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Lignocellulosic enzymatic hydrolysis

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
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
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
María Ángeles Bermúdez Alcántara, Justyna Dobruchowska, Parastoo Azadi, Bruno Díez García, Fernando P Molina-Heredia, Francisco Manuel Reyes-Sosa
BACKGROUND: To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis...
2016: Biotechnology for Biofuels
Yang Xing, Lingxi Bu, Tianran Zheng, Shijie Liu, Jianxin Jiang
Co-production of glucose, furfural and other green materials based on a lignocellulosic biorefinery is a promising way to realize the commercial application of corncob residues. An effective process was developed for glucose production using low temperature bisulfite pretreatment and high-solids enzymatic hydrolysis. Corncob residues from furfural production (FRs) were pretreated with 0.1g NaHSO3/g dry substrate at 100°C for 3h. Lignin was sulfonated and sulfonic groups were produced during pretreatment, which resulted in decreasing the zeta potential of the samples...
December 2016: Bioresource Technology
N Pérez-Rodríguez, D García-Bernet, J M Domínguez
Due to their lignocellulosic nature, corn cob and vine trimming shoots (VTS) could be valorized by anaerobic digestion for biogas production. To enhance the digestibility of substrates, pretreatments of lignocellulosic materials are recommended. The effect of enzymatic hydrolysis, ultrasounds pretreatments (US) and the combination of both was assayed in lignocellulosic composition, methane, and biogas yields. The pretreatments leaded to a reduction in lignin and an increase in neutral detergent soluble compounds making corn cob and VTS more amendable for biogas conversion...
December 2016: Bioresource Technology
Camila Florencio, Alberto C Badino, Cristiane S Farinas
Addition of surfactants, polymers, and non-catalytic proteins can improve the enzymatic hydrolysis of lignocellulosic materials by blocking the exposed lignin surfaces, but involves extra expense. Here, soybean protein, one of the cheapest proteins available, was evaluated as an alternative additive for the enzymatic hydrolysis of pretreated sugarcane bagasse. The effect of the enzyme source was investigated using enzymatic cocktails from A. niger and T. reesei cultivated under solid-state, submerged, and sequential fermentation...
December 2016: Bioresource Technology
G Brodeur, J Telotte, J J Stickel, S Ramakrishnan
A two stage pretreatment approach for biomass is developed in the current work in which dilute acid (DA) pretreatment is followed by a solvent based pretreatment (N-methyl morpholine N oxide - NMMO). When the combined pretreatment (DAWNT) is applied to sugarcane bagasse and corn stover, the rates of hydrolysis and overall yields (>90%) are seen to dramatically improve and under certain conditions 48h can be taken off the time of hydrolysis with the additional NMMO step to reach similar conversions. DAWNT shows a 2-fold increase in characteristic rates and also fractionates different components of biomass - DA treatment removes the hemicellulose while the remaining cellulose is broken down by enzymatic hydrolysis after NMMO treatment to simple sugars...
November 2016: Bioresource Technology
Johanna Méndez Arias, Anelize de Oliveira Moraes, Luiz Felipe Amarante Modesto, Aline Machado de Castro, Nei Pereira
Poly(ethylene glycol) (PEG 4000) and bovine serum albumin (BSA) were investigated with the purpose of evaluating their influence on enzymatic hydrolysis of sugarcane bagasse. Effects of these supplements were assayed for different enzymatic cocktails (Trichoderma harzianum and Penicillium funiculosum) that acted on lignocellulosic material submitted to different pretreatment methods with varying solid (25 and 100 g/L) and protein (7.5 and 20 mg/g cellulose) loadings. The highest levels of glucose release were achieved using partially delignified cellulignin as substrate, along with the T...
September 8, 2016: Applied Biochemistry and Biotechnology
Lital Davidi, Sarah Moraïs, Lior Artzi, Doriv Knop, Yitzhak Hadar, Yonathan Arfi, Edward A Bayer
Efficient breakdown of lignocellulose polymers into simple molecules is a key technological bottleneck limiting the production of plant-derived biofuels and chemicals. In nature, plant biomass degradation is achieved by the action of a wide range of microbial enzymes. In aerobic microorganisms, these enzymes are secreted as discrete elements in contrast to certain anaerobic bacteria, where they are assembled into large multienzyme complexes termed cellulosomes. These complexes allow for very efficient hydrolysis of cellulose and hemicellulose due to the spatial proximity of synergistically acting enzymes and to the limited diffusion of the enzymes and their products...
September 27, 2016: Proceedings of the National Academy of Sciences of the United States of America
Christian P Kubicek, Eva M Kubicek
Lignocellulosic plant biomass is the world's most abundant carbon source and has consequently attracted attention as a renewable resource for production of biofuels and commodity chemicals. Still the process is economically not fit enough to compete with then use of fossil resources, and the costs associated with enzymatic hydrolysis and product recovery are the major obstacle. The discovery of the role of non-hydrolytic enzymes in lignocellulose hydrolysis has recently contributed significant improvements to hydrolysis but also added new challenges to the biomass to ethanol process...
