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Lignocellulosic enzymatic hydrolysis

Ariane S S Pinto, Marcelo P A Ribeiro, Cristiane S Farinas
One of the main challenges of second generation (2G) ethanol production is the high quantities of phenolic compounds and furan derivatives generated in the pretreatment of the lignocellulosic biomass, which inhibit the enzymatic hydrolysis and fermentation steps. Fast monitoring of these inhibitory compounds could provide better control of the pretreatment, hydrolysis, and fermentation processes by enabling the implementation of strategic process control actions. We investigated the feasibility of monitoring these inhibitory compounds by ultraviolet-visible (UV-Vis) spectroscopy associated with partial least squares (PLS) regression...
November 14, 2017: Bioresource Technology
Luana Parras Meleiro, Sibeli Carli, Raquel Fonseca-Maldonado, Marcela da Silva Torricillas, Ana Lucia Ribeiro Latorre Zimbardi, Richard John Ward, João Atílio Jorge, Rosa Prazeres Melo Furriel
Enzyme reaction products and by-products from pretreatment steps can inhibit endoglucanases and are major factors limiting the efficiency of enzymatic lignocellulosic biomass hydrolysis. The gene encoding the endoglucanase from Scytalidium thermophilum (egst) was cloned and expressed as a soluble protein in Pichia pastoris GS115. The recombinant enzyme (Egst) was monomeric (66 kDa) and showed an estimated carbohydrate content of 53.3% (w/w). The optimum temperature and pH of catalysis were 60-70 °C and pH of 5...
November 18, 2017: Applied Biochemistry and Biotechnology
Sacha Escamez, Madhavi Latha Gandla, Marta Derba-Maceluch, Sven-Olof Lundqvist, Ewa J Mellerowicz, Leif J Jönsson, Hannele Tuominen
Wood represents a promising source of sugars to produce bio-based renewables, including biofuels. However, breaking down lignocellulose requires costly pretreatments because lignocellulose is recalcitrant to enzymatic saccharification. Increasing saccharification potential would greatly contribute to make wood a competitive alternative to petroleum, but this requires improving wood properties. To identify wood biomass traits associated with saccharification, we analyzed a total of 65 traits related to wood chemistry, anatomy and structure, biomass production and saccharification in 40 genetically engineered Populus tree lines...
November 17, 2017: Scientific Reports
Paula Squinca, Alberto C Badino, Cristiane S Farinas
Use of the same lignocellulosic biomass as feedstock for enzymes and ethanol production has been suggested as a lower cost option in future biorefineries. Here, we propose a closed-loop strategy to produce the cellulolytic enzymes required for biomass hydrolysis using sugarcane bagasse liquefied by a home-made enzymatic cocktail as carbon source and inducer. The fed-batch liquefaction conditions were firstly evaluated using commercial enzymes. Subsequently, the effects of different liquefied materials and solids loadings on endoglucanase production by Aspergillus niger cultivated in submerged fermentation were investigated...
November 4, 2017: Bioresource Technology
Zhao Wang, John Gräsvik, Leif J Jönsson, Sandra Winestrand
BACKGROUND: Ionic liquids (ILs) draw attention as green solvents for pretreatment of lignocellulose before enzymatic saccharification. Imidazolium-based ILs with different anionic constituents ([HSO4](-), [Cl](-), [MeCO2](-)) were compared with regard to pretreatment of wood from aspen and spruce. The objective was to elucidate how the choice of anionic constituent affected the suitability of using the IL for pretreatment of hardwood, such as aspen, and softwood, such as spruce. The investigation covered a thorough analysis of the mass balance of the IL pretreatments, the effects of pretreatment on the cell wall structure as assessed by fluorescence microscopy, and the effects of pretreatment on the susceptibility to enzymatic saccharification...
November 15, 2017: BMC Biotechnology
Xiaojie Yu, Xinjie Bao, Cunshan Zhou, Lei Zhang, Abu El-Gasim A Yagoub, Hongpeng Yang, Haile Ma
The purpose of this paper was to investigate the effect of ultrasound-ionic liquid (IL) pretreatment on the enzymatic and acid hydrolysis of the sugarcane bagasse and wheat straw. The lignocellulosic biomass was dissociated in ILs ([Bmim]Cl and [Bmim]AOC) aided by ultrasound waves. Sonication was performed at different frequencies (20, 28, 35, 40, and 50kHz), a power of 100W, a time of 30min and a temperature of 80°C. The changes in the structure and crystallinity of the cellulose were studied by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA)...
