the aqueous solution is about 0.1ppb. Adding corresponding amount methenamine in vermicelli sample, the lower limit is about 10ppm. This is a safest and pollution-free detection process. Furthermore, the pretreatment process is simple, which will be finished in 20 minutes. Hence, it is better than other detection methods. SERS technology provides a simple, rapid and efficient detection method for field measurement and real time detection modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

Disintegration in the biogas sector--technologies and effects.

PubMed

Schumacher, Britt; Wedwitschka, Harald; Hofmann, Josephine; Denysenko, Velina; Lorenz, Helge; Liebetrau, Jan

2014-09-01

Pretreatment of organic material prior to anaerobic digestion is seen as an option to increase the overall efficiency of the process. An overview of physical, chemical, and biological disintegration (DT) of substrates in the biogas sector is given. The energy demands DT were surveyed. The technologies were evaluated by reference to the Technology Readiness Assessment Guide of the U.S. Department of Energy. The evaluation focuses on ligno-cellulosic substrates like straw. Data of a survey among biogas plant operators were analyzed regarding the prevalence of disintegration technology classes in Germany. Furthermore, biochemical methane potential tests were conducted in laboratory scale to determine the specific methane yields of un-/treated barley straw (thermal pressure hydrolysis (TPH)). A methane potential of 228 ml CH4/g VS was measured for untreated barley straw; and of 251 ml CH4/g VS for TPH-straw (190 °C, 30 min). The reaction rates in BMP were calculated between 0.0976 and 0.1443 d(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Phosphomolybdic acid and ferric iron as efficient electron mediators for coupling biomass pretreatment to produce bioethanol and electricity generation from wheat straw

Treesearch

Yi Ding; Bo Du; Xuebing Zhao; J.Y. Zhu; Dehua Liu

2017-01-01

Phosphomolybdic acid (PMo12) was used as an electron mediator and proton carrier to mediate biomass pretreatment for ethanol production and electricity generation from wheat straw. In the pretreatment, lignin was oxidized anaerobically by PMo12 with solubilization of a fraction of hemicelluloses, and the PMo12...

On energy consumption for size-reduction and yields from subsequent enzymatic saccharification of pretreated lodgepole pine

Treesearch

W. Zhu; Junyong Zhu; Roland Gleisner; X.J. Pan

2010-01-01

This study investigated the effects of chemical pretreatment and disk-milling conditions on energy consumption for size-reduction and the efficiency of enzymatic cellulose saccharification of a softwood. Lodgepole pine wood chips produced from thinnings of a 100-year-old unmanaged forest were pretreated by hot-water, dilute-acid, and two SPORL processes (Sulfite...

Detoxification of Corncob Acid Hydrolysate with SAA Pretreatment and Xylitol Production by Immobilized Candida tropicalis

PubMed Central

Deng, Li-Hong; Tang, Yong; Liu, Yun

2014-01-01

Xylitol fermentation production from corncob acid hydrolysate has become an attractive and promising process. However, corncob acid hydrolysate cannot be directly used as fermentation substrate owing to various inhibitors. In this work, soaking in aqueous ammonia (SAA) pretreatment was employed to reduce the inhibitors in acid hydrolysate. After detoxification, the corncob acid hydrolysate was fermented by immobilized Candida tropicalis cell to produce xylitol. Results revealed that SAA pretreatment showed high delignification and efficient removal of acetyl group compounds without effect on cellulose and xylan content. Acetic acid was completely removed, and the content of phenolic compounds was reduced by 80%. Furthermore, kinetic behaviors of xylitol production by immobilized C. tropicalis cell were elucidated from corncob acid hydrolysate detoxified with SAA pretreatment and two-step adsorption method, respectively. The immobilized C. tropicalis cell showed higher productivity efficiency using the corncob acid hydrolysate as fermentation substrate after detoxification with SAA pretreatment than by two-step adsorption method in the five successive batch fermentation rounds. After the fifth round fermentation, about 60 g xylitol/L fermentation substrate was obtained for SAA pretreatment detoxification, while about 30 g xylitol/L fermentation substrate was obtained for two-step adsorption detoxification. PMID:25133211

Pretreatment on Miscanthus lutarioriparious by liquid hot water for efficient ethanol production

PubMed Central

2013-01-01

Background The C4 perennial grass Miscanthus giganteus has proved to be a promising bio-energy crop. However, the biomass recalcitrance is a major challenge in biofuel production. Effective pretreatment is necessary for achieving a high efficiency in converting the crop to fermentable sugars, and subsequently biofuels and other valued products. Results Miscanthus lutarioriparious was pretreated with a liquid hot water (LHW) reactor. Between the pretreatment severity (PS) of 2.56-4.71, the solid recovery was reduced; cellulose recovery remained nearly unchanged; and the Klason lignin content was slightly increased which was mainly due to the dissolving of hemicellulose and the production of a small amount of pseudo-lignin. The result shows that a LHW PS of 4.71 could completely degrade the hemicellulose in Miscanthus. Hemicellulose removal dislodged the enzymatic barrier of cellulose, and the ethanol conversion of 98.27% was obtained. Conclusions Our study demonstrated that LHW served as an effective pretreatment in case that Miscanthus lutarioriparious was used for ethanol production by simultaneous saccharification and fermentation. The combination and the pretreatment method of Miscanthus feedstock holds a great potential for biofuel production. PMID:23663476

Surfactant assisted disperser pretreatment on the liquefaction of Ulva reticulata and evaluation of biodegradability for energy efficient biofuel production through nonlinear regression modelling.

PubMed

Kumar, M Dinesh; Tamilarasan, K; Kaliappan, S; Banu, J Rajesh; Rajkumar, M; Kim, Sang Hyoun

2018-05-01

The present study aimed to increase the disintegration potential of marine macroalgae, (Ulva reticulata) through chemo mechanical pretreatment (CMP) in an energy efficient manner. By combining surfactant with disperser, the specific energy input was considerably reduced from 437.1 kJ/kg TS to 264.9 kJ/kg TS to achieve 10.7% liquefaction. A disperser rpm (10,000), pretreatment time (30 min) and tween 80 dosage (21.6 mg/L) were considered as an optimum for effective liquefaction of algal biomass. CMP was designated as an appropriate pretreatment resulting in a higher soluble organic release 1250 mg/L, respectively. Anaerobic fermentation results revealed that the volatile fatty acid (VFA) concentration was doubled (782 mg/L) in CMP when compared to mechanical pretreatment (MP) (345 mg/L). CMP pretreated algal biomass was considered as the suitable for biohydrogen production with highest H 2 yield of about 63 mL H 2 /g COD than (MP) (45 mL H 2 /g COD) and control (10 mL H 2 /g COD). Copyright © 2018 Elsevier Ltd. All rights reserved.

Reduction of the "burst release" of copper ions from copper-based intrauterine devices by organic inhibitors.

PubMed

Alvarez, Florencia; Schilardi, Patricia L; de Mele, Monica Fernández Lorenzo

2012-01-01

The copper intrauterine device is a contraceptive method that is based on the release of copper ions from a copper wire. Immediately after insertion, the dissolution of copper in the uterine fluid is markedly higher ("burst release") than that necessary for contraception action, leading to a variety of harmful effects. Pretreatments with organic compounds [thiourea (TU) and purine (PU), 10(-4)-10(-2) M concentration range, 1- and 3-h immersion times] were tested. The dissolution of copper with and without pretreatments in TU and PU solutions was analyzed by conventional electrochemical techniques and surface analysis. Pretreatments in PU solutions reduced the initial corrosion rate of copper in simulated uterine solutions, with inhibitory efficiencies that depend on the PU concentration and on the immersion time assayed. Inhibitory efficiency values higher than 98% for pretreatments with ≥10(-3) M PU were found. Conversely, after TU pretreatments, a high copper release was measured. It was concluded that 10(-3) M PU pretreatment is a promising strategy able to reduce the "burst release" of copper and to ensure contraceptive action. Copyright © 2012 Elsevier Inc. All rights reserved.

Assessment of microbial viability in municipal sludge following ultrasound and microwave pretreatments and resulting impacts on the efficiency of anaerobic sludge digestion.

PubMed

Cella, Monica Angela; Akgul, Deniz; Eskicioglu, Cigdem

2016-03-01

A range of ultrasonication (US) and microwave irradiation (MW) sludge pretreatments were compared to determine the extent of cellular destruction in micro-organisms within secondary sludge and how this cellular destruction translated to anaerobic digestion (AD). Cellular lysis/inactivation was measured using two microbial viability assays, (1) Syto 16® Green and Sytox® Orange counter-assay to discern the integrity of cellular membranes and (2) a fluorescein diacetate assay to understand relative enzymatic activity. A range of MW intensities (2.17-6.48 kJ/g total solids or TS, coinciding temperatures of 60-160 °C) were selected for comparison via viability assays; a range of corresponding US intensities (2.37-27.71 kJ/g TS, coinciding sonication times of 10-60 min at different amplitudes) were also compared to this MW range. The MW pretreatment of thickened waste activated sludge (tWAS) caused fourfold to fivefold greater cell death than non-pretreated and US-pretreated tWAS. The greatest microbial destruction occurred at MW intensities greater than 2.62 kJ/g TS of sludge, after which increased energy input via MW did not appear to cause greater microbial death. In addition, the optimal MW pretreatment (80 °C, 2.62 kJ/g TS) and corresponding US pretreatment (10 min, 60 % amplitude, 2.37 kJ/g TS) were administered to the tWAS of a mixed sludge and fed to anaerobic digesters over sludge retention times (SRTs) of 20, 14, and 7 days to compare effects of feed pretreatment on AD efficiency. The digester utilizing MW-pretreated tWAS (80 °C, 2.62 kJ/g TS) had the greatest fecal coliform removal (73.4 and 69.8 % reduction, respectively), greatest solids removal (44.2 % TS reduction), and highest overall methane production (248.2 L CH4/kg volatile solids) at 14- and 7-day SRTs. However, despite the fourfold to fivefold increases in cell death upon pretreatment, improvements from the digester fed MW-pretreated sludge were marginal (i.e., increases in efficiency of less than 3-10 %) and likely due to a smaller proportion of cells (10-20 %) in the polymeric network and mixed sludge fed to digesters.

Multi-scale processes of beech wood disintegration and pretreatment with 1-ethyl-3-methylimidazolium acetate/water mixtures.

PubMed

Viell, Jörn; Inouye, Hideyo; Szekely, Noemi K; Frielinghaus, Henrich; Marks, Caroline; Wang, Yumei; Anders, Nico; Spiess, Antje C; Makowski, Lee

2016-01-01

The valorization of biomass for chemicals and fuels requires efficient pretreatment. One effective strategy involves the pretreatment with ionic liquids which enables enzymatic saccharification of wood within a few hours under mild conditions. This pretreatment strategy is, however, limited by water and the ionic liquids are rather expensive. The scarce understanding of the involved effects, however, challenges the design of alternative pretreatment concepts. This work investigates the multi length-scale effects of pretreatment of wood in 1-ethyl-3-methylimidazolium acetate (EMIMAc) in mixtures with water using spectroscopy, X-ray and neutron scattering. The structure of beech wood is disintegrated in EMIMAc/water mixtures with a water content up to 8.6 wt%. Above 10.7 wt%, the pretreated wood is not disintegrated, but still much better digested enzymatically compared to native wood. In both regimes, component analysis of the solid after pretreatment shows an extraction of few percent of lignin and hemicellulose. In concentrated EMIMAc, xylan is extracted more efficiently and lignin is defunctionalized. Corresponding to the disintegration at macroscopic scale, SANS and XRD show isotropy and a loss of crystallinity in the pretreated wood, but without distinct reflections of type II cellulose. Hence, the microfibril assembly is decrystallized into rather amorphous cellulose within the cell wall. The molecular and structural changes elucidate the processes of wood pretreatment in EMIMAc/water mixtures. In the aqueous regime with >10.7 wt% water in EMIMAc, xyloglucan and lignin moieties are extracted, which leads to coalescence of fibrillary cellulose structures. Dilute EMIMAc/water mixtures thus resemble established aqueous pretreatment concepts. In concentrated EMIMAc, the swelling due to decrystallinization of cellulose, dissolution of cross-linking xylan, and defunctionalization of lignin releases the mechanical stress to result in macroscopic disintegration of cells. The remaining cell wall constituents of lignin and hemicellulose, however, limit a recrystallization of the solvated cellulose. These pretreatment mechanisms are beyond common pretreatment concepts and pave the way for a formulation of mechanistic requirements of pretreatment with simpler pretreatment liquors.

Biochemical degradation and physical migration of polyphenolic compounds in osmotic dehydrated blueberries with pulsed electric field and thermal pretreatments.

PubMed

Yu, Yuanshan; Jin, Tony Z; Fan, Xuetong; Wu, Jijun

2018-01-15

Fresh blueberries were pretreated by pulsed electric fields (PEF) or thermal pretreatment and then were subject to osmotic dehydration. The changes in contents of anthocyanins, predominantly phenolic acids and flavonols, total phenolics, polyphenol oxidase (PPO) activity and antioxidant activity in the blueberry samples during pretreatment and osmotic dehydration were investigated. Biochemical degradation and physical migration of these nutritive compounds from fruits to osmotic solutions were observed during the pretreatments and osmotic dehydration. PEF pretreated samples had the least degradation loss but the most migration loss of these compounds compared to thermally pretreated and control samples. Higher rates of water loss and solid gain during osmotic dehydration were also obtained by PEF pretreatment, reducing the dehydration time from 130 to 48h. PEF pretreated and dehydrated fruits showed superior appearance to thermally pretreated and control samples. Therefore, PEF pretreatment is a preferred technology that balances nutritive quality, appearance, and dehydration rate. Published by Elsevier Ltd.

VOCs elimination and health risk reduction in e-waste dismantling workshop using integrated techniques of electrostatic precipitation with advanced oxidation technologies.

PubMed

Chen, Jiangyao; Huang, Yong; Li, Guiying; An, Taicheng; Hu, Yunkun; Li, Yunlu

2016-01-25

Volatile organic compounds (VOCs) emitted during the electronic waste dismantling process (EWDP) were treated at a pilot scale, using integrated electrostatic precipitation (EP)-advanced oxidation technologies (AOTs, subsequent photocatalysis (PC) and ozonation). Although no obvious alteration was seen in VOC concentration and composition, EP technology removed 47.2% of total suspended particles, greatly reducing the negative effect of particles on subsequent AOTs. After the AOT treatment, average removal efficiencies of 95.7%, 95.4%, 87.4%, and 97.5% were achieved for aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, as well as nitrogen- and oxygen-containing compounds, respectively, over 60-day treatment period. Furthermore, high elimination capacities were also seen using hybrid technique of PC with ozonation; this was due to the PC unit's high loading rates and excellent pre-treatment abilities, and the ozonation unit's high elimination capacity. In addition, the non-cancer and cancer risks, as well as the occupational exposure cancer risk, for workers exposed to emitted VOCs in workshop were reduced dramatically after the integrated technique treatment. Results demonstrated that the integrated technique led to highly efficient and stable VOC removal from EWDP emissions at a pilot scale. This study points to an efficient approach for atmospheric purification and improving human health in e-waste recycling regions. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparative biochemical analysis after steam pretreatment of lignocellulosic agricultural waste biomass from Williams Cavendish banana plant (Triploid Musa AAA group).

PubMed

Kamdem, Irénée; Jacquet, Nicolas; Tiappi, Florian Mathias; Hiligsmann, Serge; Vanderghem, Caroline; Richel, Aurore; Jacques, Philippe; Thonart, Philippe

2015-11-01

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on six combined morphological parts of Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82 ± 3.51 and 49.78 ± 1.39%w/w WCLB dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56 ± 1.33%w/w DM) and SFSC180 (44.47 ± 0.00%w/w DM), while the lowest was found in unpretreated WCLB (22.70 ± 0.71%w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2%w/w of the LF DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210 °C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerization, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors, such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210, were the highest (41 and 21 µg ml(-1), respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments. © The Author(s) 2015.

Lactic acid production from Sophora flavescens residues pretreated with sodium hydroxide: Reutilization of the pretreated liquor during fermentation.

PubMed

Wang, Juan; Gao, Ming; Liu, Jianguo; Wang, Qunhui; Wang, Cong; Yin, Zihe; Wu, Chuanfu

2017-10-01

The feasibility of lactic acid production from Sophora flavescens residues (SFRs) pretreated with sodium hydroxide with the reutilization of the pretreated liquor during fermentation was investigated. After sodium hydroxide pretreatment, 67.5% of the lignin was removed, and hydrolysis efficiency increased from 37.3% to 79.2%. The reutilization of pretreated liquor at 50% loading during open fermentation of unwashed SFR increased lactic acid production by 34.1%. The pretreated liquor acted as pH buffer and resulted in stable pH and high cellulase activity during fermentation. Inhibitors in the pretreated liquor did not affect the growth of lactic acid bacteria but severely inhibited the growth of ethanol-producing yeast. Consequently, lactic acid production increased and ethanol production was zero at 50% loading. Water consumption during pretreatment and fermentation with 50% pretreated liquor was 1.341L per 100g SFR, which was 67.6% lower than that during fermentation with washed SFR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pretreatment of corn straw using the alkaline solution of ionic liquids.

PubMed

Liu, Zhen; Li, Longfei; Liu, Cheng; Xu, Airong

2018-07-01

In the present work, the pretreatment of corn stalk with the solution of 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) ionic liquid containing NaOH was explored for its lignin removal. The effects of reaction temperature, reaction time, and solid-liquid ratio on the lignin removal efficiency were determined by the response surface methodology (RSM). The pretreatment conditions were optimized by the Box-Behnken design and the comparative study of the composition and structure of corn straw before and after the pretreatment to be: reaction temperature 98.5 °C, reaction time 1.31 h, and solid-liquid ratio 1:8.7. Under the optimized conditions, the cellulose and hemicellulose contents of the corn straw were increased to 85.69% and 9.1%, respectively, and the lignin content was reduced to 2.27% with the lignin removal efficiency up to 87.4%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA.

PubMed

Kavitha, S; Adish Kumar, S; Yogalakshmi, K N; Kaliappan, S; Rajesh Banu, J

2013-12-01

In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2 g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ball milling pretreatment of corn stover for enhancing the efficiency of enzymatic hydrolysis.

PubMed

Lin, Zengxiang; Huang, He; Zhang, Hongman; Zhang, Lin; Yan, Lishi; Chen, Jingwen

2010-11-01

Ethanol can be produced from lignocellulosic biomass with the usage of ball milling pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields from lignocellulosic feed stocks are critical parameters for ethanol production process. The research results from this paper indicated that the yields of glucose and xylose were improved by adding any of the following dilute chemical reagents: H(2)SO(4), HCl, HNO(3), CH(3)COOH, HCOOH, H(3)PO(4), and NaOH, KOH, Ca(OH)(2), NH(3)·H(2)O in the ball milling pretreatment of corn stover. The optimal enzymatic hydrolysis efficiencies were obtained under the conditions of ball milling in the alkali medium that was due to delignification. The data also demonstrated that ball milling pretreatment was a robust process. From the microscope image of ball milling-pretreated corn stover, it could be observed that the particle size of material was decreased and the fiber structure was more loosely organized. Meanwhile, the results indicate that the treatment effect of wet milling is better than that of dry milling. The optimum parameters for the milling process were ball speed of 350 r/min, solid/liquid ratio of 1:10, raw material particle size with 0.5 mm, and number of balls of 20 (steel ball, Φ = 10 mm), grinding for 30 min. In comparison with water milling process, alkaline milling treatment could increase the enzymatic hydrolysis efficiency of corn stover by 110%; and through the digestion process with the combination of xylanase and cellulase mixture, the hydrolysis efficiency could increase by 160%.

Over production of fermentable sugar for bioethanol production from carbohydrate-rich Malaysian food waste via sequential acid-enzymatic hydrolysis pretreatment.

PubMed

Hafid, Halimatun Saadiah; Nor 'Aini, Abdul Rahman; Mokhtar, Mohd Noriznan; Talib, Ahmad Tarmezee; Baharuddin, Azhari Samsu; Umi Kalsom, Md Shah

2017-09-01

In Malaysia, the amount of food waste produced is estimated at approximately 70% of total municipal solid waste generated and characterised by high amount of carbohydrate polymers such as starch, cellulose, and sugars. Considering the beneficial organic fraction contained, its utilization as an alternative substrate specifically for bioethanol production has receiving more attention. However, the sustainable production of bioethanol from food waste is linked to the efficient pretreatment needed for higher production of fermentable sugar prior to fermentation. In this work, a modified sequential acid-enzymatic hydrolysis process has been developed to produce high concentration of fermentable sugars; glucose, sucrose, fructose and maltose. The process started with hydrothermal and dilute acid pretreatment by hydrochloric acid (HCl) and sulphuric acid (H 2 SO 4 ) which aim to degrade larger molecules of polysaccharide before accessible for further steps of enzymatic hydrolysis by glucoamylase. A kinetic model is proposed to perform an optimal hydrolysis for obtaining high fermentable sugars. The results suggested that a significant increase in fermentable sugar production (2.04-folds) with conversion efficiency of 86.8% was observed via sequential acid-enzymatic pretreatment as compared to dilute acid pretreatment (∼42.4% conversion efficiency). The bioethanol production by Saccharomyces cerevisiae utilizing fermentable sugar obtained shows ethanol yield of 0.42g/g with conversion efficiency of 85.38% based on the theoretical yield was achieved. The finding indicates that food waste can be considered as a promising substrate for bioethanol production. Copyright © 2017. Published by Elsevier Ltd.

Joint DoD Demonstration And Validation Of Magnesium-Rich Primer Coating Technology

DTIC Science & Technology

2012-01-01

Recovery Act SCE .....................................Standard Calomel Electrode xi TCP ..................................... Trivalent Chromium ...8 performed the best, followed by trivalent chromium pretreatment (TCP), with the panel that did not receive any chemical pretreatment performing...Abraded) MIL-DTL-81706 Type II – Trivalent Chromium (Alodine T5900) MIL-DTL-81706 Type I – Hexavalent Chromium No Chemical Pretreatment MIL-DTL-81706

Ethanol production from SPORL-pretreated lodgepole pine : preliminary evaluation of mass balance and process energy efficiency

Treesearch

Junyong Zhu; Wenyuan Zhu; Patricia OBryan; Bruce S. Dien; Shen Tian; Roland Gleisner; X.J. Pan

2010-01-01

Lodgepole pine from forest thinnings is a potential feedstock for ethanol production. In this study, lodgepole pine was converted to ethanol with a yield of 276 L per metric ton of wood or 72% of theoretical yield. The lodgepole pine chips were directly subjected to sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) pretreatment and then disk-...

Low-energy biomass pretreatment with deep eutectic solvents for bio-butanol production.

PubMed

Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Rehmann, Lars; Marzocchella, Antonio

2017-11-01

Waste lettuce leaves - from the "fresh cut vegetable" industry - were pretreated with the deep eutectic solvent (DES) made of choline chloride - glycerol. Reaction time (3-16h) and the operation temperature (80-150°C) were investigated. Enzymatic glucose and xylose yields of 94.9% and 75.0%, respectively were obtained when the biomass was pretreated at 150°C for 16h. Sugars contained in the biomass hydrolysate were fermented in batch cultures of Clostridium acetobutylicum DSMZ 792. The energy consumption and the energy efficiency related to the DES pretreatment were calculated and compared to the most common lignocellulosic pretreatment processes reported in the literature. The DES pretreatment process was characterized by lower energy required (about 28% decrease and 72% decrease) than the NAOH pretreatment and steam explosion process respectively. The Net Energy Ratio (NER) value related to butanol production via DES biomass pretreatment was assessed. Copyright © 2017 Elsevier Ltd. All rights reserved.

An evaluation of dilute acid and ammonia fiber explosion pretreatment for cellulosic ethanol production.

PubMed

Mathew, Anil Kuruvilla; Parameshwaran, Binod; Sukumaran, Rajeev Kumar; Pandey, Ashok

2016-01-01

The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hyaluronidase and Collagenase Increase the Transfection Efficiency of Gene Electrotransfer in Various Murine Tumors

PubMed Central

Golzio, Muriel; Sersa, Gregor; Escoffre, Jean-Michel; Coer, Andrej; Vidic, Suzana; Teissie, Justin

2012-01-01

Abstract One of the applications of electroporation/electropulsation in biomedicine is gene electrotransfer, the wider use of which is hindered by low transfection efficiency in vivo compared with viral vectors. The aim of our study was to determine whether modulation of the extracellular matrix in solid tumors, using collagenase and hyaluronidase, could increase the transfection efficiency of gene electrotransfer in histologically different solid subcutaneous tumors in mice. Tumors were treated with enzymes before electrotransfer of plasmid DNA encoding either green fluorescent protein or luciferase. Transfection efficiency was determined 3, 9, and 15 days posttransfection. We demonstrated that pretreatment of tumors with a combination of enzymes significantly increased the transfection efficiency of electrotransfer in tumors with a high extracellular matrix area (LPB fibrosarcoma). In tumors with a smaller extracellular matrix area and less organized collagen lattice, the increase was not so pronounced (SA-1 fibrosarcoma and EAT carcinoma), whereas in B16 melanoma, in which only traces of collagen are present, pretreatment of tumors with hyaluronidase alone was more efficient than pretreatment with both enzymes. In conclusion, our results suggest that modification of the extracellular matrix could improve distribution of plasmid DNA in solid subcutaneous tumors, demonstrated by an increase in transfection efficiency, and thus have important clinical implications for electrogene therapy. PMID:21797718

Powerful peracetic acid-ionic liquid pretreatment process for the efficient chemical hydrolysis of lignocellulosic biomass.

PubMed

Uju; Goto, Masahiro; Kamiya, Noriho

2016-08-01

The aim of this work was to design a new method for the efficient saccharification of lignocellulosic biomass (LB) using a combination of peracetic acid (PAA) pretreatment with ionic liquid (IL)-HCl hydrolysis. The pretreatment of LBs with PAA disrupted the lignin fractions, enhanced the dissolution of LB and led to a significant increase in the initial rate of the IL-HCl hydrolysis. The pretreatment of Bagasse with PAA prior to its 1-buthyl-3-methylimidazolium chloride ([Bmim][Cl])-HCl hydrolysis, led to an improvement in the cellulose conversion from 20% to 70% in 1.5h. Interestingly, the 1-buthyl-3-methylpyridium chloride ([Bmpy][Cl])-HCl hydrolysis of Bagasse gave a cellulose conversion greater than 80%, with or without the PAA pretreatment. For LB derived from seaweed waste, the cellulose conversion reached 98% in 1h. The strong hydrolysis power of [Bmpy][Cl] was attributed to its ability to transform cellulose I to II, and lowering the degree of polymerization of cellulose. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of dilute sulfuric acid pretreatment to maximize combined sugar yield from sugarcane bagasse for ethanol production.

PubMed

Benjamin, Y; Cheng, H; Görgens, J F

2014-01-01

Increasing fermentable sugar yields per gram of biomass depends strongly on optimal selection of varieties and optimization of pretreatment conditions. In this study, dilute acid pretreatment of bagasse from six varieties of sugarcane was investigated in connection with enzymatic hydrolysis for maximum combined sugar yield (CSY). The CSY from the varieties were also compared with the results from industrial bagasse. The results revealed considerable differences in CSY between the varieties. Up to 22.7 % differences in CSY at the optimal conditions was observed. The combined sugar yield difference between the best performing variety and the industrial bagasse was 34.1 %. High ratio of carbohydrates to lignin and low ash content favored the release of sugar from the substrates. At mild pretreatment conditions, the differences in bioconversion efficiency between varieties were greater than at severe condition. This observation suggests that under less severe conditions the glucose recovery was largely determined by chemical composition of biomass. The results from this study support the possibility of increasing sugar yields or improving the conversion efficiency when pretreatment optimization is performed on varieties with improved properties.

Chemically pretreating slaughterhouse solid waste to increase the efficiency of anaerobic digestion.

PubMed

Flores-Juarez, Cyntia R; Rodríguez-García, Adrián; Cárdenas-Mijangos, Jesús; Montoya-Herrera, Leticia; Godinez Mora-Tovar, Luis A; Bustos-Bustos, Erika; Rodríguez-Valadez, Francisco; Manríquez-Rocha, Juan

2014-10-01

The combined effect of temperature and pretreatment of the substrate on the anaerobic treatment of the organic fraction of slaughterhouse solid waste was studied. The goal of the study was to evaluate the effect of pretreating the waste on the efficiency of anaerobic digestion. The effect was analyzed at two temperature ranges (the psychrophilic and the mesophilic ranges), in order to evaluate the effect of temperature on the performance of the anaerobic digestion process for this residue. The experiments were performed in 6 L batch reactors for 30 days. Two temperature ranges were studied: the psychrophilic range (at room temperature, 18°C average) and the mesophilic range (at 37°C). The waste was pretreated with NaOH before the anaerobic treatment. The result of pretreating with NaOH was a 194% increase in the soluble chemical oxygen demand (COD) with a dose of 0.6 g NaOH per g of volatile suspended solids (VSS). In addition, the soluble chemical oxygen demand/total chemical oxygen demand ratio (sCOD/tCOD) increased from 0.31 to 0.7. For the anaerobic treatment, better results were observed in the mesophilic range, achieving 70.7%, 47% and 47.2% removal efficiencies for tCOD, total solids (TS), and volatile solids (VS), respectively. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Combined alkaline and ultrasonic pretreatment of sludge before aerobic digestion.

PubMed

Jin, Yiying; Li, Huan; Mahar, Rasool Bux; Wang, Zhiyu; Nie, Yongfeng

2009-01-01

Alkaline and ultrasonic sludge disintegration can be used as the pretreatment of waste activated sludge (WAS) to promote the subsequent anaerobic or aerobic digestion. In this study, different combinations of these two methods were investigated. The evaluation was based on the quantity of soluble chemical oxygen demand (SCOD) in the pretreated sludge as well as the degradation of organic matter in the subsequent aerobic digestion. For WAS samples with combined pretreatment, the released COD levels were higher than those with ultrasonic or alkaline pretreatment alone. When combined with the ultrasonic treatment, NaOH treatment was more efficient than Ca(OH)2 for WAS solubilization. The COD levels released in various sequential options of combined NaOH and ultrasonic treatments were in the the following descending order: simultaneous treatment > NaOH treatment followed by ultrasonic treatment > ultrasonic treatment followed by NaOH treatment. For simultaneous treatment, low NaOH dosage (100 g/kg dry solid), short duration (30 min) of NaOH treatment, and low ultrasonic specific energy (7500 kJ/kg dry solid) were suitable for sludge disintegration. Using combined NaOH and ultrasonic pretreatment with optimal parameters, the degradation efficiency of organic matter was increased from 38.0% to 50.7%, which is much higher than that with ultrasonic (42.5%) or with NaOH pretreatment (43.5%) in the subsequent aerobic digestion at the same retention time.

Chemical and physicochemical pretreatment of lignocellulosic biomass: a review.

PubMed

Brodeur, Gary; Yau, Elizabeth; Badal, Kimberly; Collier, John; Ramachandran, K B; Ramakrishnan, Subramanian

2011-01-01

Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility.

Chemical and Physicochemical Pretreatment of Lignocellulosic Biomass: A Review

PubMed Central

Brodeur, Gary; Yau, Elizabeth; Badal, Kimberly; Collier, John; Ramachandran, K. B.; Ramakrishnan, Subramanian

2011-01-01

Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility. PMID:21687609

Analysis of by-product formation and sugar monomerization in sugarcane bagasse pretreated at pilot plant scale: differences between autohydrolysis, alkaline and acid pretreatment.

PubMed

van der Pol, Edwin; Bakker, Rob; van Zeeland, Alniek; Sanchez Garcia, David; Punt, Arjen; Eggink, Gerrit

2015-04-01

Sugarcane bagasse is an interesting feedstock for the biobased economy since a large fraction is polymerized sugars. Autohydrolysis, alkaline and acid pretreatment conditions combined with enzyme hydrolysis were used on lignocellulose rich bagasse to acquire monomeric. By-products found after pretreatment included acetic, glycolic and coumaric acid in concentrations up to 40, 21 and 2.5 g/kg dry weight bagasse respectively. Alkaline pretreated material contained up to 45 g/kg bagasse DW of sodium. Acid and autohydrolysis pretreatment results in a furan formation of 14 g/kg and 25 g/kg DW bagasse respectively. Enzyme monomerization efficiencies of pretreated solid material after 72 h were 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment. Solid material was washed with superheated water to decrease the amount of by-products. Washing decreased organic acid, phenol and furan concentrations in solid material by at least 60%, without a major sugar loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improving enzymatic hydrolysis of corn stover pretreated by ethylene glycol-perchloric acid-water mixture.

PubMed

He, Yu-Cai; Liu, Feng; Gong, Lei; Lu, Ting; Ding, Yun; Zhang, Dan-Ping; Qing, Qing; Zhang, Yue

2015-02-01

To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol.

Understanding the influences of different pretreatments on recalcitrance of Populus natural variants

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

Yao, Lan; Yang, Haitao; Yoo, Chang Geun

Here, four different pretreatment technologies were applied to two Populus natural variants and the effects of each pretreatment on glucose release were compared. Physicochemical properties of pretreated biomass were analyzed by attenuated total reflection Fourier transform infrared spectroscopy, gel permeation chromatography, and cross polarization/magic angle spinning carbon-13 nuclear magnetic resonance techniques. The results revealed that hemicellulose and lignin were removed to different extents during various pretreatments. The degree of polymerization of cellulose was decreased in the order of alkali > hydrothermal > organosolv > dilute acid pretreatment. Cellulose crystallinity index was slightly increased after each pretreatment. The results also demonstratedmore » that organosolv pretreatment resulted in the highest glucose yield. Among the tested properties of Populus, degree of polymerization of cellulose was negatively correlated with glucose release, whereas hemicellulose and lignin removal, and cellulose accessibility were positively associated with glucose release from the two Populus natural variants.« less

Understanding the influences of different pretreatments on recalcitrance of Populus natural variants

DOE PAGES

Yao, Lan; Yang, Haitao; Yoo, Chang Geun; ...

2018-05-18

Here, four different pretreatment technologies were applied to two Populus natural variants and the effects of each pretreatment on glucose release were compared. Physicochemical properties of pretreated biomass were analyzed by attenuated total reflection Fourier transform infrared spectroscopy, gel permeation chromatography, and cross polarization/magic angle spinning carbon-13 nuclear magnetic resonance techniques. The results revealed that hemicellulose and lignin were removed to different extents during various pretreatments. The degree of polymerization of cellulose was decreased in the order of alkali > hydrothermal > organosolv > dilute acid pretreatment. Cellulose crystallinity index was slightly increased after each pretreatment. The results also demonstratedmore » that organosolv pretreatment resulted in the highest glucose yield. Among the tested properties of Populus, degree of polymerization of cellulose was negatively correlated with glucose release, whereas hemicellulose and lignin removal, and cellulose accessibility were positively associated with glucose release from the two Populus natural variants.« less

Enhanced enzymatic hydrolysis of spruce by alkaline pretreatment at low temperature.

PubMed

Zhao, Yulin; Wang, Ying; Zhu, J Y; Ragauskas, Art; Deng, Yulin

2008-04-15

Alkaline pretreatment of spruce at low temperature in both presence and absence of urea was studied. It was found that the enzymatic hydrolysis rate and efficiency can be significantly improved by the pretreatment. At low temperature, the pretreatment chemicals, either NaOH alone or NaOH-urea mixture solution, can slightly remove lignin, hemicelluloses, and cellulose in the lignocellulosic materials, disrupt the connections between hemicelluloses, cellulose, and lignin, and alter the structure of treated biomass to make cellulose more accessible to hydrolysis enzymes. Moreover, the wood fiber bundles could be broken down to small and loose lignocellulosic particles by the chemical treatment. Therefore, the enzymatic hydrolysis efficiency of untreated mechanical fibers can also be remarkably enhanced by NaOH or NaOH/urea solution treatment. The results indicated that, for spruce, up to 70% glucose yield could be obtained for the cold temperature pretreatment (-15 degrees C) using 7% NaOH/12% urea solution, but only 20% and 24% glucose yields were obtained at temperatures of 23 degrees C and 60 degrees C, respectively, when other conditions remained the same. The best condition for the chemical pretreatment regarding this study was 3% NaOH/12% urea, and -15 degrees C. Over 60% glucose conversion was achieved upon this condition. Copyright 2007 Wiley Periodicals, Inc.

Alkali pretreated of wheat straw and its enzymatic hydrolysis.

PubMed

Han, Lirong; Feng, Juntao; Zhang, Shuangxi; Ma, Zhiqing; Wang, Yonghong; Zhang, Xing

2012-01-01

The efficiency of enzymatic hydrolysis of cellulose can be improved by various pretreatments of the substrate. In order to increase the efficiency of enzymatic saccharification of the wheat straw, we determined the effect of different pretreatments on the physical structure, chemical components and enzymatic saccharification of wheat straw. Our results showed that combination of grinding and sodium hydroxide (NaOH) treatment had high effect on the enzymatic hydrolysis of wheat straws. The optimal pretreatment condition was to grind the wheat straws into the sizes of 120 meshes followed by treatment with 1.0% NaOH for 1.5 h (121°C/15psi). Under this condition, the cellulose content of wheat straw was increased by 44.52%, while the content of hemicellulose and lignin was decreased by 44.15% and 42.52%, respectively. Scanning Electronic Microscopy and infrared spectrum analyses showed that significant changes occurred in the structure of wheat straws after pretreatment, which is favorable for the hydrolysis and saccharification. Cellulase produced by Penicillium waksmanii F10-2 was used to hydrolyze the pretreated wheat straw and the optimal condition was determined to be 30 h of enzymatic reaction under the temperature of 55°C, pH 5.5 and substrate concentration of 3%.

Ethanol production from SPORL-pretreated lodgepole pine: preliminary evaluation of mass balance and process energy efficiency.

PubMed

Zhu, J Y; Zhu, Wenyuan; Obryan, Patricia; Dien, Bruce S; Tian, Shen; Gleisner, Rolland; Pan, X J

2010-05-01

Lodgepole pine from forest thinnings is a potential feedstock for ethanol production. In this study, lodgepole pine was converted to ethanol with a yield of 276 L per metric ton of wood or 72% of theoretical yield. The lodgepole pine chips were directly subjected to sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) pretreatment and then disk-milled; the recovered cellulose substrate was quais-simultaneously saccharified enzymatically and fermented to ethanol using commercial cellulases and Saccharomyces cerevisiae D5A. The liquor stream from the pretreatment containing hydrolyzed sugars mainly from hemicelluloses was fermented by the same yeast strain after detoxification using an XAD resin column. The SPORL pretreatment was conducted at 180 degrees C for a period of 25 min with a liquor-to-wood ratio of 3:1 (v/w) in a laboratory digester. Three levels of sulfuric acid charge (0.0%, 1.4%, and 2.2% on an oven dried wood basis in w/w) and three levels of sodium bisulfite charge (0.0%, 4.0%, and 8.0% in w/w) were applied. Mechanical and thermal energy consumption for milling and pretreatment were determined. These data were used to determine the efficiency of sugar recoveries and net ethanol energy production values and to formulate a preliminary mass and energy balance.

Evaluation of polymeric adsorbent resins for efficient detoxification of liquor generated during acid pretreatment of lignocellulosic biomass.

PubMed

Sandhya, Soolamkandath Variem; Kiran, Kumar; Kuttiraja, Mathiyazhakan; Preeti, Varghese Elizabeth; Sindhu, Raveendran; Vani, Sankar; Kumar, Sukumaran Rajeev; Pandey, Ashok; Binod, Parameswaran

2013-11-01

Production of fuel ethanol from lignocellulosic biomass conventionally includes biomass pretreatment, hydrolysis, and fermentation. The liquor generated during dilute acid pretreatment of biomass contains considerable quantities of pentose sugars as well as various degradation products of sugars and lignin, like furfural, hydroxymethyl furfural (HMF), organic acids, aldehydes and others, which are known to be inhibitory for microbial growth. This pentose rich liquor is a potent resource which can be used to produce alcohol or other value added metabolites by microbial fermentation. However, the presence of these inhibitory compounds is a major hindrance and their removal is essential for efficient utilization of this byproduct stream. In the present work, the polymeric adsorbent resins, XAD-4, XAD-7 and XAD-16 were evaluated for their ability to adsorb fermentation inhibitors like furfural and HMF from the acid pretreated liquor. These resins could remove 55-75% of furfural and 100% of HMF and more than 90% sugar remained un-adsorbed in the pretreated liquor. Desorption of furfural from stationary phase was evaluated by using ethanol and hot water. The results suggest that these polymeric resins may be used for detoxification of acid pretreatment liquor with selective removal of sugar degradation products without affecting the sugar content in the solution.

Impact of lignin polymer backbone esters on ionic liquid pretreatment of poplar

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

Kim, Kwang Ho; Dutta, Tanmoy; Ralph, John

Biomass pretreatment remains an essential step in lignocellulosic biofuel production, largely to facilitate the efficient removal of lignin and increase enzyme accessibility to the polysaccharides. In recent years, there have been significant efforts in planta to reduce lignin content or modify its composition to overcome the inherent recalcitrance that it imposes on lignocellulosic biomass during processing. Here, transgenic poplar lines in which monolignol ferulate conjugates were synthesized during cell wall development to introduce, during lignification, readily cleavable ester linkages into the lignin polymer backbone (i.e., "zip lignin"), along with wild-type (WT) controls, were pretreated with different ionic liquids (ILs). Themore » strategic introduction of ester bonds into the lignin backbone resulted in increased pretreatment efficiency and released more carbohydrates with lower energy input. After pretreatment with any of three different ILs, and after limited saccharification, the transgenic poplars, especially those with relatively higher amounts of incorporated monolignol ferulate conjugates, yielded up to 23% higher sugar levels compared to WT plants. Our findings clearly demonstrate that the introduction of ester linkages into the lignin polymer backbone decreases biomass recalcitrance in poplar has the potential to reduce the energy and/or amount of IL required for effective pretreatment, and could enable the development of an economically viable and sustainable biorefinery process.« less

Impact of lignin polymer backbone esters on ionic liquid pretreatment of poplar

DOE PAGES

Kim, Kwang Ho; Dutta, Tanmoy; Ralph, John; ...

2017-04-20

Biomass pretreatment remains an essential step in lignocellulosic biofuel production, largely to facilitate the efficient removal of lignin and increase enzyme accessibility to the polysaccharides. In recent years, there have been significant efforts in planta to reduce lignin content or modify its composition to overcome the inherent recalcitrance that it imposes on lignocellulosic biomass during processing. Here, transgenic poplar lines in which monolignol ferulate conjugates were synthesized during cell wall development to introduce, during lignification, readily cleavable ester linkages into the lignin polymer backbone (i.e., "zip lignin"), along with wild-type (WT) controls, were pretreated with different ionic liquids (ILs). Themore » strategic introduction of ester bonds into the lignin backbone resulted in increased pretreatment efficiency and released more carbohydrates with lower energy input. After pretreatment with any of three different ILs, and after limited saccharification, the transgenic poplars, especially those with relatively higher amounts of incorporated monolignol ferulate conjugates, yielded up to 23% higher sugar levels compared to WT plants. Our findings clearly demonstrate that the introduction of ester linkages into the lignin polymer backbone decreases biomass recalcitrance in poplar has the potential to reduce the energy and/or amount of IL required for effective pretreatment, and could enable the development of an economically viable and sustainable biorefinery process.« less

Energy efficacy used to score organic refuse pretreatment processes for hydrogen anaerobic production.

PubMed

Ruggeri, Bernardo; Luongo Malave, Andrea C; Bernardi, Milena; Fino, Debora

2013-11-01

The production of hydrogen through Anaerobic Digestion (AD) has been investigated to verify the efficacy of several pretreatment processes. Three types of waste with different carbon structures have been tested to obtain an extensive representation of the behavior of the materials present in Organic Waste (OW). The following types of waste were selected: Sweet Product Residue (SPR), i.e., confectionary residue removed from the market after the expiration date, Organic Waste Market (OWM) refuse from a local fruit and vegetable market, and Coffee Seed Skin (CSS) waste from a coffee production plant. Several pretreatment processes have been applied, including physical, chemical, thermal, and ultrasonic processes and a combination of these processes. Two methods have been used for the SPR to remove the packaging, manual (SPR) and mechanical (SPRex). A pilot plant that is able to extrude the refuse to 200atm was utilized. Two parameters have been used to score the different pretreatment processes: efficiency (ξ), which takes into account the amount of energy produced in the form of hydrogen compared with the available energy embedded in the refuse, and efficacy (η), which compares the efficiency obtained using the pretreated refuse with that obtained using the untreated refuse. The best result obtained for the SPR was the basic pretreatment, with η=6.4, whereas the thermal basic pretreatment gave the highest value, η=17.0 for SPRex. The best result for the OWM was obtained through a combination of basic/thermal pretreatments with η=9.9; lastly, the CSS residue with ultrasonic pretreatment produced the highest quantity of hydrogen, η=5.2. Copyright © 2013 Elsevier Ltd. All rights reserved.

Energy, wealth, and human development: why and how biomass pretreatment research must improve.

PubMed

Dale, Bruce E; Ong, Rebecca G

2012-07-01

A high level of human development is dependent on energy consumption (roughly 4 kW per person), and most developed countries that have reached this level have done so through the extensive use of fossil energy. However, given that fossil resources are finite, in order for developed countries to maintain their level of development and simultaneously allow developing countries to reach their potential, it is essential to develop viable renewable energy alternatives. Of particular importance are liquid fuel replacements for petroleum, the fossil resource that primarily drives commerce and economic growth. The intent of this article is to remind our fellow biofuel researchers, particularly those involved in lignocellulosic pretreatment, of these global issues and the serious nature of our work. We hope that this will inspire us to generate and report higher quality and more thorough data than has been done in the past. Only in this way can accurate comparisons and technoeconomic evaluations be made for the many different pretreatment technologies that are currently being researched. The data that primarily influence biorefinery economics can be subdivided into three main categories: yield, concentration, and rate. For these three categories we detail the specific data that should be reported for pretreatment research. In addition, there is other information that is needed to allow for a thorough comparison of pretreatment technologies. An overview of these criteria and our comparison of the current state of a number of pretreatment technologies with respect to these criteria are covered in the last section. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

Biofuels done right: land efficient animal feeds enable large environmental and energy benefits.

