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Lignocellulosic fermentation

Clelton A Santos, Mariana A B Morais, Oliver M Terrett, Jan J Lyczakowski, Letícia M Zanphorlin, Jaire A Ferreira-Filho, Celisa C C Tonoli, Mario T Murakami, Paul Dupree, Anete P Souza
β-glucosidases play a critical role among the enzymes in enzymatic cocktails designed for plant biomass deconstruction. By catalysing the breakdown of β-1, 4-glycosidic linkages, β-glucosidases produce free fermentable glucose and alleviate the inhibition of other cellulases by cellobiose during saccharification. Despite this benefit, most characterised fungal β-glucosidases show weak activity at high glucose concentrations, limiting enzymatic hydrolysis of plant biomass in industrial settings. In this study, structural analyses combined with site-directed mutagenesis efficiently improved the functional properties of a GH1 β-glucosidase highly expressed by Trichoderma harzianum (ThBgl) under biomass degradation conditions...
March 20, 2019: Scientific Reports
Alexandria T N Holland, Michael J Danson, Albert Bolhuis
BACKGROUND: Parageobacillus thermoglucosidasius is a thermophilic and ethanol-producing bacterium capable of utilising both hexose and pentose sugars for fermentation. The organism has been proposed to be a suitable organism for the production of bioethanol from lignocellulosic feedstocks. These feedstocks may be difficult to degrade, and a potential strategy to optimise this process is to engineer strains that secrete hydrolases that liberate increased amounts of sugars from those feedstocks...
March 20, 2019: BMC Biotechnology
Meilin Zhao, Dingchang Shi, Xinyao Lu, Hong Zong, Bin Zhuge
The aim of this work was to realize 1,2,4-butantriol (BT) production from sugarcane bagasse hydrolysates by microbial fermentation, and obtain co-production of BT and ethanol. Candida glycerinogenes UG21 was utilized to reduce the effect of osmolality resulting from high glucose concentration and furfural in hydrolysates on cell growth of BT-producing strains, and produced 54.1 g/L ethanol from glucose. After ethanol recovering, xylose containing stillage was obtained and used for BT production. 1.3 g/L BT was generated by a BT-producing strain...
March 12, 2019: Bioresource Technology
Manuel Benedetti, Valeria Vecchi, Nico Betterle, Alberto Natali, Roberto Bassi, Luca Dall'Osto
The biological conversion of lignocellulose into fermentable sugars is a key process for the sustainable production of biofuels from plant biomass. Polysaccharides in plant feedstock can be valorized using thermostable mixtures of enzymes that degrade the cell walls, thus avoiding harmful and expensive pre-treatments. (Hyper)thermophilic bacteria of the phylum Thermotogae provide a rich source of enzymes for such industrial applications. Here we selected T. neapolitana as a source of hyperthermophilic hemicellulases for the degradation of lignocellulosic biomass...
March 15, 2019: Journal of Biotechnology
Xun Zhuang, Oliver Kilian, Eric Monroe, Masakazu Ito, Mary Bao Tran-Gymfi, Fang Liu, Ryan W Davis, Mona Mirsiaghi, Eric Sundstrom, Todd Pray, Jeffrey M Skerker, Anthe George, John M Gladden
BACKGROUND: Due to their high energy density and compatible physical properties, several monoterpenes have been investigated as potential renewable transportation fuels, either as blendstocks with petroleum or as drop-in replacements for use in vehicles (both heavy and light-weight) or in aviation. Sustainable microbial production of these biofuels requires the ability to utilize cheap and readily available feedstocks such as lignocellulosic biomass, which can be depolymerized into fermentable carbon sources such as glucose and xylose...
March 18, 2019: Microbial Cell Factories
Nicola Di Fidio, Federico Liuzzi, Silvio Mastrolitti, Roberto Albergo, Isabella De Bari
The use of low-cost substrates represents one key issue to make single cell oil production sustainable. Among low-input crops, Arundo donax L . is a perennial herbaceous rhizomatous grass containing both C5 and C6 carbohydrates. The scope of the present work was to investigate and optimize the production of lipids by the oleaginous yeast Cutaneotrichosporon curvatus from undetoxified lignocellulosic hydrolysates of steam-pretreated A. donax . The growth of C. curvatus was first optimized in synthetic media, similar in terms of sugar concentration to hydrolysates, by applying the response surface methodology (RSM) analysis...
February 28, 2019: Journal of Microbiology and Biotechnology
Beatriz Vieira Dos Santos, Patrísia Oliveira Rodrigues, Carlos Juliano Brant Albuquerque, Daniel Pasquini, Milla Alves Baffi
This study evaluated the production of lignocellulose-degrading enzymes by solid-state fermentation (SSF) using a microbial consortium of Aspergillus fumigatus SCBM6 and A. niger SCBM1 (AFN extract). The fungal strains were cultivated in sugarcane bagasse (SCB) and wheat bran (WB) as lignocellulosic substrates for 7 days at 30 °C. After SSF, the highest peaks of enzyme production were 150 and 80 U g-1 for β-xylosidase and β-glucosidase at 48 h, 375 U g-1 for xylanase at 96 h, and 80 U g-1 for endoglucanase and 4 U g-1 for cellulase activity on filter paper (FPase) at 144 h...
