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Lignocellulosic enzymatic hydrolysis

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https://www.readbyqxmd.com/read/27913169/liquid-nitrogen-pretreatment-of-eucalyptus-sawdust-and-rice-hull-for-enhanced-enzymatic-saccharification
#1
Rafael Castoldi, Vanesa G Correa, Gutierrez Rodrigues de Morais, Cristina G M de Souza, Adelar Bracht, Rosely A Peralta, Regina F Peralta-Muniz Moreira, Rosane M Peralta
In this work, liquid nitrogen was used for the first time in the pretreatment of plant biomasses for purposes of enzymatic saccharification. After treatment (cryocrushing), the initial rates of the enzymatic hydrolysis of eucalyptus sawdust and rice hull were increased more than ten-fold. Cryocrushing did not modify significantly the contents of cellulose, hemicellulose and lignin in both eucalyptus sawdust and rice hulls. However, substantial disorganization of the lignocellulosic materials in consequence of the pretreatment could be observed by electron microscopy...
November 25, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27905534/pore-scale-dynamics-of-enzyme-adsorption-swelling-and-reactive-dissolution-determine-sugar-yield-in-hemicellulose-hydrolysis-for-biofuel-production
#2
Sajal Kanti Dutta, Saikat Chakraborty
Hemicelluloses are the earth's second most abundant structural polymers, found in lignocellulosic biomass. Efficient enzymatic depolymerization of xylans by cleaving their β-(1 → 4)-glycosidic bonds to produce soluble sugars is instrumental to the cost-effective production of liquid biofuels. Here we show that the multi-scale two-phase process of enzymatic hydrolysis of amorphous hemicelluloses is dominated by its smallest scale-the pores. In the crucial first five hours, two to fourfold swelling of the xylan particles allow the enzymes to enter the pores and undergo rapid non-equilibrium adsorption on the pore surface before they hydrolyze the solid polymers, albeit non-competitively inhibited by the products xylose and xylobiose...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27898203/biorefining-of-lignocellulosic-feedstock-by-a-modified-ammonia-fiber-expansion-pretreatment-and-enzymatic-hydrolysis-for-production-of-fermentable-sugars
#3
Birgit Kamm, Sebastian Leiß, Petra Schönicke, Matthias Bierbaum
Wheat straw was pretreated and afterwards enzymatically hydrolyzed using a modified ammonia fiber expansion (AFEX) process under different reaction conditions to produce fermentable sugars. Instead of liquid ammonia, aqueous ammonia (25 % w/v) was used to test its influence on the sugar concentration and yield of the sugars. It is shown that a protein extraction after the pretreatment can distinctly improve the result obtained for the enzymatic hydrolysis. This modified AFEX process using aqueous ammonia represents a simpler and less expensive variant of the AFEX process usually described in literature...
November 29, 2016: ChemSusChem
https://www.readbyqxmd.com/read/27895707/fungal-fermentation-on-anaerobic-digestate-for-lipid-based-biofuel-production
#4
Yuan Zhong, Zhiguo Liu, Christine Isaguirre, Yan Liu, Wei Liao
BACKGROUND: Anaerobic digestate is the effluent from anaerobic digestion of organic wastes. It contains a significant amount of nutrients and lignocellulosic materials, even though anaerobic digestion consumed a large portion of organic matters in the wastes. Utilizing the nutrients and lignocellulosic materials in the digestate is critical to significantly improve efficiency of anaerobic digestion technology and generate value-added chemical and fuel products from the organic wastes...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27888662/toward-high-solids-loading-process-for-lignocellulosic-biofuel-production-at-a-low-cost
#5
Mingjie Jin, Cory Sarks, Bryan D Bals, Nick Posawatz, Christa Gunawan, Bruce E Dale, Venkatesh Balan
High solids loadings (>18 wt%) in enzymatic hydrolysis and fermentation are desired for lignocellulosic biofuel production at a high titer and low cost. However, sugar conversion and ethanol yield decrease with increasing solids loading. The factor(s) limiting sugar conversion at high solids loading is not clearly understood. In the present study, we investigated the effect of solids loading on simultaneous saccharification and co-fermentation (SSCF) of AFEX(TM) (ammonia fiber expansion) pretreated corn stover for ethanol production using a xylose fermenting strain Saccharomyces cerevisiae 424A(LNH-ST)...
November 26, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27875764/biological-pretreatment-of-sugarcane-bagasse-with-basidiomycetes-producing-varied-patterns-of-biodegradation
#6
Angela da Silva Machado, André Ferraz
This work evaluated sugarcane bagasse pretreatment with wood-decay fungi, producing varied patterns of biodegradation. The overall mass balance of sugars released after pretreatment and enzymatic hydrolysis indicated that a selective white-rot was necessary to provide glucose yields similar to the ones observed from leading physico-chemical pretreatment technologies. The selective white-rot Ceriporiopsis subvermispora was selective for lignin degradation in the lignocellulosic material, preserved most of the glucan fraction, and increased the cellulose digestibility of biotreated material...