PubMed

Dale, Bruce E; Bals, Bryan D; Kim, Seungdo; Eranki, Pragnya

2010-11-15

There is an intense ongoing debate regarding the potential scale of biofuel production without creating adverse effects on food supply. We explore the possibility of three land-efficient technologies for producing food (actually animal feed), including leaf protein concentrates, pretreated forages, and double crops to increase the total amount of plant biomass available for biofuels. Using less than 30% of total U.S. cropland, pasture, and range, 400 billion liters of ethanol can be produced annually without decreasing domestic food production or agricultural exports. This approach also reduces U.S. greenhouse gas emissions by 670 Tg CO₂-equivalent per year, or over 10% of total U.S. annual emissions, while increasing soil fertility and promoting biodiversity. Thus we can replace a large fraction of U.S. petroleum consumption without indirect land use change.

Effectiveness and mechanism of potassium ferrate(VI) preoxidation for algae removal by coagulation.

PubMed

Ma, Jun; Liu, Wei

2002-02-01

Jar tests were conducted to evaluate the effectiveness of potassium ferrate preoxidation on algae removal by coagulation. Laboratory studies demonstrated that pretreatment with potassium ferrate obviously enhanced the algae removal by coagulation with alum [Al2(SO4)3 . 18H2O]. Algae removal efficiency increased remarkably when the water was pretreated with ferrate. A very short time of preoxidation was enough to achieve substantial algae removal efficiency, and the effectiveness was further increased at a prolonged pretreatment time. Pretreatment with ferrate resulted in a reduction of alum dosage required to cause an efficient coagulation for algae removal. The obvious impact of cell architecture by potassium ferrate was found through scanning electron microscopy. Upon oxidation with ferrate. the cells were inactivated and some intracellular and extracelluar components were released into the water, which may be helpful to the coagulation by their bridging effect. Efficient removal of algae by potassium ferrate preoxidation is believed to be a consequence of several process mechanisms. Ferrate preoxidation inactivated algae, induced the formation of coagulant aid, which are the cellular components secreted by algal cells. The coagulation was also improved by increasing particle concentration in water, because of the formation of the intermediate forms of precipitant iron species during preoxidation. In addition, it was also observed that ferrate preoxidation caused algae agglomerate formation before the addition of coagulant, the subsequent application of alum resulted in further coagulation.

Energy implications of mechanical and mechanical–biological treatment compared to direct waste-to-energy

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

Cimpan, Ciprian, E-mail: cic@kbm.sdu.dk; Wenzel, Henrik

2013-07-15

Highlights: • Compared systems achieve primary energy savings between 34 and 140 MJ{sub primary}/100 MJ{sub input} {sub waste.} • Savings magnitude is foremost determined by chosen primary energy and materials production. • Energy consumption and process losses can be upset by increased technology efficiency. • Material recovery accounts for significant shares of primary energy savings. • Direct waste-to-energy is highly efficient if cogeneration (CHP) is possible. - Abstract: Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical–biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogasmore » and/or recover additional materials for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation). The systems achieved net primary energy savings in a range between 34 and 140 MJ{sub primary}/100 MJ{sub input} {sub waste}, in the different scenario settings. The energy footprint of transportation needs, pre-treatment and reprocessing of recyclable materials was 3–9.5%, 1–18% and 1–8% respectively, relative to total energy savings. Mass combustion WtE achieved the highest savings in scenarios with CHP production, nonetheless, MBT-based systems had similarly high performance if SRF streams were co-combusted with coal. When RDF and SRF was only used in dedicated WtE plants, MBT-based systems totalled lower savings due to inherent system losses and additional energy costs. In scenarios without heat recovery, the biodrying MBS-based system achieved the highest savings, on the condition of SRF co-combustion. As a sensitivity scenario, alternative utilisation of SRF in cement kilns was modelled. It supported similar or higher net savings for all pre-treatment systems compared to mass combustion WtE, except when WtE CHP was possible in the first two background energy scenarios. Recovery of plastics for recycling before energy recovery increased net energy savings in most scenario variations, over those of full stream combustion. Sensitivity to assumptions regarding virgin plastic substitution was tested and was found to mostly favour plastic recovery.« less

Enhanced enzymatic saccharification of sugarcane bagasse pretreated by combining O2 and NaOH.

PubMed

Bi, Shuaizhu; Peng, Lincai; Chen, Keli; Zhu, Zhengliang

2016-08-01

Sugarcane bagasse pretreated by combining O2 and NaOH with different variables was conducted to improve its enzymatic digestibility and sugar recovery, and the results were compared with sole NaOH pretreatment. Lignin removal for O2-NaOH pretreatment was around 10% higher than that for sole NaOH pretreatment under the same conditions, and O2-NaOH pretreatment resulted in higher glucan recovery in the solid remain. Subsequently, O2-NaOH pretreated sugarcane bagasse presented more efficient enzymatic digestibility than sole NaOH pretreatment. Under the moderate pretreatment conditions of combining 1% NaOH and 0.5MPa O2 at 80°C for 120min, a high glucan conversion of 95% was achieved after 48h enzymatic hydrolysis. Coupled with the operations of pretreatment and enzymatic hydrolysis, an admirable total sugar recovery of 89% (glucose recovery of 93% and xylose recovery of 84%) was obtained. The susceptibility of the substrates to enzymatic digestibility was explained by their physical and chemical characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pretreatment of grass waste using combined ionizing radiation-acid treatment for enhancing fermentative hydrogen production.

PubMed

Yang, Guang; Wang, Jianlong

2018-05-01

In this study, the combined ionizing radiation-acid pretreatment process was firstly applied to enhance hydrogen fermentation of grass waste. Results showed that the combined pretreatment synergistically enhanced hydrogen fermentation of grass waste. The SCOD and soluble polysaccharide contents of grass waste increased by 1.6 and 2.91 times after the combined pretreatment, respectively. SEM observation and crystallinity test showed the combined pretreatment effectively disrupted the grass structure. Owing to the more favorable substrate conditions, the hydrogen yield achieved 68 mL/g-dry grass added after the combined pretreatment, which was 161.5%, 112.5% and 28.3% higher than those from raw, ionizing radiation pretreated and acid pretreated grass waste, respectively. The VS removal also increased from 13.9% to 25.6% by the combined pretreatment. Microbial community analysis showed that the abundance of dominant hydrogen producing genus Clostridium sensu stricto 1 increased from 37.9% to 69.4% after the combined pretreatment, which contributed to more efficient hydrogen fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of liquid hot water and alkaline pretreatments of giant reed for improved enzymatic digestibility and biogas energy production.

PubMed

Jiang, Danping; Ge, Xumeng; Zhang, Quanguo; Li, Yebo

2016-09-01

Liquid hot water (LHW) and alkaline pretreatments of giant reed biomass were compared in terms of digestibility, methane production, and cost-benefit efficiency for electricity generation via anaerobic digestion with a combined heat and power system. Compared to LHW pretreatment, alkaline pretreatment retained more of the dry matter in giant reed biomass solids due to less severe conditions. Under their optimal conditions, LHW pretreatment (190°C, 15min) and alkaline pretreatment (20g/L of NaOH, 24h) improved glucose yield from giant reed by more than 2-fold, while only the alkaline pretreatment significantly (p<0.05) increased cumulative methane yield (by 63%) over that of untreated biomass (217L/kgVS). LHW pretreatment obtained negative net electrical energy production due to high energy input. Alkaline pretreatment achieved 27% higher net electrical energy production than that of non-pretreatment (3859kJ/kg initial total solids), but alkaline liquor reuse is needed for improved net benefit. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pretreating lignocellulosic biomass by the concentrated phosphoric acid plus hydrogen peroxide (PHP) for enzymatic hydrolysis: evaluating the pretreatment flexibility on feedstocks and particle sizes.

PubMed

Wang, Qing; Wang, Zhanghong; Shen, Fei; Hu, Jinguang; Sun, Fubao; Lin, Lili; Yang, Gang; Zhang, Yanzong; Deng, Shihuai

2014-08-01

In order to seek a high-efficient pretreatment path for converting lignocellulosic feedstocks to fermentable sugars by enzymatic hydrolysis, the concentrated H₃PO₄ plus H₂O₂ (PHP) was attempted to pretreat different lignocellulosic biomass for evaluating the pretreatment flexibility on feedstocks. Meanwhile, the responses of pretreatment to particle sizes were also evaluated. When the PHP-pretreatment was employed (final H₂O₂ and H₃PO₄ concentration of 1.77% and 80.0%), 71-96% lignin and more than 95% hemicellulose in various feedstocks (agricultural residues, hardwood, softwood, bamboo, and their mixture, and garden wastes mixture) can be removed. Consequently, more than 90% glucose conversion was uniformly achieved indicating PHP greatly improved the pretreatment flexibility to different feedstocks. Moreover, when wheat straw and oak chips were PHP-pretreated with different sizes, the average glucose conversion reached 94.9% and 100% with lower coefficient of variation (7.9% and 0.0%), which implied PHP-pretreatment can significantly weaken the negative effects of feedstock sizes on subsequent conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Liquid hot water pretreatment of multi feedstocks and enzymatic hydrolysis of solids obtained thereof.

PubMed

Michelin, Michele; Teixeira, José António

2016-09-01

Agricultural feedstocks (brewers' spent grain - BSG, corncob - CC, corn husk - CH, wheat straw - WS and Luffa sponge - LS) were pretreated by liquid hot water (LHW) in order to increase cellulose recovery and enzymatic saccharification. LHW-pretreatment resulted in hemicellulose solubilization, and solids enriched in cellulose. Chemical analysis showed different susceptibilities of the feedstocks to LHW-pretreatment and enzymatic hydrolysis. Pretreated feedstocks presented higher crystallinity (determined through X-ray diffraction) and thermal stability (determined through thermogravimetric analysis) than untreated feedstocks. SEM images confirmed the effect of LHW-pretreatment on structural changes. Moreover, enzymatic hydrolysis and cellulose conversion to glucose (CCG) were improved for pretreated feedstocks, with exception of LS. CCG (in relation to glucose potential on solids) followed the order: BSG>CH>WS>CC>LS. LHW-pretreatment showed to be a good technology to pretreat multi feedstocks and for improving the enzymatic hydrolysis of recalcitrant agricultural feedstocks to sugars, which can be further converted to ethanol-fuel and other value-added chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sodium hydroxide pretreatment and enzymatic hydrolysis of coastal Bermuda grass.

PubMed

Wang, Ziyu; Keshwani, Deepak R; Redding, Arthur P; Cheng, Jay J

2010-05-01

Coastal Bermuda grass was pretreated with NaOH at concentrations from 0.5% to 3% (w/v) for a residence time from 15 to 90min at 121 degrees C. The pretreatments were evaluated based on total lignin removal and production of total reducing sugars, glucose and xylose from enzymatic hydrolysis of the pretreated biomass. Up to 86% lignin removal was observed. The optimal NaOH pretreatment conditions at 121 degrees C for total reducing sugars production as well as glucose and xylose yields are 15min and 0.75% NaOH. Under these optimal pretreatment conditions, total reducing sugars yield was about 71% of the theoretical maximum, and the overall conversion efficiencies for glucan and xylan were 90.43% and 65.11%, respectively. Copyright 2009 Elsevier Ltd. All rights reserved.

Decolourization of remazol black-5 textile dyes using moving bed bio-film reactor

NASA Astrophysics Data System (ADS)

Pratiwi, R.; Notodarmojo, S.; Helmy, Q.

2018-01-01

The desizing and dyeing processes in the textile industries produces wastewaster containing high concentration of organic matter and colour, so it needs treatment before released to environment. In this research, removal of azo dye (Remazol Black 5/RB 5) and organic as COD was performed using Moving Bed Biofilm Reactor (MBBR). MBBR is biological treatment process with attached growth media system that can increase removal of organic matter in textile wastewater. The effectiveness of ozonation as pre-treatment process to increase the removal efficiency in MBBR was studied. The results showed that in MBBR batch system with detention time of 1 hour, pre-treatment with ozonation prior to MBBR process able to increase the colour removal efficiency of up to 86.74%. While on the reactor without ozone pre-treatment, the colour removal efficiency of up to 68.6% was achieved. From the continuous reactor experiments found that both colour and COD removal efficiency depends on time detention of RB-5 dyes in the system. The higher of detention time, the higher of colour and COD removal efficiency. It was found that optimum removal of colour and COD was achieved in 24 hour detention time with its efficiency of 96.9% and 89.13%, respectively.

Improved enzymatic hydrolysis of lignocellulosic biomass through pretreatment with plasma electrolysis.

PubMed

Gao, Jing; Chen, Li; Zhang, Jian; Yan, Zongcheng

2014-11-01

A comprehensive research on plasma electrolysis as pretreatment method for water hyacinth (WH) was performed based on lignin content, crystalline structure, surface property, and enzymatic hydrolysis. A large number of active particles, such as HO and H2O2, generated by plasma electrolysis could decompose the lignin of the biomass samples and reduce the crystalline index. An efficient pretreatment process made use of WH pretreated at a load of 48 wt% (0.15-0.18 mm) in FeCl3 solution for 30 min at 450 V. After the pretreatment, the sugar yield of WH was increased by 126.5% as compared with unpretreated samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pretreatment Characteristics of Waste Oak Wood by Ammonia Percolation

NASA Astrophysics Data System (ADS)

Kim, Jun-Seok; Kim, Hyunjoon; Lee, Jin-Suk; Lee, Joon-Pyo; Park, Soon-Chul

A log of waste oak wood collected from a Korean mushroom farm has been tested for ammonia percolation pretreatment. The waste log has different physical characteristics from that of virgin oak wood. The density of the waste wood was 30% lower than that of virgin oak wood. However, there is little difference in the chemical compositions between the woods. Due to the difference in physical characteristics, the optimal pretreatment conditions were also quite different. While for waste oak the optimum temperature was determined to be 130°C, for virgin oak wood the optimum pretreatment was only achieved at 170°C. Presoaking for 12 h with ammonia solution before pretreatment was helpful to increase the delignification efficiency.

Elimination of pharmaceutical residues in biologically pre-treated hospital wastewater using advanced UV irradiation technology: a comparative assessment.

PubMed

Köhler, C; Venditti, S; Igos, E; Klepiszewski, K; Benetto, E; Cornelissen, A

2012-11-15

UV irradiation technology as a membrane bioreactor (MBR) post-treatment was investigated and assessed. Both UV low pressure (LP) and medium pressure (MP) lamps were examined. The technology was installed in a pilot plant treating hospital wastewater to provide the study with adequate field data. The effect of the UV irradiation was enhanced with varying dosages of H2O2 to establish an advanced oxidation process (AOP). The efficiency of the pharmaceutical removal process was assessed by examining 14 micropollutants (antibiotics, analgesics, anticonvulsants, beta-blockers, cytostatics and X-ray contrast media) which are typically released by hospitals and detected with liquid chromatography coupled tandem mass spectrometry (LC-MS/MS). While the MBR treatment generally showed only a low degradation capacity for persistent pharmaceuticals, much better degradation was obtained by applying UV irradiation and H2O2 as AOP. The "conventional" cost-benefit analysis of the different technology options taking into account both electrical energy consumption and pharmaceutical removal efficiency, revealed clearly better performance of low pressure UV lamps as AOP. However, a holistic comparison between the different scenarios was carried out by evaluating their environmental impacts using the life cycle assessment (LCA) methodology. Decisive advantages were highlighted to include this approach in the decision making process. Copyright © 2012 Elsevier B.V. All rights reserved.

Anaerobic fermentation of biogas liquid pretreated maize straw by rumen microorganisms in vitro.

PubMed

Jin, Wenyao; Xu, Xiaochen; Gao, Yang; Yang, Fenglin; Wang, Gang

2014-02-01

This study intended to investigate the effect of pretreatment of maize straw with biogas liquid on followed fermentation by rumen microorganisms in vitro. The multiple effects including treated time, temperature and dosage of biogas liquid in pretreatment on the followed fermentation performance were analyzed by orthogonal array. The optimum conditions of pretreatment were 9days, 25°C and 50% (v/w) dosage of biogas liquid, which were indicated by the corresponding crystallinity index, dry matter digestibility (DMD) and acetate limiting-step concentration were 57.5%, 73.76% and 1756mg/L, respectively. The ordering sequence of the influential factors for pretreatment was treated time > temperature > dosage of biogas liquid. The results of fermentation showed that the maize straw pretreated by biogas liquid was an efficient and economic pretreatment method of maize straw. Copyright © 2013 Elsevier Ltd. All rights reserved.

Wet air oxidation pretreatment of biomethanated distillery effluent: mapping pretreatment efficiency in terms color, toxicity reduction and biogas generation.

PubMed

Sarat Chandra, T; Malik, S N; Suvidha, G; Padmere, M L; Shanmugam, P; Mudliar, S N

2014-04-01

The effluents from molasses-based distilleries after biomethanation are beset with problems of intensified dark brown color, high residual COD, low biodegradability index (BOD/COD ratio <0.2) and toxicity issues for possible land application as a potential fertilizer. Wet air oxidation (WAO) pretreatment of biomethanated distillery effluent resulted in substantial enhancement in the biodegradability index (BI) (up to 0.8). WAO pretreated effluent on anaerobic digestion indicated favorable biogas generation with methane content up to 64% along with concomitant COD reduction up to 54.75%. The HPLC analysis indicated that the pretreatment facilitated degradation of major color containing compounds-namely melanoidins, up to 97.8%. The pretreated effluent with enhanced biodegradability along with substantially reduced color also indicated positive effect on seed germination (up to 100%), implying toxicity reduction of the effluent post WAO pretreatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

An advanced pretreatment strategy involving hydrodynamic and acoustic cavitation along with alum coagulation for the mineralization and biodegradability enhancement of tannery waste effluent.

PubMed

Saxena, Shivendu; Rajoriya, Sunil; Saharan, Virendra Kumar; George, Suja

2018-06-01

In the present study, coagulation followed by cavitation was studied as a pretreatment tool for tannery waste effluent (TWE) with the aim of reducing its COD, TOC, TSS etc. and enhancing its biodegradability to make it suitable for anaerobic digestion. Initially, coagulation was applied to TWE using alum as a coagulant. The residual pH of treated effluent was found to be around pH of 4.5 where maximum COD and TSS reduction was achieved. In order to enhance the efficiency of pretreatment process, coagulated tannery waste effluent (CTWE) was further subjected to hydrodynamic cavitation (HC) and ultrasonication (US). In case of HC, effect of process parameters such as inlet pressure and dilution on the treatment of CTWE was initially investigated. Lower operating pressure (5 bar) was more favorable for the treatment of CTWE using HC in order to enhance the biodegradability index (BI) from 0.14 to 0.57 in 120 min. The CTWE samples when subjected to 50% dilution, HC pretreatment exhibited higher percentage and quantum reduction in TOC and COD. On the other hand, pretreatment of TWE using coagulation followed by US demonstrated that BI of effluent was enhanced from 0.10 to 0.41 in 150 min. Energy efficiency evaluation for all processes at their optimized conditions was done based on the actual amount of COD reduced per unit energy delivered to the system. Coagulation followed by HC for the pretreatment of TWE was found to be six times more energy efficient as compared to coagulation followed by US. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic anaerobic bacteria.

PubMed

Dhiman, Saurabh Sudha; David, Aditi; Shrestha, Namita; Johnson, Glenn R; Benjamin, Kenneth M; Gadhamshetty, Venkataramana; Sani, Rajesh K

2017-11-01

The one-pot CRUDE (Conversion of Raw and Untreated Disposal into Ethanol) process was developed for simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic (growing at 65°C) anaerobic bacteria. Unlike existing waste to energy technologies, the CRUDE process obviates the need for any pre-treatment or enzyme addition. A High-Temperature-High-Pressure (HTHP) distillation technique was also applied that facilitated efficient use of fermentation medium, inoculum recycling, and in-situ ethanol collection. For material balancing of the process, each characterized component was represented in terms of C-mol. Recovery of 94% carbon at the end confirmed the operational efficiency of CRUDE process. The overall energy retaining efficiency calculated from sugars to ethanol was 1262.7kJdryweightkg -1 of volatile solids using HTHP. These results suggest that the CRUDE process can be a starting point for the development of a commercial ethanol production process. Copyright © 2017 Elsevier Ltd. All rights reserved.

High yielding tropical energy crops for bioenergy production: Effects of plant components, harvest years and locations on biomass composition.

PubMed

Surendra, K C; Ogoshi, Richard; Zaleski, Halina M; Hashimoto, Andrew G; Khanal, Samir Kumar

2018-03-01

The composition of lignocellulosic feedstock, which depends on crop type, crop management, locations and plant parts, significantly affects the conversion efficiency of biomass into biofuels and biobased products. Thus, this study examined the composition of different parts of two high yielding tropical energy crops, Energycane and Napier grass, collected across three locations and years. Significantly higher fiber content was found in the leaves of Energycane than stems, while fiber content was significantly higher in the stems than the leaves of Napier grass. Similarly, fiber content was higher in Napier grass than Energycane. Due to significant differences in biomass composition between the plant parts within a crop type, neither biological conversion, including anaerobic digestion, nor thermochemical pretreatment alone is likely to efficiently convert biomass components into biofuels and biobased products. However, combination of anaerobic digestion with thermochemical conversion technologies could efficiently utilize biomass components in generating biofuels and biobased products. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of sanitary landfill leachate aging on the biological treatment and assessment of photoelectrooxidation as a pre-treatment process

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

Müller, Gabriel Timm; Giacobbo, Alexandre; Santos Chiaramonte, Edson Abel dos

Highlights: • Photoelectrooxidation (PEO) emerges as a new technology for leachate treatment. • Aging of sanitary landfills acts on leachate composition and biodegradability. • PEO is applied as leachate pretreatment before the biological processes. • PEO produced significant changes in the leachate matrix, easing biological process. - Abstract: The sanitary landfill leachate is a dark liquid, of highly variable composition, with recalcitrant features that hamper conventional biological treatment. The physical–chemical characteristics of the leachate along the landfill aging, as well as their effects on the efficiency of the conventional treatment, were evaluated at this paper. The feasibility of photoelectrooxidation processmore » as an alternative technique for treatment of landfill leachates was also determined. Photoelectrooxidation experiments were conducted in a bench-scale reactor. Analysis of the raw leachate revealed many critical parameters demonstrating that the recalcitrance of leachate tends to increase with time, directly influencing the decline in efficiency of the conventional treatment currently employed. The effects of current density and lamp power were investigated. Using a 400 W power lamp and a current density of 31.5 mA cm{sup −2}, 53% and 61% efficiency for the removal of ammoniacal nitrogen and chemical oxygen demand were respectively achieved by applying photoelectrooxidation process. With the removal of these pollutants, downstream biological treatment should be improved. These results demonstrate that photoelectrooxidation is a feasible technique for the treatment of sanitary landfill leachate, even considering this effluent’s high resistance to treatment.« less

Hydrolyzabilities of different corn stover fractions after aqueous ammonia pretreatment.

PubMed

Sun, Zongping; Ge, Xiaoyan; Xin, Donglin; Zhang, Junhua

2014-02-01

The effect of aqueous ammonia pretreatment on the hydrolysis of different corn stover fractions (rind, husk, leaf, and pith) by xylanase (XYL) with cellulases (CELs) was evaluated. The aqueous ammonia pretreatment had excellent delignification ability (above 66%) for different corn stover fractions. The corn rind exhibited the lowest susceptibility to aqueous ammonia pretreatment. The pretreated rind showed the lowest hydrolyzability by CEL and XYL, which was supported by a high content of crystalline cellulose in the hydrolyzed residues of rind, as confirmed by X-ray diffraction (XRD). With the addition of 1 mg XYL/g dry matter, a high glucose yield (above 90%) could be obtained from the pretreated rind by CEL. The results revealed that a high hydrolyzate yield of corn rind after aqueous ammonia pretreatment could be obtained with 1 mg xylanase/g dry matter, showing that aqueous ammonia pretreatment and xylanase addition to cellulases have great potential for the efficient hydrolysis of corn stover without previous fractionation.

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

PubMed

Xu, Lei; Tschirner, Ulrike

2014-08-01

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.

Dissolved air flotation and me.

PubMed

Edzwald, James K

2010-04-01

This paper is mainly a critical review of the literature and an assessment of what we know about dissolved air flotation (DAF). A few remarks are made at the outset about the author's personal journey in DAF research, his start and its progression. DAF has been used for several decades in drinking water treatment as an alternative clarification method to sedimentation. DAF is particularly effective in treating reservoir water supplies; those supplies containing algae, natural color or natural organic matter; and those with low mineral turbidity. It is more efficient than sedimentation in removing turbidity and particles for these type supplies. Furthermore, it is more efficient in removing Giardia cysts and Cryptosporidium oocysts. In the last 20 years, fundamental models were developed that provide a basis for understanding the process, optimizing it, and integrating it into water treatment plants. The theories were tested through laboratory and pilot-plant studies. Consequently, there have been trends in which DAF pretreatment has been optimized resulting in better coagulation and a decrease in the size of flocculation tanks. In addition, the hydraulic loading rates have increased reducing the size of DAF processes. While DAF has been used mainly in conventional type water plants, there is now interest in the technology as a pretreatment step in ultrafiltration membrane plants and in desalination reverse osmosis plants. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Gamma irradiation and steam pretreatment of jute stick powder for the enhancement of dye adsorption efficiency

NASA Astrophysics Data System (ADS)

Parvin, Fahmida; Sultana, Nargis; Habib, S. M. Ahsan; Bhoumik, Nikhil Chandra

2017-11-01

The aim of this study is to find out the facile and effective pretreatment technique to enhance the capacity of jute stick powder (JSP) in adsorbing dye from raw textile effluent. Hence, different pretreatment techniques, i.e., radiation treatment, alkali treatment, ammonia treatment, steam treatment and CaCl2 treatment were applied to JSP and the adsorbing performance were examined for synthetic dye solutions (Blue FCL and Red RL dye). Different gamma radiation doses were applied on JSP and optimum dye removal efficiency was found at 500 krad in removing these two dyes (50 ppm) from solutions. Among the different pretreatment techniques, gamma irradiated JSP (500 Krad) exhibits highest dye uptake capacity for RED RL dye, whereas steam-treated JSP shows highest performance in adsorbing blue FCL dye. Subsequently, we applied the gamma irradiated and steam-treated JSP on real textile effluent (RTE) and these two techniques shows potentiality in adsorbing dye from raw textile effluent and in reducing BOD5, COD load and TOC to some extent as well. Fourier transform infrared spectroscopy (FTIR) analysis also proved that dye has been adsorbed on pretreated JSP.

Antisense pre-treatment increases gene therapy efficacy in dystrophic muscles.

PubMed

Peccate, Cécile; Mollard, Amédée; Le Hir, Maëva; Julien, Laura; McClorey, Graham; Jarmin, Susan; Le Heron, Anita; Dickson, George; Benkhelifa-Ziyyat, Sofia; Piétri-Rouxel, France; Wood, Matthew J; Voit, Thomas; Lorain, Stéphanie

2016-08-15

In preclinical models for Duchenne muscular dystrophy, dystrophin restoration during adeno-associated virus (AAV)-U7-mediated exon-skipping therapy was shown to decrease drastically after six months in treated muscles. This decline in efficacy is strongly correlated with the loss of the therapeutic AAV genomes, probably due to alterations of the dystrophic myofiber membranes. To improve the membrane integrity of the dystrophic myofibers at the time of AAV-U7 injection, mdx muscles were pre-treated with a single dose of the peptide-phosphorodiamidate morpholino (PPMO) antisense oligonucleotides that induced temporary dystrophin expression at the sarcolemma. The PPMO pre-treatment allowed efficient maintenance of AAV genomes in mdx muscles and enhanced the AAV-U7 therapy effect with a ten-fold increase of the protein level after 6 months. PPMO pre-treatment was also beneficial to AAV-mediated gene therapy with transfer of micro-dystrophin cDNA into muscles. Therefore, avoiding vector genome loss after AAV injection by PPMO pre-treatment would allow efficient long-term restoration of dystrophin and the use of lower and thus safer vector doses for Duchenne patients. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparison of sodium carbonate-oxygen and sodium hydroxide-oxygen pretreatments on the chemical composition and enzymatic saccharification of wheat straw.

PubMed

Geng, Wenhui; Huang, Ting; Jin, Yongcan; Song, Junlong; Chang, Hou-Min; Jameel, Hasan

2014-06-01

Pretreatment of wheat straw with a combination of sodium carbonate (Na2CO3) or sodium hydroxide (NaOH) with oxygen (O2) 0.5MPa was evaluated for its delignification ability at relatively low temperature 110°C and for its effect on enzymatic hydrolysis efficiency. In the pretreatment, the increase of alkali charge (as Na2O) up to 12% for Na2CO3 and 6% for NaOH, respectively, resulted in enhancement of lignin removal, but did not significantly degrade cellulose and hemicellulose. When the pretreated solid was hydrolyzed with a mixture of cellulases and hemicellulases, the sugar yield increased rapidly with the lignin removal during the pretreatment. A total sugar yield based on dry matter of raw material, 63.8% for Na2CO3-O2 and 71.9% for NaOH-O2 was achieved under a cellulase loading of 20FPU/g-cellulose. The delignification efficiency and total sugar yield from enzymatic hydrolysis were comparable to the previously reported results at much higher temperature without oxygen. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of bioethanol and value added compounds from wheat straw through combined alkaline/alkaline-peroxide pretreatment.

PubMed

Yuan, Zhaoyang; Wen, Yangbing; Li, Guodong

2018-07-01

An efficient scheme was developed for the conversion of wheat straw (WS) into bioethanol, silica and lignin. WS was pre-extracted with 0.2 mol/L sodium hydroxide at 30 °C for 5 h to remove about 91% of initial silica. Subsequently, the alkaline-pretreated solids were subjected to alkaline hydrogen peroxide (AHP) pretreatment with 40 mg hydrogen peroxide (H 2 O 2 )/g biomass at 50 °C for 7 h to prepare highly digestible substrate. The results of enzymatic hydrolysis demonstrated that the sequential alkaline-AHP pretreated WS was efficiently hydrolyzed at 10% (w/v) solids loading using an enzyme dosage of 10 mg protein/g glucan. The total sugar conversion of 92.4% was achieved. Simultaneous saccharification and co-fermentation (SSCF) was applied to produce ethanol from the two-stage pretreated substrate using Saccharomyces cerevisiae SR8u strain. Ethanol with concentration of 31.1 g/L was produced. Through the proposed process, about 86.4% and 54.1% of the initial silica and lignin were recovered, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Chemical Pretreatment-Independent Saccharifications of Xylan and Cellulose of Rice Straw by Bacterial Weak Lignin-Binding Xylanolytic and Cellulolytic Enzymes

PubMed Central

Teeravivattanakit, Thitiporn; Baramee, Sirilak; Phitsuwan, Paripok; Sornyotha, Somphit; Waeonukul, Rattiya; Pason, Patthra; Tachaapaikoon, Chakrit; Poomputsa, Kanokwan; Kosugi, Akihiko; Sakka, Kazuo

2017-01-01

ABSTRACT Complete utilization of carbohydrate fractions is one of the prerequisites for obtaining economically favorable lignocellulosic biomass conversion. This study shows that xylan in untreated rice straw was saccharified to xylose in one step without chemical pretreatment, yielding 58.2% of the theoretically maximum value by Paenibacillus curdlanolyticus B-6 PcAxy43A, a weak lignin-binding trifunctional xylanolytic enzyme, endoxylanase/β-xylosidase/arabinoxylan arabinofuranohydrolase. Moreover, xylose yield from untreated rice straw was enhanced to 78.9% by adding endoxylanases PcXyn10C and PcXyn11A from the same bacterium, resulting in improvement of cellulose accessibility to cellulolytic enzyme. After autoclaving the xylanolytic enzyme-treated rice straw, it was subjected to subsequent saccharification by a combination of the Clostridium thermocellum endoglucanase CtCel9R and Thermoanaerobacter brockii β-glucosidase TbCglT, yielding 88.5% of the maximum glucose yield, which was higher than the glucose yield obtained from ammonia-treated rice straw saccharification (59.6%). Moreover, this work presents a new environment-friendly xylanolytic enzyme pretreatment for beneficial hydrolysis of xylan in various agricultural residues, such as rice straw and corn hull. It not only could improve cellulose saccharification but also produced xylose, leading to an improvement of the overall fermentable sugar yields without chemical pretreatment. IMPORTANCE Ongoing research is focused on improving “green” pretreatment technologies in order to reduce energy demands and environmental impact and to develop an economically feasible biorefinery. The present study showed that PcAxy43A, a weak lignin-binding trifunctional xylanolytic enzyme, endoxylanase/β-xylosidase/arabinoxylan arabinofuranohydrolase from P. curdlanolyticus B-6, was capable of conversion of xylan in lignocellulosic biomass such as untreated rice straw to xylose in one step without chemical pretreatment. It demonstrates efficient synergism with endoxylanases PcXyn10C and PcXyn11A to depolymerize xylan in untreated rice straw and enhanced the xylose production and improved cellulose hydrolysis. Therefore, it can be considered an enzymatic pretreatment. Furthermore, the studies here show that glucose yield released from steam- and xylanolytic enzyme-treated rice straw by the combination of CtCel9R and TbCglT was higher than the glucose yield obtained from ammonia-treated rice straw saccharification. This work presents a novel environment-friendly xylanolytic enzyme pretreatment not only as a green pretreatment but also as an economically feasible biorefinery method. PMID:28864653

Chemical Pretreatment-Independent Saccharifications of Xylan and Cellulose of Rice Straw by Bacterial Weak Lignin-Binding Xylanolytic and Cellulolytic Enzymes.

PubMed

Teeravivattanakit, Thitiporn; Baramee, Sirilak; Phitsuwan, Paripok; Sornyotha, Somphit; Waeonukul, Rattiya; Pason, Patthra; Tachaapaikoon, Chakrit; Poomputsa, Kanokwan; Kosugi, Akihiko; Sakka, Kazuo; Ratanakhanokchai, Khanok

2017-11-15

Complete utilization of carbohydrate fractions is one of the prerequisites for obtaining economically favorable lignocellulosic biomass conversion. This study shows that xylan in untreated rice straw was saccharified to xylose in one step without chemical pretreatment, yielding 58.2% of the theoretically maximum value by Paenibacillus curdlanolyticus B-6 PcAxy43A, a weak lignin-binding trifunctional xylanolytic enzyme, endoxylanase/β-xylosidase/arabinoxylan arabinofuranohydrolase. Moreover, xylose yield from untreated rice straw was enhanced to 78.9% by adding endoxylanases PcXyn10C and PcXyn11A from the same bacterium, resulting in improvement of cellulose accessibility to cellulolytic enzyme. After autoclaving the xylanolytic enzyme-treated rice straw, it was subjected to subsequent saccharification by a combination of the Clostridium thermocellum endoglucanase CtCel9R and Thermoanaerobacter brockii β-glucosidase TbCglT, yielding 88.5% of the maximum glucose yield, which was higher than the glucose yield obtained from ammonia-treated rice straw saccharification (59.6%). Moreover, this work presents a new environment-friendly xylanolytic enzyme pretreatment for beneficial hydrolysis of xylan in various agricultural residues, such as rice straw and corn hull. It not only could improve cellulose saccharification but also produced xylose, leading to an improvement of the overall fermentable sugar yields without chemical pretreatment. IMPORTANCE Ongoing research is focused on improving "green" pretreatment technologies in order to reduce energy demands and environmental impact and to develop an economically feasible biorefinery. The present study showed that PcAxy43A, a weak lignin-binding trifunctional xylanolytic enzyme, endoxylanase/β-xylosidase/arabinoxylan arabinofuranohydrolase from P. curdlanolyticus B-6, was capable of conversion of xylan in lignocellulosic biomass such as untreated rice straw to xylose in one step without chemical pretreatment. It demonstrates efficient synergism with endoxylanases PcXyn10C and PcXyn11A to depolymerize xylan in untreated rice straw and enhanced the xylose production and improved cellulose hydrolysis. Therefore, it can be considered an enzymatic pretreatment. Furthermore, the studies here show that glucose yield released from steam- and xylanolytic enzyme-treated rice straw by the combination of CtCel9R and TbCglT was higher than the glucose yield obtained from ammonia-treated rice straw saccharification. This work presents a novel environment-friendly xylanolytic enzyme pretreatment not only as a green pretreatment but also as an economically feasible biorefinery method. Copyright © 2017 American Society for Microbiology.

Nitrogen-doped diamond electrode shows high performance for electrochemical reduction of nitrobenzene.

PubMed

Zhang, Qing; Liu, Yanming; Chen, Shuo; Quan, Xie; Yu, Hongtao

2014-01-30

Effective electrode materials are critical to electrochemical reduction, which is a promising method to pre-treat anti-oxidative and bio-refractory wastewater. Herein, nitrogen-doped diamond (NDD) electrodes that possess superior electrocatalytic properties for reduction were fabricated by microwave-plasma-enhanced chemical vapor deposition technology. Nitrobenzene (NB) was chosen as the probe compound to investigate the material's electro-reduction activity. The effects of potential, electrolyte concentration and pH on NB reduction and aniline (AN) formation efficiencies were studied. NDD exhibited high electrocatalytic activity and selectivity for reduction of NB to AN. The NB removal efficiency and AN formation efficiency were 96.5% and 88.4% under optimal conditions, respectively; these values were 1.13 and 3.38 times higher than those of graphite electrodes. Coulombic efficiencies for NB removal and AN formation were 27.7% and 26.1%, respectively; these values were 4.70 and 16.6 times higher than those of graphite electrodes under identical conditions. LC-MS analysis revealed that the dominant reduction pathway on the NDD electrode was NB to phenylhydroxylamine (PHA) to AN. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation on Microalgae Biomass for Bioethanol Production

NASA Astrophysics Data System (ADS)

Chng, L. M.; Lee, K. T.; Chan, D. C. J.

2017-06-01

The depletion of energy resources has triggered worldwide concern for alternative sources, especially renewable energy. Microalgae biomass offers the most promising feedstock for renewable energy because of their impressive efficient growing characteristics and valuable composition. Simple cell structure of the microalgae would simplify the pretreatment technology thus increase the cost-effectiveness of biofuel production. Scenedesmus dimorphus is a carbohydrate-rich microalgae that has potential as biomass for bioethanol. The cultivation of Scenedesmus dimorphus under aeration of carbon dioxide enriched air resulted 1.47 g/L of dry biomass with composition of 12 w/w total lipid, 53.7 w/w carbohydrate and 17.4 protein. Prior to ethanolic fermentation with Saccharomyces cerevisiae, various pre-treatment methods were investigated to release and degrade the complex carbohydrate in cell biomass thus obtaining the maximal amount of digestible sugar for ethanolic yeast. In this study, sulfuric acid was used as hydrolysis agent while amyloglucosidase as enzymatic agent. Dried biomass via hydrothermal acidic hydrolysis yielded sugar which is about 89 of total carbohydrate at reaction temperature of 125 °C and acid concentration of 4 v/v. While combination of organosolv treatment (mixture of methanol and chloroform) with enzymatic hydrolysis yielded comparable amount of sugar with 0.568 g glucose/g treated-biomass. In this study, the significant information in pre-treatment process ensures the sustainability of the biofuel produced.

Surface and ultrastructural characterization of raw and pretreated switchgrass.

PubMed

Donohoe, Bryon S; Vinzant, Todd B; Elander, Richard T; Pallapolu, Venkata Ramesh; Lee, Y Y; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Falls, Matthew; Holtzapple, Mark T; Sierra-Ramirez, Rocio; Shi, Jian; Ebrik, Mirvat A; Redmond, Tim; Yang, Bin; Wyman, Charles E; Hames, Bonnie; Thomas, Steve; Warner, Ryan E

2011-12-01

The US Department of Energy-funded Biomass Refining CAFI (Consortium for Applied Fundamentals and Innovation) project has developed leading pretreatment technologies for application to switchgrass and has evaluated their effectiveness in recovering sugars from the coupled operations of pretreatment and enzymatic hydrolysis. Key chemical and physical characteristics have been determined for pretreated switchgrass samples. Several analytical microscopy approaches utilizing instruments in the Biomass Surface Characterization Laboratory (BSCL) at the National Renewable Energy Laboratory (NREL) have been applied to untreated and CAFI-pretreated switchgrass samples. The results of this work have shown that each of the CAFI pretreatment approaches on switchgrass result in different structural impacts at the plant tissue, cellular, and cell wall levels. Some of these structural changes can be related to changes in chemical composition upon pretreatment. There are also apparently different structural mechanisms that are responsible for achieving the highest enzymatic hydrolysis sugar yields. Copyright © 2011. Published by Elsevier Ltd.

An evaluation of technologies for the heavy metal remediation of dredged sediments.

PubMed

Mulligan, C N; Yong, R N; Gibbs, B F

2001-07-30

Sediments dewatering is frequently necessary after dredging to remediate and treat contaminants. Methods include draining of the water in lagoons with or without coagulants and flocculants, or using presses or centrifuges. Treatment methods are similar to those used for soil and include pretreatment, physical separation, thermal processes, biological decontamination, stabilization/solidification and washing. However, compared to soil treatment, few remediation techniques have been commercially used for sediments. In this paper, a review of the methods that have been used and an evaluation of developed and developing technologies is made. Sequential extraction technique can be a useful tool for determining metal speciation before and after washing. Solidification/stabilization techniques are successful but significant monitoring is required, since the solidification process can be reversible. In addition, the presence of organics can reduce treatment efficiency. Vitrification is applicable for sediments but expensive. Only if a useful glass product can be sold will this process be economically viable. Thermal processes are only applicable for removal of volatile metals, such as mercury and costs are high. Biological processes are under development and have the potential to be low cost. Since few low cost metal treatment processes for sediments are available, there exists significant demand for further development. Pretreatment may be one of the methods that can reduce costs by reducing the volumes of sediments that need to be treated.

Influence of filling ratio and carrier type on organic matter removal in a moving bed biofilm reactor with pretreatment of electrocoagulation in wastewater treatment.

PubMed

Lopez-Lopez, C; Martín-Pascual, J; González-Martínez, A; Calderón, K; González-López, J; Hontoria, E; Poyatos, J M

2012-01-01

At present, there is great concern about limited water resources and water quality, which require a more advanced technology. The Moving Bed Biofilm Reactor (MBBR) has been shown to be an efficient technology for removal of organic matter and nutrients in industrial and urban wastewater treatment. However, there are some pollutants which are more difficult to remove by biological processes, so this process can be improved with additional physical and chemical treatments such as electrocoagulation, which appears to be a promising technology in electrochemical treatments. In this research, urban wastewater was treated in an MBBR plant with an electrocoagulation pre-treatment. K1 from AnoxKaldnes and AQWISE ABC5 from Aqwise were the carriers studied under three different filling ratios (20, 35, and 50%). The experimental pilot plant had four bioreactors with 20 L of operation volume and a common feed tank with 100 L of operation volume. The movement of the carriers was generated by aeration and stirrer systems. Organic matter removal was studied by analysis of soluble chemical oxygen demand (sCOD). The maximum organic matter removal in this MBBR system was 65.8% ± 1.4% and 78.4% ± 0.1% for K1 and Aqwise ABC5 carriers, respectively. Moreover, the bacterial diversity of the biofilm was studied by temperature-gradient gel electrophoresis (TGGE) of PCR-amplified partial 16S rRNA genes. 20 prominent TGGE bands were successfully reamplified and sequenced, being the predominant population: β-Proteobacteria, α-Proteobacteria, and Actinobacteria.

Free ammonia pre-treatment of secondary sludge significantly increases anaerobic methane production.

PubMed

Wei, Wei; Zhou, Xu; Wang, Dongbo; Sun, Jing; Wang, Qilin

2017-07-01

Energy recovery in the form of methane from sludge/wastewater is restricted by the poor and slow biodegradability of secondary sludge. An innovative pre-treatment technology using free ammonia (FA, i.e. NH 3 ) was proposed in this study to increase anaerobic methane production. The solubilisation of secondary sludge was significantly increased after FA pre-treatment at up to 680 mg NH 3 -N/L for 1 day, under which the solubilisation (i.e. 0.4 mg SCOD/mg VS; SCOD: soluble chemical oxygen demand; VS: volatile solids) was >10 times higher than that without FA pre-treatment (i.e. 0.03 mg SCOD/mg VS). Biochemical methane potential assays showed that FA pre-treatment at above 250 mg NH 3 -N/L is effective in improving anaerobic methane production. The highest improvement in biochemical methane potential (B 0 ) and hydrolysis rate (k) was achieved at FA concentrations of 420-680 mg NH 3 -N/L, and was determined as approximately 22% (from 160 to 195 L CH 4 /kg VS added) and 140% (from 0.22 to 0.53 d -1 ) compared to the secondary sludge without pre-treatment. More analysis revealed that the FA induced improvement in B 0 and k could be attributed to the rapidly biodegradable substances rather than the slowly biodegradable substances. Economic and environmental analyses showed that the FA-based technology is economically favourable and environmentally friendly. Since this FA technology aims to use the wastewater treatment plants (WWTPs) waste (i.e. anaerobic digestion liquor) to enhance methane production from the WWTPs, it will set an example for the paradigm shift of the WWTPs from 'linear economy' to 'circular economy'. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pretreatment of furfural industrial wastewater by Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate processes: a comparative study.

