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https://www.readbyqxmd.com/read/28432102/two-distinct-%C3%AE-l-arabinofuranosidases-in-caldicellulosiruptor-species-drive-degradation-of-arabinose-based-polysaccharides
#1
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/28428823/combining-manipulation-of-transcription-factors-and-overexpression-of-the-target-genes-to-enhance-lignocellulolytic-enzyme-production-in-penicillium-oxalicum
#2
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/28390722/factors-influencing-ruminal-bacterial-community-diversity-and-composition-and-microbial-fibrolytic-enzyme-abundance-in-lactating-dairy-cows-with-a-focus-on-the-role-of-active-dry-yeast
#3
Ousama AlZahal, Fuyong Li, Le Luo Guan, Nicola D Walker, Brian W McBride
The objective of the current study was to employ a DNA-based sequencing technology to study the effect of active dry yeast (ADY) supplementation, diet type, and sample location within the rumen on rumen bacterial community diversity and composition, and to use an RNA-based method to study the effect of ADY supplementation on rumen microbial metabolism during high-grain feeding (HG). Our previous report demonstrated that the supplementation of lactating dairy cows with ADY attenuated the effect of subacute ruminal acidosis...
April 5, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28360940/comprehensive-characterization-of-non-cellulosic-recalcitrant-cell-wall-carbohydrates-in-unhydrolyzed-solids-from-afex-pretreated-corn-stover
#4
Christa Gunawan, Saisi Xue, Sivakumar Pattathil, Leonardo da Costa Sousa, Bruce E Dale, Venkatesh Balan
BACKGROUND: Inefficient carbohydrate conversion has been an unsolved problem for various lignocellulosic biomass pretreatment technologies, including AFEX, dilute acid, and ionic liquid pretreatments. Previous work has shown 22% of total carbohydrates are typically unconverted, remaining as soluble or insoluble oligomers after hydrolysis (72 h) with excess commercial enzyme loading (20 mg enzymes/g biomass). Nearly one third (7 out of 22%) of these total unconverted carbohydrates are present in unhydrolyzed solid (UHS) residues...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28330237/biocatalytic-activity-of-aspergillus-niger-xylanase-in-paper-pulp-biobleaching
#5
A Sridevi, A Sandhya, G Ramanjaneyulu, G Narasimha, P Suvarnalatha Devi
Xylanase is a hemicellulase enzyme that catalyses the hydrolysis of xylan to xylose which is widely used in processing of feed, pulp and paper. It is produced by many microorganisms especially filamentous fungi like Trichoderma and Aspergillus. A potential xylanolytic fungal isolate Aspergillus niger was isolated from forest soils of Tirumala, AP, India, and its crude enzyme was checked for its potential in paper bleaching. Under submerged fermentation, production of xylanase, cellulase, biomass, total protein and sugar released were analysed after 7 days of incubation at room temperature...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330103/profiling-and-production-of-hemicellulases-by-thermophilic-fungus-malbranchea-flava-and-the-role-of-xylanases-in-improved-bioconversion-of-pretreated-lignocellulosics-to-ethanol
#6
Manju Sharma, Chhavi Mahajan, Manpreet S Bhatti, Bhupinder Singh Chadha
This study reports thermophilic fungus Malbranchea flava as a potent source of xylanase and xylan-debranching accessory enzymes. M. flava produced high levels of xylanase on sorghum straw containing solidified culture medium. The optimization of culture conditions for production of hemicellulases was carried out using one factor at a time approach and Box-Behnken design of experiments with casein (%), inoculum age (h) and inoculum level (ml) as process variables and xylanase, β-xylosidase, acetyl esterases and arabinofuranosidase as response variables...
June 2016: 3 Biotech
https://www.readbyqxmd.com/read/28268000/speciation-analysis-and-bioaccessibility-evaluation-of-trace-elements-in-goji-berries-lycium-barbarum-l
#7
Justyna Wojcieszek, Piotr Kwiatkowski, Lena Ruzik
Goji berries (Lycium Barbarum, L.) are known for their nutritional potential as a great source of trace metals (e.g., copper, zinc and manganese) which are present in the form of highly bioaccessible compounds. In order to assess the bioaccessibility of trace elements and to identify compounds responsible for better bioaccessibility of copper and zinc, an in vitro simulation of gastrointestinal digestion was used in this study. The total content of trace metals was evaluated using sample digestion followed by inductively coupled plasma mass spectrometry...
April 7, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28265700/starch-biorefinery-enzymes
#8
Albrecht Läufer
Nature uses enzymes to build and convert biomass; mankind uses the same enzymes and produces them on a large scale to make optimum use of biomass in biorefineries. Bacterial α-amylases and fungal glucoamylases have been the workhorses of starch biorefineries for many decades. Pullulanases were introduced in the 1980s. Proteases, cellulases, hemicellulases, and phytases have been on the market for a few years as process aids, improving yields, performance, and costs. Detailed studies of the complex chemical structures of biomass and of the physicochemical limitations of industrial biorefineries have led enzyme developers to produce novel tailor-made solutions for improving yield and profitability in the industry...