September 7, 2016: Current Opinion in Chemical Biology
Man Bo Lee, Jae Yoon Kim, Yong Weon Seo
BACKGROUND: Brachypodium distachyon (L.) Beauv. is a monocotyledonous model plant that has been studied to understand a range of biological phenomena for lignocellulosic bioethanol feedstocks and other cereal crops. The lignin makes its cell walls recalcitrant to saccharification, constituting the main barrier to lignocellulosic bioethanol production. In this study, lignin-deficient mutants of B. distachyon induced by chronic radiation were selected and the effects of the mutants on fermentable glucose production were identified...
October 5, 2016: Journal of the Science of Food and Agriculture
Sara Gómez, Asia M Payne, Martin Savko, Gavin C Fox, William E Shepard, Francisco J Fernandez, M Cristina Vega
BACKGROUND: Replacing fossil fuel with renewable sources such as lignocellulosic biomass is currently a promising alternative for obtaining biofuel and for fighting against the consequences of climate change. However, the recalcitrant structure of lignocellulosic biomass residues constitutes a major limitation for its widespread use in industry. The efficient hydrolysis of lignocellulosic materials requires the complementary action of multiple enzymes including xylanases and β-xylosidases, which are responsible for cleaving exo- and endoxylan linkages, that release oligocarbohydrates that can be further processed by other enzymes...
2016: Biotechnology for Biofuels
Gerdt Müller, Dayanand Chandrahas Kalyani, Svein Jarle Horn
Enzymatic catalysis plays a key role in the conversion of lignocellulosic biomass to fuels and chemicals such as lactic acid. In the last decade, the efficiency of commercial cellulase cocktails has increased significantly, in part due to the inclusion of lytic polysaccharide monooxygenases (LPMOs). However, the LPMOs' need for molecular oxygen to break down cellulose demands reinvestigations of process conditions. In this study, we evaluate the efficiency of lactic acid production from steam-exploded birch using an LPMO-containing cellulase cocktail in combination with lactic acid bacteria, investigating both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF)...
September 6, 2016: Biotechnology and Bioengineering
Neil Conroy, Ian Tebble, Gary J Lye
BACKGROUND: Cellulosic bioethanol processes involve several steps, all of which require experimental optimisation. A significant aid to this research would be a validated ultra scale-down (USD) model that could be used to perform rapid, wide ranging screening and optimisation experiments using limited materials under process relevant conditions. RESULTS: In this work, the use of 30 mL shaken conical tubes as a USD model for an enzymatic hydrolysis process is established...
November 2015: Journal of Chemical Technology and Biotechnology
Haiyan Zhang, Longjian Chen, Minsheng Lu, Junbao Li, Lujia Han
BACKGROUND: Ultrafine grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by ultrafine grinding. RESULTS: The ultrafine grinding pretreatment was executed on corn stover...
2016: Biotechnology for Biofuels
Manuel Eibinger, Karin Sigl, Jürgen Sattelkow, Thomas Ganner, Jonas Ramoni, Bernhard Seiboth, Harald Plank, Bernd Nidetzky
BACKGROUND: Through binding to cellulose, expansin-like proteins are thought to loosen the structural order of crystalline surface material, thus making it more accessible for degradation by hydrolytic enzymes. Swollenin SWO1 is the major expansin-like protein from the fungus Trichoderma reesei. Here, we have performed a detailed characterization of a recombinant native form of SWO1 with respect to its possible auxiliary role in the enzymatic saccharification of lignocellulosic substrates...
2016: Biotechnology for Biofuels
Margareth Øverland, Anders Skrede
The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation...
August 25, 2016: Journal of the Science of Food and Agriculture
Han-Yin Li, Xue Chen, Chen-Zhou Wang, Shao-Ni Sun, Run-Cang Sun
BACKGROUND: The biomass recalcitrance resulting from its chemical compositions and physical structures impedes the conversion of biomass into fermentable sugars. Pretreatment is a necessary procedure to increase the cellulase accessibility for bioconversion of lignocelluloses into bioethanol. Alternatively, ionic liquids, a series of promising solvents, provide unique opportunities for pretreating a wide range of lignocellulosic materials. In this study, a two-step treatment including ionic liquids pretreatment and successive alkali fractionations was performed on Eucalyptus to achieve a high enzymatic digestibility...
2016: Biotechnology for Biofuels
Aymerick Eudes, Nanxia Zhao, Noppadon Sathitsuksanoh, Edward E K Baidoo, Jeemeng Lao, George Wang, Sasha Yogiswara, Taek Soon Lee, Seema Singh, Jenny C Mortimer, Jay D Keasling, Blake A Simmons, Dominique Loqué
Plant biomass is a large source of fermentable sugars for the synthesis of bioproducts using engineered microbes. These sugars are stored as cell wall polymers, mainly cellulose and hemicellulose, and are embedded with lignin, which makes their enzymatic hydrolysis challenging. One of the strategies to reduce cell wall recalcitrance is the modification of lignin content and composition. Lignin is a phenolic polymer of methylated aromatic alcohols and its synthesis in tissues developing secondary cell walls is a significant sink for the consumption of the methyl donor S-adenosylmethionine (AdoMet)...
2016: Frontiers in Bioengineering and Biotechnology
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