PubMed

Yang, C W; Wang, D; Tang, Q

2014-01-01

The Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate (PDS) processes have been applied for the treatment of actual furfural industrial wastewater in this paper. Through the comparative study of the three processes, a suitable pretreatment technology for actual furfural wastewater treatment was obtained, and the mechanism and dynamics process of this technology is discussed. The experimental results show that Fenton technology has a good and stable effect without adjusting pH of furfural wastewater. At optimal conditions, which were 40 mmol/L H₂O₂ initial concentration and 10 mmol/L Fe²⁺ initial concentration, the chemical oxygen demand (COD) removal rate can reach 81.2% after 90 min reaction at 80 °C temperature. The PDS process also has a good performance. The COD removal rate could attain 80.3% when Na₂S₂O₈ initial concentration was 4.2 mmol/L, Fe²⁺ initial concentration was 0.1 mol/L, the temperature remained at 70 °C, and pH value remained at 2.0. The electro-Fenton process was not competent to deal with the high-temperature furfural industrial wastewater and only 10.2% COD was degraded at 80 °C temperature in the optimal conditions (2.25 mA/cm² current density, 4 mg/L Na₂SO₄, 0.3 m³/h aeration rate). For the Fenton, electro-Fenton and PDS processes in pretreatment of furfural wastewater, their kinetic processes follow the pseudo first order kinetics law. The pretreatment pathways of furfural wastewater degradation are also investigated in this study. The results show that furfural and furan formic acid in furfural wastewater were preferentially degraded by Fenton technology. Furfural can be degraded into low-toxicity or nontoxic compounds by Fenton pretreatment technology, which could make furfural wastewater harmless and even reusable.

Oxalic acid pretreatment for mechanical pulping greatly improves paper strength while maintaining scattering power and reducing shives and triglycerides

Treesearch

Ross Swaney; Masood Akhtar; Eric Horn; Michael Lentz; John Klungness; Marc Sabourin

2003-01-01

In this paper we introduce a new technology based on a mild chemical pretreatment process prior to mechanical pulping. Chips are treated with a dilute solution of oxalic acid (OA) for only 10 minute at 130°C, in a typical example. The properties of the pulp produced by this OA process are quite different from those obtained via conventional chemical pretreatments,...

Effect of ultrasonic and ozone pre-treatments on pharmaceutical waste activated sludge's solubilisation, reduction, anaerobic biodegradability and acute biological toxicity.

PubMed

Pei, Jin; Yao, Hong; Wang, Hui; Shan, Dan; Jiang, Yichen; Ma, Lanqianya; Yu, Xiaohua

2015-09-01

Ultrasonic and ozone pre-treatment technologies were employed in this study to improve the anaerobic digestion efficiency of pharmaceutical waste activated sludge. The sludge solubilisation achieved 30.01% (150,000 kJ/kg TS) and 28.10% (0.1g O3/g TS) after ultrasonic treatment and ozone treatment. The anaerobic biodegradability after ultrasonic treatment was higher compared to ozonation due to the higher cumulative methane volume observed after 6 days (249 ml vs 190 ml). The ozonated sludge released the highest concentration of Cu(2+) into the liquid phase (6.640 mg L(-1)) compared to 0.530 mg/L for untreated sludge and 0.991 mg/L for sonicated sludge. The acute toxicity test measured by luminescent bacteria showed that anaerobic digestion could degrade toxic compounds and result in a reduction in toxicity. The main mechanism of action led to some differences in the treated sludge exhibiting higher potential for methane production from pharmaceutical waste sludge with ultrasonic treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermogravimetric kinetics of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata.

PubMed

Wu, Jianguo; Gao, Shi; Wan, Jilin; Zeng, Yelin; Ma, Fuying; Zhang, Xiaoyu

2011-04-01

The thermogravimetric and composition of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata had been studied in this paper. Results indicated that pretreatment by oleaginous fungi C. echinulata could decrease the activation energy and make the pyrolysis more efficient and energy-saving. By bio-pretreatment, the contents of elements agreed with the weight loss, sugar content, and oil contents, especially the sulfur content was greatly decreased, greatly eliminating the inventory of gas contamination such as the emission of SOx and making the pyrolysis more environmentally friendly. Therefore, corn stalk with sugar pretreated by oleaginous fungi C. echinulata should be a good pyrolysis material to obtain high quality bio-oil. Copyright © 2011 Elsevier Ltd. All rights reserved.

Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge

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

Uma Rani, R.; Adish Kumar, S.; Kaliappan, S.

2013-05-15

Highlights: ► Microwave pretreatment of dairy WAS was studied. ► MW pretreatment at 70% intensity for 12 min, COD solubilization was 18.6%. ► Biogas production and SS reduction was 35% and 14% higher than control. ► In digester at 15 days SRT with medium OLR, SS and VS reduction was 67% and 64%. ► Biogas and methane production was 57% and 49% higher than control, in digesters. - Abstract: Microwave (MW) irradiation is one of the new and possible methods used for pretreating the sludge. Following its use in different fields, this MW irradiation method has proved to be moremore » appropriate in the field of environmental research. In this paper, we focused on the effects of MW irradiation at different intensities on solubilization, biodegradation and anaerobic digestion of sludge from the dairy sludge. The changes in the soluble fractions of the organic matter, the biogas yield, the methane content in the biogas were used as control parameters for evaluating the efficiency of the MW pretreatment. Additionally, the energetic efficiency was also examined. In terms of an energetic aspect, the most economical pretreatment of sludge was at 70% intensity for 12 min irradiation time. At this, COD solubilization, SS reduction and biogas production were found to be 18.6%, 14% and 35% higher than the control, respectively. Not only the increase in biogas production was investigated, excluding protein and carbohydrate hydrolysis was also performed successfully by this microwave pretreatment even at low irradiation energy input. Also, experiments were carried out in semi continuous anaerobic digesters, with 3.5 L working volume. Combining microwave pretreatment with anaerobic digestion led to 67%, 64% and 57% of SS reduction, VS reduction and biogas production higher than the control, respectively.« less

A new approach to enhance the selectivity of liberation and the efficiency of coal grinding

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

Wang, X.H.; Guo, Q.; Parekh, B.K.

1993-12-31

An innovative process has been developed at the University of Kentucky to enhance the liberation of mineral matter from coal and the efficiency of grinding energy utilization. Through treating coal with a swelling agent prior to grinding, the grindability of coals can be considerably improved. The Hardgrove Grindability tests show that the HGI of a KY. No. 9 coal increases from 41 for the untreated coal to 60-90 after swelling pretreatment for a short time. Batch stirred ball mill grinding results demonstrate that this new technique has a great potential in reducing the energy consumption of fine coal grinding. Dependingmore » on the pretreatment conditions, the specific energy consumption of producing less than 10 {mu}m product is reduced to 41-60% of that of the untreated coal feed. The production rate of -10 {mu}m particles increases considerably for the pretreated coal. The Energy-Dispersive-X-ray Analytical Scanning Electron Microscope (EDXA-SEM) studies clearly demonstrate that intensive cracking and fracturing were developed during the swelling pretreatment. Cracks and fractures were induced in the coal matrix, preferentially along the boundaries between the pyrite particles and coal matrix. These may be responsible for enhancement in both the efficiency of grinding energy consumption and the selectivity of liberation.« less

A comparison of the autohydrolysis and ammonia fiber explosion (AFEX) pretreatments on the subsequent enzymatic hydrolysis of coastal Bermuda grass.

PubMed

Lee, Jung Myoung; Jameel, Hasan; Venditti, Richard A

2010-07-01

Two distinct pretreatment technologies, autohydrolysis and AFEX, have been applied to coastal Bermuda grass (CBG) followed by enzymatic hydrolysis in order to compare the effects of pretreatment on the subsequent sugar generation. Furthermore, the influence of structural features from each pretreatment on biomass digestibility was characterized with SEM, ATR-FTIR, and XRD. Enzymatic conversion of pretreated solids from the pretreatments increased with elevated temperature and longer residence times. AFEX pretreatment at 100 degrees C for 30 min produced a sugar yield of 94.8% of theoretical possible with 30 FPU/g enzymatic loading, the maximum achieved with AFEX. It was also shown that with autohydrolysis at 170 degrees C for 60 min that 55.4% sugar yield of the theoretical possible was produced with a 30 FPU/g enzymatic loading, the maximum with autohydrolysis. AFEX pretreatment does not change the chemical composition of CBG but autohydrolysis reduces hemicellulose content in the pretreated solids. Both pretreatments cause re-localization of lignin components. There was no observed correlation between crystallinity and enzyme digestibility of the pretreated solids. AFEX pretreatment developed more enzymatic accessibility to pretreated solids of CBG than did autohydrolysis pretreatment, leading to more sugar generation through the whole process. The total amount of sugars accounted for with autohydrolysis decreases with increasing temperature, consistent with increased byproduct generation via thermal degradation reactions. Published by Elsevier Ltd.

Synergism of cellulase, xylanase, and pectinase on hydrolyzing sugarcane bagasse resulting from different pretreatment technologies.

PubMed

Li, Jingbo; Zhou, Pengfei; Liu, Hongmei; Xiong, Chunjiang; Lin, Jianghai; Xiao, Wenjuan; Gong, Yingxue; Liu, Zehuan

2014-03-01

Sugarcane bagasse (SCB) resulting from different pretreatments was hydrolyzed by enzyme cocktails based on replacement of cellulase (Celluclast 1.5 L:Novozym 188=1FPU:4pNPGU) by xylanase or pectinase at different proportions. Lignin content of NaOH pretreated SCB and hemicellulose content of H2SO4 pretreated SCB were the lowest. NaOH pretreatment showed the best for monosaccharide production among the four pretreatments. Synergism was apparently observed between cellulase and xylanase for monosaccharide production from steam exploded SCB (SESB), NaOH, and H2O2 pretreated SCB. No synergism was observed between cellulase and pectinase for producing glucose. Additionally, no synergism was present when H2SO4 pretreated SCB was used. Replacement of 20% of the cellulase by xylanase enhanced the glucose yield by 6.6%, 8.8%, and 9.5% from SESB, NaOH, and H2O2 pretreated SCB, respectively. Degree of synergism between cellulase and xylanase had positive relationship with xylan content and was affected by hydrolysis time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Monitoring and Analyzing Process Streams Towards Understanding Ionic Liquid Pretreatment of Switchgrass (Panicum virgatum L.)

USDA-ARS?s Scientific Manuscript database

Fundamental understanding of biomass pretreatment and its influence on sacchrification kinetics, total sugar yield, and inhibitor formation is essential to develop efficient next-generation biofuels strategies, capable of displacing fossil fuels at a commercial level. In this study we investigate t...

PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

EPA Science Inventory

Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,
a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causes
swelling and efficient delignification of biomass at high temperatures. The ARP
process solubilizes abou...

Improved sugar yields from biomass sorghum feedstocks: comparing low-lignin mutants and pretreatment chemistries.

PubMed

Godin, Bruno; Nagle, Nick; Sattler, Scott; Agneessens, Richard; Delcarte, Jérôme; Wolfrum, Edward

2016-01-01

For biofuel production processes to be economically efficient, it is essential to maximize the production of monomeric carbohydrates from the structural carbohydrates of feedstocks. One strategy for maximizing carbohydrate production is to identify less recalcitrant feedstock cultivars by performing some type of experimental screening on a large and diverse set of candidate materials, or by identifying genetic modifications (random or directed mutations or transgenic plants) that provide decreased recalcitrance. Economic efficiency can also be increased using additional pretreatment processes such as deacetylation, which uses dilute NaOH to remove the acetyl groups of hemicellulose prior to dilute acid pretreatment. In this work, we used a laboratory-scale screening tool that mimics relevant thermochemical pretreatment conditions to compare the total sugar yield of three near-isogenic brown midrib ( bmr ) mutant lines and the wild-type (WT) sorghum cultivar. We then compared results obtained from the laboratory-scale screening pretreatment assay to a large-scale pretreatment system. After pretreatment and enzymatic hydrolysis, the bmr mutants had higher total sugar yields than the WT sorghum cultivar. Increased pretreatment temperatures increased reactivity for all sorghum samples reducing the differences observed at lower reaction temperatures. Deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples, and reduced the differences in total sugar yields among them, but solubilized a sizable fraction of the non-structural carbohydrates. The general trends of increased total sugar yield in the bmr mutant compared to the WT seen at the laboratory scale were observed at the large-scale system. However, in the larger reactor system, the measured total sugar yields were lower and the difference in total sugar yield between the WT and bmr sorghum was larger. Sorghum bmr mutants, which have a reduced lignin content showed higher total sugar yields than the WT cultivar after dilute acid pretreatment and enzymatic hydrolysis. Deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples. However, since deacetylation also solubilizes a large fraction of the non-structural carbohydrates, the ability to derive value from these solubilized sugars will depend greatly on the proposed conversion process.

Improved sugar yields from biomass sorghum feedstocks: comparing low-lignin mutants and pretreatment chemistries

DOE PAGES

Godin, Bruno; Nagle, Nick; Sattler, Scott; ...

2016-11-21

For biofuel production processes to be economically efficient, it is essential to maximize the production of monomeric carbohydrates from the structural carbohydrates of feedstocks. One strategy for maximizing carbohydrate production is to identify less recalcitrant feedstock cultivars by performing some type of experimental screening on a large and diverse set of candidate materials, or by identifying genetic modifications (random or directed mutations or transgenic plants) that provide decreased recalcitrance. Economic efficiency can also be increased using additional pretreatment processes such as deacetylation, which uses dilute NaOH to remove the acetyl groups of hemicellulose prior to dilute acid pretreatment. In thismore » work, we used a laboratory-scale screening tool that mimics relevant thermochemical pretreatment conditions to compare the total sugar yield of three near-isogenic brown midrib (bmr) mutant lines and the wild-type (WT) sorghum cultivar. We then compared results obtained from the laboratory-scale screening pretreatment assay to a large-scale pretreatment system. After pretreatment and enzymatic hydrolysis, the bmr mutants had higher total sugar yields than the WT sorghum cultivar. Increased pretreatment temperatures increased reactivity for all sorghum samples reducing the differences observed at lower reaction temperatures. Deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples, and reduced the differences in total sugar yields among them, but solubilized a sizable fraction of the non-structural carbohydrates. The general trends of increased total sugar yield in the bmr mutant compared to the WT seen at the laboratory scale were observed at the large-scale system. However, in the larger reactor system, the measured total sugar yields were lower and the difference in total sugar yield between the WT and bmr sorghum was larger. Sorghum bmr mutants, which have a reduced lignin content showed higher total sugar yields than the WT cultivar after dilute acid pretreatment and enzymatic hydrolysis. In conclusion, deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples. However, since deacetylation also solubilizes a large fraction of the non-structural carbohydrates, the ability to derive value from these solubilized sugars will depend greatly on the proposed conversion process.« less

Improved sugar yields from biomass sorghum feedstocks: comparing low-lignin mutants and pretreatment chemistries

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

Godin, Bruno; Nagle, Nick; Sattler, Scott

For biofuel production processes to be economically efficient, it is essential to maximize the production of monomeric carbohydrates from the structural carbohydrates of feedstocks. One strategy for maximizing carbohydrate production is to identify less recalcitrant feedstock cultivars by performing some type of experimental screening on a large and diverse set of candidate materials, or by identifying genetic modifications (random or directed mutations or transgenic plants) that provide decreased recalcitrance. Economic efficiency can also be increased using additional pretreatment processes such as deacetylation, which uses dilute NaOH to remove the acetyl groups of hemicellulose prior to dilute acid pretreatment. In thismore » work, we used a laboratory-scale screening tool that mimics relevant thermochemical pretreatment conditions to compare the total sugar yield of three near-isogenic brown midrib (bmr) mutant lines and the wild-type (WT) sorghum cultivar. We then compared results obtained from the laboratory-scale screening pretreatment assay to a large-scale pretreatment system. After pretreatment and enzymatic hydrolysis, the bmr mutants had higher total sugar yields than the WT sorghum cultivar. Increased pretreatment temperatures increased reactivity for all sorghum samples reducing the differences observed at lower reaction temperatures. Deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples, and reduced the differences in total sugar yields among them, but solubilized a sizable fraction of the non-structural carbohydrates. The general trends of increased total sugar yield in the bmr mutant compared to the WT seen at the laboratory scale were observed at the large-scale system. However, in the larger reactor system, the measured total sugar yields were lower and the difference in total sugar yield between the WT and bmr sorghum was larger. Sorghum bmr mutants, which have a reduced lignin content showed higher total sugar yields than the WT cultivar after dilute acid pretreatment and enzymatic hydrolysis. In conclusion, deacetylation prior to dilute acid pretreatment increased the total sugar yield for all four sorghum samples. However, since deacetylation also solubilizes a large fraction of the non-structural carbohydrates, the ability to derive value from these solubilized sugars will depend greatly on the proposed conversion process.« less

Li+-Permeable Film on Lithium Anode for Lithium Sulfur Battery.

PubMed

Yang, Yan-Bo; Liu, Yun-Xia; Song, Zhiping; Zhou, Yun-Hong; Zhan, Hui

2017-11-08

Lithium-sulfur (Li-S) battery is an important candidate for next-generation energy storage. However, the reaction between polysulfide and lithium (Li) anode brings poor cycling stability, low Coulombic efficiency, and Li corrosion. Herein, we report a Li protection technology. Li metal was treated in crown ether containing electrolyte, and thus, treated Li was further used as the anode in Li-S cell. Due to the coordination between Li + and crown ether, a Li + -permeable film can be formed on Li, and the film is proved to be able to block the detrimental reaction between Li anode and polysulfide. By using the Li anode pretreated in 2 wt % B15C5-containing electrolyte, Li-S cell exhibits significantly improved cycling stability, such as∼900 mAh g -1 after 100 cycles, and high Coulombic efficiency of>93%. In addition, such effect is also notable when high S loading condition is applied.

Simultaneous separation/enrichment and detection of trace ciprofloxacin and lomefloxacin in food samples using thermosensitive smart polymers aqueous two-phase flotation system combined with HPLC.

PubMed

Lu, Yang; Chen, Bo; Yu, Miao; Han, Juan; Wang, Yun; Tan, Zhenjiang; Yan, Yongsheng

2016-11-01

Smart polymer aqueous two phase flotation system (SPATPF) is a new separation and enrichment technology that integrated the advantages of the three technologies, i.e., aqueous two phase system, smart polymer and flotation sublation. Ethylene oxide and propylene oxide copolymer (EOPO)-(NH4)2SO4 SPATPF is a pretreatment technique, and it is coupled with high-performance liquid chromatography to analyze the trace ciprofloxacin and lomefloxacin in real food samples. The optimized conditions of experiment were determined in the multi-factor experiment by using response surface methodology. The flotation efficiency of lomefloxacin and ciprofloxacin was 94.50% and 98.23% under the optimized conditions. The recycling experimentsshowed that the smart polymer EOPO could use repeatedly, which will reduce the cost in the future application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process simulation of ethanol production from biomass gasification and syngas fermentation.

PubMed

Pardo-Planas, Oscar; Atiyeh, Hasan K; Phillips, John R; Aichele, Clint P; Mohammad, Sayeed

2017-12-01

The hybrid gasification-syngas fermentation platform can produce more bioethanol utilizing all biomass components compared to the biochemical conversion technology. Syngas fermentation operates at mild temperatures and pressures and avoids using expensive pretreatment processes and enzymes. This study presents a new process simulation model developed with Aspen Plus® of a biorefinery based on a hybrid conversion technology for the production of anhydrous ethanol using 1200tons per day (wb) of switchgrass. The simulation model consists of three modules: gasification, fermentation, and product recovery. The results revealed a potential production of about 36.5million gallons of anhydrous ethanol per year. Sensitivity analyses were also performed to investigate the effects of gasification and fermentation parameters that are keys for the development of an efficient process in terms of energy conservation and ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lignin structural alterations in thermochemical pretreatments with limited delignification

DOE PAGES

Pu, Yunqiao; Hu, Fan; Huang, Fang; ...

2015-08-02

Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion,more » and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.« less

Enhanced membrane filtration of wood hydrolysates for hemicelluloses recovery by pretreatment with polymeric adsorbents.

PubMed

Koivula, Elsi; Kallioinen, Mari; Sainio, Tuomo; Antón, Enrique; Luque, Susana; Mänttäri, Mika

2013-09-01

In this study adsorption of foulants from birch and pine/eucalyptus wood hydrolysates on two polymeric adsorbents was studied aiming to reduce the membrane fouling. The effect of the pretreatment of hydrolysate on polyethersulphone membrane performance was studied in dead-end filtration experiments. Adsorption pretreatment improved significantly filtration capacity and decreased membrane fouling. Especially high-molecular weight lignin was efficiently removed. A multistep adsorption pretreatment was found to reduce the amount of adsorbent required. While large adsorbent amount was shown to increase flux in filtration, it was found also to cause significant hemicellulose losses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pretreatment Capabilities and Benefits of Electrocoagulation

DTIC Science & Technology

2004-12-01

PRETREATMENT CAPABILITIES AND BENEFITS OF ELECTROCOAGULATION Michael Mickley Mickley & Associates Boulder, Colorado...DATES COVERED - 4. TITLE AND SUBTITLE Pretreatment Capabilities and Benefits of Electrocoagulation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...4 2.1 Background for Electrocoagulation Technology ………………………. 4 2.1.1 Applications ……………………………………………………. 4 2.1.2

Electricity generation directly using human feces wastewater for life support system

NASA Astrophysics Data System (ADS)

Fangzhou, Du; Zhenglong, Li; Shaoqiang, Yang; Beizhen, Xie; Hong, Liu

2011-05-01

Wastewater reuse and power regeneration are key issues in the research of bioregeneration life support system (BLSS). Microbial fuel cell (MFC) can generate electricity during the process of wastewater treatment, which might be promising to solve the two problems simultaneously. We used human feces wastewater containing abundant organic compounds as the substrate of MFC to generate electricity, and the factors concerning electricity generation capacity were investigated. The removal efficiency of total chemical oxygen demand (TCOD), Soluble chemical oxygen demand (SCOD) and NH4+ reached 71%, 88% and 44%, respectively with two-chamber MFC when it was fed with the actual human feces wastewater and operated for 190 h. And the maximum power density reached 70.8 mW/m 2, which implicated that MFC technology was feasible and appropriate for treating human feces wastewater. In order to improve the power generation of MFC further, human feces wastewater were fermented before poured into MFC, and the result showed that fermentation pretreatment could improve the MFC output obviously. The maximum power density of MFC fed with pretreated human feces wastewater was 22 mW/m 2, which was 47% higher than that of the control without pretreatment (15 mW/m 2). Furthermore, the structure of MFC was studied and it was found that both enlarging the area of electrodes and shortening the distance between electrodes could increase the electricity generation capacity. Finally, an automatic system, controlled by time switches and electromagnetic valves, was established to process one person's feces wastewater (1 L/d) while generating electricity. The main parts of this system comprised a pretreatment device and 3 one-chamber air-cathode MFCs. The total power could reach 787.1 mW and power density could reach the maximum of about 240 mW/m 2.

Use of ozone in a pilot-scale plant for textile wastewater pre-treatment: physico-chemical efficiency, degradation by-products identification and environmental toxicity of treated wastewater.

PubMed

Somensi, Cleder A; Simionatto, Edésio L; Bertoli, Sávio L; Wisniewski, Alberto; Radetski, Claudemir M

2010-03-15

In this study, ozonation of raw textile wastewater was conducted in a pilot-scale plant and the efficiency of this treatment was evaluated based on the parameters color removal and soluble organic matter measured as chemical oxygen demand (COD), at two pH values (9.1 and 3.0). Identification of intermediate and final degradation products of ozone pre-treatment, as well as the evaluation of the final ecotoxicity (Lumistox test) of pre-treated wastewater, was also carried out. After 4h of ozone treatment with wastewater recirculation (flow rate of 0.45 m(3)h(-1)) the average efficiencies for color removal were 67.5% (pH 9.1) and 40.6% (pH 3.0), while COD reduction was 25.5% (pH 9.1) and 18.7% (pH 3.0) for an ozone production capacity of 20 g h(-1). Furthermore, ozonation enhances the biodegradability of textile wastewater (BOD(5)/COD ratios) by a factor of up to 6.8-fold. A GC-MS analysis of pre-treated textile wastewater showed that some products were present at the end of the pre-treatment time. In spite of this fact, the bacterial luminescence inhibition test (Lumistox test) showed a significant toxicity reduction on comparing the raw and treated textile wastewater. In conclusion, pre-ozonation of textile wastewater is an important step in terms of improving wastewater biodegradability, as well as reducing acute ecotoxicity, which should be removed completely through sequential biological treatment. (c) 2009. Published by Elsevier B.V.

Improving the amenability of municipal waste activated sludge for biological pretreatment by phase-separated sludge disintegration method.

PubMed

Kavitha, S; Adish Kumar, S; Kaliappan, S; Yeom, Ick Tae; Rajesh Banu, J

2014-10-01

The significance of citric acid, a cation binding agent, was investigated for the exclusion of extracellular polymeric substance (EPS) from waste activated sludge (WAS) and anaerobic biodegradability following enzymatic bacterial pretreatment. EPS was removed with 0.05 g/g SS of citric acid. The results of pretreatment found that the suspended solids reduction and chemical oxygen demand solubilisation were 21.4% and 16.2% for deflocculated-bacterially pretreated sludge, 14.28% and 10.0% for flocculated sludge (without EPS removal and bacterially pretreated) and 8.5% and 6.5% for control sludge (raw sludge), respectively. Further assessing anaerobic biodegradability, the biogas yield potential of deflocculated and bacterially pretreated, flocculated, and control sludges were found to be 0.455 L/(g VS), 0.343 L/(g VS), and 0.209 L/(g VS), respectively. Thus, phase-separated disintegration enhanced anaerobic biodegradability efficiently. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of biological pretreatments in enhancing corn straw biogas production.

PubMed

Zhong, Weizhang; Zhang, Zhongzhi; Luo, Yijing; Sun, Shanshan; Qiao, Wei; Xiao, Meng

2011-12-01

A biological pretreatment with new complex microbial agents was used to pretreat corn straw at ambient temperature (about 20°C) to improve its biodegradability and anaerobic biogas production. A complex microbial agent dose of 0.01% (w/w) and pretreatment time of 15 days were appropriate for biological pretreatment. These treatment conditions resulted in 33.07% more total biogas yield, 75.57% more methane yield, and 34.6% shorter technical digestion time compared with the untreated sample. Analyses of chemical compositions showed 5.81-25.10% reductions in total lignin, cellulose, and hemicellulose contents, and 27.19-80.71% increases in hot-water extractives; these changes contributed to the enhancement of biogas production. Biological pretreatment could be an effective method for improving biodegradability and enhancing the highly efficient biological conversion of corn straw into bioenergy. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Hashim, Muzna; Univ. of Tennessee, Knoxville, TN; Sun, Qining

The aim of this work was to evaluate the efficiency of an ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) pretreatment (110 C for 30 min) in comparison to high severity autohydrolysis pretreatment in terms of delignification, cellulose crystallinity and enzymatic digestibility. The increase in severity of autohydrolysis pretreatment had positive effect on glucan digestibility, but was limited by the crystallinity of cellulose. [C4mim][OAc] pretreated sugarcane bagasse exhibited a substantial decrease in lignin content, reduced cellulose crystallinity, and enhanced glucan and xylan digestibility. Glucan and xylan digestibility was determined as 97.4% and 98.6% from [C4mim][OAc] pretreated bagasse, and 62.1% and 57.5% frommore » the bagasse autohydrolyzed at 205 C for 6 min, respectively. The results indicated the improved digestibility and hydrolysis rates after [C4mim][OAc] pretreatment when compared against a comparable autohydrolyzed biomass.« less

Steam explosion pretreatment for enhancing biogas production of late harvested hay.

PubMed

Bauer, Alexander; Lizasoain, Javier; Theuretzbacher, Franz; Agger, Jane W; Rincón, María; Menardo, Simona; Saylor, Molly K; Enguídanos, Ramón; Nielsen, Paal J; Potthast, Antje; Zweckmair, Thomas; Gronauer, Andreas; Horn, Svein J

2014-08-01

Grasslands are often abandoned due to lack of profitability. Extensively cultivating grassland for utilization in a biogas-based biorefinery concept could mend this problem. Efficient bioconversion of this lignocellulosic biomass requires a pretreatment step. In this study the effect of different steam explosion conditions on hay digestibility have been investigated. Increasing severity in the pretreatment induced degradation of the hemicellulose, which at the same time led to the production of inhibitors and formation of pseudo-lignin. Enzymatic hydrolysis showed that the maximum glucose yields were obtained under pretreatment at 220 °C for 15 min, while higher xylose yields were obtained at 175 °C for 10 min. Pretreatment of hay by steam explosion enhanced 15.9% the methane yield in comparison to the untreated hay. Results indicate that hay can be effectively converted to methane after steam explosion pretreatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Integrated chemical and multi-scale structural analyses for the processes of acid pretreatment and enzymatic hydrolysis of corn stover.

PubMed

Chen, Longjian; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Zhang, Haiyan; Han, Lujia

2016-05-05

Corn stover was pretreated with acid under moderate conditions (1.5%, w/w, 121°C, 60min), and kinetic enzymolysis experiments were performed on the pretreated substrate using a mixture of Celluclast 1.5L (20FPU/g dry substrate) and Novozyme 188 (40CBU/g dry substrate). Integrated chemical and multi-scale structural methods were then used to characterize both processes. Chemical analysis showed that acid pretreatment removed considerable hemicellulose (from 19.7% in native substrate to 9.28% in acid-pretreated substrate) and achieved a reasonably high conversion efficiency (58.63% of glucose yield) in the subsequent enzymatic hydrolysis. Multi-scale structural analysis indicated that acid pretreatment caused structural changes via cleaving acetyl linkages, solubilizing hemicellulose, relocating cell wall surfaces and enlarging substrate porosity (pore volume increased from 0.0067cm(3)/g in native substrate to 0.019cm(3)/g in acid-pretreated substrate), thereby improving the polysaccharide digestibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhancement of biogas production from microalgal biomass through cellulolytic bacterial pretreatment.

PubMed

Kavitha, S; Subbulakshmi, P; Rajesh Banu, J; Gobi, Muthukaruppan; Tae Yeom, Ick

2017-06-01

Generation of bioenergy from microalgal biomass has been a focus of interest in recent years. The recalcitrant nature of microalgal biomass owing to its high cellulose content limits methane generation. Thus, the present study investigates the effect of bacterial-based biological pretreatment on liquefaction of the microalga Chlorella vulgaris prior to anaerobic biodegradation to gain insights into energy efficient biomethanation. Liquefaction of microalgae resulted in a higher biomass stress index of about 18% in the experimental (pretreated with cellulose-secreting bacteria) vs. 11.8% in the control (non-pretreated) group. Mathematical modelling of the biomethanation studies implied that bacterial pretreatment had a greater influence on sustainable methane recovery, with a methane yield of about 0.08 (g Chemical Oxygen Demand/g Chemical Oxygen Demand), than did control pretreatment, with a yield of 0.04 (g Chemical Oxygen Demand/g Chemical Oxygen Demand). Energetic analysis of the proposed method of pretreatment showed a positive energy ratio of 1.04. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Different Sugar Beet Pulp Pretreatments on Biogas Production Efficiency.

PubMed

Ziemiński, Krzysztof; Kowalska-Wentel, Monika

2017-03-01

The objective of this study was to determine the effect of different sugar beet pulp (SBP) pretreatments on biogas yield from anaerobic digestion. SBP was subjected to grinding, thermal-pressure processing, enzymatic hydrolysis, or combination of these pretreatments. It was observed that grinding of SBP to 2.5-mm particles resulted in the cumulative biogas productivity of 617.2 mL/g volatile solids (VS), which was 20.2 % higher compared to the biogas yield from the not pretreated SBP, and comparable to that from not ground, enzymatically hydrolyzed SBP. The highest cumulative biogas productivity, 898.7 mL/g VS, was obtained from the ground, thermal-pressure pretreated and enzymatically hydrolyzed SBP. The latter pretreatment variant enabled to achieve the highest glucose concentration (24.765 mg/mL) in the enzymatic hydrolysates. The analysis of energy balance showed that the increase in the number of SBP pretreatment operations significantly reduced the gain of electric energy.

Comparison of autohydrolysis and ionic liquid 1-butyl-3-methylimidazolium acetate pretreatment to enhance enzymatic hydrolysis of sugarcane bagasse

DOE PAGES

Hashim, Muzna; Univ. of Tennessee, Knoxville, TN; Sun, Qining; ...

2016-11-02

The aim of this work was to evaluate the efficiency of an ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) pretreatment (110 C for 30 min) in comparison to high severity autohydrolysis pretreatment in terms of delignification, cellulose crystallinity and enzymatic digestibility. The increase in severity of autohydrolysis pretreatment had positive effect on glucan digestibility, but was limited by the crystallinity of cellulose. [C4mim][OAc] pretreated sugarcane bagasse exhibited a substantial decrease in lignin content, reduced cellulose crystallinity, and enhanced glucan and xylan digestibility. Glucan and xylan digestibility was determined as 97.4% and 98.6% from [C4mim][OAc] pretreated bagasse, and 62.1% and 57.5% frommore » the bagasse autohydrolyzed at 205 C for 6 min, respectively. The results indicated the improved digestibility and hydrolysis rates after [C4mim][OAc] pretreatment when compared against a comparable autohydrolyzed biomass.« less

Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

PubMed

Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

2017-08-01

Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of municipal sludge and grease co-digestion using disintegration technologies.

PubMed

Bouchy, L; Pérez, A; Camacho, P; Rubio, P; Silvestre, G; Fernández, B; Cano, R; Polanco, M; Díaz, N

2012-01-01

Many drivers tend to foster the development of renewable energy production in wastewater treatment plants as many expectations rely upon energy recovery from sewage sludge, for example through biogas use. This paper is focused on the assessment of grease waste (GW) as an adequate substrate for co-digestion with municipal sludge, as it has a methane potential of 479-710 LCH(4)/kg VS, as well as the evaluation of disintegration technologies as a method to optimize the co-digestion process. With this objective three different pre-treatments have been selected for evaluation: thermal hydrolysis, ultrasound and enzymatic treatment. Results have shown that co-digestion processes without pre-treatment had a maximum increment of 128% of the volumetric methane productivity when GW addition was 23% inlet (at 20 days of HRT and with an OLR of 3.0 kg COD/m(3)d), compared with conventional digestion of sewage sludge alone. Concerning the application of the selected disintegration technologies, all pre-treatments showed improvements in terms of methane yield (51.8, 89.5 and 57.6% more for thermal hydrolysis, ultrasound and enzymatic treatment, respectively, compared with non-pretreated wastes), thermal hydrolysis of GW and secondary sludge being the best configuration as it improved the solubilization of the organic matter and the hydrodynamic characteristics of digestates.

Evaluation of Multiple Immunoassay Technology Platforms to Select the Anti-Drug Antibody Assay Exhibiting the Most Appropriate Drug and Target Tolerance

PubMed Central

Collet-Brose, Justine

2016-01-01

The aim of this study was, at the assay development stage and thus with an appropriate degree of rigor, to select the most appropriate technology platform and sample pretreatment procedure for a clinical ADA assay. Thus, ELISA, MSD, Gyrolab, and AlphaLISA immunoassay platforms were evaluated in association with target depletion and acid dissociation sample pretreatment steps. An acid dissociation step successfully improved the drug tolerance for all 4 technology platforms and the required drug tolerance was achieved with the Gyrolab and MSD platforms. The target tolerance was shown to be better for the ELISA format, where an acid dissociation treatment step alone was sufficient to achieve the desired target tolerance. However, inclusion of a target depletion step in conjunction with the acid treatment raised the target tolerance to the desired level for all of the technologies. A higher sensitivity was observed for the MSD and Gyrolab assays and the ELISA, MSD, and Gyrolab all displayed acceptable interdonor variability. This study highlights the usefulness of evaluating the performance of different assay platforms at an early stage in the assay development process to aid in the selection of the best fit-for-purpose technology platform and sample pretreatment steps. PMID:27243038

Evaluation of physical structural features on influencing enzymatic hydrolysis efficiency of micronized wood

Treesearch

Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

2016-01-01

Enzymatic hydrolysis of lignocellulosic biomass is highly dependent on the changes in structural features after pretreatment. Mechanical milling pretreatment is an effective approach to alter the physical structure of biomass and thus improve enzymatic hydrolysis. This study examined the influence of structural characteristics on the enzymatic hydrolysis of micronized...

Enhanced Dissolution of Platinum Group Metals Using Electroless Iron Deposition Pretreatment

NASA Astrophysics Data System (ADS)

Taninouchi, Yu-ki; Okabe, Toru H.

2017-12-01

In order to develop a new method for efficiently recovering platinum group metals (PGMs) from catalyst scraps, the authors investigated an efficient dissolution process where the material was pretreated by electroless Fe deposition. When Rh-loaded alumina powder was kept in aqua regia at 313 K (40 °C) for 30 to 60 minutes, the Rh hardly dissolved. Meanwhile, after electroless Fe plating using a bath containing sodium borohydride and potassium sodium tartrate as the reducing and complexing agents, respectively, approximately 60 pct of Rh was extracted by aqua regia at 313 K (40 °C) after 30 minutes. Furthermore, when heat treatment was performed at 1200 K (927 °C) for 60 minutes in vacuum after electroless plating, the extraction of Rh approached 100 pct for the same leaching conditions. The authors also confirmed that the Fe deposition pretreatment enhanced the dissolution of Pt and Pd. These results indicate that an effective and environmentally friendly process for the separation and extraction of PGMs from catalyst scraps can be developed utilizing this Fe deposition pretreatment.

Solubilization of municipal sewage waste activated sludge by novel lytic bacterial strains.

PubMed

Lakshmi, M Veera; Merrylin, J; Kavitha, S; Kumar, S Adish; Banu, J Rajesh; Yeom, Ick-Tae

2014-02-01

Extracellular polymeric substances (EPS) are an extracellular matrix found in sludge which plays a crucial role in flocculation by interacting with the organic solids. Therefore, to enhance pretreatment of sludge, EPS have to be removed. In this study, EPS were removed with a chemical extractant, NaOH, to enhance the bacterial pretreatment. A lysozyme secreting bacterial consortium was isolated from the waste activated sludge (WAS). The result of density gradient gel electrophoresis (DGGE) analysis revealed that the isolated consortium consists of two strains. The two novel strains isolated were named as Jerish03 (NCBI accession number KC597266) and Jerish 04 (NCBI accession number KC597267) and they belong to the genus Bacillus. Pretreatment with these novel strains enhances the efficiency of the aerobic digestion of sludge. Sludge treated with the lysozyme secreting bacterial consortium produced 29 % and 28.5 % increase in suspended solids (SS) reduction and chemical oxygen demand (COD) removal compared to the raw activated sludge (without pretreatment) during aerobic digestion. It is specified that these two novel strains had a high potential to enhance WAS degradation efficiency in aerobic digestion.

Improvement of the energy conversion efficiency of Chlorella pyrenoidosa biomass by a three-stage process comprising dark fermentation, photofermentation, and methanogenesis.

PubMed

Xia, Ao; Cheng, Jun; Ding, Lingkan; Lin, Richen; Huang, Rui; Zhou, Junhu; Cen, Kefa

2013-10-01

The effects of pre-treatment methods on saccharification and hydrogen fermentation of Chlorella pyrenoidosa biomass were investigated. When raw biomass and biomass pre-treated by steam heating, by microwave heating, and by ultrasonication were used as feedstock, the hydrogen yields were only 8.8-12.7 ml/g total volatile solids (TVS) during dark fermentation. When biomass was pre-treated by steam heating with diluted acid and by microwave heating with diluted acid, the dark hydrogen yields significantly increased to 75.6 ml/g TVS and 83.3 ml/g TVS, respectively. Steam heating with diluted acid is the preferred pre-treatment method of C. pyrenoidosa biomass to improve hydrogen yield during dark fermentation and photofermentation, which is followed by methanogenesis to increase energy conversion efficiency (ECE). A total hydrogen yield of 198.3 ml/g TVS and a methane yield of 186.2 ml/g TVS corresponding to an overall ECE of 34.0% were obtained through the three-stage process (dark fermentation, photofermentation, and methanogenesis). Copyright © 2013 Elsevier Ltd. All rights reserved.

Pseudo-lignin Formation during Dilute Acid Pretreatment for Cellulosic Ethanol

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

Meng, Xianzhi; Ragauskas, Arthur J.

Dilute acid-based pretreatment represents one of the most important pretreatment technologies to reduce biomass recalcitrance and it has been successfully applied to a wide range of feedstocks. During this type of pretreatment, the relative lignin content usually increases partially due to the loss of carbohydrates. More importantly, it has been reported that the increase of lignin content after dilute acid pretreatment is mainly due to the formation of pseudo-lignin. Furthermore, the exact reaction mechanisms leading to the formation of pseudo-lignin is still under investigation. However, it has been proposed that rearrangement of hydroxymethylfurfural (HMF) or furfural can produce aromatic typemore » of compounds which can further undergo polymerization reactions to from a lignin-like polyphenolic structures termed as pseudo-lignin. Likewise, this mini-review mainly covers recent advances in understanding the fundamentals of pseudo-lignin formation during dilute acid pretreatment, the impact of its formation on enzymatic hydrolysis, and how to suppress its formation during dilute acid pretreatment.« less

Pseudo-lignin Formation during Dilute Acid Pretreatment for Cellulosic Ethanol

DOE PAGES

Meng, Xianzhi; Ragauskas, Arthur J.

2017-04-17

Dilute acid-based pretreatment represents one of the most important pretreatment technologies to reduce biomass recalcitrance and it has been successfully applied to a wide range of feedstocks. During this type of pretreatment, the relative lignin content usually increases partially due to the loss of carbohydrates. More importantly, it has been reported that the increase of lignin content after dilute acid pretreatment is mainly due to the formation of pseudo-lignin. Furthermore, the exact reaction mechanisms leading to the formation of pseudo-lignin is still under investigation. However, it has been proposed that rearrangement of hydroxymethylfurfural (HMF) or furfural can produce aromatic typemore » of compounds which can further undergo polymerization reactions to from a lignin-like polyphenolic structures termed as pseudo-lignin. Likewise, this mini-review mainly covers recent advances in understanding the fundamentals of pseudo-lignin formation during dilute acid pretreatment, the impact of its formation on enzymatic hydrolysis, and how to suppress its formation during dilute acid pretreatment.« less

Pretreatment of Cellulose By Electron Beam Irradiation Method

NASA Astrophysics Data System (ADS)

Jusri, N. A. A.; Azizan, A.; Ibrahim, N.; Salleh, R. Mohd; Rahman, M. F. Abd

2018-05-01

Pretreatment process of lignocellulosic biomass (LCB) to produce biofuel has been conducted by using various methods including physical, chemical, physicochemical as well as biological. The conversion of bioethanol process typically involves several steps which consist of pretreatment, hydrolysis, fermentation and separation. In this project, microcrystalline cellulose (MCC) was used in replacement of LCB since cellulose has the highest content of LCB for the purpose of investigating the effectiveness of new pretreatment method using radiation technology. Irradiation with different doses (100 kGy to 1000 kGy) was conducted by using electron beam accelerator equipment at Agensi Nuklear Malaysia. Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses were studied to further understand the effect of the suggested pretreatment step to the content of MCC. Through this method namely IRR-LCB, an ideal and optimal condition for pretreatment prior to the production of biofuel by using LCB may be introduced.

Saccharification of recalcitrant biomass and integration options for lignocellulosic sugars from Catchlight Energy's sugar process (CLE Sugar).

PubMed

Gao, Johnway; Anderson, Dwight; Levie, Benjamin

2013-01-28

Woody biomass is one of the most abundant biomass feedstocks, besides agriculture residuals in the United States. The sustainable harvest residuals and thinnings alone are estimated at about 75 million tons/year. These forest residuals and thinnings could produce the equivalent of 5 billion gallons of lignocellulosic ethanol annually. Softwood biomass is the most recalcitrant biomass in pretreatment before an enzymatic hydrolysis. To utilize the most recalcitrant lignocellulosic materials, an efficient, industrially scalable and cost effective pretreatment method is needed. Obtaining a high yield of sugar from recalcitrant biomass generally requires a high severity of pretreatment with aggressive chemistry, followed by extensive conditioning, and large doses of enzymes. Catchlight Energy's Sugar process, CLE Sugar, uses a low intensity, high throughput variation of bisulfite pulping to pretreat recalcitrant biomass, such as softwood forest residuals. By leveraging well-proven bisulfite technology and the rapid progress of enzyme suppliers, CLE Sugar can achieve a high yield of total biomass carbohydrate conversion to monomeric lignocellulosic sugars. For example, 85.8% of biomass carbohydrates are saccharified for un-debarked Loblolly pine chips (softwood), and 94.0% for debarked maple chips (hardwood). Furan compound formation was 1.29% of biomass feedstock for Loblolly pine and 1.10% for maple. At 17% solids hydrolysis of pretreated softwood, an enzyme dose of 0.075 g Sigma enzyme mixture/g dry pretreated (unwashed) biomass was needed to achieve 8.1% total sugar titer in the hydrolysate and an overall prehydrolysate liquor plus enzymatic hydrolysis conversion yield of 76.6%. At a much lower enzyme dosage of 0.044 g CTec2 enzyme product/g dry (unwashed) pretreated softwood, hydrolysis at 17% solids achieved 9.2% total sugar titer in the hydrolysate with an overall sugar yield of 85.0% in the combined prehydrolysate liquor and enzymatic hydrolysate. CLE Sugar has been demonstrated to be effective on hardwood and herbaceous biomass, making it truly feedstock flexible. Different options exist for integrating lignocellulosic sugar into sugar-using operations. A sugar conversion plant may be adjacent to a CLE Sugar plant, and the CLE Sugar can be concentrated from the initial 10% sugar as needed. Concentrated sugars, however, can be shipped to remote sites such as ethanol plants or other sugar users. In such cases, options for shipping a dense form of sugars include (1) pretreated biomass with enzyme addition, (2) lignocellulosic sugar syrup, and (3) lignocellulosic sugar solid. These could provide the advantage of maximizing the use of existing assets.

Unraveling the structure of sugarcane bagasse after soaking in concentrated aqueous ammonia (SCAA) and ethanol production by Scheffersomyces (Pichia) stipitis.