March 7, 2017: Advances in Biochemical Engineering/biotechnology
https://www.readbyqxmd.com/read/28253318/transgenic-expression-of-fungal-accessory-hemicellulases-in-arabidopsis-thaliana-triggers-transcriptional-patterns-related-to-biotic-stress-and-defense-response
#9
Alex Yi-Lin Tsai, Kin Chan, Chi-Yip Ho, Thomas Canam, Resmi Capron, Emma R Master, Katharina Bräutigam
The plant cell wall is an abundant and renewable resource for lignocellulosic applications such as the production of biofuel. Due to structural and compositional complexities, the plant cell wall is, however, recalcitrant to hydrolysis and extraction of platform sugars. A cell wall engineering strategy to reduce this recalcitrance makes use of microbial cell wall modifying enzymes that are expressed directly in plants themselves. Previously, we constructed transgenic Arabidopsis thaliana constitutively expressing the fungal hemicellulases: Phanerochaete carnosa glucurnoyl esterase (PcGCE) and Aspergillus nidulans α-arabinofuranosidase (AnAF54)...
2017: PloS One
https://www.readbyqxmd.com/read/28197133/metatranscriptomics-reveals-the-active-bacterial-and-eukaryotic-fibrolytic-communities-in-the-rumen-of-dairy-cow-fed-a-mixed-diet
#10
Sophie Comtet-Marre, Nicolas Parisot, Pascale Lepercq, Frédérique Chaucheyras-Durand, Pascale Mosoni, Eric Peyretaillade, Ali R Bayat, Kevin J Shingfield, Pierre Peyret, Evelyne Forano
Ruminants have a unique ability to derive energy from the degradation of plant polysaccharides through the activity of the rumen microbiota. Although this process is well studied in vitro, knowledge gaps remain regarding the relative contribution of the microbiota members and enzymes in vivo. The present study used RNA-sequencing to reveal both the expression of genes encoding carbohydrate-active enzymes (CAZymes) by the rumen microbiota of a lactating dairy cow and the microorganisms forming the fiber-degrading community...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28184244/solid-binding-peptides-for-immobilisation-of-thermostable-enzymes-to-hydrolyse-biomass-polysaccharides
#11
Andrew Care, Kerstin Petroll, Emily S Y Gibson, Peter L Bergquist, Anwar Sunna
BACKGROUND: Solid-binding peptides (SBPs) bind strongly to a diverse range of solid materials without the need for any chemical reactions. They have been used mainly for the functionalisation of nanomaterials but little is known about their use for the immobilisation of thermostable enzymes and their feasibility in industrial-scale biocatalysis. RESULTS: A silica-binding SBP sequence was fused genetically to three thermostable hemicellulases. The resulting enzymes were active after fusion and exhibited identical pH and temperature optima but differing thermostabilities when compared to their corresponding unmodified enzymes...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28130302/distinct-growth-and-secretome-strategies-for-two-taxonomically-divergent-brown-rot-fungi
#12
Gerald N Presley, Jonathan S Schilling
Brown rot fungi are wood-degrading fungi that employ both oxidative and hydrolytic mechanisms to degrade wood. Hydroxyl radicals that facilitate the oxidative component are powerful nonselective oxidants and are incompatible with hydrolytic enzymes unless they are spatially segregated in wood. Differential gene expression has been implicated in the segregation of these reactions in Postia placenta, but it is unclear if this two-step mechanism varies in other brown rot fungi with different traits and life history strategies that occupy different niches in nature...
April 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28107376/deletion-of-ph-regulator-pac-3-affects-cellulase-and-xylanase-activity-during-sugarcane-bagasse-degradation-by-neurospora-crassa
#13
Amanda Cristina Campos Antoniêto, Wellington Ramos Pedersoli, Lílian Dos Santos Castro, Rodrigo da Silva Santos, Aline Helena da Silva Cruz, Karoline Maria Vieira Nogueira, Rafael Silva-Rocha, Antonio Rossi, Roberto Nascimento Silva
Microorganisms play a vital role in bioethanol production whose usage as fuel energy is increasing worldwide. The filamentous fungus Neurospora crassa synthesize and secrete the major enzymes involved in plant cell wall deconstruction. The production of cellulases and hemicellulases is known to be affected by the environmental pH; however, the regulatory mechanisms of this process are still poorly understood. In this study, we investigated the role of the pH regulator PAC-3 in N. crassa during their growth on sugarcane bagasse at different pH conditions...
2017: PloS One
https://www.readbyqxmd.com/read/28058637/efficient-screening-of-potential-cellulases-and-hemicellulases-produced-by-bosea-sp-fbzp-16-using-the-combination-of-enzyme-assays-and-genome-analysis
#14
Aicha Asma Houfani, Tomáš Větrovský, Petr Baldrian, Said Benallaoua
Identification of bacteria that produce carbohydrolytic enzymes is extremely important given the increased demand for these enzymes in many industries. Twenty lignocellulose-degrading bacterial isolates from Algerian compost and different soils were screened for their potential to produce different enzymes involved in biomass deconstruction. Based on 16S rRNA gene sequencing, the isolates belonged to Proteobacteria and Actinobacteria. Differences among species were reflected both as the presence/absence of enzymes or at the level of enzyme activity...
