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https://www.readbyqxmd.com/read/28440059/production-of-itaconic-acid-from-pentose-sugars-by-aspergillus-terreus
#1
Badal C Saha, Gregory J Kennedy, Nasib Qureshi, Michael J Bowman
Itaconic acid (IA), an unsaturated 5-carbon dicarboxylic acid, is a building block platform chemical that is currently produced industrially from glucose by fermentation with Aspergillus terreus. However, lignocellulosic biomass has potential to serve as low cost source of sugars for production of IA. Research needs to be performed to find a suitable A. terreus strain that can use lignocellulose derived pentose sugars and produce IA. One hundred A. terreus strains were evaluated for the first time for production of IA from xylose and arabinose...
April 25, 2017: Biotechnology Progress
https://www.readbyqxmd.com/read/28439296/oxidation-of-a-non-phenolic-lignin-model-compound-by-two-irpex-lacteus-manganese-peroxidases-evidence-for-implication-of-carboxylate-and-radicals
#2
Xing Qin, Xianhua Sun, Huoqing Huang, Yingguo Bai, Yuan Wang, Huiying Luo, Bin Yao, Xiaoyu Zhang, Xiaoyun Su
BACKGROUND: Manganese peroxidase is one of the Class II fungal peroxidases that are able to oxidize the low redox potential phenolic lignin compounds. For high redox potential non-phenolic lignin degradation, mediators such as GSH and unsaturated fatty acids are required in the reaction. However, it is not known whether carboxylic acids are a mediator for non-phenolic lignin degradation. RESULTS: The white rot fungus Irpex lacteus is one of the most potent fungi in degradation of lignocellulose and xenobiotics...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28439294/impact-of-lignin-polymer-backbone-esters-on-ionic-liquid-pretreatment-of-poplar
#3
Kwang Ho Kim, Tanmoy Dutta, John Ralph, Shawn D Mansfield, Blake A Simmons, Seema Singh
BACKGROUND: 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...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28437609/source-and-biological-response-of-biochar-organic-compounds-released-into-water-relationships-with-bio-oil-composition-and-carbonization-degree
#4
Michele Ghidotti, Daniele Fabbri, Ondřej Mašek, Colin Logan Mackay, Marco Montalti, Andreas Hornung
Water-soluble organic compounds (WSOCs) were extracted from corn stalk biochar produced at increasing pyrolysis temperatures (350-650°C) and from the corresponding vapors, collected as bio-oil. WSOCs were characterized by gas chromatography (semi-volatile fraction), negative electron spray ionization high resolution mass spectrometry (hydrophilic fraction) and fluorescence spectroscopy. The pattern of semi-volatile WSOCs in bio-oil was dominated by aromatic products from lignocellulose, while in biochar was featured by saturated carboxylic acids from hemi/cellulose and lipids with concentrations decreased with decreasing H/C ratios...
April 24, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28437478/metal-accumulation-by-sunflower-helianthus-annuus-l-and-the-efficacy-of-its-biomass-in-enzymatic-saccharification
#5
Saurabh Sudha Dhiman, Xin Zhao, Jinglin Li, Dongwook Kim, Vipin C Kalia, In-Won Kim, Jae Young Kim, Jung-Kul Lee
Accumulation of metal contaminants in soil as a result of various industrial and anthropogenic activities has reduced soil fertility significantly. Phytoextraction of metal contaminants can improve soil fertility and provide inexpensive feedstock for biorefineries. We investigated the hyperaccumulation capacity of sunflower (Helianthus annuus) biomass by cultivating these plants in various concentrations of metal contaminants. Sunflowers were grown in soils contaminated with various levels of heavy metals (10-2,000 mg/kg dry soil)...