PubMed

Chandel, Anuj K; Antunes, Felipe Af; Silva, Messias B; da Silva, Silvio Silvério

2013-01-01

Fuel ethanol production from sustainable and largely abundant agro-residues such as sugarcane bagasse (SB) provides long term, geopolitical and strategic benefits. Pretreatment of SB is an inevitable process for improved saccharification of cell wall carbohydrates. Recently, ammonium hydroxide-based pretreatment technologies have gained significance as an effective and economical pretreatment strategy. We hypothesized that soaking in concentrated aqueous ammonia-mediated thermochemical pretreatment (SCAA) would overcome the native recalcitrance of SB by enhancing cellulase accessibility of the embedded holocellulosic microfibrils. In this study, we designed an experiment considering response surface methodology (Taguchi method, L8 orthogonal array) to optimize sugar recovery from ammonia pretreated sugarcane bagasse (SB) by using the method of soaking in concentrated aqueous ammonia (SCAA-SB). Three independent variables: ammonia concentration, temperature and time, were selected at two levels with center point. The ammonia pretreated bagasse (SCAA-SB) was enzymatically hydrolysed by commercial enzymes (Celluclast 1.5 L and Novozym 188) using 15 FPU/g dry biomass and 17.5 Units of β-glucosidase/g dry biomass at 50°C, 150 rpm for 96 h. A maximum of 28.43 g/l reducing sugars corresponding to 0.57 g sugars/g pretreated bagasse was obtained from the SCAA-SB derived using a 20% v/v ammonia solution, at 70°C for 24 h after enzymatic hydrolysis. Among the tested parameters, pretreatment time showed the maximum influence (p value, 0.053282) while ammonia concentration showed the least influence (p value, 0.612552) on sugar recovery. The changes in the ultra-structure and crystallinity of native SCAA-SB and enzymatically hydrolysed SB were observed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy. The enzymatic hydrolysates and solid SCAA-SB were subjected to ethanol fermentation under separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) by Scheffersomyces (Pichia) stipitis NRRL Y-7124 respectively. Higher ethanol production (10.31 g/l and yield, 0.387 g/g) was obtained through SSF than SHF (3.83 g/l and yield, 0.289 g/g). SCAA treatment showed marked lignin removal from SB thus improving the accessibility of cellulases towards holocellulose substrate as evidenced by efficient sugar release. The ultrastructure of SB after SCAA and enzymatic hydrolysis of holocellulose provided insights of the degradation process at the molecular level.

Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection.

PubMed

Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling

2016-01-01

Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for disinfection enhancement methods combined with ClO2 in terms of both disinfection efficiency and disinfection by-product formation. Copyright © 2015 Elsevier B.V. All rights reserved.

A novel GH10 xylanase from Penicillium sp. accelerates saccharification of alkaline-pretreated bagasse by an enzyme from recombinant Trichoderma reesei expressing Aspergillus β-glucosidase.

PubMed

Shibata, Nozomu; Suetsugu, Mari; Kakeshita, Hiroshi; Igarashi, Kazuaki; Hagihara, Hiroshi; Takimura, Yasushi

2017-01-01

Trichoderma reesei is considered a candidate fungal enzyme producer for the economic saccharification of cellulosic biomass. However, performance of the saccharifying enzymes produced by T. reesei is insufficient. Therefore, many attempts have been made to improve its performance by heterologous protein expression. In this study, to increase the conversion efficiency of alkaline-pretreated bagasse to sugars, we conducted screening of biomass-degrading enzymes that showed synergistic effects with enzyme preparations produced by recombinant T. reesei . Penicillium sp. strain KSM-F532 produced the most effective enzyme to promote the saccharification of alkaline-pretreated bagasse. Biomass-degrading enzymes from strain KSM-F532 were fractionated and analyzed, and a xylanase, named PspXyn10, was identified. The amino acid sequence of PspXyn10 was determined by cDNA analysis: the enzyme shows a modular structure consisting of glycoside hydrolase family 10 (GH10) and carbohydrate-binding module family 1 (CBM1) domains. Purified PspXyn10 was prepared from the supernatant of a recombinant T. reesei strain. The molecular weight of PspXyn10 was estimated to be 55 kDa, and its optimal temperature and pH for xylanase activity were 75 °C and pH 4.5, respectively. More than 80% of the xylanase activity was maintained at 65 °C for 10 min. With beechwood xylan as the substrate, the enzyme had a K m of 2.2 mg/mL and a V max of 332 μmol/min/mg. PspXyn10ΔCBM, which lacked the CBM1 domain, was prepared by limited proteolysis. PspXyn10ΔCBM showed increased activity against soluble xylan, but decreased saccharification efficiency of alkaline-pretreated bagasse. This result indicated that the CBM1 domain of PspXyn10 contributes to the enhancement of the saccharification efficiency of alkaline-pretreated bagasse. A recombinant T. reesei strain, named X2PX10, was constructed from strain X3AB1. X3AB1 is an Aspergillus aculeatus β-glucosidase-expressing T. reesei PC-3-7. X2PX10 also expressed PspXyn10 under the control of the xyn2 promoter. An enzyme preparation from X2PX10 showed almost the same saccharification efficiency of alkaline-pretreated bagasse at half the enzyme dosage as that used for an enzyme preparation from X3AB1. Our results suggest that PspXyn10 promotes the saccharification of alkaline-pretreated bagasse more efficiently than TrXyn3, a GH10 family xylanase from T. reesei , and that the PspXyn10-expressing strain is suitable for enzyme production for biomass saccharification.

Comparative techno-economic analysis of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments of corn stover.

PubMed

Baral, Nawa Raj; Shah, Ajay

2017-05-01

Pretreatment is required to destroy recalcitrant structure of lignocelluloses and then transform into fermentable sugars. This study assessed techno-economics of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments, and identified bottlenecks and operational targets for process improvement. Techno-economic models of these pretreatment processes for a cellulosic biorefinery of 113.5 million liters butanol per year excluding fermentation and wastewater treatment sections were developed using a modelling software-SuperPro Designer. Experimental data of the selected pretreatment processes based on corn stover were gathered from recent publications, and used for this analysis. Estimated sugar production costs ($/kg) via steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological methods were 0.43, 0.42, 0.65 and 1.41, respectively. The results suggest steam explosion and sulfuric acid pretreatment methods might be good alternatives at present state of technology and other pretreatment methods require research and development efforts to be competitive with these pretreatment methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermal Pretreatment For TRU Waste Sorting

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

Sasaki, T.; Aoyama, Y.; Miyamoto, Y.

2008-07-01

Japan Atomic Energy Agency conducted a study on thermal treatment of TRU waste to develop a removal technology for materials that are forbidden for disposal. The thermal pretreatment in which hot nitrogen and/or air is introduced to the waste is a process of removing combustibles, liquids, and low melting point metals from PVC wrapped TRU waste. In this study, thermal pretreatment of simulated waste was conducted using a desktop thermal treatment vessel and a laboratory scale thermal pretreatment system. Combustibles and low melting point metals are effectively separated from wastes by choosing appropriate temperature of flowing gases. Combustibles such asmore » papers, PVC, oil, etc. were removed and low melting point metals such as zinc, lead, and aluminum were separated from the simulated waste by the thermal pretreatment. (authors)« less

Biodetoxification of toxins generated from lignocellulose pretreatment using a newly isolated fungus, Amorphotheca resinae ZN1, and the consequent ethanol fermentation.

PubMed

Zhang, Jian; Zhu, Zhinan; Wang, Xiaofeng; Wang, Nan; Wang, Wei; Bao, Jie

2010-11-22

Degradation of the toxic compounds generated in the harsh pretreatment of lignocellulose is an inevitable step in reducing the toxin level for conducting practical enzymatic hydrolysis and ethanol fermentation processes. Various detoxification methods have been tried and many negative outcomes were found using these methods, such as the massive freshwater usage and wastewater generation, loss of the fine lignocellulose particles and fermentative sugars and incomplete removal of inhibitors. An alternate method, biodetoxification, which degrades the toxins as part of their normal metabolism, was considered a promising option for the removal of toxins without causing the above problems. A kerosene fungus strain, Amorphotheca resinae ZN1, was isolated from the microbial community growing on the pretreated corn stover material. The degradation of the toxins as well as the lignocelluloses-derived sugars was characterized in different ways, and the results show that A. resinae ZN1 utilized each of these toxins and sugars as the sole carbon sources efficiently and grew quickly on the toxins. It was found that the solid-state culture of A. resinae ZN1 on various pretreated lignocellulose feedstocks such as corn stover, wheat straw, rice straw, cotton stalk and rape straw degraded all kinds of toxins quickly and efficiently. The consequent simultaneous saccharification and ethanol fermentation was performed at the 30% (wt/wt) solid loading of the detoxified lignocellulosic feedstocks without a sterilization step, and the ethanol titer in the fermentation broth reached above 40 g/L using food crop residues as feedstocks. The advantages of the present biodetoxification by A. resinae ZN1 over the known detoxification methods include zero energy input, zero wastewater generation, complete toxin degradation, processing on solid pretreated material, no need for sterilization and a wide lignocellulose feedstock spectrum. These advantages make it possible for industrial applications with fast and efficient biodetoxification to remove toxins generated during intensive lignocellulose pretreatment.

Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

PubMed

Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

2009-10-15

The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

Coagulation-flocculation as pre-treatment for micro-scale Fe/Cu/O3 process (CF-mFe/Cu/O3) treatment of the coating wastewater from automobile manufacturing.

PubMed

Xiong, Zhaokun; Cao, Jinyan; Yang, Dan; Lai, Bo; Yang, Ping

2017-01-01

A coagulation-flocculation as pre-treatment combined with mFe/Cu/O 3 (CF-mFe/Cu/O 3 ) process was developed to degrade the pollutants in automobile coating wastewater (ACW). In coagulation-flocculation (CF) process, high turbidity removal efficiency (97.1%) and low COD removal efficiency (10.5%) were obtained under the optimal conditions using Al 2 (SO 4 ) 3 ·18H 2 O and CaO. The effluent of CF process (ECF) was further disposed by mFe/Cu/O 3 process, and its key operating parameters were optimized by batch experiments. Optimally, COD removal efficiency of ECF obtained by the mFe/Cu/O 3 process (i.e., 87.6% after 30 min treatment) was much higher than those of mFe/Cu alone (8.3%), ozone alone (46.6%), and mFe/Cu/air (6.1%), which confirms the superiority of the mFe/Cu/O 3 process. In addition, the analysis results of UV-vis, excitation-emission matrix (EEM) fluorescence spectra and GC/MS further confirm that the phenol pollutants of ECF had been effectively decomposed or transformed after CF-mFe/Cu/O 3 process treatment. Meanwhile, B/C ratio of ACW increased from 0.19 to 0.56, which suggests the biodegradability was improved significantly. Finally, the operating cost of CF-mFe/Cu/O 3 process was about 1.83 USD t -1 for ACW treatment. Therefore, the combined process is a promising treatment technology for the coating wastewater from automobile manufacturing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Production of isoprene, one of the high-density fuel precursors, from peanut hull using the high-efficient lignin-removal pretreatment method.

PubMed

Wang, Sumeng; Wang, Zhaobao; Wang, Yongchao; Nie, Qingjuan; Yi, Xiaohua; Ge, Wei; Yang, Jianming; Xian, Mo

2017-01-01

Isoprene as the feedstock can be used to produce renewable energy fuels, providing an alternative to replace the rapidly depleting fossil fuels. However, traditional method for isoprene production could not meet the demands for low-energy consumption and environment-friendliness. Moreover, most of the previous studies focused on biofuel production out of lignocellulosic materials such as wood, rice straw, corn cob, while few studies concentrated on biofuel production using peanut hull (PH). As is known, China is the largest peanut producer in the globe with an extremely considerable amount of PH to be produced each year. Therefore, a novel, renewable, and environment-friendly pretreatment strategy to increase the enzymatic hydrolysis efficiency of cellulose and reduce the inhibitors generation was developed to convert PH into isoprene. The optimal pretreatment conditions were 100 °C, 60 min, 10% (w/v) solid loading with a 2:8 volume ratio of phosphoric acid and of hydrogen peroxide. In comparison with the raw PH, the hemicellulose and lignin were reduced to 85.0 and 98.0%, respectively. The cellulose-glucose conversion of pretreated PH reached up to 95.0% in contrast to that of the raw PH (19.1%). Only three kinds of inhibitors including formic acid, levulinic acid, and a little furfural were formed during the pretreatment process, whose concentrations were too low to inhibit the isoprene yield for Escherichia coli fermentation. Moreover, compared with the isoprene yield of pure glucose fermentation (298 ± 9 mg/L), 249 ± 6.7 and 294 ± 8.3 mg/L of isoprene were produced using the pretreated PH as the carbon source by the engineered strain via separate hydrolysis and fermentation and simultaneous saccharification and fermentation (SSF) methods, respectively. The isoprene production via SSF had a 9.8% glucose-isoprene conversion which was equivalent to 98.8% of isoprene production via the pure glucose fermentation. The optimized phosphoric acid/hydrogen peroxide combination pretreatment approach was proved effective to remove lignin and hemicellulose from lignocellulosic materials. Meanwhile, the pretreated PH could be converted into isoprene efficiently in the engineered Escherichia coli . It is concluded that this novel strategy of isoprene production using lignocellulosic materials pretreated by phosphoric acid/hydrogen peroxide is a promising alternative to isoprene production using traditional way which can fully utilize non-renewable fossil sources.

Influences of mechanical pretreatment on the non-biological treatment of municipal wastewater by forward osmosis.

PubMed

Hey, Tobias; Zarebska, Agata; Bajraktari, Niada; Vogel, Jörg; Hélix-Nielsen, Claus; la Cour Jansen, Jes; Jönsson, Karin

2017-09-01

Municipal wastewater treatment involves mechanical, biological and chemical treatment steps for protecting the environment from adverse effects. The biological treatment step consumes the most energy and can create greenhouse gases. This study investigates municipal wastewater treatment without the biological treatment step, including the effects of different pretreatment configurations, for example, direct membrane filtration before forward osmosis. Forward osmosis was tested using raw wastewater and wastewater subjected to different types of mechanical pretreatment, for example, microsieving and microfiltration permeation, as a potential technology for municipal wastewater treatment. Forward osmosis was performed using Aquaporin Inside™ and Hydration Technologies Inc. (HTI) membranes with NaCl as the draw solution. Both types of forward osmosis membranes were tested in parallel for the different types of pretreated feed and evaluated in terms of water flux and solute rejection, that is, biochemical oxygen demand (BOD 7 ) and total and soluble phosphorus contents. The Aquaporin and HTI membranes achieved a stable water flux with rejection rates of more than 96% for BOD 7 and total and soluble phosphorus, regardless of the type of mechanical pretreated wastewater considered. This result indicates that forward osmosis membranes can tolerate exposure to municipal waste water and that the permeate can fulfil the Swedish discharge limits.

Study on the pre-treatment of oxidized zinc ore prior to flotation

NASA Astrophysics Data System (ADS)

He, Dong-sheng; Chen, Yun; Xiang, Ping; Yu, Zheng-jun; Potgieter, J. H.

2018-02-01

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

[Study on the advanced pre-treatments of reclaimed water used for groundwater recharge].

PubMed

Gao, Yu-Tuan; Zhang, Xue; Zhao, Xuan; Zhao, Gang

2012-03-01

To prevent groundwater contamination, pretreatments of reclaimed water are needed before the groundwater recharge. In this study, five treatments, including ultrafiltration (UF), ozonation, magnetic ion exchange (MIEX), UF coupled with ozonation and MIEX coupled with ozonation, were evaluated for their purification efficiencies of the reclaimed water and their influences on the following soil aquifer treatments. For organic matters in the secondary effluents, identified as dissolved organic carbon (DOC) and specific ultraviolet absorbance (SUVA), 20% DOC and 10% SUVA are removed by MIEX treatment with dose of 5 mL x L(-1), while only 10% DOC and no SUVA are removed by UF, but neither of these two pretreatments enhance the purification of soil aquifer treatments. Differently, SUVA of the secondary effluents are removed by 60%-79% by ozonation alone or coupled with UF/MIEX, increasing the biodegradability of the reclaimed water. These pretreatments significantly enhance the removal of organic matters by the following soil aquifer with DOC in the final effluents reducing to 1-2 mg x L(-1). For nitrogen, MIEX can remove 25% NO3(-) -N, and ozonation can remove 72% NH4(+) -N. The soil aquifer treatment could efficiently remove NH4(+) -N to below 0.5 mg x L(-1), while no obvious removal is detected for NO3(-) -N. In conclusion, more attentions should be paid to the organic matters and NO3(-) -N during the pretreatments of reclaimed water. Among all the pretreatments tested here, ozonation coupled with MIEX is capable of increasing the biodegradability of the reclaimed water and removing NO3(-) -N, which is a good choice for the pretreatment of groundwater recharge.

Lignocellulosic biomass pretreatment using AFEX.

PubMed

Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P S; Marshall, Derek; Dale, Bruce E

2009-01-01

Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

Lignocellulosic Biomass Pretreatment Using AFEX

NASA Astrophysics Data System (ADS)

Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P. S.; Marshall, Derek; Dale, Bruce E.

Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

Optimization of alkaline sulfite pretreatment and comparative study with sodium hydroxide pretreatment for improving enzymatic digestibility of corn stover.

PubMed

Liu, Huan; Pang, Bo; Wang, Haisong; Li, Haiming; Lu, Jie; Niu, Meihong

2015-04-01

In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield. The optimum pretreatment conditions were obtained, as follows: the total titratable alkali (TTA) of 12%, liquid/solid ratio of 6:1, temperature of 140 °C, and holding time of 20 min. Under those conditions, the solid yield was 55.24%, and the removal of lignin was 82.68%. Enzymatic hydrolysis rates of glucan and xylan for pretreated corn stover were 85.38% and 70.36%, and the total sugar yield was 74.73% at cellulase loading of 20 FPU/g and β-glucosidase loading of 10 IU/g for 48 h. Compared with sodium hydroxide pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 10.43%. Additionally, the corn stover pretreated under the optimum pretreatment conditions was beaten by PFI at 1500 revolutions. After beating, enzymatic hydrolysis rates of glucan and xylan were 89.74% and 74.06%, and the total sugar yield was 78.58% at the same enzymatic hydrolysis conditions. Compared with 1500 rpm of PFI beating after sodium pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 14.05%.

Effect of Hot-Pressing Temperature on the Subsequent Enzymatic Saccharification and Fermentation Performance of SPORL Pretreated Forest Biomass

Treesearch

Jingzhi Zhang; Andrea Laguna; Craig Clemons; Michael P. Wolcott; Rolland Gleisner; J.Y. Zhu; Xu Zhang

2015-01-01

Methods to increase the energy density ofbiofuel feedstock for shipment are important towards improving supply chain efficiency in upstream processes. Towards this end, densified pretreated lignocellulosic biomass was produced using hot-pressing. The effects offiber hornification induced by hot-pressing on enzymatic digestibilities of lodgepolepine and poplar NE222...

Use of anaerobic hydrolysis pretreatment to enhance ultrasonic disintegration of excess sludge.

PubMed

Li, Xianjin; Zhu, Tong; Shen, Yang; Chai, Tianyu; Xie, Yuanhua; You, Meiyan; Wang, Youzhao

2016-01-01

To improve the excess sludge disintegration efficiency, reduce the sludge disintegration cost, and increase sludge biodegradability, a combined pretreatment of anaerobic hydrolysis (AH) and ultrasonic treatment (UT) was proposed for excess sludge. Results showed that AH had an advantage in dissolving flocs, modifying sludge characteristics, and reducing the difficulty of sludge disintegration, whereas UT was advantageous in damaging cell walls, releasing intracellular substances, and decomposing macromolecular material. The combined AH-UT process was an efficient method for excess sludge pretreatment. The optimized solution involved AH for 3 days, followed by UT for 10 min. After treatment, chemical oxygen demand, protein, and peptidoglycan concentrations reached 3,949.5 mg O2/L, 752.5 mg/L and 619.1 mg/L, respectively. This work has great significance for further engineering applications, namely, reducing energy consumption, increasing the sludge disintegration rate, and improving the biochemical properties of sludge.

Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous catalytic ozonation and biological process.

PubMed

Zhuang, Haifeng; Han, Hongjun; Jia, Shengyong; Hou, Baolin; Zhao, Qian

2014-08-01

Advanced treatment of biologically pretreated coal gasification wastewater (CGW) was investigated employing heterogeneous catalytic ozonation integrated with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process. The results indicated that catalytic ozonation with the prepared catalyst (i.e. MnOx/SBAC, sewage sludge was converted into sludge based activated carbon (SBAC) which loaded manganese oxides) significantly enhanced performance of pollutants removal by generated hydroxyl radicals. The effluent of catalytic ozonation process was more biodegradable and less toxic than that in ozonation alone. Meanwhile, ANMBBR-BAF showed efficient capacity of pollutants removal in treatment of the effluent of catalytic ozonation at a shorter reaction time, allowing the discharge limits to be met. Therefore, the integrated process with efficient, economical and sustainable advantages was suitable for advanced treatment of real biologically pretreated CGW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Seawater-cultured Botryococcus braunii for efficient hydrocarbon extraction.

PubMed

Furuhashi, Kenichi; Saga, Kiyotaka; Okada, Shigeru; Imou, Kenji

2013-01-01

As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking. Seawater was used for efficient hydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment.

The Effect of Ionic Liquid Pretreatment on the Bioconversion of Tomato Processing Waste to Fermentable Sugars and Biogas.

PubMed

Allison, Brittany J; Cádiz, Juan Canales; Karuna, Nardrapee; Jeoh, Tina; Simmons, Christopher W

2016-08-01

Tomato pomace is an abundant lignocellulosic waste stream from industrial tomato processing and therefore a potential feedstock for production of renewable biofuels. However, little research has been conducted to determine if pretreatment can enhance release of fermentable sugars from tomato pomace. Ionic liquids (ILs) are an emerging pretreatment technology for lignocellulosic biomass to increase enzymatic digestibility and biofuel yield while utilizing recyclable chemicals with low toxicity. In this study, pretreatment of tomato pomace with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) was investigated. Changes in pomace enzymatic digestibility were affected by pretreatment time and temperature. Certain pretreatment conditions significantly improved reducing sugar yield and hydrolysis time compared to untreated pomace. Compositional analyses suggested that pretreatment primarily removed water-soluble compounds and enriched for lignocellulose in pomace, with only subtle changes to the composition of the lignocellulose. While tomato pomace was effectively pretreated with [C2mim][OAc] to improve enzymatic digestibility, as of yet, unknown factors in the pomace caused ionic liquid pretreatment to negatively affect anaerobic digestion of pretreated material. This result, which is unique compared to similar studies on IL pretreatment of grasses and woody biomass, highlights the need for additional research to determine how the unique chemical composition of tomato pomace and other lignocellulosic fruit residues may interact with ionic liquids to generate inhibitors for downstream fermentation to biofuels.

Effect of iron salt type and dosing mode on Fenton-based pretreatment of rice straw for enzymatic hydrolysis.

PubMed

Gan, Yu-Yan; Zhou, Si-Li; Dai, Xiao; Wu, Han; Xiong, Zi-Yao; Qin, Yuan-Hang; Ma, Jiayu; Yang, Li; Wu, Zai-Kun; Wang, Tie-Lin; Wang, Wei-Guo; Wang, Cun-Wen

2018-06-15

Fenton-based processes with four different iron salts in two different dosing modes were used to pretreat rice straw (RS) samples to increase their enzymatic digestibility. The composition analysis shows that the RS sample pretreated by the dosing mode of iron salt adding into H 2 O 2 has a much lower hemicellulose content than that pretreated by the dosing mode of H 2 O 2 adding into iron salt, and the RS sample pretreated by the chloride salt-based Fenton process has a much lower lignin content and a slightly lower hemicellulose content than that pretreated by the sulphate salt-based Fenton process. The higher concentration of reducing sugar observed on the RS sample with lower lignin and hemicellulose contents justifies that the Fenton-based process could enhance the enzymic hydrolysis of RS by removing hemicellulose and lignin and increasing its accessibility to cellulase. FeCl 3 ·6H 2 O adding into H 2 O 2 is the most efficient Fenton-based process for RS pretreatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

The enhancement of anaerobic biodegradability of waste activated sludge by surfactant mediated biological pretreatment.

PubMed

Kavitha, S; Jayashree, C; Adish Kumar, S; Yeom, Ick Tae; Rajesh Banu, J

2014-09-01

In this study, the role of sodium dodecyl sulfate (SDS) was explored for the removal of extracellular polymeric substance (EPS) from waste activated sludge (WAS) followed by enzymatic bacterial pretreatment, which enhanced the subsequent anaerobic biodegradability. EPS was removed with 0.02 g/g SS of SDS. In the results of pretreatment, the suspended solids reduction and chemical oxygen demand solubilization were found to be 25.7% and 19.79% for deflocculated and bacterially pretreated sludge, whereas they were found to be 15.7% and 11% for flocculated sludge (without EPS removal and bacterially pretreated) and 7.85% and 6% for control sludge (raw sludge), respectively. Upon examining the anaerobic biodegradability, the biogas yield potential of deflocculated and bacterially pretreated, flocculated, deflocculated alone, and control sludges were found to be 0.467 L/(g VS), 0.355 L/(g VS), 0.315 L/(g VS), and 0.212 L/(g VS), respectively. Thus, the deflocculation and bacterial pretreatment improved the anaerobic biodegradability efficiently. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pretreatment of eucalyptus with recycled ionic liquids for low-cost biorefinery.

PubMed

Xu, Jikun; Liu, Bingchuan; Hou, Huijie; Hu, Jingping

2017-06-01

It is urgent to develop recycled ionic liquids (ILs) as green solvents for sustainable biomass pretreatment. The goal of this study is to explore the availability and performance of reusing 1-allyl-3-methylimidazolium chloride ([amim]Cl) and 1-butyl-3-methylimidazolium acetate ([bmim]OAc) for pretreatment, structural evolution, and enzymatic hydrolysis of eucalyptus. Cellulose enzymatic digestibility slightly decreased with the increased number of pretreatment recycles. The hydrolysis efficiencies of eucalyptus pretreated via 4th recycled ILs were 54.3% for [amim]Cl and 72.8% for [bmim]OAc, which were 5.0 and 6.7-folds higher than that of untreated eucalyptus. Deteriorations of ILs were observed by the relatively lower sugar conversion and lignin removal from eucalyptus after 4th reuse. No appreciable changes in fundamental framework and thermal stability of [amim]Cl were observed even after successive pretreatments, whereas the anionic structure of [bmim]OAc was destroyed or replaced. This study suggested that the biomass pretreatment with recycled ILs was a potential alternative for low-cost biorefinery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrasonic and Thermal Pretreatments on Anaerobic Digestion of Petrochemical Sludge: Dewaterability and Degradation of PAHs

PubMed Central

Zhou, Jun; Xu, Weizhong; Wong, Jonathan W. C.; Yong, Xiaoyu; Yan, Binghua; Zhang, Xueying; Jia, Honghua

2015-01-01

Effects of different pretreatment methods on sludge dewaterability and polycyclic aromatic hydrocarbons (PAHs) degradation during petrochemical sludge anaerobic digestion were studied. Results showed that the total biogas production volume in the thermal pretreatment system was 4 and 5 times higher than that in the ultrasound pretreatment and in the control system, and the corresponding volatile solid removal efficiencies reached 28%, 15%, and 8%. Phenanthrene, paranaphthalene, fluoranthene, benzofluoranthene, and benzopyrene removal rates reached 43.3%, 55.5%, 30.6%, 42.9%, and 41.7%, respectively, in the thermal pretreatment system, which were much higher than those in the ultrasound pretreatment and in the control system. Moreover, capillary suction time (CST) of sludge increased after pretreatment, and then reduced after 20 days of anaerobic digestion, indicating that sludge dewaterability was greatly improved after anaerobic digestion. The decrease of protein and polysaccharide in the sludge could improve sludge dewaterability during petrochemical sludge anaerobic digestion. This study suggested that thermal pretreatment might be a promising enhancement method for petrochemical sludge solubilization, thus contributing to degradation of the PAHs, biogas production, and improvement of dewaterability during petrochemical sludge anaerobic digestion. PMID:26327510

Technological pretreatment of the synchysite non-oxidized ore

NASA Astrophysics Data System (ADS)

Munkhtsetseg, B.; Burmaa, G.

2013-06-01

Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

Optimisation of intradermal DNA electrotransfer for immunisation.

PubMed

Vandermeulen, Gaëlle; Staes, Edith; Vanderhaeghen, Marie Lise; Bureau, Michel Francis; Scherman, Daniel; Préat, Véronique

2007-12-04

The development of DNA vaccines requires appropriate delivery technologies. Electrotransfer is one of the most efficient methods of non-viral gene transfer. In the present study, intradermal DNA electrotransfer was first optimised. Strong effects of the injection method and the dose of DNA on luciferase expression were demonstrated. Pre-treatments were evaluated to enhance DNA diffusion in the skin but neither hyaluronidase injection nor iontophoresis improved efficiency of intradermal DNA electrotransfer. Then, DNA immunisation with a weakly immunogenic model antigen, luciferase, was investigated. After intradermal injection of the plasmid encoding luciferase, electrotransfer (HV 700 V/cm 100 micros, LV 200 V/cm 400 ms) was required to induce immune response. The response was Th1-shifted compared to immunisation with the luciferase recombinant protein. Finally, DNA electrotransfer in the skin, the muscle or the ear pinna was compared. Muscle DNA electrotransfer resulted in the highest luciferase expression and the best IgG response. Nevertheless electrotransfer into the skin, the muscle and the ear pinna all resulted in IFN-gamma secretion by luciferase-stimulated splenocytes suggesting that an efficient Th1 response was induced in all case.

Effectiveness and efficiency of a CAD/CAM orthodontic bracket system.

PubMed

Brown, Matthew W; Koroluk, Lorne; Ko, Ching-Chang; Zhang, Kai; Chen, Mengqi; Nguyen, Tung

2015-12-01

The first straight-wire appliance was introduced over 40 years ago to increase the consistency and efficiency of orthodontic treatment. More recently, computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been used to create individualized orthodontic appliances. The purpose of this study was to investigate the clinical effectiveness and efficiency of CAD/CAM customized orthodontic appliances compared with direct and indirect bonded stock orthodontic brackets. This retrospective study included 3 treatment groups: group 1 patients were direct bonded with self-ligating appliances, group 2 patients were indirect bonded with self-ligating appliances, and group 3 patients were indirect bonded with CAD/CAM self-ligating appliances. Complete pretreatment and posttreatment records were obtained for all patients. The American Board of Orthodontics (ABO) Discrepancy Index was used to evaluate the pretreatment records, and the posttreatment outcomes were analyzed using the ABO Cast-Radiograph Evaluation. All data collection and analysis were completed by 1 evaluator. There were no statistically significant differences in the ABO Discrepancy Index or the ABO Cast-Radiograph Evaluation among the groups. Treatment times for the 3 groups were significantly different; the CAD/CAM group was the shortest at 13.8 ± 3.4 months, compared with 21.9 ± 5.0 and 16.9 ± 4.1 months for the direct bonded and indirect bonded groups, respectively. The number of treatment appointments for the CAD/CAM group was significantly fewer than for the direct bonded group. The CAD/CAM orthodontic bracket system evaluated in this study was as effective in treatment outcome measures as were standard brackets bonded both directly and indirectly. The CAD/CAM appliance was more efficient in regard to treatment duration, although the decrease in total archwire appointments was minimal. Further investigation is needed to better quantify the clinical benefits of CAD/CAM orthodontic appliances. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Organic acid pretreatment of oil palm trunk: effect on enzymatic saccharification and ethanol production.

PubMed

Rattanaporn, Kittipong; Tantayotai, Prapakorn; Phusantisampan, Theerawut; Pornwongthong, Peerapong; Sriariyanun, Malinee

2018-04-01

Effective lignocellulosic biomass saccharification is one of the crucial requirements of biofuel production via fermentation process. Organic acid pretreatments have been gained much interests as one of the high potential methods for promoting enzymatic saccharification of lignocellulosic materials due to their lower hazardous properties and lower production of inhibitory by-products of fermentation than typical chemical pretreatment methods. In this study, three organic acids, including acetic acid, oxalic acid, and citric acid, were examined for improvement of enzymatic saccharification and bioethanol production from oil palm trunk biomass. Based on response surface methodology, oxalic acid pretreated biomass released the maximum reducing sugar of 144 mg/g-pretreated biomass at the optimum condition, which was higher than untreated samples for 2.30 times. The released sugar yield of oil palm trunk also corresponded to the results of FT-IR analysis, which revealed the physical modification of cellulose and hemicellulose surface structures of pretreated biomass. Nevertheless, citric acid pretreatment is the most efficient pretreatment method to improve bioethanol fermentation of Saccharomyces cerevisiae TISTR 5606 at 1.94 times higher than untreated biomass. These results highlighted the selection of organic acid pretreatment as a potential method for biofuel production from oil palm trunk feedstocks.

Effect of hydrothermal pretreatment on solubility and formation of kenaf cellulose membrane and hydrogel.

PubMed

Gan, Sinyee; Zakaria, Sarani; Chia, Chin Hua; Padzil, Farah Nadia Mohammad; Ng, Peivun

2015-01-22

The hydrothermal pretreatment on kenaf core pulp (KCP) was carried out using an autoclave heated in a oil bath at 140°C for 0.5/1/3/5h. The hydrothermal pretreated kenaf (HPK) was dissolved in a LiOH/urea aqueous solution and subsequently used to produce cellulose membrane and hydrogel. The effects of hydrothermal pretreatment time on solubility, viscosity, crystallinity and morphology of the cellulose membrane and hydrogel were investigated. The hydrothermal pretreatment leads to higher cellulose solubility and higher viscosity of the cellulose solution. The formation of cellulose II and crystallinity index of the cellulose membrane and hydrogel were examined by X-ray diffraction (XRD). The pore size of the cellulose membrane and hydrogel displayed an upward trend with respect to the hydrothermal pretreatment period observed under a field emission scanning electron microscope (FESEM). This finding provides an efficient procedure to improve the solubility, viscosity and properties of regenerated cellulose products. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of pretreatment severity in continuous steam explosion on enzymatic conversion of wheat straw: Evidence from kinetic analysis of hydrolysis time courses.

PubMed

Monschein, Mareike; Nidetzky, Bernd

2016-01-01

Focusing on continuous steam explosion, the influence of pretreatment severity due to varied acid loading on hydrolysis of wheat straw by Trichoderma reesei cellulases was investigated based on kinetic evaluation of the saccharification of each pretreated substrate. Using semi-empirical descriptors of the hydrolysis time course, key characteristics of saccharification efficiency were captured in a quantifiable fashion. Not only hydrolysis rates per se, but also the transition point of their bi-phasic decline was crucial for high saccharification degree. After 48h the highest saccharification was achieved for substrate pretreated at relatively low severity (1.2% acid). Higher severity increased enzyme binding to wheat straw, but reduced the specific hydrolysis rates. Higher affinity of the lignocellulosic material for cellulases does not necessarily result in increased saccharification, probably because of lignin modifications occurring at high pretreatment severities. At comparable severity, continuous pretreatment produced a substrate more susceptible to enzymatic hydrolysis than the batch process. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of a combined biological and thermo-mechanical pretreatment of wheat straw on energy yields in coupled ethanol and methane generation.

PubMed

Theuretzbacher, Franz; Blomqvist, Johanna; Lizasoain, Javier; Klietz, Lena; Potthast, Antje; Horn, Svein Jarle; Nilsen, Paal J; Gronauer, Andreas; Passoth, Volkmar; Bauer, Alexander

2015-10-01

Ethanol and biogas are energy carriers that could contribute to a future energy system independent of fossil fuels. Straw is a favorable bioenergy substrate as it does not compete with food or feed production. As straw is very resistant to microbial degradation, it requires a pretreatment to insure efficient conversion to ethanol and/or methane. This study investigates the effect of combining biological pretreatment and steam explosion on ethanol and methane yields in order to improve the coupled generation process. Results show that the temperature of the steam explosion pretreatment has a particularly strong effect on possible ethanol yields, whereas combination with the biological pretreatment showed no difference in overall energy yield. The highest overall energy output was found to be 10.86 MJ kg VS(-1) using a combined biological and steam explosion pretreatment at a temperature of 200°C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermo-chemical pretreatment of rice straw for further processing for levulinic acid production.

PubMed

Elumalai, Sasikumar; Agarwal, Bhumica; Sangwan, Rajender S

2016-10-01

A variety of pretreatment protocols for rice straw fiber reconstruction were evaluated under mild conditions (upto 0.2%wt. and 121°C) with the object of improving polymer susceptibility to chemical attack while preserving carbohydrate sugars for levulinic acid (LA) production. Each of the protocols tested significantly enhanced pretreatment recoveries of carbohydrate sugars and lignin, and a NaOH protocol showed the most promise, with enhanced carbohydrate preservation (upto 20% relative to the other protocols) and more effective lignin dissolution (upto 60%). Consequently, post-pretreatment fibers were evaluated for LA preparation using an existing co-solvent system consisting of HCl and THF, in addition supplementation of DMSO was attempted, in order to improve final product recovery. In contrast to pretreatment response, H2SO4 protocol fibers yielded highest LA conc. (21%wt. with 36% carbohydrate conversion efficiency) under the modest reaction conditions. Apparent spectroscopic analysis witnessed for fiber destruction and delocalization of inherent constituents during pretreatment protocols. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pilot-scale study on the acid-catalyzed steam explosion of rice straw using a continuous pretreatment system.

PubMed

Chen, Wen-Hua; Tsai, Chia-Chin; Lin, Chih-Feng; Tsai, Pei-Yuan; Hwang, Wen-Song

2013-01-01

A continuous acid-catalyzed steam explosion pretreatment process and system to produce cellulosic ethanol was developed at the pilot-scale. The effects of the following parameters on the pretreatment efficiency of rice straw feedstocks were investigated: the acid concentration, the reaction temperature, the residence time, the feedstock size, the explosion pressure and the screw speed. The optimal presteaming horizontal reactor conditions for the pretreatment process are as follows: 1.7 rpm and 100-110 °C with an acid concentration of 1.3% (w/w). An acid-catalyzed steam explosion is then performed in the vertical reactor at 185 °C for 2 min. Approximately 73% of the total saccharification yield was obtained after the rice straw was pretreated under optimal conditions and subsequent enzymatic hydrolysis at a combined severity factor of 0.4-0.7. Moreover, good long-term stability and durability of the pretreatment system under continuous operation was observed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced simultaneous saccharification and fermentation of pretreated beech wood by in situ treatment with the white rot fungus Irpex lacteus in a membrane aerated biofilm reactor.

PubMed

Brethauer, Simone; Robert Lawrence, Shahab; Michael Hans-Peter, Studer

2017-08-01

The aim of the present study was to investigate the combination of steam pretreatment and biological treatment with lignin degrading fungal strains in order to enable efficient bioprocessing of beech wood to ethanol. In a sequential process of steam and fungal pretreatment followed by enzymatic hydrolysis, Irpex lacteus almost doubled the glucose yield for mildly pretreated beech wood, but could not improve yields for more severely pretreated substrates. However, when simultaneous saccharification and fermentation is combined with in situ I. lacteus treatment, which is enabled by the application of a membrane aerated biofilm reactor, ethanol yields of optimally steam pretreated beech could be improved from 65 to 80%. Generally, in situ fungal treatment during bioprocessing of lignocellulose is an interesting method to harness the versatile abilities of white rot fungi. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The anaerobic digestion of biologically and physicochemically pretreated oily wastewater.

PubMed

Peng, Liyu; Bao, Meidan; Wang, Qingfeng; Wang, Fangchao; Su, Haijia

2014-01-01

To enhance the degradation of oily wastewater and its biogas production, a biological-physicochemical pretreatment was introduced prior to the anaerobic digestion system. The digestion thereafter proceeded more efficiently due to the inoculation by oil degrading bacteria (Bacillus). A 2-stage pre-mixing is more effective than directly mixing. The effects on the methane production were also investigated by pre-treatment with ultrasonic (US) treatment, combined with citric acid (CA) addition. US pre-treatment was found to improve the initial methane production, and CA pre-treatment could maintain this improvement during the whole digestion stage. Pre-mixing Bacillus at 9 wt.% inoculation, combined with US for 10 min and a CA concentration of 500 mg/L provided the optimum conditions. The most effective enhancement of methane yield was 1100.46 ml/g VS, exceeding that of the control by 280%. The change of coenobium shape and fatty acid content further proved that such pretreatment of oily wastewater can facilitate digestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Lipase pre-hydrolysis enhance anaerobic biodigestion of soap stock from an oil refining industry.

PubMed

Cherif, Slim; Aloui, Fathi; Carrière, Frédéric; Sayadi, Sami

2014-01-01

A novel alcalophilic Staphylococcus haemolyticus strain with the lipolytic activity was used to perform enzymatic hydrolysis pretreatment of soap stock: a lipid rich solid waste from an oil refining industry. The culture liquid of the selected bacteria and an enzymatic preparation obtained by precipitation with ammonium sulphate from a filtrate of the same culture liquid were used for enzymatic pretreatment. The hydrolysis was carried with different incubation concentrations (10, 20 and 30%) of soap stock and the pretreatment efficiency was verified by running comparative biodegradability tests (crude and treated lipid waste). All pretreated assays showed higher reaction rate compared to crude lipid waste, which was confirmed by the increased levels of biogas production. The pretreatment of solutions containing 10% emulsified soap stock was optimized for 24 h hydrolysis time, enabling high-biogaz formation (800 ml). The use of enzymatic pre-treatment seemed to be a very promising alternative for treating soap stock having high fat contents.

Research Regarding Membrane Filtration Capacity of Water Collected from Siret River

NASA Astrophysics Data System (ADS)

Mihalache, I.; Pintilie, Ş. C.; Bîrsan, I. G.; Dănăila, E.; Baltă, Ş.

2018-06-01

In the past decade, the high demand and strict legislations regarding pure and potable water production and quality require finding new treatment technologies with higher effectiveness. When compared with conventional treatment technologies, membrane technology is a viable option in water and wastewater treatment due to high performance, ease in implementation, cost-efficiency among other advantages, also, leading to a rapid expansion in use in almost all areas of industry. Polymeric ultrafiltration membranes have been successfully used in various industries since 1969, and in later years they were studied in the water purification sector, mainly as a pre-treatment step to reduce severe fouling that could occur in reverse osmosis filtration stage. Polysulfone (PSf) was the polymer of choice in this study with two concentrations, 25 wt.% and 30 wt.%. Surface SEM morphology, roughness and water affinity were analyzed for the studied membranes. Water from Siret river was used in the permeation tests in order to analyze the retention capacity and anti-fouling ability. The present study revealed higher retention for the 30 wt.% PSf membranes, from the physico-chemical and microbiological point-of-view and lower fouling, also.

Review of dust transport and mitigation technologies in lunar and Martian atmospheres

NASA Astrophysics Data System (ADS)

Afshar-Mohajer, Nima; Wu, Chang-Yu; Curtis, Jennifer Sinclair; Gaier, James R.

2015-09-01

Dust resuspension and deposition is a ubiquitous phenomenon in all lunar and Martian missions. The near-term plans to return to the Moon as a stepping stone to further exploration of Mars and beyond bring scientists' attention to development and evaluation of lunar and Martian dust mitigation technologies. In this paper, different lunar and Martian dust transport mechanisms are presented, followed by a review of previously developed dust mitigation technologies including fluidal, mechanical, electrical and passive self-cleaning methods for lunar/Martian installed surfaces along with filtration for dust control inside cabins. Key factors in choosing the most effective dust mitigation technology are recognized to be the dust transport mechanism, energy consumption, environment, type of surface materials, area of the surface and surface functionality. While electrical methods operating at higher voltages are identified to be suitable for small but light sensitive surfaces, pre-treatment of the surface is effective for cleaning thermal control surfaces, and mechanical methods are appropriate for surfaces with no concerns of light blockage, surface abrasion and 100% cleaning efficiency. Findings from this paper can help choose proper surface protection/cleaning for future space explorations. Hybrid techniques combining the advantages of different methods are recommended.

Characterization of halogenated DBPs and identification of new DBPs trihalomethanols in chlorine dioxide treated drinking water with multiple extractions.

PubMed

Han, Jiarui; Zhang, Xiangru; Liu, Jiaqi; Zhu, Xiaohu; Gong, Tingting

2017-08-01

Chlorine dioxide (ClO 2 ) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen (TOX), a collective parameter for all halogenated DBPs, formed in ClO 2 -treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid-liquid extraction (LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO 2 -treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time LLE. With the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols, were detected in the drinking water sample pretreated with multiple extractions; two of them, trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO 2 disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water. Copyright © 2017. Published by Elsevier B.V.

Comparative microstructure study of oil palm fruit bunch fibre, mesocarp and kernels after microwave pre-treatment

NASA Astrophysics Data System (ADS)

Chang, Jessie S. L.; Chan, Y. S.; Law, M. C.; Leo, C. P.

2017-07-01

The implementation of microwave technology in palm oil processing offers numerous advantages; besides elimination of polluted palm oil mill effluent, it also reduces energy consumption, processing time and space. However, microwave exposure could damage a material’s microstructure which affected the quality of fruit that can be related to its physical structure including the texture and appearance. In this work, empty fruit bunches, mesocarp and kernel was microwave dried and their respective microstructures were examined. The microwave pretreatments were conducted at 100W and 200W and the microstructure investigation of both treated and untreated samples were evaluated using scanning electron microscope. The micrographs demonstrated that microwave does not significantly influence kernel and mesocarp but noticeable change was found on the empty fruit bunches where the sizes of the granular starch were reduced and a small portion of the silica bodies were disrupted. From the experimental data, the microwave irradiation was shown to be efficiently applied on empty fruit bunches followed by mesocarp and kernel as significant weight loss and size reduction was observed after the microwave treatments. The current work showed that microwave treatment did not change the physical surfaces of samples but sample shrinkage is observed.

Response surface methodology for the optimization of sludge solubilization by ultrasonic pre-treatment

NASA Astrophysics Data System (ADS)

Zheng, Mingyue; Zhang, Xiaohui; Lu, Peng; Cao, Qiguang; Yuan, Yuan; Yue, Mingxing; Fu, Yiwei; Wu, Libin

2018-02-01

The present study examines the optimization of the ultrasonic pre-treatment conditions with response surface experimental design in terms of sludge disintegration efficiency (solubilisation of organic components). Ultrasonic pre-treatment for the maximum solubilization with residual sludge enhanced the SCOD release. Optimization of the ultrasonic pre-treatment was conducted through a Box-Behnken design (three variables, a total of 17 experiments) to determine the effects of three independent variables (power, residence time and TS) on COD solubilization of sludge. The optimal COD was obtained at 17349.4mg/L, when the power was 534.67W, the time was 10.77, and TS was 2%, while the SE of this condition was 28792J/kg TS.