February 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28031033/the-aceii-recombinant-trichoderma-reesei-qm9414-strains-with-enhanced-xylanase-production-and-its-applications-in-production-of-xylitol-from-tree-barks
#15
Lili Xiong, Ayyappa Kumar Sista Kameshwar, Xi Chen, Zhiyun Guo, Canquan Mao, Sanfeng Chen, Wensheng Qin
BACKGROUND: ACEII transcription factor plays a significant role in regulating the expression of cellulase and hemicellulase encoding genes. Apart from ACEII, transcription factors such as XYR1, CRE1, HAP2/3/5 complex and ACEI function in a coordinated pattern for regulating the gene expression of cellulases and hemicellulases. Studies have demonstrated that ACEII gene deletion results in decreased total cellulase and xylanase activities with reduced transcript levels of lignocellulolytic enzymes...
December 28, 2016: Microbial Cell Factories
https://www.readbyqxmd.com/read/28003194/laci-transcriptional-regulatory-networks-in-clostridium-thermocellum-dsm1313
#16
Charlotte M Wilson, Dawn M Klingeman, Caleb Schlachter, Mustafa H Syed, Chia-Wei Wu, Adam M Guss, Steven D Brown
Organisms regulate gene expression in response to the environment to coordinate metabolic reactions. Clostridium thermocellum expresses enzymes for both lignocellulose solubilization and its fermentation to produce ethanol. One LacI regulator termed GlyR3 in C. thermocellum ATCC 27405 was previously identified as a repressor of neighboring genes with repression relieved by laminaribiose (a β-1,3 disaccharide). To better understand the three C. thermocellum LacI regulons, deletion mutants were constructed using the genetically tractable DSM1313 strain...
March 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27997079/optimization-of-enzymatic-hydrolysis-and-fermentation-conditions-for-improved-bioethanol-production-from-potato-peel-residues
#17
Imen Ben Taher, Patrick Fickers, Sofien Chniti, Mnasser Hassouna
The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments...
March 2017: Biotechnology Progress
https://www.readbyqxmd.com/read/27986827/potential-of-semiarid-soil-from-caatinga-biome-as-a-novel-source-for-mining-lignocellulose-degrading-enzymes
#18
Gileno Lacerda Júnior, Melline Noronha, Sanderson Tarciso de Sousa, Lucélia Cabral, Daniela Domingos, Mírian Sáber, Itamar de Melo, Valéria Oliveira
The litterfall is the major organic material deposited in soil of Brazilian Caatinga biome, thus providing the ideal conditions for plant biomass-degrading microorganisms to thrive. Herein, the phylogenetic composition and lignocellulose degrading capacity have been explored for the first time from a fosmid library dataset of Caatinga soil by sequence-based screening. A complex bacterial community dominated by Proteobacteria and Actinobacteria was unraveled. SEED subsystems-based annotations revealed a broad range of genes assigned to carbohydrate and aromatic compounds metabolism, indicating microbial ability to utilize plant-derived material...
December 15, 2016: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/27936240/composting-like-conditions-are-more-efficient-for-enrichment-and-diversity-of-organisms-containing-cellulase-encoding-genes-than-submerged-cultures
#19
Senta Heiss-Blanquet, Françoise Fayolle-Guichard, Vincent Lombard, Agnès Hébert, Pedro M Coutinho, Alexis Groppi, Aurélien Barre, Bernard Henrissat
Cost-effective biofuel production from lignocellulosic biomass depends on efficient degradation of the plant cell wall. One of the major obstacles for the development of a cost-efficient process is the lack of resistance of currently used fungal enzymes to harsh conditions such as high temperature. Adapted, thermophilic microbial communities provide a huge reservoir of potentially interesting lignocellulose-degrading enzymes for improvement of the cellulose hydrolysis step. In order to identify such enzymes, a leaf and wood chip compost was enriched on a mixture of thermo-chemically pretreated wheat straw, poplar and Miscanthus under thermophile conditions, but in two different set-ups...
2016: PloS One
https://www.readbyqxmd.com/read/27919810/immobilization-of-indigenous-holocellulase-on-iron-oxide-fe2o3-nanoparticles-enhanced-hydrolysis-of-alkali-pretreated-paddy-straw
#20
Ajay Kumar, Surender Singh, Rameshwar Tiwari, Renu Goel, Lata Nain
The holocellulase from Aspergillus niger SH3 was characterized and found to contain 125 proteins including cellulases (26), hemicellulases (21), chitinases (10), esterases (6), amylases (4) and hypothetical protein (32). The crude enzyme was immobilized on five different nanoparticles (NPs) via physical adsorption and covalent coupling methods. The enzyme-nanoparticle complexes (ENC) were screened for protein binding, enzymatic activities and immobilization efficiency. Magnetic enzyme-nanoparticle complexes (MENC) showed higher immobilization efficiency (60-80%) for most of the enzymes...
March 2017: International Journal of Biological Macromolecules
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