2017: PloS One
https://www.readbyqxmd.com/read/28436165/production-of-high-concentration-of-l-lactic-acid-from-oil-palm-empty-fruit-bunch-by-thermophilic-b-coagulans-ji12
#6
Veeresh Juturu, Jin Chuan Wu
Thermophilic Bacillus coagulans JI12 was used to ferment hemicellulose hydrolysate obtained by acid hydrolysis of oil palm empty fruit bunch (EFB) at 50°C and pH6, producing 105.4 g/L of L-lactic acid with a productivity of 9.3 g/L/h by fed batch fermentation under unsterilized conditions. Simultaneous saccharification and fermentation (SSF) was performed at pH5.5 and 50°C to convert both hemicellulose hydrolysate and cellulose-lignin complex in the presence of Cellic Ctec2 cellulases using yeast extract (20 g/L) as the nitrogen source, giving 114...
April 24, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28436149/transgenic-mir156-switchgrass-in-the-field-growth-recalcitrance-and-rust-susceptibility
#7
Holly L Baxter, Mitra Mazarei, Alexandru Dumitrache, Jace Natzke, Miguel Rodriguez, Jiqing Gou, Chunxiang Fu, Robert W Sykes, Geoffrey B Turner, Mark F Davis, Steven Brown, Brian Davison, Zeng-Yu Wang, C Neal Stewart
Sustainable utilization of lignocellulosic perennial grass feedstocks will be enabled by high biomass production and optimized cell wall chemistry for efficient conversion into biofuels. MicroRNAs are regulatory elements that modulate the expression of genes involved in various biological functions in plants, including growth and development. In greenhouse studies, overexpressing a microRNA (miR156) gene in switchgrass had dramatic effects on plant architecture and flowering, which appeared to be driven by transgene expression levels...
April 24, 2017: Plant Biotechnology Journal
https://www.readbyqxmd.com/read/28435444/role-of-trichoderma-reesei-mitogen-activated-protein-kinases-mapks-in-cellulase-formation
#8
Mingyu Wang, Meiling Zhang, Ling Li, Yanmei Dong, Yi Jiang, Kuimei Liu, Ruiqin Zhang, Baojie Jiang, Kangle Niu, Xu Fang
BACKGROUND: Despite being the most important cellulase producer, the cellulase-regulating carbon source signal transduction processes in Trichoderma reesei are largely unknown. Elucidating these processes is the key for unveiling how external carbon sources regulate cellulase formation, and ultimately for the improvement of cellulase production and biofuel production from lignocellulose. RESULTS: In this work, the role of the mitogen-activated protein kinase (MAPK) signal transduction pathways on cellulase formation was investigated...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28433914/accumulation-of-sugar-from-pulp-and-xylitol-from-xylose-by-pyruvate-decarboxylase-negative-white-rot-fungus-phlebia-sp-mg-60
#9
Taku Tsuyama, Megumi Yamaguchi, Ichiro Kamei
Phlebia sp. MG-60 is a white-rot fungus that produces ethanol with high efficiency from lignocellulosic biomass without additional enzymes. Through engineering of this powerful metabolic pathway for fermentation in Phlebia sp. MG-60, chemical compounds other than ethanol could be produced. Here, we demonstrate sugar accumulation from unbleached hardwood kraft pulp and conversion of xylose to xylitol by pyruvate decarboxylase (pdc)-negative Phlebia sp. MG-60. We isolated Phlebia sp. strain MG-60-P2 from protoplasts to unify the protoplast phenotypes of the regenerated strains...
April 7, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28433190/evaluation-of-the-effects-of-isolated-lignin-on-enzymatic-hydrolysis-of-cellulose
#10
Hongdan Zhang, Shubin Wu, Jun Xie
The different physical and chemical properties of lignin might have various effects on the enzymatic hydrolysis of lignocellulosic substrates. In this study, the influence of lignin on enzymatic digestibility of cellulose was assessed. Addition of 20% (4g/L) isolated enzymatic lignin (lignin 2 and 3) and kraft lignin (lignin 4) resulted in 5-20% drop of glucose yield, depending on lignin sources. The inhibitory effect of lignin was abated as the enzyme loading increased from 10 to 20FPU/g dry substrate. However, the increasing lignin amount to 40% (8g/L) did not appear to further decrease the cellulose hydrolysis efficiency...