Standardization and optimization of fluorescence in situ hybridization (FISH) for HER-2 assessment in breast cancer: A single center experience.

PubMed

Bogdanovska-Todorovska, Magdalena; Petrushevska, Gordana; Janevska, Vesna; Spasevska, Liljana; Kostadinova-Kunovska, Slavica

2018-05-20

Accurate assessment of human epidermal growth factor receptor 2 (HER-2) is crucial in selecting patients for targeted therapy. Commonly used methods for HER-2 testing are immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Here we presented the implementation, optimization and standardization of two FISH protocols using breast cancer samples and assessed the impact of pre-analytical and analytical factors on HER-2 testing. Formalin fixed paraffin embedded (FFPE) tissue samples from 70 breast cancer patients were tested for HER-2 using PathVysion™ HER-2 DNA Probe Kit and two different paraffin pretreatment kits, Vysis/Abbott Paraffin Pretreatment Reagent Kit (40 samples) and DAKO Histology FISH Accessory Kit (30 samples). The concordance between FISH and IHC results was determined. Pre-analytical and analytical factors (i.e., fixation, baking, digestion, and post-hybridization washing) affected the efficiency and quality of hybridization. The overall hybridization success in our study was 98.6% (69/70); the failure rate was 1.4%. The DAKO pretreatment kit was more time-efficient and resulted in more uniform signals that were easier to interpret, compared to the Vysis/Abbott kit. The overall concordance between IHC and FISH was 84.06%, kappa coefficient 0.5976 (p < 0.0001). The greatest discordance (82%) between IHC and FISH was observed in IHC 2+ group. A standardized FISH protocol for HER-2 assessment, with high hybridization efficiency, is necessary due to variability in tissue processing and individual tissue characteristics. Differences in the pre-analytical and analytical steps can affect the hybridization quality and efficiency. The use of DAKO pretreatment kit is time-saving and cost-effective.

Pretreatment of Eucalyptus in biphasic system for furfural production and accelerated enzymatic hydrolysis.

PubMed

Zhang, Xiudong; Bai, Yuanyuan; Cao, Xuefei; Sun, Runcang

2017-08-01

Herein, an efficient biphasic pretreatment process was developed to improve the production of furfural (FF) and glucose from Eucalyptus. The influence of formic acid and NaCl on FF production from xylose in water and various biphasic systems was investigated. Results showed that the addition of formic acid and NaCl significantly promoted the FF yield, and the biphasic system of MIBK (methyl isobutyl ketone)/water exhibited the best performance for FF production. Then the Eucalyptus was pretreated in the MIBK/water system, and a maximum FF yield of 82.0% was achieved at 180°C for 60min. Surface of the pretreated Eucalyptus became relatively rough and loose, and its crystallinity index increased obviously due to the removal of hemicelluloses and lignin. The pretreated Eucalyptus samples showed much higher enzymatic hydrolysis rates (26.2-70.7%) than the raw Eucalyptus (14.5%). Copyright © 2017 Elsevier Ltd. All rights reserved.

Should we pretreat solid waste prior to anaerobic digestion? An assessment of its environmental cost.

PubMed

Carballa, Marta; Duran, Cecilia; Hospido, Almudena

2011-12-15

Many studies have shown the effectiveness of pretreatments prior to anaerobic digestion of solid wastes, but to our knowledge, none analyzes their environmental consequences/costs. In this work, seven different pretreatments applied to two types of waste (kitchen waste and sewage sludge) have been environmentally evaluated by using life cycle assessment (LCA) methodology. The results show that the environmental burdens associated to the application of pretreatments prior to anaerobic digestion cannot be excluded. Among the options tested, the pressurize-depressurize and chemical (acid or alkaline) pretreatments could be recommended on the basis of their beneficial net environmental performance, while thermal and ozonation alternatives require energy efficiency optimization to reduce their environmental burdens. Reconciling operational, economic and environmental aspects in a holistic approach for the selection of the most sustainable option, mechanical (e.g., pressurize-depressurize) and chemical methods appear to be the most appropriate alternatives at this stage.

Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

PubMed

Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

2017-11-01

Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH) 2 ) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH) 2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH) 2 -glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl 2 ) at room temperature, but that in Ca(OH) 2 -water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH) 2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exploring crystalline-structural variations of cellulose during alkaline pretreatment for enhanced enzymatic hydrolysis.

PubMed

Ling, Zhe; Chen, Sheng; Zhang, Xun; Xu, Feng

2017-01-01

The study aimed to explore the crystallinity and crystalline structure of alkaline pretreated cellulose. The enzymatic hydrolysis followed by pretreatment was conducted for measuring the efficiency of sugar conversion. For cellulose Iβ dominated samples, alkaline pretreatment (<8wt%) caused increased cellulose crystallinity and depolymerized hemicelluloses, that were superimposed to affect the enzymatic conversion to glucose. Varying crystallite sizes and lattice spacings indicated the separation of cellulose crystals during mercerization (8-12wt% NaOH). Completion of mercerization was proved under higher alkaline concentration (14-18wt% NaOH), leading to distortion of crystalline cellulose to some extent. Cellulose II crystallinity showed a stimulative impact on enzymatic hydrolysis due to the weakened hydrophobic interactions within cellulose chains. The current study may provide innovative explanations for enhanced enzymatic digestibility of alkaline pretreated lignocellulosic materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrodynamic cavitation-assisted alkaline pretreatment as a new approach for sugarcane bagasse biorefineries.

PubMed

Terán Hilares, Ruly; Dos Santos, Júlio César; Ahmed, Muhammad Ajaz; Jeon, Seok Hwan; da Silva, Silvio Silvério; Han, Jong-In

2016-08-01

Hydrodynamic cavitation (HC) was employed in order to improve the efficiency of alkaline pretreatment of sugarcane bagasse (SCB). Response surface methodology (RSM) was used to optimize pretreatment parameters: NaOH concentration (0.1-0.5M), solid/liquid ratio (S/L, 3-10%) and HC time (15-45min), in terms of glucan content, lignin removal and enzymatic digestibility. Under an optimal HC condition (0.48M of NaOH, 4.27% of S/L ratio and 44.48min), 52.1% of glucan content, 60.4% of lignin removal and 97.2% of enzymatic digestibility were achieved. Moreover, enzymatic hydrolysis of the pretreated SCB resulted in a yield 82% and 30% higher than the untreated and alkaline-treated controls, respectively. HC was found to be a potent and promising approach to pretreat lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of chemical pretreatments on corn stalk bagasse as immobilizing carrier of Clostridium acetobutylicum in the performance of a fermentation-pervaporation coupled system.

PubMed

Cai, Di; Li, Ping; Chen, Changjing; Wang, Yong; Hu, Song; Cui, Caixia; Qin, Peiyong; Tan, Tianwei

2016-11-01

In this study, different pretreatment methods were evaluated for modified the corn stalk bagasse and further used the pretreated bagasse as immobilized carrier in acetone-butanol-ethanol fermentation process. Structural changes of the bagasses pretreated by different methods were analyzed by Fourier transform infrared, crystallinity index and scanning pictures by electron microscope. And the performances of batch fermentation using the corn stalk based carriers were evaluated. Results indicated that the highest ABE concentration of 23.86g/L was achieved using NaOH pretreated carrier in batch fermentation. Immobilized fermentation-pervaporation integration process was further carried out. The integration process showed long-term stability with 225-394g/L of ABE solvents on the permeate side of pervaporation membrane. This novel integration process was found to be an efficient method for biobutanol production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Upgrading the hydrolytic potential of immobilized bacterial pretreatment to boost biogas production.

PubMed

Ushani, U; Kavitha, S; Johnson, M; Yeom, Ick Tae; Banu, J Rajesh

2017-01-01

In this study, surfactant dioctyl sodium sulphosuccinate (DOSS)-mediated immobilized bacterial pretreatment of waste activated sludge (WAS) was experimentally proved to be an efficient and economically feasible process for enhancing the biodegradability of WAS. The maximal floc disruption with negligible cell cleavage was achieved at surfactant dosage of 0.009 g/g SS. Results of the outcome of bacterial pretreatment of sludge biomass revealed that chemical oxygen demand (COD) solubilization for deflocculated (EPS removed-bacterially pretreated) sludge was 20 %, which was higher than that of flocculated (14 %) or control (5 %). The pretreatment was swift in deflocculated sludge with a rate constant of about 0.064 h -1 . Biochemical methane potential (BMP) assay resulted in significant methane yield at 0.24 gCOD/gCOD for deflocculated sludge. Economic assessment of the proposed method showed a net profit of about 57.39 USD/ton of sludge.

Improving enzymatic hydrolysis efficiency of wheat straw through sequential autohydrolysis and alkaline post-extraction.

PubMed

Wu, Xinxing; Huang, Chen; Zhai, Shengcheng; Liang, Chen; Huang, Caoxing; Lai, Chenhuan; Yong, Qiang

2018-03-01

In this work, a two-step pretreatment process of wheat straw was established by combining autohydrolysis pretreatment and alkaline post-extraction. The results showed that employing alkaline post-extraction to autohydrolyzed wheat straw could significantly improve its enzymatic hydrolysis efficiency from 36.0% to 83.7%. Alkaline post-extraction lead to the changes of the structure characteristics of autohydrolyzed wheat straw. Associations between enzymatic hydrolysis efficiency and structure characteristics were also studied. The results showed that the factors of structure characteristics such as delignification, xylan removal yield, crystallinity, accessibility and hydrophobicity are positively related to enzymatic hydrolysis efficiency within a certain range for alkaline post-extracted wheat straw. The results demonstrated that autohydrolysis coupled with alkaline post-extraction is an effective and promising method to gain fermentable sugars from biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

Process and technoeconomic analysis of leading pretreatment technologies for lignocellulosic ethanol production using switchgrass.

PubMed

Tao, Ling; Aden, Andy; Elander, Richard T; Pallapolu, Venkata Ramesh; Lee, Y Y; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Falls, Matthew; Holtzapple, Mark T; Sierra, Rocio; Shi, Jian; Ebrik, Mirvat A; Redmond, Tim; Yang, Bin; Wyman, Charles E; Hames, Bonnie; Thomas, Steve; Warner, Ryan E

2011-12-01

Six biomass pretreatment processes to convert switchgrass to fermentable sugars and ultimately to cellulosic ethanol are compared on a consistent basis in this technoeconomic analysis. The six pretreatment processes are ammonia fiber expansion (AFEX), dilute acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide-impregnated steam explosion (SO(2)). Each pretreatment process is modeled in the framework of an existing biochemical design model so that systematic variations of process-related changes are consistently captured. The pretreatment area process design and simulation are based on the research data generated within the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) 3 project. Overall ethanol production, total capital investment, and minimum ethanol selling price (MESP) are reported along with selected sensitivity analysis. The results show limited differentiation between the projected economic performances of the pretreatment options, except for processes that exhibit significantly lower monomer sugar and resulting ethanol yields. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microwave-assisted acid pretreatment of alkali lignin: Effect on characteristics and pyrolysis behavior.

PubMed

Duan, Dengle; Ruan, Roger; Wang, Yunpu; Liu, Yuhuan; Dai, Leilei; Zhao, Yunfeng; Zhou, Yue; Wu, Qiuhao

2018-03-01

This study performed microwave-assisted acid pretreatment on pure lignin. The effects of microwave temperature, microwave time, and hydrochloric acid concentration on characteristics and pyrolysis behavior of lignin were examined. Results of ultimate analysis revealed better properties of all pretreated samples than those of raw lignin. Fourier transform infrared spectroscopy analysis showed breakage of βO4 bond and aliphatic side chain, decrease in OH groups, and formation of CO groups in pretreatment. Microwave temperature exerted more significant influence on lignin structure. Thermal stability of treated lignin was improved and insensitive to short microwave time and acid concentration under mild conditions. Resulting from improved alkyl-phenols and decreased alkoxy-phenols, microwave-assisted acid pretreatment of lignin yielded bio-oil with excellent quality. Total yield of phenols in pyrolysis vapors (200 °C) improved to 14.15%, whereas that of guaiacols decreased to 22.36%. This study shows that microwave-assisted acid pretreatment is a promising technology for lignin conversion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ethanosolv Pretreatment of Bamboo with Dilute Acid for Efficient Enzymatic Saccharification

Treesearch

Zhiqiang Li; Zehui Jiang; Benhua Fei; Zhiyong Cai; Xuejun Pan

2012-01-01

Bamboo is a potential lignocellulosic biomass for the production of bioethanol because of its high cellulose and hemicelluloses content. In this research, ethanosolv pretreatment catalyzed by sulfuric acid was studied in order to enhance enzymatic saccharification of moso bamboo. The addition of 2% (w/w on bamboo) sulfuric acid in water or 75% (v/v) ethanol was...

Biorefining of wheat straw: accounting for the distribution of mineral elements in pretreated biomass by an extended pretreatment-severity equation.

PubMed

Le, Duy Michael; Sørensen, Hanne R; Knudsen, Niels Ole; Schjoerring, Jan K; Meyer, Anne S

2014-01-01

Mineral elements present in lignocellulosic biomass feedstocks may accumulate in biorefinery process streams and cause technological problems, or alternatively can be reaped for value addition. A better understanding of the distribution of minerals in biomass in response to pretreatment factors is therefore important in relation to development of new biorefinery processes. The objective of the present study was to examine the levels of mineral elements in pretreated wheat straw in response to systematic variations in the hydrothermal pretreatment parameters (pH, temperature, and treatment time), and to assess whether it is possible to model mineral levels in the pretreated fiber fraction. Principal component analysis of the wheat straw biomass constituents, including mineral elements, showed that the recovered levels of wheat straw constituents after different hydrothermal pretreatments could be divided into two groups: 1) Phosphorus, magnesium, potassium, manganese, zinc, and calcium correlated with xylose and arabinose (that is, hemicellulose), and levels of these constituents present in the fiber fraction after pretreatment varied depending on the pretreatment-severity; and 2) Silicon, iron, copper, aluminum correlated with lignin and cellulose levels, but the levels of these constituents showed no severity-dependent trends. For the first group, an expanded pretreatment-severity equation, containing a specific factor for each constituent, accounting for variability due to pretreatment pH, was developed. Using this equation, the mineral levels could be predicted with R(2) > 0.75; for some with R(2) up to 0.96. Pretreatment conditions, especially pH, significantly influenced the levels of phosphorus, magnesium, potassium, manganese, zinc, and calcium in the resulting fiber fractions. A new expanded pretreatment-severity equation is proposed to model and predict mineral composition in pretreated wheat straw biomass.

Impact of Mixed Feedstocks and Feedstock Densification on Ionic Liquid Pretreatment Efficiency

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

Jian Shi; Vicki S. Thompson; Neal A. Yancey

2013-01-01

Background: Lignocellulosic biorefineries must be able to efficiently process the regional feedstocks that are available at cost-competitive prices year round. These feedstocks typically have low energy densities and vary significantly in composition. One potential solution to these issues is blending and/or densifying the feedstocks in order to create a uniform feedstock. Results/discussion: We have mixed four feedstocks - switchgrass, lodgepole pine, corn stover, and eucalyptus - in flour and pellet form and processed them using the ionic liquid 1-ethyl-3-methylimidazolium acetate. Sugar yields from both the mixed flour and pelletized feedstocks reach 90% within 24 hours of saccharification. Conclusions: Mixed feedstocks,more » in either flour or pellet form, are efficiently processed using this pretreatment process, and demonstrate that this approach has significant potential.« less

The effect of drying and size reduction pretreatments on recovery of inorganic crop nutrients from inedible wheat residues

NASA Technical Reports Server (NTRS)

Strayer, R. F.; Alazraki, M. P.; Judkins, J.

2003-01-01

Inorganic nutrients can be easily recovered from ALS crop residue solid wastes by aqueous leaching. However, oven drying and milling pretreatment of these residues has been frequently required to accommodate crop scientists and facility storage limitations. As part of a research study that will compare three different bioreactor technologies for processing these wastes, we realized that different drying and size-reduction pretreatments had been utilized for each technology. This paper compares the effects of residue pretreatment on recovery of nutrients by leaching. Pretreatments included three drying methods [fresh, oven-dried (70 degrees C overnight), and freeze-dried] and two size reduction methods [chopped (2 cm length) and milled (2 mm diameter)]. Determination of mass balances (dry weight and ash content of solids) before and after leaching indicated solubilization was least for fresh residues (23% dry weight loss and 50% for ash loss), and most for freeze-dried residues (41-47% dry weight loss and nearly 100% for ash loss). Mineral recovery of major elements (NO3, PO4, K, Ca, and Mg) in leachates was poorest for fresh residues. P and K recovery in leachates were best for oven-dried residues and Ca, Mg, and N recovery best for freeze-dried residues. The differences in recovery for N, P, and K in leachates were minimal between chopping and milling and slightly better for Ca and Mg from milled residues.

Thermotolerant Yeasts for Bioethanol Production Using Lignocellulosic Substrates

NASA Astrophysics Data System (ADS)

Pasha, Chand; Rao, L. Venkateswar

No other sustainable option for production of transportation fuels can match ethanol made from lignocellulosic biomass with respect to its dramatic environmental, economic, strategic and infrastructure advantages. Substantial progress has been made in advancing biomass ethanol (bioethanol) production technology to the point that it now has commercial potential, and several firms are engaged in the demanding task of introducing first-of-a-kind technology into the marketplace to make bioethanol a reality in existing fuel-blending markets. In order to lower pollution India has a long-term goal to use biofuels (bioethanol and biodiesel). Ethanol may be used either in pure form, or as a blend in petrol in different proportions. Since the cost of raw materials, which can account up to 50 % of the total production cost, is one of the most significant factors affecting the economy of alcohol, nowadays efforts are more concentrated on using cheap and abundant raw materials. Several forms of biomass resources exist (starch or sugar crops, weeds, oil plants, agricultural, forestry and municipal wastes) but of all biomass cellulosic resources represent the most abundant global source. The lignocellulosic materials include agricultural residues, municipal solid wastes (MSW), pulp mill refuse, switchgrass and lawn, garden wastes. Lignocellulosic materials contain two types of polysaccharides, cellulose and hemicellulose, bound together by a third component lignin. The principal elements of the lignocellulosic research include: i) evaluation and characterization of the waste feedstock; ii) pretreatment including initial clean up or dewatering of the feedstock; and iii) development of effective direct conversion bioprocessing to generate ethanol as an end product. Pre-treatment of lignocellulosic materials is a step in which some of the hemicellulose dissolves in water, either as monomeric sugars or as oligomers and polymers. The cellulose cannot be enzymatically hydrolyzed to glucose without a physical and chemical pre-treatment. The pre-treatment processes normally applied on the different substrates are acidic hydrolysis, steam explosion and wet oxidation. A problem for most pretreatment methods is the generation of compounds that are inhibitory towards the fermenting microorganisms, primarily phenols. Degradation products that could have inhibitory action in later fermentation steps are avoided during pre-treatment by wet oxidation. Followed by pre treatment, hydrolysed with enzymes known as cellulases and hemicellulases, which hydrolyse cellulose and hemicellulose respectively. The production of bioethanol requires two steps, fermentation and distillation. Practically all ethanol fermentation is still based on Saccharomyces cerevisiae . The fermentation using thermotolerant yeasts has more advantageous in that they have faster fermentation rates, avoid the cooling costs, and decrease the over all fermentation costs, so that ethanol can be made available at cheaper rates. In addition they can be used for efficient simultaneous saccharification and fermentation of cellulose by cellulases because the temperature optimum of cellulase enzymes (about 40 ° C to 45 ° C) is close to the fermentation temperature of thermotolerant yeasts. Hence selection and improvement of thermotolerant yeasts for bioconversion of lignocellulosic substrates is very useful.

Process design and evaluation of production of bioethanol and β-lactam antibiotic from lignocellulosic biomass.

PubMed

Kim, Sung Bong; Park, Chulhwan; Kim, Seung Wook

2014-11-01

To design biorefinery processes producing bioethanol from lignocellulosic biomass with dilute acid pretreatment, biorefinery processes were simulated using the SuperPro Designer program. To improve the efficiency of biomass use and the economics of biorefinery, additional pretreatment processes were designed and evaluated, in which a combined process of dilute acid and aqueous ammonia pretreatments, and a process of waste media containing xylose were used, for the production of 7-aminocephalosporanic acid. Finally, the productivity and economics of the designed processes were compared. Copyright © 2014 Elsevier Ltd. All rights reserved.

An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation.

PubMed

Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

2013-11-15

Lab-scale High Efficiency Digestion (HED) systems containing a Mesophilic Anaerobic Reactor (MAR), Thermophilic Aerobic Reactor (TAR), liquid/solid separation unit, and thermal-alkaline treatment were developed to evaluate the efficiencies of sludge reduction and methane production. The HED process was divided into three phases to examine the influence of sludge pretreatment and pretreated sludge recirculation using TCOD and VSS reduction, COD solubilization, and methane production. The VSS removal with a solid/liquid separation unit, sludge recirculation, and thermal-alkaline treatment drastically increased up to 95% compared to the feed concentration. In addition, the results of COD solubilization and VSS/TSS showed that the solubilization of cells and organic matters by the thermal-alkaline treatment was highly increased, which was also consistent with the SEM images. In particular, the methane production rate increased 24-fold when the feed sludge and recirculated sludge were pretreated together. Collectively, the HED experiments performed with sludge recirculation and thermal-alkaline treatment demonstrated that the HED systems can be successfully employed for highly efficient sewage sludge reduction and methane gas production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application for oxytetracycline wastewater pretreatment by Fenton iron mud based cathodic-anodic-electrolysis ceramic granular fillers.

PubMed

Zhang, Feilong; Yue, Qinyan; Gao, Yuan; Gao, Baoyu; Xu, Xing; Ren, Zhongfei; Jin, Yang

2017-09-01

In this study, Fenton iron mud applied as main raw material of cathodic-anodic-electrolysis ceramic granular fillers (ICMF) in a continuous reactor, which were used to pretreat oxytetracycline (OTC) wastewater. The ICMF was characterized by Scanning Electron Microscope and Energy Dispersive Spectrometer analysis. The effects of pH value, hydraulic retention time, OTC concentrations and aeration on removal efficiency of total organic carbon (TOC) and OTC were studied. The degradation byproducts of OTC were analyzed by UV-2450, High Performance Liquid Chromatography and Liquid Chromatography-mass Spectrometry. The SEM images showed that the surface ICMF was porous. This system had a higher stability, and good removal efficiency of TOC of 80.5% and OTC of 98.5% under the optimal conditions, which were influent pH of 3, HRT of 4 h, and anaerobic condition. After running for 60 d, the removal efficiency of TOC was stable and the ICMF did not become hardened. The reactor was back washed by acid solution (pH: 1) in 20 d approximately. This paper provides useful information for approaching in wastewater pretreatment and recycling the Fenton iron mud. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzymolysis kinetics and structural characteristics of rice protein with energy-gathered ultrasound and ultrasound assisted alkali pretreatments.

PubMed

Li, Suyun; Yang, Xue; Zhang, Yanyan; Ma, Haile; Qu, Wenjuan; Ye, Xiaofei; Muatasim, Rahma; Oladejo, Ayobami Olayemi

2016-07-01

This research investigated the structural characteristics and enzymolysis kinetics of rice protein which was pretreated by energy-gathered ultrasound and ultrasound assisted alkali. The structural characteristics of rice protein before and after the pretreatment were performed with surface hydrophobicity and Fourier transform infrared (FTIR). There was an increase in the intensity of fluorescence spectrum and changes in functional groups after the pretreatment on rice protein compared with the control (without ultrasound and ultrasound assisted alkali processed), thus significantly enhancing efficiency of the enzymatic hydrolysis. A simplified kinetic equation for the enzymolysis model with the impeded reaction of enzyme was deduced to successfully describe the enzymatic hydrolysis of rice protein by different pretreatments. The initial observed rate constants (Kin,0) as well as ineffective coefficients (kimp) were proposed and obtained based on the experimental observation. The results showed that the parameter of kin,0 increased after ultrasound and ultrasound assisted alkali pretreatments, which proved the effects of the pretreatments on the substrate enhancing the enzymolysis process and had relation to the structure changes of the pretreatments on the substrate. Furthermore, the applicability of the simplified model was demonstrated by the enzymatic hydrolysis process for other materials. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasonic pretreatment in lipase-catalyzed synthesis of structured lipids with high 1,3-dioleoyl-2-palmitoylglycerol content.

PubMed

Liu, Si-lei; Dong, Xu-yan; Wei, Fang; Wang, Xiang; Lv, Xin; Zhong, Juan; Wu, Lin; Quek, Siew-young; Chen, Hong

2015-03-01

Production of structured lipid 1,3-dioleoyl-2-palmitoylglycerol (OPO), from tripalmitin (PPP) and oleic acid (OA) using lipases and ultrasonic pretreatment was conducted. Factors influencing both the ultrasonic conditions and enzymatic reaction were investigated. Optimum conditions could be attained with 6 min pretreatment time, 50% ultrasonic power, 3 s/9 s (work/pause) cycle of ultrasonic pulse, 1:8 PPP/OA molar ratio, 12% enzyme dosage and 50 °C temperature of. At the optimum conditions, the OPO yield of 51.8% could be achieved in 4h. Studies showed that the OPO content increased to 35.9% in 1h with ultrasonic pretreatment, in comparison to 4h without ultrasonic pretreatment. Reuse of Lipozyme RM IM for 10 cycles under ultrasonic irradiation did not cause essential damage to its lipase activity. Reaction kinetic model fitted well with the proposed Ping-Pong mechanism. The apparent kinetic constant (Vm'/K₂) of ultrasound pretreatment reaction was 2.52 times higher than the conventional mechanical stirring, indicating that ultrasound pretreatment enhanced the substrates affinity to the enzyme. This study confirmed that ultrasonic pretreatment was more efficient in OPO production than conventional mechanical agitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Experimental binding of lead to a low cost on biosorbent: Nopal (Opuntia streptacantha).

PubMed

Miretzky, Patricia; Muñoz, Carolina; Carrillo-Chávez, Alejandro

2008-03-01

The use of nopal cladodes (Opuntia streptacantha) as raw material for Pb(2+) biosorption was investigated. Batch experiments were carried out to determine Pb(2+) sorption capacity and the efficiency of the sorption process under different pH, initial Pb(2+) and nopal biomass concentrations. The experimental data showed a good fit to Langmuir and Freundlich isotherms models. The maximum adsorption capacity for Pb(2+) was 0.14 mmol g(-1) with an efficiency higher than 94% (pH 5.0 and 2.5 g L(-1) nopal biomass). The Pb(2+) kinetics were best described by the pseudo-second-order rate model. The rate constant, the initial sorption rate and the equilibrium sorption capacity were determined. The practical implication of this study is the development of an effective and economic technology in which the nopal biomass did not undergo any chemical or physical pretreatment, which added to nopal abundance in Mexico and its low cost makes it a good option for Pb(2+) removal from contaminated waters.

A review on bioconversion of lignocellulosic biomass to H2: Key challenges and new insights.

PubMed

Ren, Nan-Qi; Zhao, Lei; Chen, Chuan; Guo, Wan-Qian; Cao, Guang-Li

2016-09-01

With the increasing energy crisis and rising concern over climate change, the development of clean alternative energy sources is of great importance. Biohydrogen produced from lignocellulosic biomass is a promising candidate, because of its positives such as readily available, no harmful emissions, environment friendly, efficient, and renewable. However, obstacles still exist to enable the commercialization of biological hydrogen production from lignocellulosic biomass. Thus the objective of this work is to provide update information about the recent progress on lignocellulosic hydrogen conversion via dark fermentation. In this review, the most important technologies associated with lignocellulosic hydrogen fermentation were covered. Firstly, pretreatment methods for better utilization of lignocellulosic biomass are presented, at the same time, hydrolysis methods assisting to achieve efficient hydrogen fermentation were discussed. Afterwards, issues related to bioprocesses for hydrogen production purposes were presented. Additionally, the paper gave challenges and new insights of lignocellulosic biohydrogen production. Copyright © 2016. Published by Elsevier Ltd.

Effects of Oligosaccharides Isolated From Pinewood Hot Water Pre-hydrolyzates on Recombinant Cellulases.

PubMed

Fang, Hong; Kandhola, Gurshagan; Rajan, Kalavathy; Djioleu, Angele; Carrier, Danielle Julie; Hood, Kendall R; Hood, Elizabeth E

2018-01-01

Loblolly pine residues have enormous potential to be the raw material for advanced biofuel production due to extensive sources and high cellulose content. Hot water (HW) pretreatment, while being a relatively economical and clean technology for the deconstruction of lignocellulosic biomass, could also inhibit the ensuing enzymatic hydrolysis process because of the production of inhibitors. In this study, we investigated the effect of oligosaccharide fractions purified from HW pre-hydrolyzate of pinewood using centrifugal partition chromatography (CPC) on three recombinant cellulolytic enzymes (E1, CBHI and CBHII), which were expressed in the transgenic corn grain system. The efficiency of recombinant enzymes was measured using either a 4-methylumbelliferyl-β-D-cellobioside (MUC) or a cellulose-dinitrosalicylic acid (DNS) assay system. The results showed that HW pre-hydrolyzate CPC fractions contain phenolics, furans, and monomeric and oligomeric sugars. Among CPC fractions, oligomers composed of xylan, galactan, and mannan were inhibitory to the three recombinant enzymes and to the commercial cellulase cocktail, reducing the enzymatic efficiency to as low as 10%.

Novel micronized woody biomass process for production of cost-effective clean fermentable sugars.

PubMed

Fu, Yu; Gu, Bon-Jae; Wang, Jinwu; Gao, Johnway; Ganjyal, Girish M; Wolcott, Michael P

2018-07-01

Thermo-chemical pretreatments of biomass typically result in environmental impacts from water use and emission. The degradation byproducts in the resulting sugars can be inhibitory to the activities of enzymes and yeasts. The results of this study showed that combining existing commercial comminution technology can reduce total energy consumption with improved saccharification yield while eliminating chemical use. Impact mill was found to be the most efficient milling for size reduction of forest residual chips from ca. 2 mm to a specific value below 100 µm. The further micronization effectively disrupted the recalcitrance of the woody biomass and produced the highly saccharifiable substrates for downstream processing. In addition, extrusion can be integrated into a clean cellulosic sugar process for further fibrillation in place of the conventional mixing processing. The highest energy efficiency was observed on the impact-milled samples with 0.515 kg sugars kWh -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Anaerobic digestion of thermal pre-treated sludge at different solids concentrations--Computation of mass-energy balance and greenhouse gas emissions.

PubMed

Pilli, Sridhar; More, Tanaji; Yan, Song; Tyagi, Rajeshwar Dayal; Surampalli, Rao Y

2015-07-01

The effect of thermal pre-treatment on sludge anaerobic digestion (AD) efficiency was studied at different total solids (TS) concentrations (20.0, 30.0 and 40.0 g TS/L) and digestion times (0, 5, 10, 15, 20 and 30 days) for primary, secondary and mixed wastewater sludge. Moreover, sludge pre-treatment, AD and disposal processes were evaluated based on a mass-energy balance and corresponding greenhouse gas (GHG) emissions. Mass balance revealed that the least quantity of digestate was generated by thermal pre-treated secondary sludge at 30.0 g TS/L. The net energy (energy output-energy input) and energy ratio (energy output/energy input) for thermal pre-treated sludge was greater than control in all cases. The reduced GHG emissions of 73.8 × 10(-3) g CO2/g of total dry solids were observed for the thermal pre-treated secondary sludge at 30.0 g TS/L. Thermal pre-treatment of sludge is energetically beneficial and required less retention time compared to control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient sugar release by acetic acid ethanol-based organosolv pretreatment and enzymatic saccharification.

PubMed

Zhang, Hongdan; Wu, Shubin

2014-12-03

Acetic acid ethanol-based organosolv pretreatment of sugar cane bagasse was performed to enhance enzymatic hydrolysis. The effect of different parameters (including temperature, reaction time, solvent concentration, and acid catalyst dose) on pretreatment prehydrolyzate and subsequent enzymatic digestibility was determined. During the pretreatment process, 11.83 g of xylose based on 100 g of raw material could be obtained. After the ethanol-based pretreatment, the enzymatic hydrolysis was enhanced and the highest glucose yield of 40.99 g based on 100 g of raw material could be obtained, representing 93.8% of glucose in sugar cane bagasse. The maximum total sugar yields occurred at 190 °C, 45 min, 60:40 ethanol/water, and 5% dosage of acetic acid, reaching 58.36 g (including 17.69 g of xylose and 40.67 g of glucose) based on 100 g of raw material, representing 85.4% of total sugars in raw material. Furthermore, characterization of the pretreated sugar cane bagasse using X-ray diffraction and scanning electron microscopy analyses were also developed. The results suggested that ethanol-based organosolv pretreatment could enhance enzymatic digestibilities because of the delignification and removal of xylan.

Microwave-Assisted Simplified Simultaneous Distillation Coupled with Ionic Liquid Pretreatment for the Analysis of Essential Oil in Schisandra sphenanthera.

PubMed

Yu, Guo-Wei; Nie, Jing; Song, Zhi-Yu; Li, Zu-Guang; Lee, Maw-Rong; Wang, Shen-Peng

2017-11-01

Simultaneous distillation extraction (SDE) is quite useful for the separation of volatile compounds from an analyte when their contents are quite low. In this study, a simplified SDE approach is applied for the extraction of essential oil from Schisandra sphenanthera, with microwave as heating source, [Bmim][Cl] as the medium for pretreatment, and gas chromatography-mass spectrometry as the analytical approach. Consequently, the improvement resulted from [Bmim][Cl] pretreatment is demonstrated by taking comparison with blank experiments. Totally 61 compounds have been detected in the essential oil obtained by using [Bmim][Cl] pretreatment, while without [Bmim][Cl] pretreatment, only 53 compounds can be detected. Moreover, [Bmim][Cl] pretreatment can also resulted in a higher yield of essential oil. The experimental results demonstrate that the simplified SDE coupled with ionic liquid pretreatment is a feasible approach for the extraction of essential oil from S. sphenanthera with high efficiency as 0.85% of essential oil yield has been obtained, and can be potentially extended to the extraction of essential oil or other target volatile compounds with low content. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Enhanced micropropagation and tiller formation in sugarcane through pretreatment of explants with thidiazuron (TDZ).

PubMed

Kumari, Kavita; Lal, Madan; Saxena, Sangeeta

2017-10-01

An efficient, simple and commercially applicable protocol for rapid micropropagation of sugarcane has been designed using variety Co 05011. Pretreatment of shoot tip explants with thidiazuron (TDZ) induced high frequency regeneration of shoot cultures with improved multiplication ratio. The highest frequency (80%) of shoot initiation in explants pretreated with 10 mg/l of TDZ was obtained during the study. Maximum 65% shoot cultures could be established from the explants pretreated with TDZ as compared to minimum 40% establishment in explants without pretreatment. The explants pretreated with 10 mg/l of TDZ required minimum 40 days for the establishment of shoot cultures as compared to untreated explants which required 60 days. The highest average number of shoots per culture (19.1) could be obtained from the explants pretreated with 10 mg/l of TDZ, indicating the highest multiplication ratio (1:6). Highest rooting (over 94%) was obtained in shoots regenerated from pretreated explants on ½ strength MS medium containing 5.0 mg/l of NAA and 50 g/l of sucrose within 15 days. Higher number of tillers/clump (15.3) could be counted in plants regenerated from pretreated explants than untreated ones (10.9 tillers/clump) in field condition, three months after transplantation. Molecular analysis using RAPD and DAMD markers suggested that the pretreatment of explants with TDZ did not adversely affect the genetic stability of regenerated plants and maintained high clonal purity.

Integration of National Laboratory and Low-Activity Waste Pre-Treatment System Technology Service Providers - 16435

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

Subramanian, Karthik H.; Thien, Michael G.; Wellman, Dawn M.

The National Laboratories are a critical partner and provide expertise in numerous aspects of the successful execution of the Direct-Feed Low Activity Waste Program. The National Laboratories are maturing the technologies of the Low-Activity Waste Pre-Treatment System (LAWPS) consistent with DOE Order 413.3B “Program and Project Management for the Acquisition of Capital Assets” expectations. The National Laboratories continue to mature waste forms, i.e. glass and secondary waste grout, for formulations and predictions of long-term performance as inputs to performance assessments. The working processes with the National Laboratories have been developed in procurements, communications, and reporting to support the necessary delivery-basedmore » technology support. The relationship continues to evolve from planning and technology development to support of ongoing operations and integration of multiple highly coordinated facilities.« less

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals

PubMed Central

Den, Walter; Sharma, Virender K.; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S.

2018-01-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment. PMID:29755972

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals.

PubMed

Den, Walter; Sharma, Virender K; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S

2018-01-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals

NASA Astrophysics Data System (ADS)

Den, Walter; Sharma, Virender K.; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S.

2018-04-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

Study on electroplating technology of diamond tools for machining hard and brittle materials

NASA Astrophysics Data System (ADS)

Cui, Ying; Chen, Jian Hua; Sun, Li Peng; Wang, Yue

2016-10-01

With the development of the high speed cutting, the ultra-precision machining and ultrasonic vibration technique in processing hard and brittle material , the requirement of cutting tools is becoming higher and higher. As electroplated diamond tools have distinct advantages, such as high adaptability, high durability, long service life and good dimensional stability, the cutting tools are effective and extensive used in grinding hard and brittle materials. In this paper, the coating structure of electroplating diamond tool is described. The electroplating process flow is presented, and the influence of pretreatment on the machining quality is analyzed. Through the experimental research and summary, the reasonable formula of the electrolyte, the electroplating technologic parameters and the suitable sanding method were determined. Meanwhile, the drilling experiment on glass-ceramic shows that the electroplating process can effectively improve the cutting performance of diamond tools. It has laid a good foundation for further improving the quality and efficiency of the machining of hard and brittle materials.

LCA of local strategies for energy recovery from waste in England, applied to a large municipal flow

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

Tunesi, Simonetta, E-mail: s.tunesi@ucl.ac.uk

An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the 'fuel from waste' so produced. Each energy recovery strategy willmore » result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing 'fuel from waste' market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The contribution and relative importance of recycling and treatment/recovery processes change with the impact category. The lack of reprocessing plants in the area of the case study has shown the relevance of transport distances for recyclate material in reducing the efficiency of a WM system. Highly relevant to the current English WM infrastructural debate, these results for the first time highlight the risk of a significant reduction in the energy that could be recovered by local WM strategies relying only on the market to dispose of the 'fuel from waste' in a non dedicated plant in the case that the SRF had to be sent to landfill for lack of treatment capacity.« less

LCA of local strategies for energy recovery from waste in England, applied to a large municipal flow.

PubMed

Tunesi, Simonetta

2011-03-01

An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the 'fuel from waste' so produced. Each energy recovery strategy will result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing 'fuel from waste' market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The contribution and relative importance of recycling and treatment/recovery processes change with the impact category. The lack of reprocessing plants in the area of the case study has shown the relevance of transport distances for recyclate material in reducing the efficiency of a WM system. Highly relevant to the current English WM infrastructural debate, these results for the first time highlight the risk of a significant reduction in the energy that could be recovered by local WM strategies relying only on the market to dispose of the 'fuel from waste' in a non dedicated plant in the case that the SRF had to be sent to landfill for lack of treatment capacity. Copyright © 2010 Elsevier Ltd. All rights reserved.

Simultaneous saccharification and fermentation of fungal pretreated cornstalk for hydrogen production using Thermoanaerobacterium thermosaccharolyticum W16.

PubMed

Zhao, Lei; Cao, Guang-Li; Wang, Ai-Jie; Guo, Wan-Qian; Ren, Hong-Yu; Ren, Nan-Qi

2013-10-01

In this research, environmentally friendly fungal pretreatment was first adopted for deconstruction of cornstalk. Then the fungal-pretreated cornstalk was employed to produce hydrogen in simultaneous saccharification and fermentation (SSF) using crude enzyme from Trichoderma viride and Thermoanaerobacterium thermosaccharolyticum W16. The influence of various factors including substrate concentration, initial pH, and enzyme loading on hydrogen production were evaluated. The highest hydrogen yield of 89.3 ml/g-cornstalk was obtained with an initial pH 6.5, 0.75% substrate concentration, and 34 FPU/g cellulose. Compared the result with SSF of physical or chemical pretreated lignocellulosic materials, this research suggested an economic and efficient way for hydrogen production from lignocellulosic biomass. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sonophotocatalytic degradation of dye C.I. Acid Orange 7 by TiO2 and Ag nanoparticles immobilized on corona pretreated polypropylene non-woven fabric.

PubMed

Marković, Darka; Šaponjić, Zoran; Radoičić, Marija; Radetić, Tamara; Vodnik, Vesna; Potkonjak, Branislav; Radetić, Maja

2015-05-01

This study discusses the possibility of using corona pre-treated polypropylene (PP) non-woven fabric as a support for immobilization of colloidal TiO2 and Ag nanoparticles in order to remove dye C.I. Acid Orange 7 from aqueous solution. Dye removal efficiency by sonocatalysis, photocatalysis and sonophotocatalysis was evaluated on corona pre-treated fabric loaded with TiO2 nanoparticles, corona pre-treated fabric double loaded with TiO2 nanoparticles and corona pre-treated fabrics loaded with TiO2 nanoparticles before and after deposition of Ag nanoparticles. In addition, the stability of PP non-woven fabric during these processes was investigated. The substrates were characterized by SEM, EDX and AAS analyses. The change of the dye concentration was evaluated by UV-VIS spectrophotometry. Unlike sonocatalysis and photocatalysis, complete dye removal from both solution and non-woven fabric was obtained already after 240-270 min of sonophotocatalysis. Corona pre-treated PP non-woven fabric loaded with Ag nanoparticles prior to deposition of TiO2 nanoparticles provided excellent degradation efficiency and superior reusability. Sonophotocatalytic degradation of dye in the presence of all investigated samples was the most prominent in acidic conditions. Although this nanocomposite system ensured fast discoloration of dye solution, TOC values of water measured after sonophotocatalysis were not satisfactory because of PP degradation. Therefore, it is suggested to include TOC evaluation in each case study where different supports for TiO2 nanoparticles are used since these nanoparticles may guarantee the dye removal from solution but the stability of support could be problematic causing even more serious environmental impact. Copyright © 2014 Elsevier B.V. All rights reserved.

Improved Activity of a Thermophilic Cellulase, Cel5A, from Thermotoga maritima on Ionic Liquid Pretreated Switchgrass

PubMed Central

Chen, Zhiwei; Pereira, Jose H.; Liu, Hanbin; Tran, Huu M.; Hsu, Nathan S. Y.; Dibble, Dean; Singh, Seema; Adams, Paul D.; Sapra, Rajat; Hadi, Masood Z.; Simmons, Blake A.; Sale, Kenneth L.

2013-01-01

Ionic liquid pretreatment of biomass has been shown to greatly reduce the recalcitrance of lignocellulosic biomass, resulting in improved sugar yields after enzymatic saccharification. However, even under these improved saccharification conditions the cost of enzymes still represents a significant proportion of the total cost of producing sugars and ultimately fuels from lignocellulosic biomass. Much of the high cost of enzymes is due to the low catalytic efficiency and stability of lignocellulolytic enzymes, especially cellulases, under conditions that include high temperatures and the presence of residual pretreatment chemicals, such as acids, organic solvents, bases, or ionic liquids. Improving the efficiency of the saccharification process on ionic liquid pretreated biomass will facilitate reduced enzyme loading and cost. Thermophilic cellulases have been shown to be stable and active in ionic liquids but their activity is typically at lower levels. Cel5A_Tma, a thermophilic endoglucanase from Thermotoga maritima, is highly active on cellulosic substrates and is stable in ionic liquid environments. Here, our motivation was to engineer mutants of Cel5A_Tma with higher activity on 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) pretreated biomass. We developed a robotic platform to screen a random mutagenesis library of Cel5A_Tma. Twelve mutants with 25–42% improvement in specific activity on carboxymethyl cellulose and up to 30% improvement on ionic-liquid pretreated switchgrass were successfully isolated and characterized from a library of twenty thousand variants. Interestingly, most of the mutations in the improved variants are located distally to the active site on the protein surface and are not directly involved with substrate binding. PMID:24244549

Improved activity of a thermophilic cellulase, Cel5A, from Thermotoga maritima on ionic liquid pretreated switchgrass.

PubMed

Chen, Zhiwei; Pereira, Jose H; Liu, Hanbin; Tran, Huu M; Hsu, Nathan S Y; Dibble, Dean; Singh, Seema; Adams, Paul D; Sapra, Rajat; Hadi, Masood Z; Simmons, Blake A; Sale, Kenneth L

2013-01-01

Ionic liquid pretreatment of biomass has been shown to greatly reduce the recalcitrance of lignocellulosic biomass, resulting in improved sugar yields after enzymatic saccharification. However, even under these improved saccharification conditions the cost of enzymes still represents a significant proportion of the total cost of producing sugars and ultimately fuels from lignocellulosic biomass. Much of the high cost of enzymes is due to the low catalytic efficiency and stability of lignocellulolytic enzymes, especially cellulases, under conditions that include high temperatures and the presence of residual pretreatment chemicals, such as acids, organic solvents, bases, or ionic liquids. Improving the efficiency of the saccharification process on ionic liquid pretreated biomass will facilitate reduced enzyme loading and cost. Thermophilic cellulases have been shown to be stable and active in ionic liquids but their activity is typically at lower levels. Cel5A_Tma, a thermophilic endoglucanase from Thermotoga maritima, is highly active on cellulosic substrates and is stable in ionic liquid environments. Here, our motivation was to engineer mutants of Cel5A_Tma with higher activity on 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) pretreated biomass. We developed a robotic platform to screen a random mutagenesis library of Cel5A_Tma. Twelve mutants with 25-42% improvement in specific activity on carboxymethyl cellulose and up to 30% improvement on ionic-liquid pretreated switchgrass were successfully isolated and characterized from a library of twenty thousand variants. Interestingly, most of the mutations in the improved variants are located distally to the active site on the protein surface and are not directly involved with substrate binding.