March 13, 2019: Applied Biochemistry and Biotechnology
Fuhou Li, Zitong Ding, Wencan Ke, Dongmei Xu, Ping Zhang, Jie Bai, Shah Mudassar, Ishaq Muhammad, Xusheng Guo
The effects of Acremonium cellulase and L. plantarum A1 with ferulic acid esterase activity on corn stalk silage fermentation characteristics, carbohydrate composition and enzymatic saccharification were studied at 25 and 40 °C, respectively. Corn stalk was ensiled without additive (C), Acremonium cellulase (AC), L. plantarum A1 (Lp) and AC + Lp for 60 days. Pretreatment with Lp or AC + Lp promoted the better silage fermentation and the degradation of lignocellulose as indicated by high lactic acid and low pH and lignocellulose content compared to control silages at 25 °C...
March 6, 2019: Bioresource Technology
Martina Aulitto, Salvatore Fusco, David Benjamin Nickel, Simonetta Bartolucci, Patrizia Contursi, Carl Johan Franzén
Background: Lignocellulosic biomass is an abundant and sustainable feedstock, which represents a promising raw material for the production of lactic acid via microbial fermentation. However, toxic compounds that affect microbial growth and metabolism are released from the biomass upon thermochemical pre-treatment. So far, susceptibility of bacterial strains to biomass-derived inhibitors still represents a major barrier to lactic acid production from lignocellulose. Detoxification of the pre-treated lignocellulosic material by water washing is commonly performed to alleviate growth inhibition of the production microorganism and achieve higher production rates...
2019: Biotechnology for Biofuels
Ajay Kumar Pandey, Mohit Kumar, Sonam Kumari, Priya Kumari, Farnaz Yusuf, Shaik Jakeer, Sumera Naz, Piyush Chandna, Ishita Bhatnagar, Naseem A Gaur
Background: Lignocellulosic hydrolysates contain a mixture of hexose (C6)/pentose (C5) sugars and pretreatment-generated inhibitors (furans, weak acids and phenolics). Therefore, robust yeast isolates with characteristics of C6/C5 fermentation and tolerance to pretreatment-derived inhibitors are pre-requisite for efficient lignocellulosic material based biorefineries. Moreover, use of thermotolerant yeast isolates will further reduce cooling cost, contamination during fermentation, and required for developing simultaneous saccharification and fermentation (SSF), simultaneous saccharification and co-fermentation (SScF), and consolidated bio-processing (CBP) strategies...
2019: Biotechnology for Biofuels
Javier A Ceja-Navarro, Ulas Karaoz, Markus Bill, Zhao Hao, Richard A White, Abelardo Arellano, Leila Ramanculova, Timothy R Filley, Timothy D Berry, Mark E Conrad, Meredith Blackwell, Carrie D Nicora, Young-Mo Kim, Patrick N Reardon, Mary S Lipton, Joshua N Adkins, Jennifer Pett-Ridge, Eoin L Brodie
Beneficial microbial associations enhance the fitness of most living organisms, and wood-feeding insects offer some of the most striking examples of this. Odontotaenius disjunctus is a wood-feeding beetle that possesses a digestive tract with four main compartments, each of which contains well-differentiated microbial populations, suggesting that anatomical properties and separation of these compartments may enhance energy extraction from woody biomass. Here, using integrated chemical analyses, we demonstrate that lignocellulose deconstruction and fermentation occur sequentially across compartments, and that selection for microbial groups and their metabolic pathways is facilitated by gut anatomical features...
March 11, 2019: Nature Microbiology
Chen-Guang Liu, Yi Xiao, Xiao-Xia Xia, Xin-Qing Zhao, Liangcai Peng, Penjit Srinophakun, Feng-Wu Bai
Lignocellulosic biomass is a sustainable feedstock for fuel ethanol production, but it is characterized by low mass and energy densities, and distributed production with relatively smaller scales is more suitable for cellulosic ethanol, which can better balance cost for the feedstock logistics. Lignocellulosic biomass is recalcitrant to degradation, and pretreatment is needed, but more efficient pretreatment technologies should be developed based on an in-depth understanding of its biosynthesis and regulation for engineering plant cell walls with less recalcitrance...
March 5, 2019: Biotechnology Advances
Kazuki Watanabe, Seiga Tachibana, Masaaki Konishi
Corn cob and corn stover hydrolysates are forms of lignocellulosic biomass that can be used in second generation bioethanol production and biorefinery processes. Growth and fermentation inhibitors generated during physicochemical and enzymatic hydrolysis decrease ethanol and biomaterial production during the subsequent biological processes. Here, estimates of growth and fermentation inhibition during bioethanol fermentation were made using component profiles of corn cobs and corn stover at different degrees of hydrolysis...