June 2017: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/28433150/production-of-prebiotic-xylooligosaccharides-from-alkali-pretreated-mahogany-and-mango-wood-sawdust-by-using-purified-xylanase-of-clostridium-strain-boh3
#11
Gobinath Rajagopalan, Kavitha Shanmugavelu, Kun-Lin Yang
Xylooligosaccharides (XOS) are emerging prebiotics which can be produced from lignocellulosic biomass including agro-residues and hardwood. In this study, we report the production of XOS from thermal-alkali pretreated hardwood such as mahogany and mango by using a purified xylanase from Clostridium strain BOH3. In the first approach, pure xylan is extracted from mahogany and mango hardwood and then the pure xylan is hydrolyzed by using the xylanase. In this case, 572 and 504mg XOS/g pure xylan were obtained from mahogany and mango woods, respectively...
July 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28432102/two-distinct-%C3%AE-l-arabinofuranosidases-in-caldicellulosiruptor-species-drive-degradation-of-arabinose-based-polysaccharides
#12
Md Abu Saleh, Wen-Jie Han, Ming Lu, Bing Wang, Huayue Li, Robert M Kelly, Fu-Li Li
Species in the extremely thermophilic genus Caldicellulosiruptor can degrade unpretreated plant biomass through the action of multi-modular glycoside hydrolases. To date, most focus with these bacteria has been on hydrolysis of glucans and xylans, while biodegradation mechanism for arabinose-based polysaccharides remains unclear. Here, putative α-L-arabinofuranosidases (AbFs) were identified in Caldicellulosiruptor species by homology to less thermophilic versions of these enzymes. From this screen, an extracellular XynF was determined to be a key factor in hydrolyzing α-1,2-, α-1,3-, and α-1,5-L-arabinofuranosyl residues of arabinose-based polysaccharides...
April 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28432100/casein-kinase-i-isoform-hrr25-is-a-negative-regulator-of-haa1-in-the-weak-acid-stress-response-pathway-in-saccharomyces-cerevisiae
#13
Morgan E Collins, Joshua J Black, Zhengchang Liu
Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. Many of these genes encode membrane proteins such as TPO2 and YRO2 How Haa1 is activated by weak acids is not clear. Here, we show that casein kinase I isoform Hrr25 is an important negative regulator of Haa1. Haa1 is known to be multiply phosphorylated. We found that mutations in HRR25 lead to reduced Haa1 phosphorylation and increased expression of Haa1-target genes, and that Hrr25 interacts with Haa1...
April 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28429058/effects-of-genome-duplication-on-phenotypes-and-industrial-applications-of-saccharomyces-cerevisiae-strains
#14
Ke Zhang, Ya-Hong Fang, Ke-Hui Gao, Yang Sui, Dao-Qiong Zheng, Xue-Chang Wu
Polyploidy is common in Saccharomyces cerevisiae strains, but the physiological and phenotypic effects of ploidy changes have not been fully clarified. Here, isogenic diploid, triploid, and tetraploid S. cerevisiae strains were constructed from a haploid strain, CEN.PK2-1C. Stress tolerance and ethanol fermentation performance of the four euploid strains were compared. Each euploid strain had strengths and weaknesses in tolerance to certain stressors, and no single strain was tolerant of all stressors. The diploid had higher ethanol production than the other strains in normal fermentation medium, while the triploid strain showed the fastest fermentation rate in the presence of inhibitors found in lignocellulosic hydrolysate...