Conversion of cornstalk to bio-oil in hot-compressed water: effects of ultrasonic pretreatment on the yield and chemical composition of bio-oil, carbon balance, and energy recovery.

PubMed

Shi, Wen; Gao, Yahui; Yang, Guohui; Zhao, Yaping

2013-08-07

An ultrasonic pretreatment method was developed to enhance the yield of bio-oil obtained from the liquefaction of cornstalks in hot-compressed water at different reaction temperatures (260-340 °C) and residence times (0-40 min). Influences of ultrasonic pretreatment on the physicochemical properties of cornstalks and bio-oil yields were investigated. The results show that ultrasonic pretreatment obviously increases surface areas of cornstalks, decreases crystallinities, and erodes the structures of lignin, leading to more exposure of cellulose and hemicellulose. The yield of bio-oil was increased remarkably by 10.1% for 40 min sonicated cornstalks under the optimum liquefied conditions (300 °C for 0 min of residence time). Carbon balance indicates that ultrasonic pretreatment increases the carbon conversion of cornstalks to heavy oil and water-soluble oil. Energy balance indicates that the sonicated cornstalks have positive energy efficiencies. GC-MS analyses demonstrate ultrasonic pretreatment increases the contents of the phenols in heavy oil and water-soluble oil.

Process performance assessment of advanced anaerobic digestion of sewage sludge including sequential ultrasound-thermal (55 °C) pre-treatment.

PubMed

Neumann, Patricio; Barriga, Felipe; Álvarez, Claudia; González, Zenón; Vidal, Gladys

2018-03-15

The aim of this study was to evaluate the performance and digestate quality of advanced anaerobic digestion of sewage sludge including sequential ultrasound-thermal (55 °C) pre-treatment. Both stages of pre-treatment contributed to chemical oxygen demand (COD) solubilization, with an overall factor of 11.4 ± 2.2%. Pre-treatment led to 19.1, 24.0 and 29.9% increased methane yields at 30, 15 and 7.5 days solid retention times (SRT), respectively, without affecting process stability or accumulation of intermediates. Pre-treatment decreased up to 4.2% water recovery from the digestate, but SRT was a more relevant factor controlling dewatering. Advanced digestion showed 2.4-3.1 and 1.5 logarithmic removals of coliforms and coliphages, respectively, and up to a 58% increase in the concentration of inorganics in the digestate solids compared to conventional digestion. The COD balance of the process showed that the observed increase in methane production was proportional to the pre-treatment solubilization efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-pressure carbon dioxide/water pre-treatment of sugarcane bagasse and elephant grass: Assessment of the effect of biomass composition on process efficiency.

PubMed

Toscan, Andréia; Morais, Ana Rita C; Paixão, Susana M; Alves, Luís; Andreaus, Jürgen; Camassola, Marli; Dillon, Aldo José Pinheiro; Lukasik, Rafal M

2017-01-01

The performance of two lignocellulosic biomasses was studied in high-pressure carbon dioxide/water pre-treatment. Sugarcane bagasse and elephant grass were used to produce C 5 -sugars from hemicellulose and, simultaneously, to promote cellulose digestibility for enzymatic saccharification. Different pre-treatment conditions, with combined severity factor ranging from -1.17 to -0.04, were evaluated and maximal total xylan to xylose yields of 59.2wt.% (34.4wt.% xylooligomers) and 46.4wt.% (34.9wt.% xylooligomers) were attained for sugarcane bagasse and elephant grass, respectively. Furthermore, pre-treated biomasses were highly digestible, with glucan to glucose yields of 77.2mol% and 72.4mol% for sugarcane bagasse and elephant grass, respectively. High-pressure carbon dioxide/water pre-treatment provides high total C 5 -sugars and glucose recovery from both lignocellulosic biomasses; however it is highly influenced by composition and intrinsic features of each biomass. The obtained results confirm this approach as an effective and greener alternative to conventional pre-treatment processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid.

PubMed

Li, Xiaoming; Zhao, Jianwei; Wang, Dongbo; Yang, Qi; Xu, Qiuxiang; Deng, Yongchao; Yang, Weiqiang; Zeng, Guangming

2016-02-01

Short-chain fatty acid (SCFA) production from waste activated sludge (WAS) anaerobic fermentation is often limited by the slow hydrolysis rate and poor substrate availability, thus a long fermentation time is required. This paper reports a new pretreatment approach, i.e., using free nitrous acid (FNA) to pretreat sludge, for significantly enhanced SCFA production. Experimental results showed the highest SCFA production occurred at 1.8 mg FNA/L with time of day 6, which was 3.7-fold of the blank at fermentation time of day 12. Mechanism studies revealed that FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. It was also found that FNA pretreatment benefited hydrolysis and acidification processes but inhibited the activities of methanogens, thereby promoting the yield of SCFA. In addition, the FNA pretreatment substantially stimulated the activities of key enzymes responsible for hydrolysis and acidification, which were consistent with the improvement of solubilization, hydrolysis and acidification of WAS anaerobic fermentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using ultrasound technology for the inactivation and thermal sensitization of peroxidase in green coconut water.

PubMed

Rojas, Meliza Lindsay; Trevilin, Júlia Hellmeister; Funcia, Eduardo Dos Santos; Gut, Jorge Andrey Wilhelms; Augusto, Pedro Esteves Duarte

2017-05-01

Green coconut water has unique nutritional and sensorial qualities. Despite the different technologies already studied, its enzymatic stability is still challenging. This study evaluated the use of ultrasound technology (US) for inactivating/sensitizing coconut water peroxidase (POD). The effect of both US application alone and as a pre-treatment to thermal processing was evaluated. The enzyme activity during US processing was reduced 27% after 30min (286W/L, 20kHz), demonstrating its high resistance. The thermal inactivation was described by the Weibull model under non-isothermal conditions. The enzyme became sensitized to heat after US pre-treatment. Further, the use of US resulted in more uniform heat resistance. The results suggest that US is a good technology for sensitizing enzymes before thermal processing (even for an enzyme with high thermal resistance). Therefore, the use of this technology could decrease the undesirable effects of long times and/or the high temperatures of the conventional thermal processing. Copyright © 2016 Elsevier B.V. All rights reserved.

Fungal pretreatment of willow sawdust and its combination with alkaline treatment for enhancing biogas production.

PubMed

Alexandropoulou, Maria; Antonopoulou, Georgia; Fragkou, Efsevia; Ntaikou, Ioanna; Lyberatos, Gerasimos

2017-12-01

In this study fungal pretreatment of willow sawdust (WSD) via the white rot fungi Leiotrametes menziesii and Abortiporus biennis was studied and the effect on fractionation of lignocellulosic biomass and biochemical methane potential (BMP), was evaluated. Scanning electron microscopy (SEM) and IR spectroscopy were used to investigate the changes in the structural characteristics of the pretreated WSD. Fungal pretreatment results revealed that A. biennis is more attractive, since it resulted in higher lignin degradation and lower holocellulose uptake. Samples of the 14th and 30th d of cultivation (i.e. the middle and the end of the pretreatment experiment) with both fungi were used for BMP tests and the effect of pretreatment duration was also evaluated. BMP increase by 31 and 43% was obtained due to the cultivation of WSD with A. biennis, for 14 and 30 d, respectively. In addition, combination of biological (after 30 d of cultivation) with alkaline (NaOH 20 g/100 gTS) pretreatment was performed, in order to assess the effect of the chemical agent on biologically pretreated WSD, in terms of lignocellulosic content and BMP. Combination of alkaline with fungal pretreatment led to high lignin degradation for both fungi, while the cellulose and hemicellulose removal efficiencies were higher for combined alkaline and L. menziesii pretreatment. The maximum BMP was observed for the combined alkaline and A. biennis pretreatment and was 12.5 and 50.1% higher than the respective alkaline and fungal pretreatment alone and 115% higher than the respective BMP of raw WSD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microemulsion-based lycopene extraction: Effect of surfactants, co-surfactants and pretreatments.

PubMed

Amiri-Rigi, Atefeh; Abbasi, Soleiman

2016-04-15

Lycopene is a potent antioxidant that has received extensive attention recently. Due to the challenges encountered with current methods of lycopene extraction using hazardous solvents, industry calls for a greener, safer and more efficient process. The main purpose of present study was application of microemulsion technique to extract lycopene from tomato pomace. In this respect, the effect of eight different surfactants, four different co-surfactants, and ultrasound and enzyme pretreatments on lycopene extraction efficiency was examined. Experimental results revealed that application of combined ultrasound and enzyme pretreatments, saponin as a natural surfactant, and glycerol as a co-surfactant, in the bicontinuous region of microemulsion was the optimal experimental conditions resulting in a microemulsion containing 409.68±0.68 μg/glycopene. The high lycopene concentration achieved, indicates that microemulsion technique, using a low-cost natural surfactant could be promising for a simple and safe separation of lycopene from tomato pomace and possibly from tomato industrial wastes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hydrolysis kinetics of tulip tree xylan in hot compressed water.

PubMed

Yoon, Junho; Lee, Hun Wook; Sim, Seungjae; Myint, Aye Aye; Park, Hee Jeong; Lee, Youn-Woo

2016-08-01

Lignocellulosic biomass, a promising renewable resource, can be converted into numerous valuable chemicals post enzymatic saccharification. However, the efficacy of enzymatic saccharification of lignocellulosic biomass is low; therefore, pretreatment is necessary to improve the efficiency. Here, a kinetic analysis was carried out on xylan hydrolysis, after hot compressed water pretreatment of the lignocellulosic biomass conducted at 180-220°C for 5-30min, and on subsequent xylooligosaccharide hydrolysis. The weight ratio of fast-reacting xylan to slow-reacting xylan was 5.25 in tulip tree. Our kinetic results were applied to three different reaction systems to improve the pretreatment efficiency. We found that semi-continuous reactor is promising. Lower reaction temperatures and shorter space times in semi-continuous reactor are recommended for improving xylan conversion and xylooligosaccharide yield. In the theoretical calculation, 95% of xylooligosaccharide yield and xylan conversion were achieved simultaneously with high selectivity (desired product/undesired product) of 100 or more. Copyright © 2016. Published by Elsevier Ltd.

[A simple and efficient method for establishing a mouse model of orthotopic MB49 bladder cancer].

PubMed

Liang, Zhong-kun; Zhang, Lin; Hu, Zhi-ming; Chen, Zhong; Huang, Xin; Shi, Xiang-hua; Tan, Wan-long; Gao, Ji-min

2009-04-01

To establish a simple and efficient method for establishing a mouse model of orthotopic superficial bladder cancer. C57BL/6 mice were anesthetized with sodium pentobarbital and catheterized with modified IV catheter (24 G). The mice were intravesically pretreated with HCl and then with NaOH, and after washing the bladders with phosphate-buffered saline (PBS), 100 microl (1 x 10(7)) MB49 cells were infused and allowed to incubate in the bladder for 2 h followed intravesical mitomycin C (MMC) administration. The tumor formation rate, survival, gross hematuria, and bladder weight were determined as the outcome variables, and the pathology of the bladders was observed. Instillation of MB49 tumor cells resulted in a tumor formation rates of 100% in all the pretreated groups while 0% in the control group without pretreatment. MMC significantly reduced the bladder weight as compared to PBS. We have successfully established a stable, reproducible, and reliable orthotopic bladder cancer model in mice.

Understanding the mechanisms of lipid extraction from microalga Chlamydomonas reinhardtii after electrical field solicitations and mechanical stress within a microfluidic device.

PubMed

Bensalem, Sakina; Lopes, Filipa; Bodénès, Pierre; Pareau, Dominique; Français, Olivier; Le Pioufle, Bruno

2018-06-01

One way envisioned to overcome part of the issues biodiesel production encounters today is to develop a simple, economically viable and eco-friendly process for the extraction of lipids from microalgae. This study investigates the lipid extraction efficiency from the microalga Chlamydomonas reinhardtii as well as the underlying mechanisms. We propose a new methodology combining a pulsed electric field (PEF) application and mechanical stresses as a pretreatment to improve lipid extraction with solvents. Cells enriched in lipids are therefore submitted to electric field pulses creating pores on the cell membrane and then subjected to a mechanical stress by applying cyclic pressures on the cell wall (using a microfluidic device). Results showed an increase in lipid extraction when cells were pretreated by the combination of both methods. Microscopic observations showed that both pretreatments affect the cell structure. Finally, the dependency of solvent lipid extraction efficiency with the cell wall structure is discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Seawater-Cultured Botryococcus braunii for Efficient Hydrocarbon Extraction

PubMed Central

Furuhashi, Kenichi; Saga, Kiyotaka; Okada, Shigeru; Imou, Kenji

2013-01-01

As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking. Highlights Seawater was used for efficient hydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment. PMID:23799107

Towards a method of rapid extraction of strontium-90 from urine: urine pretreatment and alkali metal removal

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

Hawkins, C.; Dietz, M.; Kaminski, M.

2016-03-01

A technical program to support the Centers of Disease Control and Prevention is being developed to provide an analytical method for rapid extraction of Sr-90 from urine, with the intent of assessing the general population’s exposure during an emergency response to a radiological terrorist event. Results are presented on the progress in urine sample preparation and chemical separation steps that provide an accurate and quantitative detection of Sr-90 based upon an automated column separation sequence and a liquid scintillation assay. Batch extractions were used to evaluate the urine pretreatment and the column separation efficiency and loading capacity based upon commercial,more » extractant-loaded resins. An efficient pretreatment process for decolorizing and removing organics from urine without measurable loss of radiostrontium from the sample was demonstrated. In addition, the Diphonix® resin shows promise for the removal of high concentrations of common strontium interferents in urine as a first separation step for Sr-90 analysis.« less

Native, acidic pre-treated and composite clay efficiency for the adsorption of dicationic dye in aqueous medium.

PubMed

Ehsan, Asma; Bhatti, Haq Nawaz; Iqbal, Munawar; Noreen, Saima

2017-02-01

Environmental applications of composites have attracted the interests of researchers due to their excellent adsorption efficiency for pollutants. Native, HCl pre-treated clay and MnFe 2 O 4 /clay composite were investigated as an adsorbent for removal of methyl green from aqueous solution. The adsorption behaviors of dye onto native, HCl pre-treated and composite clays were studied as a function of contact time, adsorbent dose, pH, initial dye concentration and temperature. Maximum dye adsorption of 44 mg/g was achieved at pH of 8, contact time 40 min, adsorbent dose 0.20 g/L and initial dye concentration of 125 mg/L using clay composite. The Langmuir isotherm and pseudo-second-order kinetic model best explained the methyl green dye adsorption onto clay adsorbents. Thermodynamic parameters revealed the endothermic and spontaneous adsorption nature of dye. From results, it is concluded that clay has potential for adsorbing methyl green and can be used for the removal of dyes from industrial effluents.

Anaerobic co-digestion of high-strength organic wastes pretreated by thermal hydrolysis.

PubMed

Choi, Gyucheol; Kim, Jaai; Lee, Seungyong; Lee, Changsoo

2018-06-01

Thermal hydrolysis (TH) pretreatment was investigated for the anaerobic digestion (AD) of a mixture of high-strength organic wastes (i.e., dewatered human feces, dewatered sewage sludge, and food wastewater) at laboratory scale to simulate a full-scale plant and evaluate its feasibility. The reactors maintained efficient and stable performance at a hydraulic retention time of 20 days, which may be not sufficient for the mesophilic AD of high-suspended-solid wastes, despite the temporal variations in organic load. The addition of FeCl 3 was effective in controlling H 2 S and resulted in significant changes in the microbial community structure, particularly the methanogens. The temporary interruption in feeding or temperature control led to immediate performance deterioration, but it recovered rapidly when normal operations were resumed. The overall results suggest that the AD process coupled with TH pretreatment can provide an efficient, robust, and resilient system to manage high-suspended-solid wastes, supporting the feasibility of its full-scale implementation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Todd Vinzant | NREL

Science.gov Websites

, microbiology, microscopy, and laboratory management and design. Areas of Expertise Structural and chemical equipment design and construction Education M.S., Microbiology, University of Denver, 1990 B.S., Biology Technologies," Bioresource Technology (2011) "Comparative Material Balances Around Pretreatment

Effects of drying pretreatment and particle size adjustment on the composting process of discarded flue-cured tobacco leaves.

PubMed

Zhao, Gui-Hong; Yu, Yan-Ling; Zhou, Xiang-Tong; Lu, Bin-Yu; Li, Zi-Mu; Feng, Yu-Jie

2017-05-01

The main characteristic of discarded flue-cured tobacco leaves is their high nicotine content. Aerobic composting is an effective method to decrease the nicotine level in tobacco leaves and stabilize tobacco wastes. However, high levels of nicotine in discarded flue-cured tobacco leaves complicate tobacco waste composting. This work proposes a drying pretreatment process to reduce the nicotine content in discarded flue-cured tobacco leaves and thus enhance its carbon-to-nitrogen ratio to a suitable level for composting. The effect of another pretreatment method, particle size adjustment, on composting efficiency was also tested in this work. The results indicated that the air-dried (nicotine content: 1.35%) and relatively long discarded flue-cured tobacco leaves (25 mm) had a higher composting efficiency than damp (nicotine content: 1.57%) and short discarded flue-cured tobacco leaves (15 mm). When dry/25 mm discarded flue-cured tobacco leaves mixed with tobacco stems in an 8:2 ratio was composted at a temperature above 55 °C for 9 days, the nicotine content dropped from 1.29% to 0.28%. Since the discarded flue-cured tobacco leaves was successfully composted to a fertile and harmless material, the germination index values increased to 85.2%. The drying pretreatment and particle size adjustment offered ideal physical and chemical conditions to support microbial growth and bioactivity during the composting process, resulting in efficient conversion of discarded flue-cured tobacco leaves into a high quality and mature compost.

An approach for upgrading biomass and pyrolysis product quality using a combination of aqueous phase bio-oil washing and torrefaction pretreatment.

PubMed

Chen, Dengyu; Cen, Kehui; Jing, Xichun; Gao, Jinghui; Li, Chen; Ma, Zhongqing

2017-06-01

Bio-oil undergoes phase separation because of poor stability. Practical application of aqueous phase bio-oil is challenging. In this study, a novel approach that combines aqueous phase bio-oil washing and torrefaction pretreatment was used to upgrade the biomass and pyrolysis product quality. The effects of individual and combined pretreatments on cotton stalk pyrolysis were studied using TG-FTIR and a fixed bed reactor. The results showed that the aqueous phase bio-oil washing pretreatment removed metals and resolved the two pyrolysis peaks in the DTG curve. Importantly, it increased the bio-oil yield and improved the pyrolysis product quality. For example, the water and acid content of bio-oil decreased significantly along with an increase in phenol formation, and the heating value of non-condensable gases improved, and these were more pronounced when combined with torrefaction pretreatment. Therefore, the combined pretreatment is a promising method, which would contribute to the development of polygeneration pyrolysis technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of enzyme loading and β-glucosidase supplementation on enzymatic hydrolysis of switchgrass processed by leading pretreatment technologies.

PubMed

Pallapolu, Venkata Ramesh; Lee, Y Y; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Falls, Matthew; Holtzapple, Mark T; Sierra-Ramirez, Rocio; Shi, Jian; Ebrik, Mirvat A; Redmond, Tim; Yang, Bin; Wyman, Charles E; Donohoe, Bryon S; Vinzant, Todd B; Elander, Richard T; Hames, Bonnie; Thomas, Steve; Warner, Ryan E

2011-12-01

The objective of this work is to investigate the effects of cellulase loading and β-glucosidase supplementation on enzymatic hydrolysis of pretreated Dacotah switchgrass. To assess the difference among various pretreatment methods, the profiles of sugars and intermediates were determined for differently treated substrates. For all pretreatments, 72 h glucan/xylan digestibilities increased sharply with enzyme loading up to 25mg protein/g-glucan, after which the response varied depending on the pretreatment method. For a fixed level of enzyme loading, dilute sulfuric acid (DA), SO(2), and Lime pretreatments exhibited higher digestibility than the soaking in aqueous ammonia (SAA) and ammonia fiber expansion (AFEX). Supplementation of Novozyme-188 to Spezyme-CP improved the 72 h glucan digestibility only for the SAA treated samples. The effect of β-glucosidase supplementation was discernible only at the early phase of hydrolysis where accumulation of cellobiose and oligomers is significant. Addition of β-glucosidase increased the xylan digestibility of alkaline treated samples due to the β-xylosidase activity present in Novozyme-188. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biochemical methane potential of microalgae: influence of substrate to inoculum ratio, biomass concentration and pretreatment.

PubMed

Alzate, M E; Muñoz, R; Rogalla, F; Fdz-Polanco, F; Pérez-Elvira, S I

2012-11-01

The anaerobic digestion of three microalgae mixtures was evaluated at different substrate to inoculum (S/I) ratios (0.5, 1 and 3), biomass concentrations (3, 10 and 20gTS/kg) and pretreatments (thermal hydrolysis, ultrasound and biological treatment). An S/I ratio of 0.5 and 10gTS/kg resulted in the highest final methane productivities regardless of the microalgae tested (ranging from 188 to 395mL CH(4)/gVS(added)). The biological pretreatment supported negligible enhancements on CH(4) productivity, while the highest increase (46-62%) was achieved for the thermal hydrolysis. The optimum temperature of this pretreatment depended on the microalgae species. The ultrasound pretreatment brought about increases in CH(4) productivity ranging from 6% to 24% at 10,000kJ/kgTS, without further increases at higher energy inputs. The results here obtained confirmed the lack of correlation between the solubilization degree and the methane enhancement potential and pointed out that anaerobic digestion of algae after thermal pretreatment is a promising technology for renewable energy production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments

PubMed Central

2013-01-01

The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usually suffers from the intrinsic recalcitrance of biomass owing to the complicated structure of plant cell walls. Currently, a pretreatment step that can effectively reduce biomass recalcitrance is generally required to make the polysaccharide fractions locked in the intricacy of plant cell walls to become more accessible and amenable to enzymatic hydrolysis. Dilute acid and hydrothermal pretreatments are attractive and among the most promising pretreatment technologies that enhance sugar release performance. This review highlights our recent understanding on molecular structure basis for recalcitrance, with emphasis on structural transformation of major biomass biopolymers (i.e., cellulose, hemicellulose, and lignin) related to the reduction of recalcitrance during dilute acid and hydrothermal pretreatments. The effects of these two pretreatments on biomass porosity as well as its contribution on reduced recalcitrance are also discussed. PMID:23356640

Ionic Liquid Pretreatment of Lignocellulosic Biomass for Enhanced Enzymatic Delignification.

PubMed

Moniruzzaman, Muhammad; Goto, Masahiro

2018-05-10

Ionic liquids (ILs), a potentially attractive "green," recyclable alternative to environmentally harmful volatile organic compounds, have been increasingly exploited as solvents and/or cosolvents and/or reagents in a wide range of applications, including pretreatment of lignocellulosic biomass for further processing. The enzymatic delignification of biomass to degrade lignin, a complex aromatic polymer, has received much attention as an environmentally friendly process for clean separation of biopolymers including cellulose and lignin. For this purpose, enzymes are generally isolated from naturally occurring fungi or genetically engineered fungi and used in an aqueous medium. However, enzymatic delignification has been found to be very slow in these conditions, sometimes taking several months for completion. In this chapter, we highlight an environmentally friendly and efficient approach for enzymatic delignification of lignocellulosic biomass using room temperature ionic liquids (ILs) as (co)solvents or/and pretreatment agents. The method comprises pretreatment of lignocellulosic biomass in IL-aqueous systems before enzymatic delignification, with the aim of overcoming the low delignification efficiency associated with low enzyme accessibility to the solid substrate and low substrate and product solubilities in aqueous systems. We believe the processes described here can play an important role in the conversion of lignocellulosic biomass-the most abundant renewable biomaterial in the world-to biomaterials, biopolymers, biofuels, bioplastics, and hydrocarbons. Graphical Abstract.

Ultrasound pre-treatment for anaerobic digestion improvement.

PubMed

Pérez-Elvira, S; Fdz-Polanco, M; Plaza, F I; Garralón, G; Fdz-Polanco, F

2009-01-01

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT=20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT=15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR=20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3-10 kW per kW of energy used.

The influence of different pretreatment methods on biogas production from Jatropha curcas oil cake.

PubMed

Jabłoński, Sławomir Jan; Kułażyński, Marek; Sikora, Ilona; Łukaszewicz, Marcin

2017-12-01

Drought and pest resistance, together with high oil content in its seeds, make Jatropha curcas a good oil source for biodiesel. Oil cake from J. curcas is not suitable for animal feeding and thus may be profitably used for additional energy production by conversion into biogas; however, the anaerobic digestion process must be optimized to obtain good efficiency. We subjected oil cake to thermal and acidic pretreatment to deactivate protease inhibitors and partially hydrolyze phytate. We then digested the samples in batch conditions to determine the effects of pretreatment on biogas production. Thermal pretreatment changed the kinetics of anaerobic digestion and reduced protease inhibitor activity and the concentration of phytate; however, biogas production efficiency was not affected (0.281 m 3  kg -1 ). To evaluate the possibility of recirculating water for SSF hydrolysis, ammonium nitrogen recovery from effluent was evaluated by its precipitation in the form of struvite (magnesium ammonium phosphate).Concentration of ammonium ions was reduced by 53% (to 980 mg L -1 ). We propose a water-saving concept based on percolation of J. curcas cake using anaerobic digestion effluent and feeding that percolate into a methanogenic bioreactor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radial Flow Fludized Filter Finds Niche as a Pretreatment System for Surface Water in Small Communities

EPA Science Inventory

An emerging technology called radial flow fluidized filter (R3f) has been developed as a low cost simplistic filtration technology for small communities of less than 10,000 people. Fouling is a major impediment to the sustainability of membrane technology particularly for small ...

Effect of xylanase supplementation of cellulase on digestion of corn stover solids prepared by leading pretreatment technologies.

PubMed

Kumar, Rajeev; Wyman, Charles E

2009-09-01

Solids resulting from pretreatment of corn stover by ammonia fiber expansion (AFEX), ammonia recycled percolation (ARP), controlled pH, dilute acid, lime, and sulfur dioxide (SO(2)) technologies were hydrolyzed by enzyme cocktails based on cellulase supplemented with beta-glucosidase at an activity ratio of 1:2, respectively, and augmented with up to 11.0 g xylanase protein/g cellulase protein for combined cellulase and beta-glucosidase mass loadings of 14.5 and 29.0 mg protein (about 7.5 and 15 FPU, respectively)/g of original potential glucose. It was found that glucose release increased nearly linearly with residual xylose removal by enzymes for all pretreatments despite substantial differences in their relative yields. The ratio of the fraction of glucan removed by enzymes to that for xylose was defined as leverage and correlated statistically at two combined cellulase and beta-glucosidase mass loadings with pretreatment type. However, no direct relationship was found between leverage and solid features following different pretreatments such as residual xylan or acetyl content. However, acetyl content not only affected how xylanase impacted cellulase action but also enhanced accessibility of cellulose and/or cellulase effectiveness, as determined by hydrolysis with purified CBHI (Cel7A). Statistical modeling showed that cellulose crystallinity, among the main substrate features, played a vital role in cellulase-xylanase interactions, and a mechanism is suggested to explain the incremental increase in glucose release with xylanase supplementation.

Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

PubMed

Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

2016-03-01

Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Utilization of hydrothermally pretreated wheat straw for production of bioethanol and carotene-enriched biomass.

PubMed

Petrik, Siniša; Kádár, Zsófia; Márová, Ivana

2013-04-01

In this work hydrothermally pretreated wheat straw was used for production of bioethanol by Saccharomyces cerevisiae and carotene-enriched biomass by red yeasts Rhodotorula glutinis, Cystofilobasidium capitatum and Sporobolomyces roseus. To evaluate the convertibility of pretreated wheat straw into ethanol, simultaneous saccharification and fermentation of S. cerevisiae was performed under semi-anaerobic conditions. The highest ethanol production efficiency of 65-66% was obtained following pretreatment at 200°C without the catalytic action of acetic acid, and at 195 and 200°C respectively in the presence of catalyst. Red yeast strain S. roseus produced 1.73-2.22 mg g(-1) of ergosterol on the filter cake, 1.15-4.17 mg g(-1) of ergosterol and 1.23-1.56 mg g(-1) of β-carotene on pretreated wheat straw hydrolysates and also the highest amount of carotenoids and ergosterol on untreated wheat straw (1.70 and 4.17 mg g(-1), respectively). Copyright © 2013 Elsevier Ltd. All rights reserved.

Enzymatic saccharification and bioethanol production from Cynara cardunculus pretreated by steam explosion.

PubMed

Fernandes, Maria C; Ferro, Miguel D; Paulino, Ana F C; Mendes, Joana A S; Gravitis, Janis; Evtuguin, Dmitry V; Xavier, Ana M R B

2015-06-01

The correct choice of the specific lignocellulosic biomass pretreatment allows obtaining high biomass conversions for biorefinery implementations and cellulosic bioethanol production from renewable resources. Cynara cardunculus (cardoon) pretreated by steam explosion (SE) was involved in second-generation bioethanol production using separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) processes. Steam explosion pretreatment led to partial solubilisation of hemicelluloses and increased the accessibility of residual polysaccharides towards enzymatic hydrolysis revealing 64% of sugars yield against 11% from untreated plant material. Alkaline extraction after SE pretreatment of cardoon (CSEOH) promoted partial removal of degraded lignin, tannins, extractives and hemicelluloses thus allowing to double glucose concentration upon saccharification step. Bioethanol fermentation in SSF mode was faster than SHF process providing the best results: ethanol concentration 18.7 g L(-1), fermentation efficiency of 66.6% and a yield of 26.6g ethanol/100 g CSEOH or 10.1 g ethanol/100 g untreated cardoon. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ethanol production from sorghum by a microwave-assisted dilute ammonia pretreatment.

PubMed

Chen, Cong; Boldor, Dorin; Aita, Giovanna; Walker, Michelle

2012-04-01

The efficiency of a batch microwave-assisted ammonia heating system was investigated as pretreatment for sweet sorghum bagasse and its effect on porosity, chemical composition, particle size, enzymatic hydrolysis and fermentation into ethanol evaluated. Sorghum bagasse, fractionated into three particle size groups (9.5-18, 4-6 and 1-2mm), was pretreated with ammonium hydroxide (28% v/v solution) and water at a ratio of 1:0.5:8 at 100, 115, 130, 145 and 160°C for 1h. Simon's stain method revealed an increase in the porosity of the biomass compared to untreated biomass. The most lignin removal (46%) was observed at 160°C. About 90% of the cellulose and 73% of the hemicellulose remained within the bagasse. The best glucose yields and ethanol yields (from glucose only) among all different pretreatment conditions averaged 42/100g dry biomass and 21/100g dry biomass, respectively with 1-2mm sorghum bagasse pretreated at 130°C for 1h. Published by Elsevier Ltd.

Transferring of components and energy output in industrial sewage sludge disposal by thermal pretreatment and two-phase anaerobic process.

PubMed

Yang, Xiaoyi; Wang, Xin; Wang, Lei

2010-04-01

For a better sewage sludge disposal and more efficient energy reclamation, transforming of components and energy in sludge by thermal and WAO pretreatment followed by two-phase anaerobic UASB process were studied in the pilot scale. Biogas outputs and the qualities and quantities of the effluent and solid residue were compared with a traditional anaerobic sludge digestion. Sludge components, including carbon, nitrogen, phosphorus, sulphur, were observed and mass balances were discussed throughout the process. The input and output energy balance was also studied. Results showed different trait to compare with biogas outputs in terms of COD added and raw sludge added. Pretreatment improved the transformation of carbon substances into biogas production with higher carbon removal and higher VSS removal. Comparing the energy obtained from biogas production with energy inputs required for pretreatment, energy output in the whole process decreased with higher pretreatment temperature. Copyright 2009 Elsevier Ltd. All rights reserved.

Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

DOE PAGES

Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; ...

2016-02-09

Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H 2O 2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H 2O 2 was added batch-wise overmore » the course of 10 h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H 2O 2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H 2O 2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin from untreated poplar. In conclusion: This study demonstrated that the fed-batch, two-stage Cu-AHP pretreatment process was effective in pretreating hybrid poplar for its conversion into fermentable sugars. Results showed sugar yields near the theoretical maximum were achieved from enzymatically hydrolyzed hybrid poplar by incorporating an alkaline extraction step prior to pretreatment and by efficiently utilizing H 2O 2 during the Cu-AHP process. Significantly, this study reports high sugar yields from woody biomass treated with an AHP pretreatment under mild reaction conditions.« less

Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge.

PubMed

Appels, Lise; Van Assche, Ado; Willems, Kris; Degrève, Jan; Van Impe, Jan; Dewil, Raf

2011-03-01

Anaerobic digestion is generally considered to be an economic and environmentally friendly technology for treating waste activated sludge, but has some limitations, such as the time it takes for the sludge to be digested and also the ineffectiveness of degrading the solids. Various pre-treatment technologies have been suggested to overcome these limitations and to improve the biogas production rate by enhancing the hydrolysis of organic matter. This paper studies the use of peracetic acid for disintegrating sludge as a pre-treatment of anaerobic digestion. It has been proved that this treatment effectively leads to a solubilisation of organic material. A maximum increase in biogas production by 21% is achieved. High dosages of PAA lead to a decrease in biogas production. This is due to the inhibition of the anaerobic micro-organisms by the high VFA-concentrations. The evolution of the various VFAs during digestion is studied and the observed trends support this hypothesis. Copyright © 2010 Elsevier Ltd. All rights reserved.

Aiming for the complete utilization of sugar-beet pulp: Examination of the effects of mild acid and hydrothermal pretreatment followed by enzymatic digestion

PubMed Central

2011-01-01

Background Biomass use for the production of bioethanol or platform chemicals requires efficient breakdown of biomass to fermentable monosaccharides. Lignocellulosic feedstocks often require physicochemical pretreatment before enzymatic hydrolysis can begin. The optimal pretreatment can be different for different feedstocks, and should not lead to biomass destruction or formation of toxic products. Methods We examined the influence of six mild sulfuric acid or water pretreatments at different temperatures on the enzymatic degradability of sugar-beet pulp (SBP). Results We found that optimal pretreatment at 140°C of 15 minutes in water was able to solubilize 60% w/w of the total carbohydrates present, mainly pectins. More severe treatments led to the destruction of the solubilized sugars, and the subsequent production of the sugar-degradation products furfural, hydroxymethylfurfural, acetic acid and formic acid. The pretreated samples were successfully degraded enzymatically with an experimental cellulase preparation. Conclusions In this study, we found that pretreatment of SBP greatly facilitated the subsequent enzymatic degradation within economically feasible time ranges and enzyme levels. In addition, pretreatment of SBP can be useful to fractionate functional ingredients such as arabinans and pectins from cellulose. We found that the optimal combined severity factor to enhance the enzymatic degradation of SBP was between log R'0 = -2.0 and log R'0 = -1.5. The optimal pretreatment and enzyme treatment solubilized up to 80% of all sugars present in the SBP, including ≥90% of the cellulose. PMID:21627804

Combination of alkaline and microwave pretreatment for disintegration of meat processing wastewater sludge.

PubMed

Erden, G

2013-01-01

Meat processing wastewater sludge has high organic content but it is very slow to degrade in biological processes. Anaerobic digestion may be a good alternative for this type of sludge when the hydrolysis, known to be the rate-limiting step of biological sludge anaerobic degradation, could be eliminated by disintegration. This investigation deals with disintegration of meat processing wastewater sludge. Microwave (MW) irradiation and combined alkaline pretreatment and MW irradiation were applied to sludge for disintegration purposes. Disintegration performance of the methods was evaluated with disintegration degree based on total and dissolved organic carbon calculations (DD(TOC)), and the solubilization of volatile solids (S(VS)) in the pretreated sludge. Optimum conditions were found to be 140 degrees C and 30 min for MW irradiation using response surface methodology (RSM) and pH = 13 for combined pretreatment. While DD(TOC) was observed as 24.6% and 54.9, S(VS) was determined as 8.54% and 42.5% for MW pretreated and combined pretreated sludge, respectively. The results clearly show that pre-conditioning of sludge with alkaline pretreatment played an important role in enhancing the disintegration efficiency of subsequent MW irradiation. Disintegration methods also affected the anaerobic biodegradability and dewaterability of sludge. An increase of 23.6% in biogas production in MW irradiated sludge was obtained, comparing to the raw sludge at the end of the 35 days of incubation. This increase was observed as 44.5% combined pretreatment application. While MW pretreatment led to a little improvement of the dewatering performance of sludge, in combined pretreatment NaOH deteriorates the sludge dewaterability.

From oleic acid-capped iron oxide nanoparticles to polyethyleneimine-coated single-particle magnetofectins

NASA Astrophysics Data System (ADS)

Cruz-Acuña, Melissa; Maldonado-Camargo, Lorena; Dobson, Jon; Rinaldi, Carlos

2016-09-01

Various inorganic nanoparticle designs have been developed and used as non-viral gene carriers. Magnetic gene carriers containing polyethyleneimine (PEI), a well-known transfection agent, have been shown to improve DNA transfection speed and efficiency in the presence of applied magnetic field gradients that promote particle-cell interactions. Here we report a method to prepare iron oxide nanoparticles conjugated with PEI that: preserves the narrow size distribution of the nanoparticles, conserves magnetic properties throughout the process, and results in efficient transfection. We demonstrate the ability of the particles to electrostatically bind with DNA and transfect human cervical cancer (HeLa) cells by the use of an oscillating magnet array. Their transfection efficiency is similar to that of Lipofectamine 2000™, a commercial transfection reagent. PEI-coated particles were subjected to acidification, and acidification in the presence of salts, before DNA binding. Results show that although these pre-treatments did not affect the ability of particles to bind DNA they did significantly enhanced transfection efficiency. Finally, we show that these magnetofectins (PEI-MNP/DNA) complexes have no effect on the viability of cells at the concentrations used in the study. The systematic preparation of magnetic vectors with uniform physical and magnetic properties is critical to progressing this non-viral transfection technology.

Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

PubMed

Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

2018-02-01

Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

Endowing non-cellulolytic microorganisms with cellulolytic activity aiming for consolidated bioprocessing.

PubMed

Yamada, Ryosuke; Hasunuma, Tomohisa; Kondo, Akihiko

2013-11-01

With the exhaustion of fossil fuels and with the environmental issues they pose, utilization of abundant lignocellulosic biomass as a feedstock for biofuels and bio-based chemicals has recently become an attractive option. Lignocellulosic biomass is primarily composed of cellulose, hemicellulose, and lignin and has a very rigid and complex structure. It is accordingly much more expensive to process than starchy grains because of the need for extensive pretreatment and relatively large amounts of cellulases for efficient hydrolysis. Efficient and cost-effective methods for the production of biofuels and chemicals from lignocellulose are required. A consolidated bioprocess (CBP), which integrates all biological steps consisting of enzyme production, saccharification, and fermentation, is considered a promising strategy for reducing production costs. Establishing an efficient CBP using lignocellulosic biomass requires both lignocellulose degradation into glucose and efficient production of biofuels or chemicals from glucose. With this aim, many researchers are attempting to endow selected microorganisms with lignocellulose-assimilating ability. In this review, we focus on studies aimed at conferring lignocellulose-assimilating ability not only to yeast strains but also to bacterial strains by recombinant technology. Recent developments in improvement of enzyme productivity by microorganisms and in improvement of the specific activity of cellulase are emphasized. Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical pyrolysis of E-waste plastics: Char characterization.

PubMed

Shen, Yafei; Chen, Xingming; Ge, Xinlei; Chen, Mindong

2018-05-15

This work studied the disposal of the non-metallic fraction from waste printed circuit board (NMF-WPCB) via the chemical pretreatments followed by pyrolysis. As a main heavy metal, the metallic Cu could be significantly removed by 92.4% using the HCl leaching process. Subsequently, the organic-Br in the brominated flame retardants (BFRs) plastics could be converted into HBr by pyrolysis. The alkali pretreatment was benefit for the Br fixation in the solid char. The Br fixation efficiency could reach up to 53.6% by the NaOH pretreatment followed by the pyrolysis process. The formed HBr could react with NaOH/KOH to generate the stabilized NaBr/KBr. Therefore, the integrated chemical pretreatment could be used for the eco-friendly disposal of the NMF-WPCB via pyrolysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Thermochemical pretreatment of underutilized woody biomass for manufacturing wood composites

NASA Astrophysics Data System (ADS)

Pelaez Samaniego, Manuel Raul

Prescribed fires, one method for reducing hazardous fuel loads from forest lands in the US, are limited by geographical, environmental, and social impacts. Mechanical operations are an alternative type of fuel treatment but these processes are constrained by the difficulty of economically harvesting and/or using large amounts of low-value woody biomass. Adoption and integration of new technologies into existing wood composite facilities offer better utilization of this material. A pretreatment that enables integration of technologies in a typical composite facility will aid with diversification of product portfolio (e.g. wood composites, fuel pellets, liquid fuels, chemicals). Hot water extraction (HWE) is an option for wood pretreatment. This work provides a fundamental understanding of the physicochemical changes to wood resulting from HWE, and how these changes impact processing and performance of composites. Specific objectives were to: 1) review literature on studies related to the manufacture of composites produced with thermally pretreated wood, 2) manufacture wood plastic composites (WPC) and particleboard using HWE wood and evaluate the impacts of pretreatment on product properties, 3) develop an understanding of the effect of HWE on lignin properties, specifically lignin at the cells surface level after migration from cell walls and middle lamella, 4) discern the influence of lignin on the fiber surface on processing WPCs, and, 5) investigate the effect of changing the pretreatment environment (inert gas instead of water) on lignin behavior. Results show that HWE enhances the resistance of both WPCs and particleboard to water with positive or no effect on mechanical properties. Reduction of hemicelluloses and lignin property changes are suggested as the main reasons for enhancing interaction between wood fiber and resins during composite processing. Lignin on the surface of particles after HWE interacts with thermoplastics during WPCs compounding, thus improving bond quality between the constituents and maintaining the mechanical properties of the composites. The amount and properties of lignin on the fiber surfaces depends on the pretreatment conditions. Thus, it seems possible to control the pretreatment process to increase or decrease the amount of lignin on particles surfaces, which is of great interest for managing downstream processes within biorefinery concepts.

[Experimental investigation of the straw pre-treatment to enhance its high solid anaerobic digestion].

PubMed

Jiang, Jian-Guo; Zhao, Zhen-Zhen; Du, Xue-Juan; Sui, Ji-Chao; Wu, Shi-Yao

2007-04-01

The straw contains a high content of lignin, which cannot be well utilized by anaerobic bacteria in high solid anaerobic digestion process. This paper presents the experimental investigation of the straw pre-treatment, which aims to destroy the complex structure of the lignin to enhance its high solid anaerobic digestion. The straw is pre-treated in different solutions including NaOH, ammonia, H2SO4, and carbamide. The pre-treating effects are expressed by COD concentration dissolved in the solutions and the 14-day biogas generation in the enhanced aerogenic experiment. Different affecting factors, such as the concentration of the chemical solution, the species of the straw, the pre-treatment reaction time, the reaction temperature and the size of the straw, are investigated. The results show that NaOH solution is the most effective pre-treatment chemical among the four different solutions. The experimental results still indicate that the accumulative biogas production can be 1 500 mL (10 g straw) in 14 days after pre-treatment in 4 mg/L NaOH solution and the dissolved COD in the solution reaches 39 000 mg/L after 24 hours. In addition, the experiment shows that the lignin content in the straw is reduced from 28% to 19% after pre-treatment in 1.5% (in weight) NaOH solution, and it can improve the straw treatment efficiency using high solid anaerobic digestion process.

Treatment of landfill leachate by the Fenton process.

PubMed

Deng, Yang; Englehardt, James D

2006-12-01

In recent years, studies of leachate treatment by conventional Fenton, photo-Fenton and electro-Fenton processes have indicated that these methods can effectively reduce concentrations of organic contaminants and color. In addition, the process can increase the biodegradable fraction of organic constituents in leachate, particularly in mature or biologically recalcitrant leachate. Oxidation and coagulation both play important roles in the removal of organics. Initial pH, dosages of Fenton reagents, aeration, final pH, reagent addition mode, temperature, and UV irradiation may influence final treatment efficiency. In this paper, current knowledge of performance and economics of Fenton processes for treatment of landfill leachate as reported for laboratory, pilot and full-scale studies is reviewed, with the conclusion that the Fenton process is an important and competitive technology for the treatment or pretreatment of landfill leachate.

Concomitant Leaching and Electrochemical Extraction of Rare Earth Elements from Monazite.

PubMed

Maes, Synthia; Zhuang, Wei-Qin; Rabaey, Korneel; Alvarez-Cohen, Lisa; Hennebel, Tom

2017-02-07

Rare earth elements (REEs) have become increasingly important in modern day technologies. Unfortunately, their recycling is currently limited, and the conventional technologies for their extraction and purification are exceedingly energy and chemical intensive. New sustainable technologies for REE extraction from both primary and secondary resources would be extremely beneficial. This research investigated a two-stage recovery strategy focused on the recovery of neodymium (Nd) and lanthanum (La) from monazite ore that combines microbially based leaching (using citric acid and spent fungal supernatant) with electrochemical extraction. Pretreating the phosphate-based monazite rock (via roasting) dramatically increased the microbial REE leaching efficiency. Batch experiments demonstrated the effective and continued leaching of REEs by recycled citric acid, with up to 392 mg of Nd L -1 and 281 mg of La L -1 leached during seven consecutive 24 h cycles. Neodymium was further extracted in the catholyte of a three-compartment electrochemical system, with up to 880 mg of Nd L -1 achieved within 4 days (at 40 A m -2 ). Meanwhile, the radioactive element thorium and counterions phosphate and citrate were separated effectively from the REEs in the anolyte, favoring REE extraction and allowing sustainable reuse of the leaching agent. This study shows a promising technology that is suitable for primary ores and can further be optimized for secondary resources.