March 2018: Ultrasonics Sonochemistry
Muhammad Tahir Ashraf, Jens Ejbye Schmidt
Biorefinery based on multi-feedstock lignocellulose can be viable where a sustainable supply of a single substrate is limited, for example in arid regions. Processing of mixed feedstocks has been studied in lab scale, however, its economics are less studied. In this study, an economic comparison was made between separate and combined (mixed) processing approaches for multi-feedstock lignocellulose for the production of monomeric sugars. This modular approach of focusing on sugar platform makes the results applicable for many applications using the sugars as feedstock...
October 27, 2017: Bioresource Technology
Anna Fabryová, Martin Kostovčík, Alexandra Díez-Méndez, Alejandro Jiménez-Gómez, Lorena Celador-Lera, Zaki Saati-Santamaría, Hana Sechovcová, Esther Menéndez, Miroslav Kolařik, Paula García-Fraile
Bark beetles reproduce and overwinter under the bark of trees, and are associated with bacteria that may influence the fitness of their hosts. As regard the aim of this study was to test the metabolic potential of bacterial strains, isolated from the bark beetle species Cryphalus piceae, Ips typographus and Pityophthorus pityophthorus and collected in the Czech Republic from fir, spruce and pine trees, respectively, to degrade plant cell compounds. The bacterial strains were identified as belonging to the genera Curtobacterium, Erwinia, Pantoea, Pseudomonas, Rahnella, Staphylococcus, and Yersinia...
November 11, 2017: Science of the Total Environment
Benedikt Leis, Claudia Held, Fabian Bergkemper, Katharina Dennemarck, Robert Steinbauer, Alarich Reiter, Matthias Mechelke, Matthias Moerch, Sigrid Graubner, Wolfgang Liebl, Wolfgang H Schwarz, Vladimir V Zverlov
BACKGROUND: Clostridium thermocellum is a paradigm for efficient cellulose degradation and a promising organism for the production of second generation biofuels. It owes its high degradation rate on cellulosic substrates to the presence of supra-molecular cellulase complexes, cellulosomes, which comprise over 70 different single enzymes assembled on protein-backbone molecules of the scaffold protein CipA. RESULTS: Although all 24 single-cellulosomal cellulases were described previously, we present the first comparative catalogue of all these enzymes together with a comprehensive analysis under identical experimental conditions, including enzyme activity, binding characteristics, substrate specificity, and product analysis...
2017: Biotechnology for Biofuels
Jiaxing Xu, Jiming Xu, Sen Zhang, Jun Xia, Xiaoyan Liu, Xiaozhong Chu, Jinao Duan, Xiangqian Li
High cost of ionic liquids (ILs) restricts the industrial application of IL-mediated lignocellulose pretreatment. In this study, a simple and economic technology for the pretreatment of natural lignocellulose was developed. The delignification capacity of aqueous choline ornithine ([Cho][Orn]) and hemicellulose-removal capacity of metal salt FeCl2 were combined. The changes of morphological structure and composition indicated a synergistic interaction of [Cho][Orn] and FeCl2 in the pretreatment process. The delignification and hemicellulose-removal capacity of aqueous [Cho][Orn]50% solution was significantly improved in the presence of FeCl2 by 28% and 53%, respectively...
October 16, 2017: Bioresource Technology
Ronglin He, Xue Bai, Penglin Cai, Cheng Sun, Dongyuan Zhang, Shulin Chen
Many species of Penicillium have exhibited great potential for lignocellulose hydrolysis. The filamentous fungus Talaromyces piceus 9-3 (anamorph: Penicillium piceum), which was isolated from compost wastes in China, was sequenced in this study. Compared with the cellulase producer T. reesei, T. piceus 9-3 processes a lignocellulolytic enzyme system comprising more diverse enzymatic components, especially hemicellulases. This report will facilitate the use of this strain for biomass degradation.
December 2017: 3 Biotech
Orkun Pinar, Kübra Karaosmanoğlu, Nihat Alpagu Sayar, Ceyda Kula, Dilek Kazan, Ahmet Alp Sayar
The present work focuses firstly on the evaluation of the effect of laccase on enzymatic hydrolysis of hazelnut husk which is one of the most abundant lignocellulosic agricultural residues generated in Turkey. In this respect, the co-enzymatic treatment of hazelnut husk by cellulase and laccase, without a conventional pretreatment step is evaluated. Using 2.75 FPU/g substrate (40 g/L substrate) and a ratio of 131 laccase U/FPU achieved the highest reducing sugars concentration. Gas chromatography mass spectrometry confirmed that the hydrolysate was composed of glucose, xylose, mannose, arabinose and galactose...