November 15, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27866803/effect-of-hydrothermal-pretreatment-on-miscanthus-anaerobic-digestion
#7
Xuefei Zhou, Qi Li, Yalei Zhang, Yu Gu
Miscanthus is a promising source of bioenergy with high lignocellulose content. This paper studied the effect of hydrothermal pretreatment on Miscanthus biogas production. Different pretreatment temperature from 125 to 200°C was tested. After pretreatment, hemicellulose was partially removed and this led to a change in cellulose accessibility. Enzymatic hydrolysis was used to examine the digestibility of different samples. There was no obvious enhancement in low temperature (125 and 150°C) conditions. According to the results, 200°C hydrothermal pretreatment was the optimal condition saving 50% on the digestion time and increasing glucose production 13...
October 31, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27847814/isoprene-production-on-enzymatic-hydrolysate-of-peanut-hull-using-different-pretreatment-methods
#8
Sumeng Wang, Ruichao Li, Xiaohua Yi, Tigao Fang, Jianming Yang, Hyeun-Jong Bae
The present study is about the use of peanut hull for isoprene production. In this study, two pretreatment methods, hydrogen peroxide-acetic acid (HPAC) and popping, were employed prior to enzymatic hydrolysis, which could destroy the lignocellulosic structure and accordingly improve the efficiency of enzymatic hydrolysis. It is proven that the isoprene production on enzymatic hydrolysate with HPAC pretreatment is about 1.9-fold higher than that of popping pretreatment. Moreover, through High Performance Liquid Chromatography (HPLC) analysis, the amount and category of inhibitors such as formic acid, acetic acid, and HMF were assayed and were varied in different enzymatic hydrolysates, which may be the reason leading to a decrease in isoprene production during fermentation...
2016: BioMed Research International
https://www.readbyqxmd.com/read/27833657/flowthrough-pretreatment-with-very-dilute-acid-provides-insights-into-high-lignin-contribution-to-biomass-recalcitrance
#9
Samarthya Bhagia, Hongjia Li, Xiadi Gao, Rajeev Kumar, Charles E Wyman
BACKGROUND: Flowthrough pretreatment is capable of removing much higher quantities of hemicellulose and lignin from lignocellulosic biomass than batch pretreatment performed at otherwise similar conditions. Comparison of these two pretreatment configurations for sugar yields and lignin removal can provide insights into lignocellulosic biomass deconstruction. Therefore, we applied liquid hot water (LHW) and extremely dilute acid (EDA, 0.05%) flowthrough and batch pretreatments of poplar at two temperatures and the same pretreatment severity for the solids...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27833656/metagenomic-and-metaproteomic-analyses-of-a-corn-stover-adapted-microbial-consortium-emsd5-reveal-its-taxonomic-and-enzymatic-basis-for-degrading-lignocellulose
#10
Ning Zhu, Jinshui Yang, Lei Ji, Jiawen Liu, Yi Yang, Hongli Yuan
BACKGROUND: Microbial consortia represent promising candidates for aiding in the development of plant biomass conversion strategies for biofuel production. However, the interaction between different community members and the dynamics of enzyme complements during the lignocellulose deconstruction process remain poorly understood. We present here a comprehensive study on the community structure and enzyme systems of a lignocellulolytic microbial consortium EMSD5 during growth on corn stover, using metagenome sequencing in combination with quantitative metaproteomics...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27833653/valorization-of-lignin-and-cellulose-in-acid-steam-exploded-corn-stover-by-a-moderate-alkaline-ethanol-post-treatment-based-on-an-integrated-biorefinery-concept
#11
Sheng Yang, Yue Zhang, Wen Yue, Wei Wang, Yun-Yan Wang, Tong-Qi Yuan, Run-Cang Sun
BACKGROUND: Due to the unsustainable consumption of fossil resources, great efforts have been made to convert lignocellulose into bioethanol and commodity organic compounds through biological methods. The conversion of cellulose is impeded by the compactness of plant cell wall matrix and crystalline structure of the native cellulose. Therefore, appropriate pretreatment and even post-treatment are indispensable to overcome this problem. Additionally, an adequate utilization of coproduct lignin will be important for improving the economic viability of modern biorefinery industries...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27816348/exploring-crystalline-structural-variations-of-cellulose-during-alkaline-pretreatment-for-enhanced-enzymatic-hydrolysis
#12
Zhe Ling, Sheng Chen, Xun Zhang, Feng Xu
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)...