April 20, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28428823/combining-manipulation-of-transcription-factors-and-overexpression-of-the-target-genes-to-enhance-lignocellulolytic-enzyme-production-in-penicillium-oxalicum
#15
Liwei Gao, Zhonghai Li, Chengqiang Xia, Yinbo Qu, Meng Liu, Piao Yang, Lele Yu, Xin Song
BACKGROUND: Lignocellulolytic enzymes are the main enzymes to saccharify lignocellulose from renewable plant biomass in the bio-based economy. The production of these enzymes is transcriptionally regulated by multiple transcription factors. We previously engineered Penicillium oxalicum for improved cellulase production via manipulation of three genes in the cellulase expression regulatory network. However, the potential of combinational engineering of multiple regulators and their targets at protein abundance and activity levels has not been fully explored...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28428822/in-muro-deacetylation-of-xylan-affects-lignin-properties-and-improves-saccharification-of-aspen-wood
#16
Prashant Mohan-Anupama Pawar, Marta Derba-Maceluch, Sun-Li Chong, Madhavi Latha Gandla, Shamrat Shafiul Bashar, Tobias Sparrman, Patrik Ahvenainen, Mattias Hedenström, Merve Özparpucu, Markus Rüggeberg, Ritva Serimaa, Martin Lawoko, Maija Tenkanen, Leif J Jönsson, Ewa J Mellerowicz
BACKGROUND: Lignocellulose from fast growing hardwood species is a preferred source of polysaccharides for advanced biofuels and "green" chemicals. However, the extensive acetylation of hardwood xylan hinders lignocellulose saccharification by obstructing enzymatic xylan hydrolysis and causing inhibitory acetic acid concentrations during microbial sugar fermentation. To optimize lignocellulose for cost-effective saccharification and biofuel production, an acetyl xylan esterase AnAXE1 from Aspergillus niger was introduced into aspen and targeted to cell walls...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28428821/genome-wide-search-for-candidate-genes-for-yeast-robustness-improvement-against-formic-acid-reveals-novel-susceptibility-trk1-and-positive-regulators-and-resistance-haa1-regulon-determinants
#17
Sílvia F Henriques, Nuno P Mira, Isabel Sá-Correia
BACKGROUND: Formic acid is an inhibitory compound present in lignocellulosic hydrolysates. Understanding the complex molecular mechanisms underlying Saccharomyces cerevisiae tolerance to this weak acid at the system level is instrumental to guide synthetic pathway engineering for robustness improvement of industrial strains envisaging their use in lignocellulosic biorefineries. RESULTS: This study was performed to identify, at a genome-wide scale, genes whose expression confers protection or susceptibility to formic acid, based on the screening of a haploid deletion mutant collection to search for these phenotypes in the presence of 60, 70 and 80 mM of this acid, at pH 4...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28425669/dissolving-lignin-in-water-through-enzymatic-sulfation-with-aryl-sulfotransferase
#18
Pepijn Prinsen, Anand Narani, Aloysius F Hartog, Ron Wever, Gadi Rothenberg
We introduce the concept of using site-specific sulfation of various lignins for increasing their aqueous solubility and thereby their processability. Using p-nitrophenylsulfate as a sulfate source and an aryl sulfotransferase enzyme as catalyst, lignins are easily sulfated at ambient conditions. We demonstrate the specific sulfation of phenolic hydroxyl groups on five different lignins: Indulin AT (Kraft softwood), Protobind 1000 (mixed wheat straw/Sarkanda grass soda) and three organosolv lignins. The reaction proceeds smoothly and the increase in solubility is visible to the naked eye...
April 20, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28425225/green-processing-of-lignocellulosic-biomass-and-its-derivatives-in-deep-eutectic-solvents
#19
Xing Tang, Miao Zuo, Zheng Li, Huai Liu, Caixia Xiong, Xianhai Zeng, Yong Sun, Lei Hu, Tingzhou Lei, Shijie Liu, Lu Lin
The scientific community has been seeking cost-competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents (DESs) are currently emerging as a new class of promising solvents, which are generally liquid eutectic mixtures formed by self-association (or hydrogen-bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs...
April 20, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28424249/lignocellulose-pretreatment-in-a-fungus-cultivating-termite
#20
Hongjie Li, Daniel J Yelle, Chang Li, Mengyi Yang, Jing Ke, Ruijuan Zhang, Yu Liu, Na Zhu, Shiyou Liang, Xiaochang Mo, John Ralph, Cameron R Currie, Jianchu Mo
Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is an essential but challenging starting point for the lignocellulosics industries. The variety of ether- and carbon-carbon interunit linkages produced via radical coupling during lignification limit chemical and biological depolymerization efficiency. In an ancient fungus-cultivating termite system, we reveal unprecedentedly rapid lignin depolymerization and degradation by combining laboratory feeding experiments, lignocellulosic compositional measurements, electron microscopy, 2D-NMR, and thermochemolysis...
April 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
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