December 2017: 3 Biotech
Jie Zhang, Yue-Hai Wang, Quan-Yuan Wei, Xiao-Jia Du, Yong-Shui Qu
As the most representative of lignocellulosic materials, corn stalk (CS) will be a great candidate to produce xylo-oligosaccharides (XOS). Owing to the high impurity content of the XOS produced by directly enzymatic hydrolysis of xylan extracted from CS, subsequent refining steps are essential. The present study was aimed to investigate desorption during ethanol elution to improve the quality and antioxidant activity of XOS from CS. The desorption was systematically investigated after optimizing the elution conditions...
October 4, 2017: Bioresource Technology
Xiaojing Jia, Xiaowei Peng, Ying Liu, Yejun Han
BACKGROUND: Acetoin (3-hydroxy-2-butanone), the precursor of biofuel 2,3-butanediol, is an important bio-based platform chemical with wide applications. Fermenting the low-cost and renewable plant biomass is undoubtedly a promising strategy for acetoin production. Isothermal simultaneous saccharification and fermentation (SSF) is regarded as an efficient method for bioconversion of lignocellulosic biomass, in which the temperature optima fitting for both lignocellulose-degrading enzymes and microbial strains...
2017: Biotechnology for Biofuels
Zongwei Guo, Liming Zhang, Lu Zhang, Guihua Yang, Feng Xu
Many positive effects of additives on enzymatic hydrolysis of lignocellulosic materials have been investigated, but limited information has been reported on the use of long-chain fatty alcohols (LFAs) for enzymatic hydrolysis by biospired models. In this study, effects of LFAs on enzymatic hydrolysis were evaluated using biomimetic film asa structure model. LFAs clearly improved the digestibility of cellulose film from 65.1% to 77.9%, which was higher than that the digestibility of lignin-cellulose film from 53...
September 27, 2017: Bioresource Technology
Zhanhui Shen, Kejing Zhang, Mengying Si, Mingren Liu, Shengnan Zhuo, Dan Liu, Lili Ren, Xu Yan, Yan Shi
We studied a new strategy for pretreatment of rice straw (RS) to enhance enzymatic hydrolysis under mild condition. This approach uses the synergy of sodium carbonate (Na2CO3) and the bacterial strain Cupriavidus basilensis B-8 (hereafter B-8). After synergistic Na2CO3 and B-8 pretreatment (SNBP), the reducing sugar yield varied from 335.3mg/g to 799.6mg/g under different conditions. This increased by 13-31% over Na2CO3 pretreatment (284.2-719.2mg/g) and 3.42-8.15times over the untreated RS (98mg/g). Moreover, the composition of RS was changed significantly through decreases in lignin and hemicellulose...
October 6, 2017: Bioresource Technology
James Sy-Keen Woon, Mukram M Mackeen, Rosli M Illias, Nor M Mahadi, William J Broughton, Abdul Munir Abdul Murad, Farah Diba Abu Bakar
BACKGROUND: Aspergillus niger, along with many other lignocellulolytic fungi, has been widely used as a commercial workhorse for cellulase production. A fungal cellulase system generally includes three major classes of enzymes i.e., β-glucosidases, endoglucanases and cellobiohydrolases. Cellobiohydrolases (CBH) are vital to the degradation of crystalline cellulose present in lignocellulosic biomass. However, A. niger naturally secretes low levels of CBH. Hence, recombinant production of A...
2017: PeerJ
Michele Michelin, Héctor A Ruiz, Maria de Lourdes T M Polizeli, José A Teixeira
This work presents an integrated and multi-step approach for the recovery and/or application of the lignocellulosic fractions from corncob in the production of high value added compounds as xylo-oligosaccharides, enzymes, fermentable sugars, and lignin in terms of biorefinery concept. For that, liquid hot water followed by enzymatic hydrolysis were used. Liquid hot water was performed using different residence times (10-50min) and holding temperature (180-200°C), corresponding to severities (log(R0)) of 3...
September 20, 2017: Bioresource Technology
Marisa Raita, Naphatsaya Denchokepraguy, Verawat Champreda, Navadol Laosiripojana
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...
October 2017: 3 Biotech
Fengchao Jiang, Lijuan Ma, Rui Cai, Qing Ma, Gaojie Guo, Liping Du, Dongguang Xiao
To improve the efficiency of enzymatic saccharification for lignocellulose, an efficient crude multi-enzyme was produced by Trichoderma reesei using corncob, a low cost inducer. Expression of cbh1, bgl1, egl1, xyn1 and positive regulator xyr1 induced by corncob increased significantly compared to that by cellulose. After 120 h induction by corncob, enzymatic activities on filter, CMC, β-glucose and xylan increased 86.5, 46.9, 120.9 and 291.2% compared to those induced by cellulose, and the concentration of secreted protein increased by 120...
October 2017: 3 Biotech
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