Anaerobes, aerobes and phototrophs. A winning team for wastewater management.

PubMed

Gijzen, H J

2001-01-01

Current mainstream technologies for wastewater treatment, such as activated sludge and tertiary nutrient removal, are too costly to provide a satisfactory solution for the increasing wastewater problems in developing regions. Besides, these technologies do not allow for re-use of valuable energy and nutrients contained in the wastewater. In light of these limitations, it is important to reconsider the technology and strategic approaches in wastewater management. This paper introduces the "Cleaner Production" concept to sewage management, which combines two approaches: pollution prevention and re-use. Pollution prevention includes a shift towards low water use sanitation technology. The more concentrated wastewater, becomes more attractive for re-use oriented treatment schemes. A combination of anaerobic pre-treatment followed by macrophyte-covered stabilisation ponds is proposed for the effective recovery of energy and nutrients from sewage. By selecting optimal applications of the plant biomass and pond effluent, nutrients will end up as fish and crop protein. This contrasts favourably to tertiary nitrogen removal in activated sludge systems, which recycles ammonia through molecular nitrogen at the expense of energy and high costs. Macrophyte ponds are proposed as a key step in waste recycling, because these form the central unit of a recycling engine, driven by photosynthesis. The process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions.

Joint Test Protocol: Environmentally Friendly Zirconium Oxide Pretreatment Demonstration

DTIC Science & Technology

2013-12-01

coatings . Loss of paint adhesion is the primary failure mode on aluminum and steel. 3.7.3 Test Methodology The test methodology for pencil hardness...conversion pretreatment coatings . Loss of paint adhesion is the primary failure mode on aluminum and steel. 3.8.3 Test Methodology The test...SUPPLEMENTARY NOTES 14. ABSTRACT There is a need to implement innovative and cost- effective replacement technologies to address the multiple health, safety

Method for aqueous gold thiosulfate extraction using copper-cyanide pretreated carbon adsorption

DOEpatents

Young, Courtney; Melashvili, Mariam; Gow, Nicholas V

2013-08-06

A gold thiosulfate leaching process uses carbon to remove gold from the leach liquor. The activated carbon is pretreated with copper cyanide. A copper (on the carbon) to gold (in solution) ratio of at least 1.5 optimizes gold recovery from solution. To recover the gold from the carbon, conventional elution technology works but is dependent on the copper to gold ratio on the carbon.

The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process

PubMed Central

2012-01-01

Background Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from lignocellulosic biomass. During dilute acid pretreatment, xylan depolymerizes to form soluble xylose monomers and oligomers. Because the xylan found in nature is highly acetylated, the formation of xylose monomers requires two steps: 1) cleavage of the xylosidic bonds, and 2) cleavage of covalently bonded acetyl ester groups. Results In this study, we show that the latter may be the rate limiting step for xylose monomer formation. Furthermore, acetyl groups are also found to be a cause of biomass recalcitrance and hydrolyzate toxicity. While the removal of acetyl groups from native corn stover by alkaline de-esterification prior to pretreatment improves overall process yields, the exact impact is highly dependent on the corn stover variety in use. Xylose monomer yields in pretreatment generally increases by greater than 10%. Compared to pretreated corn stover controls, the deacetylated corn stover feedstock is approximately 20% more digestible after pretreatment. Finally, by lowering hydrolyzate toxicity, xylose utilization and ethanol yields are further improved during fermentation by roughly 10% and 7%, respectively. In this study, several varieties of corn stover lots were investigated to test the robustness of the deacetylation-pretreatment-saccharification-fermentation process. Conclusions Deacetylation shows significant improvement on glucose and xylose yields during pretreatment and enzymatic hydrolysis, but it also reduces hydrolyzate toxicity during fermentation, thereby improving ethanol yields and titer. The magnitude of effect is dependent on the selected corn stover variety, with several varieties achieving improvements of greater than 10% xylose yield in pretreatment, 20% glucose yield in low solids enzymatic hydrolysis and 7% overall ethanol yield. PMID:22369467

GREET Pretreatment Module

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

Adom, Felix K.; Dunn, Jennifer B.; Han, Jeongwoo

2014-09-01

A wide range of biofuels and biochemicals can be produced from cellulosic biomass via different pretreatment technologies that yield sugars. Process simulations of dilute acid and ammonia fiber expansion pretreatment processes and subsequent hydrolysis were developed in Aspen Plus for four lignocellulosic feedstocks (corn stover, miscanthus, switchgrass, and poplar). This processing yields sugars that can be subsequently converted to biofuels or biochemical. Material and energy consumption data from Aspen Plus were then compiled in a new Greenhouses Gases, Regulated Emissions, and Energy Use in Transportation (GREET TM) pretreatment module. The module estimates the cradle-to-gate fossil energy consumption (FEC) and greenhousemore » gas (GHG) emissions associated with producing fermentable sugars. This report documents the data and methodology used to develop this module and the cradle-to-gate FEC and GHG emissions that result from producing fermentable sugars.« less

Scale-up and process integration of sugar production by acidolysis of municipal solid waste/corn stover blends in ionic liquids.

PubMed

Li, Chenlin; Liang, Ling; Sun, Ning; Thompson, Vicki S; Xu, Feng; Narani, Akash; He, Qian; Tanjore, Deepti; Pray, Todd R; Simmons, Blake A; Singh, Seema

2017-01-01

Lignocellulosic biorefineries have tonnage and throughput requirements that must be met year round and there is no single feedstock available in any given region that is capable of meeting the price and availability demands of the biorefineries scheduled for deployment. Significant attention has been historically given to agriculturally derived feedstocks; however, a diverse range of wastes, including municipal solid wastes (MSW), also have the potential to serve as feedstocks for the production of advanced biofuels and have not been extensively studied. In addition, ionic liquid (IL) pretreatment with certain ILs is receiving great interest as a potential process that enables fractionation of a wide range of feedstocks. Acid catalysts have been used previously to hydrolyze polysaccharides into fermentable sugars following IL pretreatment, which could potentially provide a means of liberating fermentable sugars from lignocellulose without the use of costly enzymes. However, successful optimization and scale-up of the one-pot acid-assisted IL deconstruction for further commercialization involve challenges such as reactor compatibility, mixing at high solid loading, sugar recovery, and IL recycling, which have not been effectively resolved during the development stages at bench scale. Here, we present the successful scale-up demonstration of the acid-assisted IL deconstruction on feedstock blends of municipal solid wastes and agricultural residues (corn stover) by 30-fold, relative to the bench scale (6 vs 0.2 L), at 10% solid loading. By integrating IL pretreatment and acid hydrolysis with subsequent centrifugation and extraction, the sugar and lignin products can be further recovered efficiently. This scale-up development at Advanced Biofuels/Bioproducts Process Demonstration Unit (ABPDU) will leverage the opportunity and synergistic efforts toward developing a cost-effective IL-based deconstruction technology by drastically eliminating enzyme, reducing water usage, and simplifying the downstream sugar/lignin recovery and IL recycling. Results indicate that MSW blends are viable and valuable resource to consider when assessing biomass availability and affordability for lignocellulosic biorefineries. This scale-up evaluation demonstrates that the acid-assisted IL deconstruction technology can be effectively scaled up to larger operations and the current study established the baseline of scaling parameters for this process.

Biphasic microreactor for efficient membrane protein pretreatment with a combination of formic acid assisted solubilization, on-column pH adjustment, reduction, alkylation, and tryptic digestion.

PubMed

Zhao, Qun; Liang, Yu; Yuan, Huiming; Sui, Zhigang; Wu, Qi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2013-09-17

Combining good dissolving ability of formic acid (FA) for membrane proteins and excellent complementary retention behavior of proteins on strong cation exchange (SCX) and strong anion exchange (SAX) materials, a biphasic microreactor was established to pretreat membrane proteins at microgram and even nanogram levels. With membrane proteins solubilized by FA, all of the proteomics sample processing procedures, including protein preconcentration, pH adjustment, reduction, and alkylation, as well as tryptic digestion, were integrated into an "SCX-SAX" biphasic capillary column. To evaluate the performance of the developed microreactor, a mixture of bovine serum albumin, myoglobin, and cytochrome c was pretreated. Compared with the results obtained by the traditional in-solution process, the peptide recovery (93% vs 83%) and analysis throughput (3.5 vs 14 h) were obviously improved. The microreactor was further applied for the pretreatment of 14 μg of membrane proteins extracted from rat cerebellums, and 416 integral membrane proteins (IMPs) (43% of total protein groups) and 103 transmembrane peptides were identified by two-dimensional nanoliquid chromatography-electrospray ionization tandem mass spectrometry (2D nano-LC-ESI-MS/MS) in triplicate analysis. With the starting sample preparation amount decreased to as low as 50 ng, 64 IMPs and 17 transmembrane peptides were identified confidently, while those obtained by the traditional in-solution method were 10 and 1, respectively. All these results demonstrated that such an "SCX-SAX" based biphasic microreactor could offer a promising tool for the pretreatment of trace membrane proteins with high efficiency and throughput.

Eco-friendly processing in enzymatic xylooligosaccharides production from corncob: Influence of pretreatment with sonocatalytic-synergistic Fenton reaction and its antioxidant potentials.

PubMed

Kawee-Ai, Arthitaya; Srisuwun, Aungkana; Tantiwa, Nidtaya; Nontaman, Wimada; Boonchuay, Pinpanit; Kuntiya, Ampin; Chaiyaso, Thanongsak; Seesuriyachan, Phisit

2016-07-01

Delignification can be considered as a feasible process to pretreat lignocellulosic biomass in xylooligosaccharides production after the performance and efficiency has been improved through a few modifications. This study compared various pretreatment strategies such as Fenton, sonocatalytic, and sonocatalytic-synergistic Fenton employed on corncob in order to expose lignin content and saccharides to enhance the xylooligosaccharides yield by enzymatic hydrolysis. The dissolution of lignin and xylooligosaccharides production of corncob was enhanced by ultrasound assisted TiO2 and Fenton reaction. The corncob pretreated with a sonocatalytic-synergistic Fenton reaction gave the highest release of the lignin concentration level (1.03 g/L), dissolution level (80.25%), and xylooligosaccharides content (46.45 mg/g substrate). A two-step pretreatment processes consisting of the alkali treatment (pretreatment) and sonocatalytic-synergistic Fenton process (posttreatment) illustrated that subsequent enzymatic hydrolysis could be enhanced considerably. The release of the lignin concentration and xylooligosaccharides content were 33.20 g/L and 174.81 mg/g substrate, respectively. The antioxidant potential of xylooligosaccharides showed significant differences regarding the amount of xylooligosaccharides and the phenolic compounds produced. Copyright © 2015 Elsevier B.V. All rights reserved.

Low-heat, mild alkaline pretreatment of switchgrass for anaerobic digestion.

PubMed

Jin, Guang; Bierma, Tom; Walker, Paul M

2014-01-01

This study examines the effectiveness of alkaline pretreatment under mild heat conditions (100°C or 212°F) on the anaerobic co-digestion of switchgrass. The effects of alkaline concentration, types of alkaline, heating time and rinsing were evaluated. In addition to batch studies, continuous-feed studies were performed in triplicate to identify potential digester operational problems caused by switchgrass co-digestion while accounting for uncertainty due to digester variability. Few studies have examined anaerobic digestion of switchgrass or the effects of mild heating to enhance alkaline pretreatment prior to biomass digestion. Results indicate that pretreatment can significantly enhance digestion of coarse-ground (≤ 0.78 cm particle size) switchgrass. Energy conversion efficiency as high as 63% was observed, and was comparable or superior to fine-grinding as a pretreatment method. The optimal NaOH concentration was found to be 5.5% (wt/wt alkaline/biomass) with a 91.7% moisture level. No evidence of operational problems such as solids build-up, poor mixing, or floating materials were observed. These results suggest the use of waste heat from a generator could reduce the concentration of alkaline required to adequately pretreat lignocellulosic feedstock prior to anaerobic digestion.

Effects of alkaline catalysts on acetone-based organosolv pretreatment of rice straw.

PubMed

Raita, Marisa; Denchokepraguy, Naphatsaya; Champreda, Verawat; Laosiripojana, Navadol

2017-10-01

Organosolv is an effective pretreatment strategy for increasing digestibility of lignocellulosic materials owing to selectivity of solvents on separating biopolymeric constituents of plant biomass. In the present work, a novel low-temperature alkali-catalyzed organosolv pretreatment of rice straw was studied. The effects of alkaline catalysts (i.e., NaOH, ammonia, and tri-ethylamine) and solvent types (i.e., acetone, ethanol, and water) were carried out. Addition of alkalis led to increasing sugar from enzymatic hydrolysis while acetone was found to be superior to ethanol and water on selectivity towards cellulose preservation. The optimal alkaline-catalyzed pretreatment reaction contained 5% (w/v) NaOH in an aqueous-acetone mixture (1:4) at 80 °C for 5 min. A glucose yield of 913 mg/g of pretreated biomass was achieved, equivalent to a maximal glucose recovery of 93.0% from glucan in the native biomass. Scanning electron microscope revealed efficient removal of non-cellulosic components, resulting in exposed cellulose microfibers with a reduced crystallite size as determined by X-ray diffraction. With potential on obtaining high-quality lignin, the work demonstrated potential of the novel low-temperature alkaline-catalyzed acetone-based organosolv process for pretreatment of lignocellulosic materials in biorefineries.

Pretreating wheat straw by the concentrated phosphoric acid plus hydrogen peroxide (PHP): Investigations on pretreatment conditions and structure changes.

PubMed

Wang, Qing; Hu, Jinguang; Shen, Fei; Mei, Zili; Yang, Gang; Zhang, Yanzong; Hu, Yaodong; Zhang, Jing; Deng, Shihuai

2016-01-01

Wheat straw was pretreated by PHP (the concentrated H3PO4 plus H2O2) to clarify effects of temperature, time and H3PO4 proportion on hemicellulose removal, delignification, cellulose recovery and enzymatic digestibility. Overall, hemicellulose removal was intensified by PHP comparing to the concentrated H3PO4. Moreover, efficient delignification specially happened in PHP pretreatment. Hemicellulose removal and delignification by PHP positively responded to temperature and time. Increasing H3PO4 proportion in PHP can promote hemicellulose removal, however, decrease the delignification. Maximum hemicellulose removal and delignification were achieved at 100% and 83.7% by PHP. Enzymatic digestibility of PHP-pretreated wheat straw was greatly improved by increasing temperature, time and H3PO4 proportion, and complete hydrolysis can be achieved consequently. As temperature of 30-40°C, time of 2.0 h and H3PO4 proportion of 60% were employed, more than 92% cellulose was retained in the pretreated wheat straw, and 29.1-32.6g glucose can be harvested from 100g wheat straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

PubMed

Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

2015-12-01

This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

ALA Pretreatment Improves Waterlogging Tolerance of Fig Plants

PubMed Central

An, Yuyan; Qi, Lin; Wang, Liangju

2016-01-01

5-aminolevulinic acid (ALA), a natural and environmentally friendly plant growth regulator, can improve plant tolerance to various environmental stresses. However, whether ALA can improve plant waterlogging tolerance is unknown. Here, we investigated the effects of ALA pretreatment on the waterlogging-induced damage of fig (Ficus carica Linn.) plants, which often suffer from waterlogging stress. ALA pretreatment significantly alleviated stress-induced morphological damage, increased leaf relative water content (RWC), and reduced leaf superoxide anion (O2⋅¯) production rate and malonaldehyde (MDA) content in fig leaves, indicating ALA mitigates waterlogging stress of fig plants. We further demonstrated that ALA pretreatment largely promoted leaf chlorophyll content, photosynthetic electron transfer ability, and photosynthetic performance index, indicating ALA significantly improves plant photosynthetic efficiency under waterlogging stress. Moreover, ALA pretreatment significantly increased activities of leaf superoxide dismutase (SOD) and peroxidase (POD), root vigor, and activities of root alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH), indicating ALA also significantly improves antioxidant ability and root function of fig plants under waterlogging stress. Taken together, ALA pretreatment improves waterlogging tolerance of fig plants significantly, and the promoted root respiration, leaf photosynthesis, and antioxidant ability may contribute greatly to this improvement. Our data firstly shows that ALA can improve plant waterlogging tolerance. PMID:26789407

Steam pretreatment of Saccharum officinarum L. bagasse by adding of impregnating agents for advanced bioethanol production.

PubMed

Verardi, A; Blasi, A; De Bari, I; Calabrò, V

2016-12-01

The main byproduct of the sugarcane industry, Saccharum officinarum L. bagasse (sugarcane bagasse, SCB), is widely used as lignocellulose biomass for bio-ethanol (EtOH) production. In this research study, SCB was pretreated by steam explosion (SE) method using two different impregnating agents: sulfur dioxide (SD) and hydrogen peroxide (HP). As matter of fact, the use of impregnating agents improves the performance of SE method, increasing the concentrations of fermentable sugars after enzymatic saccharification, and decreasing the inhibitor compounds produced during the steam pretreatment step. The aim of this study was to investigate and compare the use of the two impregnating agents in various SE-conditions in order to optimize pretreatment parameters. For every pretreatment condition, it has been evaluated: concentration of fermentable sugars, glucose and xylose yields, and the effects of the inhibitor compounds on enzymatic hydrolysis step. The obtained results allow to improve the efficiency of the whole process of bio-EtOH synthesis enhancing the amount of fermentable sugars produced and the eco-sustainability of the whole process. Indeed, the optimization of steam pretreatment leads to a reduction of energy requirements and to a lower environmental impact. Copyright © 2015 Elsevier Inc. All rights reserved.

Water pollution control technology and strategy for river-lake systems: a case study in Gehu Lake and Taige Canal.

PubMed

Zhang, Yimin; Zhang, Yongchun; Gao, Yuexiang; Zhang, Houhu; Cao, Jianying; Cai, Jinbang; Kong, Xiangji

2011-07-01

The Taoge water system is located in the upstream of Taihu Lake basin and is characterized by its multi-connected rivers and lakes. In this paper, current analyses of hydrology, hydrodynamics and water pollution of Gehu Lake and Taige Canal are presented. Several technologies are proposed for pollution prevention and control, and water environmental protection in the Taihu Lake basin. These included water pollution control integration technology for the water systems of Gehu Lake, Taige Canal and Caoqiao River. Additionally, river-lake water quality and quantity regulation technology, ecological restoration technology for polluted and degraded water bodies, and water environmental integration management and optimization strategies were also examined. The main objectives of these strategies are to: (a) improve environmental quality of relative water bodies, prevent pollutants from entering Gehu Lake and Taige Canal, and ensure that the clean water after the pre-treatment through Gehu Lake is not polluted before entering the Taihu Lake through Taige Canal; (b) stably and efficiently intercept and decrease the pollution load entering the lake through enhancing the river outlet ecological system structure function and water self-purifying capacity, and (c) designate Gehu Lake as a regulation system for water quality and water quantity in the Taoge water system and thus guarantee the improvement of the water quality of the inflow into Taihu Lake.

Multiple syntrophic interactions drive biohythane production from waste sludge in microbial electrolysis cells.

PubMed

Liu, Qian; Ren, Zhiyong Jason; Huang, Cong; Liu, Bingfeng; Ren, Nanqi; Xing, Defeng

2016-01-01

Biohythane is a new and high-value transportation fuel present as a mixture of biomethane and biohydrogen. It has been produced from different organic matters using anaerobic digestion. Bioenergy can be recovered from waste activated sludge through methane production during anaerobic digestion, but energy yield is often insufficient to sludge disposal. Microbial electrolysis cell (MEC) is also a promising approach for bioenergy recovery and waste sludge disposal as higher energy efficiency and biogas production. The systematic understanding of microbial interactions and biohythane production in MEC is still limited. Here, we report biohythane production from waste sludge in biocathode microbial electrolysis cells and reveal syntrophic interactions in microbial communities based on high-throughput sequencing and quantitative PCR targeting 16S rRNA gene. The alkali-pretreated sludge fed MECs (AS-MEC) showed the highest biohythane production rate of 0.148 L·L(-1)-reactor·day(-1), which is 40 and 80 % higher than raw sludge fed MECs (RS-MEC) and anaerobic digestion (open circuit MEC, RS-OCMEC). Current density, metabolite profiles, and hydrogen-methane ratio results all confirm that alkali-pretreatment and microbial electrolysis greatly enhanced sludge hydrolysis and biohythane production. Illumina Miseq sequencing of 16S rRNA gene amplicons indicates that anode biofilm was dominated by exoelectrogenic Geobacter, fermentative bacteria and hydrogen-producing bacteria in the AS-MEC. The cathode biofilm was dominated by fermentative Clostridium. The dominant archaeal populations on the cathodes of AS-MEC and RS-MEC were affiliated with hydrogenotrophic Methanobacterium (98 %, relative abundance) and Methanocorpusculum (77 %), respectively. Multiple pathways of gas production were observed in the same MEC reactor, including fermentative and electrolytic H2 production, as well as hydrogenotrophic methanogenesis and electromethanogenesis. Real-time quantitative PCR analyses showed that higher amount of methanogens were enriched in AS-MEC than that in RS-MEC and RS-OCMEC, suggesting that alkali-pretreated sludge and MEC facilitated hydrogenotrophic methanogen enrichment. This study proves for the first time that biohythane could be produced directly in biocathode MECs using waste sludge. MEC and alkali-pretreatment accelerated enrichment of hydrogenotrophic methanogen and hydrolysis of waste sludge. The results indicate syntrophic interactions among fermentative bacteria, exoelectrogenic bacteria and methanogenic archaea in MECs are critical for highly efficient conversion of complex organics into biohythane, demonstrating that MECs can be more competitive than conventional anaerobic digestion for biohythane production using carbohydrate-deficient substrates. Biohythane production from waste sludge by MEC provides a promising new way for practical application of microbial electrochemical technology.

Subtask 2.18 - Advancing CO 2 Capture Technology: Partnership for CO 2 Capture (PCO 2C) Phase III

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

Kay, John; Azenkeng, Alexander; Fiala, Nathan

2016-03-31

Industries and utilities continue to investigate ways to decrease their carbon footprint. Carbon capture and storage (CCS) can enable existing power generation facilities to meet the current national CO 2 reduction goals. The Partnership for CO2 Capture Phase III focused on several important research areas in an effort to find ways to decrease the cost of capture across both precombustion and postcombustion platforms. Two flue gas pretreatment technologies for postcombustion capture, an SO 2 reduction scrubbing technology from Cansolv Technologies Inc. and the Tri-Mer filtration technology that combines particulate, NOx, and SO 2 control, were evaluated on the Energy &more » Environmental Research Center’s (EERC’s) pilot-scale test system. Pretreating the flue gas should enable more efficient, and therefore less expensive, CO 2 capture. Both technologies were found to be effective in pretreating flue gas prior to CO 2 capture. Two new postcombustion capture solvents were tested, one from the Korea Carbon Capture and Sequestration R&D Center (KCRC) and one from CO 2 Solutions Incorporated. Both of these solvents showed the ability to capture CO 2 while requiring less regeneration energy, which would reduce the cost of capture. Hydrogen separation membranes from Commonwealth Scientific and Industrial Research Organisation were evaluated through precombustion testing. They are composed of vanadium alloy, which is less expensive than the palladium alloys that are typically used. Their performance was comparable to that of other membranes that have been tested at the EERC. Aspen Plus® software was used to model the KCRC and CO 2 Solutions solvents and found that they would result in significantly improved overall plant performance. The modeling effort also showed that the parasitic steam load at partial capture of 45% is less than half that of 90% overall capture, indicating savings that could be accrued if 90% capture is not required. Modeling of three regional power plants using the Carnegie Mellon Integrated Environmental Control Model showed that, among other things, the use of a bypass during partial capture may minimize the size of the capture tower(s) and result in a slight reduction in the revenue required to operate the capture facility. The results reinforced that a one-size-fits-all approach cannot be taken to adding capture to a power plant. Laboratory testing indicated that Fourier transform infrared spectroscopy could be used to continuously sample stack emissions at CO 2 capture facilities to detect and quantify any residual amine or its degradation products, particularly nitrosamines. The information gathered during Phase III is important for utility stakeholders as they determine how to reduce their CO 2 emissions in a carbon-constrained world. This subtask was funded through the EERC–U.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the North Dakota Industrial Commission, PPL Montana, Nebraska Public Power District, Tri-Mer Corporation, Montana–Dakota Utilities Co., Basin Electric Power Cooperative, KCRC/Korean Institute of Energy Research, Cansolv Technologies, and CO 2 Solutions, Inc.« less

[Research on Identification and Determination of Pesticides in Apples Using Raman Spectroscopy].

PubMed

Zhai, Chen; Peng, Yan-kun; Li, Yong-yu; Dhakal, Sagar; Xu, Tian-feng; Guo, Lang-hua

2015-08-01

Raman spectroscopy combined with chemometric methods has been thought to an efficient method for identification and determination of pesticide residues in fruits and vegetables. In the present research, a rapid and nondestructive method was proposed and testified based on self-developed Raman system for the identification and determination of deltamethrin and acetamiprid remaining in apple. The peaks of Raman spectra at 574 and 843 cm(-1) can be used to identify deltamethrin and acetamiprid, respectively, the characteristic peaks of deltamethrin and acetamiprid were still visible when the concentrations of the two pesticides were 0.78 and 0.15 mg · kg(-1) in apples samples, respectively. Calibration models of pesticide content were developed by partial least square (PLS) algorithm with different spectra pretreatment methods (Savitzky-Golay smoothing, first derivative transformation, second derivative transformation, baseline calibration, standard normal variable transformation). The baseline calibration methods by 8th order polynomial fitting gave the best results. For deltamethrin, the obtained prediction coefficient (Rp) value from PLS model for the results of prediction and gas chromatography measurement was 0.94; and the root mean square error of prediction (RMSEP) was 0.55 mg · kg(-1). The values of Rp and RMSEP were respective 0.85 and 0.12 mg · kg(-1) for acetamiprid. According to the detect performance, applying Raman technology in the nondestructive determination of pesticide residuals in apples is feasible. In consideration of that it needs no pretreatment before spectra collection and causes no damage to sample, this technology can be used in detection department, fruit and vegetable processing enterprises, supermarket, and vegetable market. The result of this research is promising for development of industrially feasible technology for rapid, nondestructive and real time detection of different types of pesticide with its concentration in apples. This supplies a rapid nondestructive and environmentally friendly way for the determination of fruit and vegetable quality and safety.

Hydrolysis of dilute acid-pretreated cellulose under mild hydrothermal conditions.

PubMed

Chimentão, R J; Lorente, E; Gispert-Guirado, F; Medina, F; López, F

2014-10-13

The hydrolysis of dilute acid-pretreated cellulose was investigated in a conventional oven and under microwave heating. Two acids--sulfuric and oxalic--were studied. For both hydrothermal conditions (oven and microwave) the resultant total organic carbon (TOC) values obtained by the hydrolysis of the cellulose pretreated with sulfuric acid were higher than those obtained by the hydrolysis of the cellulose pretreated with oxalic acid. However, the dicarboxylic acid exhibited higher hydrolytic efficiency towards glucose. The hydrolysis of cellulose was greatly promoted by microwave heating. The Rietveld method was applied to fit the X-ray patterns of the resultant cellulose after hydrolysis. Oxalic acid preferentially removed the amorphous region of the cellulose and left the crystalline region untouched. On the other hand, sulfuric acid treatment decreased the ordering of the cellulose by partially disrupting its crystalline structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production.

PubMed

Xie, Guo-Jun; Liu, Bing-Feng; Wang, Qilin; Ding, Jie; Ren, Nan-Qi

2016-04-15

Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H2/mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H2/g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H2/g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

SBR treatment of olive mill wastewaters: dilution or pre-treatment?

PubMed

Farabegoli, G; Chiavola, A; Rolle, E

2012-01-01

The olive-oil extraction industry is an economically important activity for many countries of the Mediterranean Sea area, with Spain, Greece and Italy being the major producers. This activity, however, may represent a serious environmental problem due to the discharge of highly polluted effluents, usually referred to as 'olive mill wastewaters' (OMWs). They are characterized by high values of chemical oxygen demand (COD) (80-300 g/L), lipids, total polyphenols (TPP), tannins and other substances difficult to degrade. An adequate treatment before discharging is therefore required to reduce the pollutant load. The aim of the present paper was to evaluate performances of a biological process in a sequencing batch reactor (SBR) fed with pre-treated OMWs. Pre-treatment consisted of a combined acid cracking (AC) and granular activated carbon (GAC) adsorption process. The efficiency of the system was compared with that of an identical SBR fed with the raw wastewater only diluted. Combined AC and GAC adsorption was chosen to be used prior to the following biological process due to its capability of providing high removal efficiencies of COD and TPP and also appreciable improvement of biodegradability. Comparing results obtained with different influents showed that best performances of the SBR were obtained by feeding it with raw diluted OMWs (dOMWs) and at the lowest dilution ratio (1:25): in this case, the removal efficiencies were 90 and 76%, as average, for COD and TPP, respectively. Feeding the SBR with either the pre-treated or the raw dOMWs at 1:50 gave very similar values of COD reduction (74%); however, an improvement of the TPP removal was observed in the former case.

A combined pretreatment of 1,25-dihydroxyvitamin D3 and sodium valproate enhances the damaging effect of ionizing radiation on prostate cancer cells.

PubMed

Gavrilov, Vladimir; Leibovich, Yaron; Ariad, Samuel; Lavrenkov, Konstantin; Shany, Shraga

2010-07-01

Radiotherapy is one of the curative treatment options for prostate cancer (PCa). However, effective doses of ionizing radiation (IR) have a high risk of side effects. To increase sensitivity of PCa to IR we pretreated human androgen-refractory DU145 PCa cells with a combination of sodium valproate (VPA), a well-tolerated drug with histone deacetylases inhibiting activity, and 1,25-dihydroxyvitamin D3, 1,25(OH)2D3, the active metabolite of vitamin D, a well known anticancer agent. The results show that irradiation (4Gy) of DU145 PCa cells pretreated with a combination of 1 mM VPA and 100 nM 1,25(OH)2D3 efficiently suppressed (87.9%) PCa cell proliferation. IR after combined pretreatment resulted in increased DNA double-strand breaks expressed as levels of phosphorylated histone H2A.X, compared with non-treated cells the increase was 58.1% in pretreated cells and 11.8% in non-pretreated cells (p<0.002). Combined pretreatment enhanced IR-induced activation of DNA damage checkpoint kinase Chk2, 39.0% in pretreated cells compared to 23.8% in non-pretreated cells (p<0.05). These molecular changes led to DNA replication blockade, S-phase cell-cycle arrest and enhanced apoptosis. Cumulatively, the results indicate that combined pretreatment with VPA and 1,25(OH)2D3 followed by IR is a highly effective treatment for human PCa cells. This observation may have important implications for reducing doses of radiation administered to cancer patients thus limiting the severity of side effects. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Characterization of hemicellulase and cellulase from the extremely thermophilic bacterium Caldicellulosiruptor owensensis and their potential application for bioconversion of lignocellulosic biomass without pretreatment.

PubMed

Peng, Xiaowei; Qiao, Weibo; Mi, Shuofu; Jia, Xiaojing; Su, Hong; Han, Yejun

2015-01-01

Pretreatment is currently the common approach for improving the efficiency of enzymatic hydrolysis on lignocellulose. However, the pretreatment process is expensive and will produce inhibitors such as furan derivatives and phenol derivatives. If the lignocellulosic biomass can efficiently be saccharified by enzymolysis without pretreatment, the bioconversion process would be simplified. The genus Caldicellulosiruptor, an obligatory anaerobic and extreme thermophile can produce a diverse set of glycoside hydrolases (GHs) for deconstruction of lignocellulosic biomass. It gives potential opportunities for improving the efficiency of converting native lignocellulosic biomass to fermentable sugars. Both of the extracellular (extra-) and intracellular (intra-) enzymes of C. owensensis cultivated on corncob xylan or xylose had cellulase (including endoglucanase, cellobiohydrolase and β-glucosidase) and hemicellulase (including xylanase, xylosidase, arabinofuranosidase and acetyl xylan esterase) activities. The enzymes of C. owensensis had high ability for degrading hemicellulose of native corn stover and corncob with the conversion rates of xylan 16.7 % and araban 60.0 %. Moreover, they had remarkable synergetic function with the commercial enzyme cocktail Cellic CTec2 (Novoyzmes). When the native corn stover and corncob were respectively, sequentially hydrolyzed by the extra-enzymes of C. owensensis and CTec2, the glucan conversion rates were 31.2 and 37.9 %,which were 1.7- and 1.9-fold of each control (hydrolyzed by CTec2 alone), whereas the glucan conversion rates of the steam-exploded corn stover and corncob hydrolyzed by CTec2 alone on the same loading rate were 38.2 and 39.6 %, respectively. These results show that hydrolysis by the extra-enzyme of C. owensensis made almost the same contribution as steam-exploded pretreatment on degradation of native lignocellulosic biomass. A new process for saccharification of lignocellulosic biomass by sequential hydrolysis is demonstrated in the present research, namely hyperthermal enzymolysis (70-80 °C) by enzymes of C. owensensis followed with mesothermal enzymolysis (50-55 °C) by commercial cellulase. This process has the advantages of no sugar loss, few inhibitors generation and consolidated with sterilization. The enzymes of C. owensensis demonstrated an enhanced ability to degrade the hemicellulose of native lignocellulose. The pretreatment and detoxification steps may be removed from the bioconversion process of the lignocellulosic biomass by using the enzymes from C. owensensis.

Alkaline-assisted screw press pretreatment affecting enzymatic hydrolysis of wheat straw.

PubMed

Yan, Qingqi; Wang, Yumei; Rodiahwati, Wawat; Spiess, Antje; Modigell, Michael

2017-02-01

Screw press processing of biomass can be considered as a suitable mechanically based pretreatment for biofuel production since it disrupts the structure of lignocellulosic biomass with high shear and pressure forces. The combination with chemical treatment has been suggested to increase the conversion of lignocellulosic biomass to fermentable sugars. Within the study, the synergetic effect of alkaline (sodium hydroxide, NaOH) soaking and screw press pretreatment on wheat straw was evaluated based on, e.g., sugar recovery and energy efficiency. After alkaline soaking (at 0.1 M for 30 min) and sequential screw press pretreatment with various screw press configurations and modified screw barrel, the lignin content of pretreated wheat straw was quantified. In addition, the structure of pretreated wheat straw was investigated by scanning electron microscopy and measurement of specific surface area. It could be shown that removal of lignin is more important than increase of surface area of the biomass to reach a high sugar recovery. The rate constant of the enzymatic hydrolysis increased from 1.1 × 10 -3  1/h for the non-treated material over 2.3 × 10 -3  1/h for the alkaline-soaked material to 26.9 × 10 -3  1/h for alkaline-assisted screw press pretreated material, indicating a nearly 25-fold improvement of the digestibility by the combined chemo-mechanical pretreatment. Finally, the screw configuration was found to be an important factor for improving the sugar recovery and for reducing the specific energy consumption of the screw press pretreatment.

Exploring accessibility of pretreated poplar cell walls by measuring dynamics of fluorescent probes.

PubMed

Paës, Gabriel; Habrant, Anouck; Ossemond, Jordane; Chabbert, Brigitte

2017-01-01

The lignocellulosic cell wall network is resistant to enzymatic degradation due to the complex chemical and structural features. Pretreatments are thus commonly used to overcome natural recalcitrance of lignocellulose. Characterization of their impact on architecture requires combinatory approaches. However, the accessibility of the lignocellulosic cell walls still needs further insights to provide relevant information. Poplar specimens were pretreated using different conditions. Chemical, spectral, microscopic and immunolabeling analysis revealed that poplar cell walls were more altered by sodium chlorite-acetic acid and hydrothermal pretreatments but weakly modified by soaking in aqueous ammonium. In order to evaluate the accessibility of the pretreated poplar samples, two fluorescent probes (rhodamine B-isothiocyanate-dextrans of 20 and 70 kDa) were selected, and their mobility was measured by using the fluorescence recovery after photobleaching (FRAP) technique in a full factorial experiment. The mobility of the probes was dependent on the pretreatment type, the cell wall localization (secondary cell wall and cell corner middle lamella) and the probe size. Overall, combinatory analysis of pretreated poplar samples showed that even the partial removal of hemicellulose contributed to facilitate the accessibility to the fluorescent probes. On the contrary, nearly complete removal of lignin was detrimental to accessibility due to the possible cellulose-hemicellulose collapse. Evaluation of plant cell wall accessibility through FRAP measurement brings further insights into the impact of physicochemical pretreatments on lignocellulosic samples in combination with chemical and histochemical analysis. This technique thus represents a relevant approach to better understand the effect of pretreatments on lignocellulose architecture, while considering different limitations as non-specific interactions and enzyme efficiency.

Structural Variation of Bamboo Lignin before and after Ethanol Organosolv Pretreatment

PubMed Central

Bai, Yuan-Yuan; Xiao, Ling-Ping; Shi, Zheng-Jun; Sun, Run-Cang

2013-01-01

In order to make better use of lignocellulosic biomass for the production of renewable fuels and chemicals, it is necessary to disrupt its recalcitrant structure through pretreatment. Specifically, organosolv pretreatment is a feasible method. The main advantage of this method compared to other lignocellulosic pretreatment technologies is the extraction of high-quality lignin for the production of value-added products. In this study, bamboo was treated in a batch reactor with 70% ethanol at 180 °C for 2 h. Lignin fractions were isolated from the hydrolysate by centrifugation and then precipitated as ethanol organosolv lignin. Two types of milled wood lignins (MWLs) were isolated from the raw bamboo and the organosolv pretreated residue separately. After the pretreatment, a decrease of lignin (preferentially guaiacyl unit), hemicelluloses and less ordered cellulose was detected in the bamboo material. It was confirmed that the bamboo MWL is of HGS type (p-hydroxyphenyl (H), vanillin (G), syringaldehyde (S)) associated with a considerable amount of p-coumarate and ferulic esters of lignin. The ethanol organosolv treatment was shown to remove significant amounts of lignin and hemicelluloses without strongly affecting lignin primary structure and its lignin functional groups. PMID:24169436

Enhanced the enzymatic hydrolysis efficiency of wheat straw after combined steam explosion and laccase pretreatment.

PubMed

Qiu, Weihua; Chen, Hongzhang

2012-08-01

Laccase, capable of selectively degrading lignin while keeping cellulose intact, has been widely applied for the modification and bio-bleaching of pulp. In this study Sclerotium sp. laccase (MSLac) was employed in combination with steam explosion to evaluate the effect of this treatment on cellulose hydrolysis. Combined steam explosion with laccase pretreatment enhanced the cellulose conversion rate of wheat straw no matter in the case of successive (MSLac-Cel) and simultaneous (MSLac+Cel) MSLac and cellulase hydrolysis. The highest cellulose conversion rate of 84.23% was obtained when steam-exploded wheat straw (SEWS) (1.3 MPa, 5 min) was treated by MSLac+Cel at a laccase loading of 0.55 U g(-1) substrate. FT-IR and SEM analyses indicated that MSLac oxidized the phenol and changed electron configuration of the ring, which contributed to loosening the compact wrap of lignin-carbohydrate complex and consequently enhancing the enzymatic hydrolysis efficiency of cellulose. This article provided a promising method for lignocellulose bio-pretreatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Impact of mild alkali dosage on immobilized Exiguobacterium spp. mediated cost and energy efficient sludge disintegration.

PubMed

Rajesh Banu, J; Ushani, U; Rajkumar, M; Naresh Kumar, R; Parthiba Karthikeyan, O

2017-12-01

Approaches to (extracellular polymeric substance) EPS removal were studied with major aim to enhance the biodegradability and sludge solubilization. In this study, a novel approach of entrapment of bacterial strain was carried out to achieve long term activity of protease secreting bacteria Exiguobacterium sp. A mild treatment of potassium hydroxide (KOH) was applied to remove EPS which was followed by entrapment under the biological pretreatment. The efficiency of Exiguobacterium was predicted through dissolvable organic and suspended solids (SS) reduction. The maximum dissolvable organic matter released was 2300mg/L with the solubilization of 23% which was obtained for sludge without EPS (SWOE). For dissolvable organic release, SWOE showed higher final methane production of 232mL/g COD at the production rate of 16.2mL/g COD.d. The SWOE pretreatment was found to be cost effective and less energy intensive beneficial in terms of energy and cost (43.9KWh and -8.2USD) when compared to sludge with EPS (SWE) pretreatment (-177.6KWh and -91.23USD). Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzymatic production of N-acetyl-d-glucosamine from crayfish shell wastes pretreated via high pressure homogenization.

PubMed

Wei, Guoguang; Zhang, Alei; Chen, Kequan; Ouyang, Pingkai

2017-09-01

This study presents an efficient pretreatment of crayfish shell using high pressure homogenization that enables N-acetyl-d-glucosamine (GlcNAc) production by chitinase. Firstly, the chitinase from Serratia proteamaculans NJ303 was screened for its ability to degrade crayfish shell and produce GlcNAc as the sole product. Secondly, high pressure homogenization, which caused the crayfish shell to adopt a fluffy netted structure that was characterized by Scanning electron microscope (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), was evaluated as the best pretreatment method. In addition, the optimal conditions of high pressure homogenization of crayfish shell were determined to be five cycles at a pressure of 400bar, which achieved a yield of 3.9g/L of GlcNAc from 25g/L of crayfish shell in a batch enzymatic reaction over 1.5h. The results showed high pressure homogenization might be an efficient method for direct utilization of crayfish shell for enzymatic production of GlcNAc. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of ultrasound pretreatment and Maillard reaction on structure and antioxidant properties of ultrafiltrated smooth-hound viscera proteins-sucrose conjugates.

PubMed

Abdelhedi, Ola; Mora, Leticia; Jemil, Ines; Jridi, Mourad; Toldrá, Fidel; Nasri, Moncef; Nasri, Rim

2017-09-01

The effect of ultrasound (US) pre-treatment on the evolution of Maillard reaction (MR), induced between low molecular weight (LMW) peptides and sucrose, was studied. LMW peptides (<1kDa) were obtained by the ultrafiltration of smooth hound viscera protein hydrolysates, produced by Neutrase, Esperase and Purafect. MR was induced by heating the LMW peptides in the presence of sucrose for 2h at 90°C, without or with US pre-treatment. During the reaction, a marked decrease in pH values, coupled to the increase in colour of the Maillard reaction products (MRPs), were recorded. In addition, after sonication, the glycation degree was significantly enhanced in Esperase-derived peptides/sucrose conjugates (p<0.05). Moreover, results showed that thermal heating, particularly after US treatment, reduced the bitter taste and enhanced the antioxidant capacities of the resulting conjugates. Hence, it could be concluded that US leads to efficient mixing of sugar-protein solution and efficient heat/mass transfer, contributing to increase the MR rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous saccharification and fermentation of broken rice: an enzymatic extrusion liquefaction pretreatment for Chinese rice wine production.

PubMed

Li, Hongyan; Jiao, Aiquan; Xu, Xueming; Wu, Chunsen; Wei, Benxi; Hu, Xiuting; Jin, Zhengyu; Tian, Yaoqi

2013-08-01

Broken rice, pretreated by enzymatic extrusion liquefaction, was used to produce Chinese rice wine by simultaneous saccharification and fermentation (SSF) process in this study. The study compared the novel process and traditional process for Chinese rice wine fermentation utilizing broken rice and head rice, respectively. With the optimum extrusion parameters (barrel temperature, 98 °C; moisture content, 42% and amylase concentration, 1‰), 18% (v/v at 20 °C) alcoholic degree, 37.66% fermentation recovery and 93.63% fermentation efficiency were achieved, indicating enzymatic extrusion-processed rice wine from broken rice exhibited much higher fermentation rate and efficiency than traditional-processed rice wine from head rice during SSF. The starch molecule distribution data indicated that the alcoholic degree was related to the oligosaccharides' formation during enzymatic extrusion. Sum of amino acid (AA) in the extrusion-processed wine was 53.7% higher than that in the traditional one. These results suggest that the enzymatic extrusion pretreatment for broken rice is a feasible and alternative process in the fermentation of Chinese rice wine.

Effect of oxidation and catalytic reduction of trace organic contaminants on their activated carbon adsorption.

PubMed

Schoutteten, Klaas V K M; Hennebel, Tom; Dheere, Ellen; Bertelkamp, Cheryl; De Ridder, David J; Maes, Synthia; Chys, Michael; Van Hulle, Stijn W H; Vanden Bussche, Julie; Vanhaecke, Lynn; Verliefde, Arne R D

2016-12-01

The combination of ozonation and activated carbon (AC) adsorption is an established technology for removal of trace organic contaminants (TrOCs). In contrast to oxidation, reduction of TrOCs has recently gained attention as well, however less attention has gone to the combination of reduction with AC adsorption. In addition, no literature has compared the removal behavior of reduction vs. ozonation by-products by AC. In this study, the effect of pre-ozonation vs pre-catalytic reduction on the AC adsorption efficiency of five TrOCs and their by-products was compared. All compounds were susceptible to oxidation and reduction, however the catalytic reductive treatment proved to be a slower reaction than ozonation. New oxidation products were identified for dinoseb and new reduction products were identified for carbamazepine, bromoxynil and dinoseb. In terms of compatibility with AC adsorption, the influence of the oxidative and reductive pretreatments proved to be compound dependent. Oxidation products of bromoxynil and diatrizoic acid adsorbed better than their parent TrOCs, but oxidation products of atrazine, carbamazepine and dinoseb showed a decreased adsorption. The reductive pre-treatment showed an enhanced AC adsorption for dinoseb and a major enhancement for diatrizoic acid. For atrazine and bromoxynil, no clear influence on adsorption was noted, while for carbamazepine, the reductive pretreatment resulted in a decreased AC affinity. It may thus be concluded that when targeting mixtures of TrOCs, a trade-off will undoubtedly have to be made towards overall reactivity and removal of the different constituents, since no single treatment proves to be superior to the other. Copyright © 2016 Elsevier Ltd. All rights reserved.

A review of biological delignification and detoxification methods for lignocellulosic bioethanol production.