October 22, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27802565/biomass-water-interactions-correlate-to-recalcitrance-and-are-intensified-by-pretreatment-an-investigation-of-water-constraint-and-retention-in-pretreated-spruce-using-low-field-nmr-and-water-retention-value-techniques
#13
Noah D Weiss, Lisbeth Garbrecht Thygesen, Christian Roslander, Keith Gourlay, Claus Felby
The underlying mechanisms of the recalcitrance of biomass to enzymatic deconstruction are still not fully understood, and this hampers the development of biomass based fuels and chemicals. With water being necessary for most biological processes, it is suggested that interactions between water and biomass may be key to understanding and controlling biomass recalcitrance. This study investigates the correlation between biomass recalcitrance and the constraint and retention of water by the biomass, using SO2 pretreated spruce, a common feedstock for lignocellulosic biofuel production, as a substrate to evaluate this relationship...
November 1, 2016: Biotechnology Progress
https://www.readbyqxmd.com/read/27777624/process-design-of-sscf-for-ethanol-production-from-steam-pretreated-acetic-acid-impregnated-wheat-straw
#14
Pia-Maria Bondesson, Mats Galbe
BACKGROUND: Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27777619/synergetic-effect-of-dilute-acid-and-alkali-treatments-on-fractional-application-of-rice-straw
#15
Shaolong Sun, Weijing Chen, Jianing Tang, Bing Wang, Xuefei Cao, Shaoni Sun, Run-Cang Sun
BACKGROUND: The biorefinery based on an effective and economical process is to fractionate the three primary constituents (cellulose, hemicelluloses, and lignin) from lignocellulosic biomass, in which the constituents can be respectively converted into high-value-added products. In this study, a successive treatment with dilute acid (0.25-1.0 % aqueous H2SO4, 100-150 °C, 0.5-3.0 h) and alkali (1.5 % aqueous NaOH, 80 °C, 3 h) was performed to produce xylooligosaccharides (XOS), high-purity lignin, and cellulose-rich substrates to produce glucose for ethanol production from rice straw (RS)...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27771527/effect-of-bisulfite-treatment-on-composition-structure-enzymatic-hydrolysis-and-cellulase-adsorption-profiles-of-sugarcane-bagasse
#16
Z J Liu, T Q Lan, H Li, X Gao, H Zhang
The effect of sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) on composition, structure, enzymatic hydrolysis and cellulase adsorption profiles of sugarcane bagasse (SCB) was investigated. SPORL gave a higher SCB hydrolysis yield (85.33%) compared to dilute acid pretreatment (DA) (64.39%). The SEM pictures showed that SPORL SCB structure became more disordered and looser, suggesting SPORL SCB was more accessible to cellulase. The zeta potential of SPORL SCB suspension (-21.89mV) was significantly different from that of DA SCB (-12...
October 15, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27766117/assessing-pretreatment-reactor-scaling-through-empirical-analysis
#17
James J Lischeske, Nathan C Crawford, Erik Kuhn, Nicholas J Nagle, Daniel J Schell, Melvin P Tucker, James D McMillan, Edward J Wolfrum
BACKGROUND: Pretreatment is a critical step in the biochemical conversion of lignocellulosic biomass to fuels and chemicals. Due to the complexity of the physicochemical transformations involved, predictively scaling up technology from bench- to pilot-scale is difficult. This study examines how pretreatment effectiveness under nominally similar reaction conditions is influenced by pretreatment reactor design and scale using four different pretreatment reaction systems ranging from a 3 g batch reactor to a 10 dry-ton/days continuous reactor...
2016: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/27763527/simultaneous-saccharification-and-fermentation-of-sugar-beet-pulp-with-mixed-bacterial-cultures-for-lactic-acid-and-propylene-glycol-production
#18
Joanna Berlowska, Weronika Cieciura, Sebastian Borowski, Marta Dudkiewicz, Michal Binczarski, Izabela Witonska, Anna Otlewska, Dorota Kregiel
Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles...
October 17, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27761655/alkaline-assisted-screw-press-pretreatment-affecting-enzymatic-hydrolysis-of-wheat-straw
#19
Qingqi Yan, Yumei Wang, Wawat Rodiahwati, Antje Spiess, Michael Modigell
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...
October 19, 2016: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/27714444/green-methods-of-lignocellulose-pretreatment-for-biorefinery-development
#20
Laura Capolupo, Vincenza Faraco
Lignocellulosic biomass is the most abundant, low-cost, bio-renewable resource that holds enormous importance as alternative source for production of biofuels and other biochemicals that can be utilized as building blocks for production of new materials. Enzymatic hydrolysis is an essential step involved in the bioconversion of lignocellulose to produce fermentable monosaccharides. However, to allow the enzymatic hydrolysis, a pretreatment step is needed in order to remove the lignin barrier and break down the crystalline structure of cellulose...
October 6, 2016: Applied Microbiology and Biotechnology
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