February 23, 2019: Bioresource Technology
Pixiang Wang, Jie Zhang, Jun Feng, Shangjun Wang, Liang Guo, Yifen Wang, Yoon Y Lee, Steven Taylor, Timothy McDonald, Yi Wang
In the clostridial acetone-butanol-ethanol (ABE) fermentation, the intermediate acetate and butyrate are re-assimilated for solvent production. Here, key genes in ABE pathways in Clostridium saccharoperbutylacetonicum N1-4 were overexpressed to enhance acid re-assimilation and solvent production. With the overexpression of sol operon, acid re-assimilation was enhanced, and ABE production was increased by 20%, with ethanol production increased by six times but almost no increase in butanol production. To further drive carbon flux for C4 metabolites and ultimate butanol production, key genes including hbd, thl, crt and bcd in butanol production pathway were further overexpressed...
February 23, 2019: Bioresource Technology
Shuangcheng Huang, Tingting Liu, Bingyin Peng, Anli Geng
Industrial production of lignocellulosic ethanol requires a microorganism utilizing both hexose and pentose, and tolerating inhibitors. In this study, a hydrolysate-cofermenting Saccharomyces cerevisiae strain was obtained through one step in vivo DNA assembly of pentose-metabolizing pathway genes, followed by consecutive adaptive evolution in pentose media containing acetic acid, and direct screening in biomass hydrolysate media. The strain was able to coferment glucose and xylose in synthetic media with the respective maximal specific rates of glucose and xylose consumption, and ethanol production of 3...
February 28, 2019: Bioprocess and Biosystems Engineering
Melanie Mindt, Maria Heuser, Volker F Wendisch
The aim of this work was to study the fermentative production of the N-methylated amino acid sarcosine by C. glutamicum. Characterization of the imine reductase DpkA from Pseudomonas putida revealed that it catalyses N-methylamination of glyoxylate to sarcosine. Heterologous expression of dpkA in a C. glutamicum strain engineered for glyoxylate overproduction enabled fermentative production of sarcosine from sugars and monomethylamine. Glucose-based fermentation reached sarcosine production titers of 2.4 ± 0...
February 19, 2019: Bioresource Technology
Jie Yang, Lu Deng, Chen Zhao, Hao Fang
The high production cost of cellulase is one of the limitations that hinder the commercialization of lignocellulose-based biorefineries. As one of the important cellulases, Neurospora crassa cellulase is not so intensively investigated as T. reesei cellulase. In this study, the cbh1gene (NCU07340) cloned from N. crassa was expressed in Pichia pastoris under the control of alcohol oxidase 1 (AOX1) promotor. Six transformants with the highest resistance to G418 were selected by two rounds of transformant screening, among which the most robust producer of the recombinant CBHI has an Avicelase activity of 0...
February 27, 2019: Biotechnology Progress
Karuna Devi Jetti, Ramesh Reddy Gns, Deviram Garlapati, Sai Kishore Nammi
Genome shuffling by recursive protoplast fusion between Saccharomyces cerevisiae and Pichia stipitis also known as Scheffersomyces stipitis resulted in a promising yeast hybrid strain with superior qualities than those of the parental strains in enhancing biofuel production. Our study focused on the substrate utilization, ethanol fermentation, and ethanol tolerance of the hybrids and the parental strains. The parental strain S. cerevisiae is limited to utilize only hexose sugars, and this leads to decrease in the ethanol yield when they are subjected to ethanol production from lignocellulosic biomass which is rich in pentose sugars...
November 15, 2018: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Susanne Steudler, Anett Werner, Thomas Walther
Fungi have a diverse spectrum of extracellular enzymes. In nature, extracellular enzymes primarily serve to procure nutrients for the survival and growth of the fungi. Complex polymers such as lignocellulose and starch as well as proteins and fats are broken down into their basic building blocks by extracellular enzymes such as amylases, proteases, lipases, xylanases, laccases, and many more.The abilities of these enzymes are made use of in diverse areas of industry, including food technology, textiles, and pharmaceuticals, and they have become indispensable for today's technology...
February 23, 2019: Advances in Biochemical Engineering/biotechnology
Ling Sun, Xinyi Li, Haile Ma, Ronghai He, Prince O Donkor
A polysaccharide of Irpex lacteus, a white-rot fungus with lignocellulose-degrading activities, has been used as a commercial medicine for nephritis treatment. Previously, a low-intensity electromagnetic field (LI-EMF) was found to increase the biomass and polysaccharide content of Irpex lacteus and induce twists on the cell surface. In this study, RNA-sequencing (RNA-seq) technology was used to analyze the underlying mechanism of LI-EMF's influence on Irpex lacteus. We identified 3268, 1377, and 941 differentially expressed genes (DEGs) in the LI-EMF-treated samples at recovery times of 0 h, 3 h, and 6 h, respectively, indicating a significant decline in the influence of the LI-EMF treatment on Irpex lacteus with the passage of recovery time...
February 20, 2019: Bioelectromagnetics
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