PubMed

Moreno, Antonio D; Ibarra, David; Alvira, Pablo; Tomás-Pejó, Elia; Ballesteros, Mercedes

2015-01-01

Future biorefineries will integrate biomass conversion processes to produce fuels, power, heat and value-added chemicals. Due to its low price and wide distribution, lignocellulosic biomass is expected to play an important role toward this goal. Regarding renewable biofuel production, bioethanol from lignocellulosic feedstocks is considered the most feasible option for fossil fuels replacement since these raw materials do not compete with food or feed crops. In the overall process, lignin, the natural barrier of the lignocellulosic biomass, represents an important limiting factor in biomass digestibility. In order to reduce the recalcitrant structure of lignocellulose, biological pretreatments have been promoted as sustainable and environmentally friendly alternatives to traditional physico-chemical technologies, which are expensive and pollute the environment. These approaches include the use of diverse white-rot fungi and/or ligninolytic enzymes, which disrupt lignin polymers and facilitate the bioconversion of the sugar fraction into ethanol. As there is still no suitable biological pretreatment technology ready to scale up in an industrial context, white-rot fungi and/or ligninolytic enzymes have also been proposed to overcome, in a separated or in situ biodetoxification step, the effect of the inhibitors produced by non-biological pretreatments. The present work reviews the latest studies regarding the application of different microorganisms or enzymes as useful and environmentally friendly delignification and detoxification technologies for lignocellulosic biofuel production. This review also points out the main challenges and possible ways to make these technologies a reality for the bioethanol industry.

Evaluation of enhanced coagulation pretreatment to improve ozone oxidation efficiency in wastewater.

PubMed

Wert, Eric C; Gonzales, Sarah; Dong, Mei Mei; Rosario-Ortiz, Fernando L

2011-10-15

Enhanced coagulation (EC) using ferric chloride was evaluated as a pretreatment process to improve the efficiency of ozone (O3) for the oxidation of trace organic contaminants in wastewater. At the applied dosages (10-30 mg/L as Fe), EC pretreatment removed between 10 and 47% of the dissolved organic carbon (DOC) from the three wastewaters studied. Size exclusion chromatography (SEC) showed that EC preferentially removed higher apparent molecular weight (AMW) compounds. Subsequent O3 testing was performed using an O3:DOC ratio of 1. Results showed that O3 exposures were similar even though the required doses were reduced by 10-47% by the EC pretreatment process. Hydroxyl radical (HO·) exposure, measured by parachlorobenzoic acid (pCBA), showed 10% reduction when using a FeCl3 dose of 30 mg/L, likely due to the lower O3 dose and decreased production of HO· during the initial phase of O3 decomposition (t<30 s). The oxidation of 13 trace organic contaminants (including atenolol, carbamazepine, DEET, diclofenac, dilantin, gemfibrozil, ibuprofen, meprobamate, naproxen, primidone, sulfamethoxazole, triclosan, and trimethoprim) was evaluated after EC and O3 treatment. EC was ineffective at removing any of the contaminants, while O3 oxidation reduced the concentration of compounds according to their reaction rate constants with O3 and HO·. Copyright © 2011. Published by Elsevier Ltd.

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa.

PubMed

Dogaris, Ioannis; Gkounta, Olga; Mamma, Diomi; Kekos, Dimitris

2012-07-01

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 °C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and β-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively.

Biological pretreatment of rice straw with Streptomyces griseorubens JSD-1 and its optimized production of cellulase and xylanase for improved enzymatic saccharification efficiency.

PubMed

Zhang, Dan; Luo, Yanqing; Chu, Shaohua; Zhi, Yuee; Wang, Bin; Zhou, Pei

2016-08-17

Biological pretreatment of rice straw and production of reducing sugars by hydrolysis of bio-pretreated material with Streptomyces griseorubens JSD-1 was investigated. After 10 days of incubation, various chemical compositions of inoculated rice straw were degraded and used for further enzymatic hydrolysis studies. The production of cellulolytic enzyme by S. griseorubens JSD-1 favored the conversion of cellulose to reducing sugars. The culture medium for cellulolytic enzyme production by using agro-industrial wastes was optimized through response surface methodology. According to the response surface analysis, the concentrations of 11.13, 20.34, 4.61, and 2.85 g L(-1) for rice straw, wheat bran, peptone, and CaCO3, respectively, were found to be optimum for cellulase and xylanase production. Then the hydrolyzed spent Streptomyces cells were used as a nitrogen source and the maximum filter paper cellulase, carboxymethylcellulase, and xylanase activities of 25.79, 78.91, and 269.53 U mL(-1) were achieved. The crude cellulase produced by S. griseorubens JSD-1 was subsequently used for the hydrolysis of bio-pretreated rice straw, and the optimum saccharification efficiency of 88.13% was obtained, indicating that the crude enzyme might be used instead of commercial cellulase during a saccharification process. These results give a basis for further study of bioethanol production from agricultural cellulosic waste.

Enhancement of ethanol production from green liquor-ethanol-pretreated sugarcane bagasse by glucose-xylose cofermentation at high solid loadings with mixed Saccharomyces cerevisiae strains.

PubMed

You, Yanzhi; Li, Pengfei; Lei, Fuhou; Xing, Yang; Jiang, Jianxin

2017-01-01

Efficient cofermentation of glucose and xylose is necessary for economically feasible bioethanol production from lignocellulosic biomass. Here, we demonstrate pretreatment of sugarcane bagasse (SCB) with green liquor (GL) combined with ethanol (GL-Ethanol) by adding different GL amounts. The common Saccharomyces cerevisiae (CSC) and thermophilic S. cerevisiae (TSC) strains were used and different yeast cell mass ratios (CSC to TSC) were compared. The simultaneous saccharification and cofermentation (SSF/SSCF) process was performed by 5-20% (w/v) dry substrate (DS) solid loadings to determine optimal conditions for the co-consumption of glucose and xylose. Compared to previous studies that tested fermentation of glucose using only the CSC, we obtained higher ethanol yield and concentration (92.80% and 23.22 g/L) with 1.5 mL GL/g-DS GL-Ethanol-pretreated SCB at 5% (w/v) solid loading and a CSC-to-TSC yeast cell mass ratio of 1:2 (w/w). Using 10% (w/v) solid loading under the same conditions, the ethanol concentration increased to 42.53 g/L but the ethanol yield decreased to 84.99%. In addition, an increase in the solid loading up to a certain point led to an increase in the ethanol concentration from 1.5 mL GL/g-DS-pretreated SCB. The highest ethanol concentration (68.24 g/L) was obtained with 15% (w/v) solid loading, using a CSC-to-TSC yeast cell mass ratio of 1:3 (w/w). GL-Ethanol pretreatment is a promising pretreatment method for improving both glucan and xylan conversion efficiencies of SCB. There was a competitive relationship between the two yeast strains, and the glucose and xylose utilization ability of the TSC was better than that of the CSC. Ethanol concentration was obviously increased at high solid loading, but the yield decreased as a result of an increase in the viscosity and inhibitor levels in the fermentation system. Finally, the SSCF of GL-Ethanol-pretreated SCB with mixed S. cerevisiae strains increased ethanol concentration and was an effective conversion process for ethanol production at high solid loading.

Lymphocyte apheresis for chimeric antigen receptor T-cell manufacturing in children and young adults with leukemia and neuroblastoma.

PubMed

Ceppi, Francesco; Rivers, Julie; Annesley, Colleen; Pinto, Navin; Park, Julie R; Lindgren, Catherine; Mgebroff, Stephanie; Linn, Naomi; Delaney, Meghan; Gardner, Rebecca A

2018-06-01

The first step in the production of chimeric antigen receptor T cells is the collection of autologous T cells using apheresis technology. The procedure is technically challenging, because patients often have low leukocyte counts and are heavily pretreated with multiple lines of chemotherapy, marrow transplantation, and/or radiotherapy. Here, we report our experience of collecting T lymphocytes for chimeric antigen receptor T-cell manufacturing in pediatric and young adult patients with leukemia, non-Hodgkin lymphoma, or neuroblastoma. Apheresis procedures were performed on a COBE Spectra machine using the mononuclear cell program, with a collection target of 1 × 10 9 total mononuclear cells per kilogram. Data were collected regarding preapheresis and postapheresis blood counts, apheresis parameters, products, and adverse events. Ninety-nine patients (ages 1.3-25.7 years) and 102 apheresis events were available for analysis. Patients underwent apheresis at a variety of absolute lymphocyte cell counts, with a median absolute lymphocyte count of 944 cells/μL (range, 142-6944 cells/μL). Twenty-two patients (21.6%) had absolute lymphocyte counts less than 500 cells/μL. The mononuclear cell target was obtained in 100% of all apheresis harvests, and chimeric antigen receptor T-cell production was possible from the majority of collections (94%). Mononuclear cell collection efficiency was 65.4%, and T-lymphocyte collection efficiency was 83.4%. Ten patients (9.8%) presented with minor adverse events during the 102 apheresis procedures, with one exception of a severe allergy. Mononuclear cell apheresis for chimeric antigen receptor T-cell therapy is well tolerated and safe, and it is possible to obtain an adequate quantity of CD3+ lymphocytes for chimeric antigen receptor T-cell manufacturing in heavily pretreated patients who have low lymphocyte counts. © 2018 AABB.

One-pot integrated biofuel production using low-cost biocompatible protic ionic liquids

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

Sun, Jian; Konda, N. V. S. N. Murthy; Parthasarathi, Ramakrishnan

The transformation of biomass into liquid fuels is of great importance. Previous work has demonstrated the capability of specific ionic liquids (ILs), such as 1-ethyl-3-methylimidazolium acetate ([C(2)C(1)Im][OAc]) and cholinium lysinate ([Ch][Lys]), to be effective biomass pretreatment solvents. Using these ILs for an integrated biomass-to-biofuel configuration is still challenging due to a significant water-wash related to the high toxicity of [C(2)C(1)Im][OAc] and pH adjustment prior to saccharification for the highly basic [Ch][Lys]. In this work, we demonstrate, for the first time, that a one-pot integrated biofuel production is enabled by a low cost (similar to$1 per kg) and biocompatible protic ILmore » (PIL), ethanolamine acetate, without pH adjustments, water-wash and solid-liquid separations. After pretreatment, the whole slurry is directly used for simultaneous saccharification and fermentation (SSF) with commercial enzyme cocktails and wild type yeast strains, generating 70% of the theoretical ethanol yield (based on switchgrass). The structure-performance relationships of PILs in terms of lignin removal, net basicity, and pH value are systematically studied. A technoeconomic analysis (TEA) revealed that an integrated biorefinery concept based on this PIL process could potentially reduce the minimum ethanol selling price by more than 40% compared to scenarios that require pH adjustment prior to SSF. Improvement of the economic performance will be made by reducing the dilution and enzyme loading during SSF as identified by TEA. This study demonstrates the impact of a biocompatible IL in terms of process optimization and conversion efficiency, and opens up avenues for realizing an IL based efficiently integrated biomass conversion technology.« less

The use of raw and acid-pretreated bivalve mollusk shells to remove metals from aqueous solutions.

PubMed

Liu, Yang; Sun, Changbin; Xu, Jin; Li, Youzhi

2009-08-30

Heavy metal removal from industrial wastewater is not only to protect living organisms in the environment but also to conserve resources such as metals and water by enabling their reuse. To overcome the disadvantage of high cost and secondary pollution by the conventional physico-chemical treatment techniques, environmentally benign and low-cost adsorbents are in demand. In this study, the use of raw and acid-pretreated bivalve mollusk shells (BMSs) to remove metals from aqueous solutions with single or mixed metal was evaluated at different BMSs doses, pH and temperatures in batch shaking experiments in laboratory conditions. When the BMSs were used to treat CuSO(4)x5H(2)O solution, the copper sorption capacities of the raw and acid-pretreated BMSs were approximately 38.93 mg/g and 138.95 mg/g, respectively. The copper removal efficiency (CRE) of the raw BMSs became greatly enhanced with increasing initial pH, reaching 99.51% at the initial pH 5. Conversely, the CRE of the acid-pretreated BMSs was maintained at 99.48-99.52% throughout the pH range of 1-5. Furthermore, the CRE values of the raw and acid-pretreated BMSs were not greatly changed when the temperature was varied from 15 degrees C to 40 degrees C. In addition, the CRE value of the raw BMSs was maintained for 12 cycles of sorption-desorption with a CRE of 98.4% being observed in the final cycle. Finally, when the BMSs were used to treat electroplating wastewater, the removal efficiencies (REs) of the raw BMSs were 99.97%, 98.99% and 87% for Fe, Zn and Cu, respectively, whereas the REs of the acid-pretreated BMSs were 99.98%, 99.43% and 92.13%, respectively. Ion exchange experiments revealed that one of mechanisms for metal sorption by the BMSs from aqueous solution is related to ion exchange, especially between the metal ions in the treated solution and Ca(2+) from BMSs. Infrared absorbance spectra analysis indicated that the acid pretreatment led to occurrence of the groups (i.e. -OH, -NH, C=O and S=O) of negative charge in treated BMSs. Scanning electron microscopy revealed that acid pretreatment enabled the used BMSs to form the flake-shaped structure with smooth surfaces that can supply a better interface for binding metal ions.

Phosphomolybdic acid and ferric iron as efficient electron mediators for coupling biomass pretreatment to produce bioethanol and electricity generation from wheat straw.

PubMed

Ding, Yi; Du, Bo; Zhao, Xuebing; Zhu, J Y; Liu, Dehua

2017-03-01

Phosphomolybdic acid (PMo 12 ) was used as an electron mediator and proton carrier to mediate biomass pretreatment for ethanol production and electricity generation from wheat straw. In the pretreatment, lignin was oxidized anaerobically by PMo 12 with solubilization of a fraction of hemicelluloses, and the PMo 12 was simultaneously reduced. In an external liquid flow cell, the reduced PMo 12 was re-oxidized with generation of electricity. The effects of several factors on pretreatment were investigated for optimizing the conditions. Enzymatic conversion of cellulose and xylan were about 80% and 45%, respectively, after pretreatment of wheat straw with 0.25M PMo 12 , at 95°C for 45min. FeCl 3 was found to be an effective liquid mediator to transfer electrons to air, the terminal electron acceptor. By investigating the effects of various operation parameters and cell structural factors, the highest output power density of about 11mW/cm 2 was obtained for discharging of the reduced PMo 12 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Alkaline-mechanical pretreatment process for enhanced anaerobic digestion of thickened waste activated sludge with a novel crushing device: Performance evaluation and economic analysis.

PubMed

Cho, Si-Kyung; Ju, Hyun-Jun; Lee, Jeong-Gyu; Kim, Sang-Hyoun

2014-08-01

Although various pretreatments have been widely investigated to enhance the anaerobic digestion (AD) of waste activated sludge (WAS), economic feasibility issues have limited real-world applications. The authors examined the performance and economic analysis of an alkaline-mechanical process with a novel mechanical crushing device for thickened WAS pretreatment. The pretreatment at 40gTS/L, pH 13, and 90min reaction time achieved 64% of solubilization efficiency and 8.3 times higher CH4 yield than the control. In addition, a synergistic CH4 yield enhancement was observed when the pretreated and raw WAS were used together as feedstock, and the greatest synergy was observed at a volumetric mixture ratio of 50:50. Economic estimates indicate that up to 22% of WAS treatment costs would be saved by the installation of the suggested process. The experimental results clearly indicate that the alkaline-mechanical process would be highly effective and economically feasible for the AD of thickened WAS. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhancing sludge biodegradability and volatile fatty acid production by tetrakis hydroxymethyl phosphonium sulfate pretreatment.

PubMed

Wu, Qing-Lian; Guo, Wan-Qian; Bao, Xian; Yin, Ren-Li; Feng, Xiao-Chi; Zheng, He-Shan; Luo, Hai-Chao; Ren, Nan-Qi

2017-09-01

A new pretreatment method based on tetrakis hydroxymethyl phosphonium sulfate (THPS) biocide was tried to enhance sludge disintegration, and improved sludge biodegradability and subsequent volatile fatty acid (VFA) production. Sludge activity decreased to less than 10% after 2 days pretreatment using 20mg/g-TSS THPS, which also obviously destroyed EPS and cell membrane, and dissolved more biodegradable substances (48.8%) than raw sludge (19.7%). Moreover, 20mg/g-TSS THPS pretreatment shortened fermentation time to 4days and improved VFA production to 2778mg COD/L (4.35 times than that in control). Therein, the sum of n-butyric, n-valeric and iso-valeric acids unexpectedly accounted for 60.5% of total VFA (only 20.1% of that in control). The more high molecular weight VFAs (C4-C5) than low molecular VFAs (C2-C3) resulted from THPS pretreatment benefited to subsequent medium-chain volatile acids (C6-C12) generation to realize the separation and recovery of organic carbon more efficiently. Copyright © 2017. Published by Elsevier Ltd.

Improvement of anaerobic digestion of sewage sludge in a wastewater treatment plant by means of mechanical and thermal pre-treatments: Performance, energy and economical assessment.

PubMed

Ruffino, Barbara; Campo, Giuseppe; Genon, Giuseppe; Lorenzi, Eugenio; Novarino, Daniel; Scibilia, Gerardo; Zanetti, Mariachiara

2015-01-01

Performances of mechanical and low-temperature (<100°C) thermal pre-treatments were investigated to improve the present efficiency of anaerobic digestion (AD) carried out on waste activated sludge (WAS) in the largest Italian wastewater treatment plant (2,300,000p.e.). Thermal pre-treatments returned disintegration rates of one order of magnitude higher than mechanical ones (about 25% vs. 1.5%). The methane specific production increased by 21% and 31%, with respect to untreated samples, for treatment conditions of respectively 70 and 90°C, 3h. Thermal pre-treatments also decreased WAS viscosity. Preliminary energy and economic assessments demonstrated that a WAS final total solid content of 5% was enough to avoid the employment of auxiliary methane for the pre-treatment at 90°C and the subsequent AD process, provided that all the heat generated was transferred to WAS through heat exchangers. Moreover, the total revenues from sale of the electricity produced from biogas increased by 10% with respect to the present scenario. Copyright © 2014 Elsevier Ltd. All rights reserved.

Combined pretreatment using ozonolysis and ball milling to improve enzymatic saccharification of corn straw.

PubMed

Shi, Feng; Xiang, Heji; Li, Yongfu

2015-03-01

Two clean pretreatments, ozonolysis (OZ) and planetary ball milling (BM) were applied separately and in combination to improve the enzymatic hydrolysis of corn straw. Pretreatment of corn straw by OZ and BM alone improved the enzymatic hydrolysis significantly, primarily through delignification and decrystallization of cellulose, respectively. When combined, OZ-BM and BM-OZ pretreatments made the enzymatic hydrolysis more efficient. The glucose and xylose yield of corn straw treated with OZ for 90 min followed by BM for 8 min (OZ90-BM8) reached to 407.8 and 101.9 mg/g-straw, respectively under cellulase loading of 15 FPU/g-straw, which was fivefold more than that of untreated straw. Under much lower cellulase loading of 1.5 FPU/g-straw, the glucose and xylose yield of treated straw OZ90-BM8 remained at 416.0 and 108.4 mg/g-straw, respectively, while the yield of untreated straw decreased. These findings indicate that the combined OZ-BM can be used as a promising pretreatment for corn straw. Copyright © 2014 Elsevier Ltd. All rights reserved.

Revealing the molecular structural transformation of hardwood and softwood in dilute acid flowthrough pretreatment

DOE PAGES

Zhang, Libing; Pu, Yunqiao; Univ. of Tennessee, Knoxville, TN; ...

2016-10-03

To understand better the intrinsic recalcitrance of lignocellulosic biomass, the main hurdle to its efficient deconstruction, the effects of dilute acid flowthrough pretreatment on the dissolution chemistry of hemicellulose, cellulose, and lignin for both hardwood (e.g., poplar wood) and softwood (e.g., lodgepole pine wood) were investigated at temperatures of 200 to 270 °C and a flow rate of 25 mL/min with 0.05% (w/w) H 2SO 4. Results suggested that the softwood cellulose was more readily degraded into monomeric sugars than that of hardwood under same pretreatment conditions. However, while the hardwood lignin was completely removed into hydrolysate, ~30% of themore » softwood lignin remained as solid residues under identical conditions, which was plausibly caused by vigorous C5-active recondensation reactions (C–C5). As a result, effects of molecular structural features (i.e., lignin molecular weight, cellulose crystallinity, and condensed lignin structures) on the recalcitrance of hardwood and softwood to dilute acid pretreatment were identified for the first time in this study, providing important insights to establish the effective biomass pretreatment.« less

Compositional and structural changes in Phoenix canariensis and Opuntia ficus-indica with pretreatment: Effects on enzymatic hydrolysis and second generation ethanol production.

PubMed

Udeh, Benard Anayo; Erkurt, Emrah Ahmet

2017-01-01

Two different plants namely Phoenix canariensis and Opuntia ficus-indica were used as substrate for reducing sugar generation and ethanol production. Dilute acid, alkaline and steam explosion were used as pretreatment methods in order to depolymerize lignin and/or hemicellulose and recover cellulose. By using alkaline pretreatment with 2.5% NaOH 71.08% for P. canariensis and 74.61% for O. ficus-indica lignin removal and 81.84% for P. canariensis and 72.66% for O. ficus-indica cellulose recovery yields were obtained. Pretreated materials were hydrolyzed by cellulase with high efficiency (87.0% and 84.5% cellulose conversion yields for P. canariensis and O. ficus-indica) and used as substrate for fermentation. Maximum ethanol production of 15.75g/L and 14.71g/L were achieved from P. canariensis and O. ficus-indica respectively. Structural differences were observed by XRD, FTIR and SEM for untreated, pretreated, hydrolyzed and fermented samples and were highly correlated with compositional analysis results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Successive pretreatment and enzymatic saccharification of sugarcane bagasse in a packed bed flow-through column reactor aiming to support biorefineries.

PubMed

Terán-Hilares, R; Reséndiz, A L; Martínez, R T; Silva, S S; Santos, J C

2016-03-01

A packed bed flow-through column reactor (PBFTCR) was used for pretreatment and subsequent enzymatic hydrolysis of sugarcane bagasse (SCB). Alkaline pretreatment was performed at 70 °C for 4h with fresh 0.3M NaOH solution or with liquor recycled from a previous pretreatment batch. Scheffersomyces stipitis NRRL-Y7124 was used for fermentation of sugars released after enzymatic hydrolysis (20 FPU g(-1) of dry SCB). The highest results for lignin removal were 61% and 52%, respectively, observed when using fresh NaOH or the first reuse of the liquor. About 50% of cellulosic and 57% of hemicellulosic fractions of pretreated SCBs were enzymatically hydrolyzed and the maximum ethanol production was 23.4 g L(-1) (ethanol yield of 0.4 gp gs(-1)), with near complete consumption of both pentoses and hexoses present in the hydrolysate during the fermentation. PBFTCR as a new alternative for SCB-biorefineries is presented, mainly considering its simple configuration and efficiency for operating with a high solid:liquid ratio. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ethanol production from bamboo using mild alkaline pre-extraction followed by alkaline hydrogen peroxide pretreatment.

PubMed

Yuan, Zhaoyang; Wen, Yangbing; Kapu, Nuwan Sella

2018-01-01

A sequential two-stage pretreatment process comprising alkaline pre-extraction and alkaline hydrogen peroxide pretreatment (AHP) was investigated to convert bamboo carbohydrates into bioethanol. The results showed that mild alkaline pre-extraction using 8% (w/w) sodium hydroxide (NaOH) at 100°C for 180min followed by AHP pretreatment with 4% (w/w) hydrogen peroxide (H 2 O 2 ) was sufficient to generate a substrate that could be efficiently digested with low enzyme loadings. Moreover, alkali pre-extraction enabled the use of lower H 2 O 2 charges in AHP treatment. Two-stage pretreatment followed by enzymatic hydrolysis with only 9FPU/g cellulose led to the recovery of 87% of the original sugars in the raw feedstock. The use of the pentose-hexose fermenting Saccharomyces cerevisiae SR8u strain enabled the utilization of 95.7% sugars in the hydrolysate to reach 4.6%w/v ethanol titer. The overall process also enabled the recovery of 62.9% lignin and 93.8% silica at high levels of purity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization study on the hydrogen peroxide pretreatment and production of bioethanol from seaweed Ulva prolifera biomass.

PubMed

Li, Yinping; Cui, Jiefen; Zhang, Gaoli; Liu, Zhengkun; Guan, Huashi; Hwang, Hueymin; Aker, Winfred G; Wang, Peng

2016-08-01

The seaweed Ulva prolifera, distributed in inter-tidal zones worldwide, contains a large percentage of cellulosic materials. The technical feasibility of using U. prolifera residue (UPR) obtained after extraction of polysaccharides as a renewable energy resource was investigated. An environment-friendly and economical pretreatment process was conducted using hydrogen peroxide. The hydrogen peroxide pretreatment improved the efficiency of enzymatic hydrolysis. The resulting yield of reducing sugar reached a maximum of 0.42g/g UPR under the optimal pretreatment condition (hydrogen peroxide 0.2%, 50°C, pH 4.0, 12h). The rate of conversion of reducing sugar in the concentrated hydrolysates to bioethanol reached 31.4% by Saccharomyces cerevisiae fermentation, which corresponds to 61.7% of the theoretical maximum yield. Compared with other reported traditional processes on Ulva biomass, the reducing sugar and bioethanol yield are substantially higher. Thus, hydrogen peroxide pretreatment is an effective enhancement of the process of bioethanol production from the seaweed U. prolifera. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ball milling pretreatment of oil palm biomass for enhancing enzymatic hydrolysis.

PubMed

Zakaria, Mohd Rafein; Fujimoto, Shinji; Hirata, Satoshi; Hassan, Mohd Ali

2014-08-01

Oil palm biomass, namely empty fruit bunch and frond fiber, were pretreated using a planetary ball mill. Particle sizes and crystallinity index values of the oil palm biomass were significantly reduced with extended ball mill processing time. The treatment efficiency was evaluated by the generation of glucose, xylose, and total sugar conversion yields from the pretreatment process compared to the amount of sugars from raw materials. Glucose and xylose contents were determined using high-performance liquid chromatography. An increasing trend in glucose and xylose yield as well as total sugar conversion yield was observed with decreasing particle size and crystallinity index. Oil palm frond fiber exhibited the best material yields using ball milling pretreatment with generated glucose, xylose, and total sugar conversion yields of 87.0, 81.6, and 85.4%, respectively. In contrast, oil palm empty fruit bunch afforded glucose and xylose of 70.0 and 82.3%, respectively. The results obtained in this study showed that ball mill-treated oil palm biomass is a suitable pretreatment method for high conversion of glucose and xylose.

Cellulase production using different streams of wheat grain- and wheat straw-based ethanol processes.

PubMed

Gyalai-Korpos, Miklós; Mangel, Réka; Alvira, Pablo; Dienes, Dóra; Ballesteros, Mercedes; Réczey, Kati

2011-07-01

Pretreatment is a necessary step in the biomass-to-ethanol conversion process. The side stream of the pretreatment step is the liquid fraction, also referred to as the hydrolyzate, which arises after the separation of the pretreated solid and is composed of valuable carbohydrates along with compounds that are potentially toxic to microbes (mainly furfural, acetic acid, and formic acid). The aim of our study was to utilize the liquid fraction from steam-exploded wheat straw as a carbon source for cellulase production by Trichoderma reesei RUT C30. Results showed that without detoxification, the fungus failed to utilize any dilution of the hydrolyzate; however, after a two-step detoxification process, it was able to grow on a fourfold dilution of the treated liquid fraction. Supplementation of the fourfold-diluted, treated liquid fraction with washed pretreated wheat straw or ground wheat grain led to enhanced cellulase (filter paper) activity. Produced enzymes were tested in hydrolysis of washed pretreated wheat straw. Supplementation with ground wheat grain provided a more efficient enzyme mixture for the hydrolysis by means of the near-doubled β-glucosidase activity obtained.

Influence of pretreatment techniques on anaerobic digestion of pulp and paper mill sludge: A review.

PubMed

Veluchamy, C; Kalamdhad, Ajay S

2017-12-01

Pulp and paper industry is one of the most polluting, energy and water intensive industries in the world. Produced pulp and paper mill sludge (PPMS) faces a major problem for handling and its management. An anaerobic digestion has become an alternative source. This review provides a detailed summary of anaerobic digestion of PPMS - An overview of the developments and improvement opportunities. This paper explores the different pretreatment methods to enhance biogas production from the PPMS. First, the paper gives an overview of PPMS production, and then it reviews PPMS as a substrate for anaerobic digestion with or without pretreatment. Finally, it discuss the optimal condition and concentration of organic and inorganic compounds required for the anaerobic metabolic activity. Future research should focus on the combination of different pretreatment technologies, relationship between sludge composition, reactor design and its operation, and microbial community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of hydrotropic pretreatment on lignocellulosic biomass.

PubMed

Devendra, Leena P; Kiran Kumar, M; Pandey, Ashok

2016-08-01

The production of cellulosic ethanol from biomass is considered as a promising alternative to fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The presence of lignin poses a significant challenge for obtaining biofuels and bioproducts from biomass. Part of that problem involves understanding fundamental aspects of lignin structure which can provide a pathway for the development of improved technologies for biomass conversion. Hydrotropic pretreatment has several attractive features that make it an attractive alternative for biofuel production. This review highlights the recent developments on hydrotropic pretreatment processes for lignocellulosic biomass on a molecular structure basis for recalcitrance, with emphasis on lignin concerning chemical structure, transformation and recalcitrance. The review also evaluates the hydrotropic delignification in comparison to alkaline delignification on lignin reduction and surface coverage by lignin. The effect of hydrotrope pretreatment on enzymatic saccharification has also been discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of plasma pre-treatment on NaHCO3 desizing of blended sizes on cotton fabrics

NASA Astrophysics Data System (ADS)

Li, Xuming; Qiu, Yiping

2012-03-01

The influence of the He/O2 atmospheric pressure plasma jet pre-treatment on subsequent NaHCO3 desizing of blends of starch phosphate and poly(vinyl alcohol) on cotton fabrics is investigated. Atomic force microscopy and scanning electron microscopy analysis indicate that the surface topography of the samples has significantly changed and the surface roughness increases with an increase in plasma exposure time. X-ray photoelectron spectroscopy analysis shows that a larger number of oxygen-containing polar groups are formed on the sized fabric surface after the plasma treatment. The results of the percent desizing ratio (PDR) indicate that the plasma pretreatment facilitated the blended sizes removal from the cotton fabrics in subsequent NaHCO3 treatment and the PDR increases with prolonging plasma treatment time. The plasma technology is a promising pretreatment for desizing of blended sizes due to dramatically reduced desizing time.

Anaerobic digestion for sustainable development: a natural approach.

PubMed

Gljzen, H J

2002-01-01

After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These 'natural reactors' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic posttreatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery.

Tapping the Bioactivity Potential of Residual Stream from Its Pretreatments May Be a Green Strategy for Low-Cost Bioconversion of Rice Straw.

PubMed

Chen, Xingxuan; Wang, Xiahui; Xue, Yiyun; Zhang, Tian-Ao; Hu, Jiajun; Tsang, Yiu Fai; Gao, Min-Tian

2018-04-16

In this study, it was found that the residual stream from pretreatments of rice straw exhibited high antioxidant activity. Assays based on the Folin-Ciocalteu colorimetric method confirmed that the residual stream contained large amounts of phenolic compounds. Three antioxidant assays were employed to evaluate the bioactivity of the residual stream. Strong linear correlations existed among the release of phenolic compounds, saccharification efficiency, and antioxidant activity. The alkaline pretreatment provided a much greater release of phenolic compounds, especially phenolic acids, compared to the acid pretreatment, and consequently, it had stronger linear correlations than the acid pretreatment. Antibacterial experiments demonstrated the ability of the phenolic compounds in the residual stream to inhibit the growth of microorganisms, indicating the potential of these compounds as antimicrobial agents. To discuss the possibility of the co-production of antimicrobial agents and biofuels/biochemicals, both acid and alkaline pretreatments were optimized using response surface methodology. Under the optimal conditions, 285.7 g glucose could be produced from 1 kg rice straw with the co-production of 3.84 g FA and 6.98 g p-CA after alkaline pretreatment. These results show that the recovery of phenolic compounds from the residual stream could be a green strategy for the low-cost bioconversion of rice straw.

Substrate-Specific Development of Thermophilic Bacterial Consortia by Using Chemically Pretreated Switchgrass.

PubMed

Eichorst, Stephanie A; Joshua, Chijioke; Sathitsuksanoh, Noppadon; Singh, Seema; Simmons, Blake A; Singer, Steven W

2014-12-01

Microbial communities that deconstruct plant biomass have broad relevance in biofuel production and global carbon cycling. Biomass pretreatments reduce plant biomass recalcitrance for increased efficiency of enzymatic hydrolysis. We exploited these chemical pretreatments to study how thermophilic bacterial consortia adapt to deconstruct switchgrass (SG) biomass of various compositions. Microbial communities were adapted to untreated, ammonium fiber expansion (AFEX)-pretreated, and ionic-liquid (IL)-pretreated SG under aerobic, thermophilic conditions using green waste compost as the inoculum to study biomass deconstruction by microbial consortia. After microbial cultivation, gravimetric analysis of the residual biomass demonstrated that both AFEX and IL pretreatment enhanced the deconstruction of the SG biomass approximately 2-fold. Two-dimensional nuclear magnetic resonance (2D-NMR) experiments and acetyl bromide-reactive-lignin analysis indicated that polysaccharide hydrolysis was the dominant process occurring during microbial biomass deconstruction, and lignin remaining in the residual biomass was largely unmodified. Small-subunit (SSU) rRNA gene amplicon libraries revealed that although the dominant taxa across these chemical pretreatments were consistently represented by members of the Firmicutes, the Bacteroidetes, and Deinococcus-Thermus, the abundance of selected operational taxonomic units (OTUs) varied, suggesting adaptations to the different substrates. Combining the observations of differences in the community structure and the chemical and physical structure of the biomass, we hypothesize specific roles for individual community members in biomass deconstruction. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: effect on sludge solubilisation and anaerobic digestion.

PubMed

Tyagi, Vinay Kumar; Lo, Shang-Lien; Rajpal, Ankur

2014-05-01

The effects of alkali-enhanced microwave (MW; 50-175 °C) and ultrasonic (US) (0.75 W/mL, 15-60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW-alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US-alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min-alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)-alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal-alkali treatment condition.

Biomass pyrolysis liquid to citric acid via 2-step bioconversion.

PubMed

Yang, Zhiguang; Bai, Zhihui; Sun, Hongyan; Yu, Zhisheng; Li, Xingxing; Guo, Yifei; Zhang, Hongxun

2014-12-31

The use of fossil carbon sources for fuels and petrochemicals has serious impacts on our environment and is unable to meet the demand in the future. A promising and sustainable alternative is to substitute fossil carbon sources with microbial cell factories converting lignocellulosic biomass into desirable value added products. However, such bioprocesses require tolerance to inhibitory compounds generated during pretreatment of biomass. In this study, the process of sequential two-step bio-conversion of biomass pyrolysis liquid containing levoglucosan (LG) to citric acid without chemical detoxification has been explored, which can greatly improve the utilization efficiency of lignocellulosic biomass. The sequential two-step bio-conversion of corn stover pyrolysis liquid to citric acid has been established. The first step conversion by Phanerochaete chrysosporium (P. chrysosporium) is desirable to decrease the content of other compounds except levoglucosan as a pretreatment for the second conversion. The remaining levoglucosan in solution was further converted into citric acid by Aspergillus niger (A. niger) CBX-209. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology. Under experimental conditions, levoglucosan yield is 12% based on the feedstock and the citric acid yield can reach 82.1% based on the levoglucosan content in the pyrolysis liquid (namely 82.1 g of citric acid per 100 g of levoglucosan). The study shows that P. chrysosporium and A. niger have the potential to be used as production platforms for value-added products from pyrolyzed lignocellulosic biomass. Selected P. chrysosporium is able to decrease the content of other compounds except levoglucosan and levoglucosan can be further converted into citric acid in the residual liquids by A. niger. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology.

Influence of feedstock particle size on lignocellulose conversion--a review.

PubMed

Vidal, Bernardo C; Dien, Bruce S; Ting, K C; Singh, Vijay

2011-08-01

Feedstock particle sizing can impact the economics of cellulosic ethanol commercialization through its effects on conversion yield and energy cost. Past studies demonstrated that particle size influences biomass enzyme digestibility to a limited extent. Physical size reduction was able to increase conversion rates to maximum of ≈ 50%, whereas chemical modification achieved conversions of >70% regardless of biomass particle size. This suggests that (1) mechanical pretreatment by itself is insufficient to attain economically feasible biomass conversion, and, therefore, (2) necessary particle sizing needs to be determined in the context of thermochemical pretreatment employed for lignocellulose conversion. Studies of thermochemical pretreatments that have taken into account particle size as a factor have exhibited a wide range of maximal sizes (i.e., particle sizes below which no increase in pretreatment effectiveness, measured in terms of the enzymatic conversion resulting from the pretreatment, were observed) from <0.15 to 50 mm. Maximal sizes as defined above were dependent on the pretreatment employed, with maximal size range decreasing as follows: steam explosion > liquid hot water > dilute acid and base pretreatments. Maximal sizes also appeared dependent on feedstock, with herbaceous or grassy biomass exhibiting lower maximal size range (<3 mm) than woody biomass (>3 mm). Such trends, considered alongside the intensive energy requirement of size reduction processes, warrant a more systematic study of particle size effects across different pretreatment technologies and feedstock, as a requisite for optimizing the feedstock supply system.

Effects of Oligosaccharides Isolated From Pinewood Hot Water Pre-hydrolyzates on Recombinant Cellulases

PubMed Central

Fang, Hong; Kandhola, Gurshagan; Rajan, Kalavathy; Djioleu, Angele; Carrier, Danielle Julie; Hood, Kendall R.; Hood, Elizabeth E.

2018-01-01

Loblolly pine residues have enormous potential to be the raw material for advanced biofuel production due to extensive sources and high cellulose content. Hot water (HW) pretreatment, while being a relatively economical and clean technology for the deconstruction of lignocellulosic biomass, could also inhibit the ensuing enzymatic hydrolysis process because of the production of inhibitors. In this study, we investigated the effect of oligosaccharide fractions purified from HW pre-hydrolyzate of pinewood using centrifugal partition chromatography (CPC) on three recombinant cellulolytic enzymes (E1, CBHI and CBHII), which were expressed in the transgenic corn grain system. The efficiency of recombinant enzymes was measured using either a 4-methylumbelliferyl-β-D-cellobioside (MUC) or a cellulose-dinitrosalicylic acid (DNS) assay system. The results showed that HW pre-hydrolyzate CPC fractions contain phenolics, furans, and monomeric and oligomeric sugars. Among CPC fractions, oligomers composed of xylan, galactan, and mannan were inhibitory to the three recombinant enzymes and to the commercial cellulase cocktail, reducing the enzymatic efficiency to as low as 10%. PMID:29868572

300 GPM Solids Removal System A True Replacement for Back Flushable Powdered Filter Systems - 13607

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

Ping, Mark R.; Lewis, Mark

2013-07-01

The EnergySolutions Solids Removal System (SRS) utilizes stainless steel cross-flow ultra-filtration (XUF) technology which allows it to reliably remove suspended solids greater than one (1) micron from liquid radwaste streams. The SRS is designed as a pre-treatment step for solids separation prior to processing through other technologies such as Ion Exchange Resin (IER) and/or Reverse Osmosis (RO), etc. Utilizing this pre-treatment approach ensures successful production of reactor grade water while 1) decreasing the amount of radioactive water being discharged to the environment; and 2) decreasing the amount of radioactive waste that must ultimately be disposed of due to the eliminationmore » of spent powdered filter media. (authors)« less

Preliminary survey of separations technology applicable to the pretreatment of Hanford tank waste (1992--1993)

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

Lawrence, W.E.; Kurath, D.E.

1994-04-01

The US Department of Energy has established the Tank Waste Remediation System (TWRS) to manage and dispose of radioactive wastes stored at the Hanford Site. Within this program are evaluations of pretreatment system alternatives through literature reviews. The information in this report was collected as part of this project at Pacific Northwest Laboratory. A preliminary survey of literature on separations recently entered into the Hanford electronic databases (1992--1993) that have the potential for pretreatment of Hanford tank waste was conducted. Separation processes that can assist in the removal of actinides (uranium, plutonium, americium), lanthanides, barium, {sup 137}Cs, {sup 90}Sr,{sup 129more » }I, {sup 63}Ni, and {sup 99}Tc were evaluated. Separation processes of interest were identified through literature searches, journal reviews, and participation in separation technology conferences. This report contains brief descriptions of the potential separation processes, the extent and/or selectivity of the separation, the experimental conditions, and observations. Information was collected on both national and international separation studies to provide a global perspective on recent research efforts.« less

Effects of thermal pretreatment and catalyst on biomass gasification efficiency and syngas composition

DOE PAGES

Cheah, Singfoong; Jablonski, Whitney S.; Olstad, Jessica L.; ...

2016-09-16

This work explores the combined effects of thermal pretreatment and using a catalyst in situ on gasification carbon conversion efficiency, as well as product gas and tar content and compositions. To compare the effects of thermal pretreatment, pelletized and ground oak with three different levels of thermal pretreatment were gasified in a fluidized bed reactor. The pretreatments applied to the oak were (1) pelletization, (2) drying at 180 °C in air, and (3) torrefaction at 270 °C in nitrogen. The oak dried at 180 °C produced syngas of similar quality and approximately the same amount of char as untreated oak.more » Torrefaction at 270 °C resulted in syngas with a higher hydrogen to CO ratio, lower methane, and less than half of the total tar -- all of which are desirable properties in terms of product gas quality. However, the oak torrefied at 270 °C also produced more than two times the amount of char as the untreated, pelletized oak. To determine the effect of catalyst, a series of experiments were conducted using olivine impregnated with nickel and cerium as the fluidized bed material in the gasifier. These tests showed that modified olivine can improve hydrogen production and reduce methane and tar levels in the syngas. The result was observed for both treated and untreated oak; although the effect was more substantial for untreated oak, for which the use of modified olivine reduced tar concentrations in the product gas by 60%, with a larger reduction in heavier tars than lighter tars. Furthermore, this result is important because reduction in heavier tar plays a more important role in benefitting downstream operations.« less

Effect of mild-temperature H2O2 oxidation on solubilization and anaerobic digestion of waste activated sludge.

PubMed

Junga, Heejung; Kim, Jaai; Lee, Seungyong; Lee, Changsoo

2014-08-01

Efficient sludge management is among the most challenging issues in wastewater treatment today, and anaerobic digestion is regarded as a viable solution. Mild-temperature H202 oxidation was examined for enhanced solubilization and biogas production of waste activated sludge (WAS). The effects of pretreatment factors (i.e. temperature and H202 concentration) on the degree of WAS disintegration (DD) and biogas yield (BY) were assessed by response surface analysis within the design space of 60-90 degrees C and 0-200mM H202. Significant sludge disintegration (up to 23.0% DD) and visibly enhanced BY (up to 26.9%) were shown in the pretreatment trials. Two response surface models to describe how DD and BY respond to changes in the pretreatment conditions were successfully constructed (R2 > 0.95, p < 0.05). The models showed totally different response surface shapes, indicating the DD and BY were influenced by pretreatment conditions in very different ways. DD was dominantly affected by temperature and showed higher model responses at the high-temperature region, while the BY response peaked in the low-temperature and mid-level H2O2 region. This observation implies that the enhanced solubilization of WAS was not directly translated into an increase in biogas production. Our results showed that WAS can be efficiently disintegrated by H202 oxidation under mild-temperature conditions for enhanced anaerobic digestibility. Within the explored region of pretreatment conditions, the maximum BY was estimated to be 82.1 mL/gCODadded (32.8% greater than the untreated control) at (60.0 degrees C, 74.2 mM H2O2).

Fast screening of Bifidobacterium longum sublethal stress conditions in a novel two-stage continuous culture strategy.

PubMed

Mozzetti, V; Grattepanche, F; Berger, B; Rezzonico, E; Arigoni, F; Lacroix, C

2013-06-01

A central issue in the application of probiotics as food additives is their fastidious production and their sensitivity to many environmental stresses. The importance of inducible cell-protective mechanisms triggered by application of sublethal stresses for survival under stress conditions has been demonstrated. Continuous cultures could be a suitable and more efficient method to test stress factors on one culture instead of several repeated batch cultures. In this study, the application of a two-stage continuous culture of Bifidobacterium longum NCC2705 was investigated. The first reactor was operated under fixed conditions at 37 °C and pH 6.0 and used to produce cells with controlled physiology, mimicking cells in the late exponential growth phase. Stress pretreatment combinations of pH (6.0, 5.0 and 4.0), temperature (37, 45 and 47 °C) and NaCl (0, 5 and 10%) were tested in the second reactor. Of all tested combinations, only those of pH 4.0 significantly decreased cell viability in the second reactor compared to control conditions (37 °C, pH 6.0, 0% NaCl) and, therefore, could not be considered as sublethal stresses. Pretreatments with 5 or 10% NaCl had a negative effect on cell viability after gastric lethal stress. A significant improvement in cell resistance to heat lethal stress (56 °C, 5 min) was observed for cells pretreated at 47 °C. In contrast, heat pretreatment negatively affected cell viability after freeze drying and osmotic lethal stresses. The two-stage continuous culture allowed for efficient screening of several stress pretreatments during the same experiment with up to four different conditions tested per day. Optimal sublethal stress conditions can also be applied for producing cells with traditional batch cultures.

Review of technologies for the pretreatment of retrieved single-shell tank waste at Hanford

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

Gerber, M.A.

1992-08-01

The purpose of the study reported here was to identify and evaluate innovative processes that could be used to pretreat mixed waste retrieved from the 149 single-shell tanks (SSTs) on the US Department of Energy's (DOE) Hanford site. The information was collected as part of the Single Shell Tank Waste Treatment project at Pacific Northwest Laboratory (PNL). The project is being conducted for Westinghouse Hanford Company under their SST Disposal Program.