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Chemical and biological routes for the valorization of macroalgal polysaccharides
Published in Antonio Trincone, Enzymatic Technologies for Marine Polysaccharides, 2019
Valerie J. Rodrigues, Annamma A. Odaneth
Glycoside hydrolases (EC 3.2.1.-) are a widespread group of enzymes that hydrolyze the glycosidic bond between two or more carbohydrates or between a carbohydrate and a noncarbohydrate moiety. These enzymes are responsible for the depolymerization of the polysaccharides in order to make them available to microbes for assimilating and metabolizing them for the production of value-added products. A large number of glycoside hydrolases such as glucosidases, fucoidanases, agarases, carrageenases, porphyranases, and unsaturated glucuronyl hydrolases are involved in the breakdown of macroalgal polysaccharides. Enzymatic depolymerization provides an indispensable tool for both structural studies and production of their oligomers with a wide spectrum of biological functions (Kusaykin et al. 2008).
Understanding the Role of a Thermophilic Genus Geobacillus in the Hydrolytic and Oxidative Degradation of Plant Biomass Insights from Genomics and Metagenomic Analyses
Published in Pratibha Dheeran, Sachin Kumar, Extremophiles, 2022
Tanvi Govil, David R. Salem, Rajesh K. Sani
In nature, the synergistic action between at least three classes of glycoside hydrolases (GHs), collectively called ‘cellulases’, are responsible for releasing a physiologically relevant amount of sugar from the crystalline cellulose present in biomass. Amongst these, 1, 4-β-endoglucanase (EC 3.2.1.4) hydrolyzes internal bonds in the cellulose, generating poly oligo-saccharides; 1, 4-β-exoglucanaseacts on the exposed chain ends in a unidirectional manner, either from non-reducing or reducing ends of cellulose polysaccharide chains, liberating cellobiose as the major product; and, lastly, β-glucosidases (EC 3.2.1.86) (β-D-glucoside glucohydrolase or cellobiase) convert cellobiose into glucose (Fig. 3).
Bioconversion of Waste Biomass to Bioethanol
Published in Prakash Kumar Sarangi, Sonil Nanda, Bioprocessing of Biofuels, 2020
Prakash Kumar Sarangi, Sonil Nanda
A variety of glycoside hydrolases are used in enzymatic saccharification of complex lignocelluloses. The family of glycoside hydrolases includes cellulases, hemicellulases, pectin-degrading enzymes and lignin-degrading enzymes. More than 130 glycoside hydrolases families have been explored for the conversion of complex carbohydrates into simpler sugars (Lombard et al. 2014), out of which 40 are cellulolytic enzymes with the ability to achieve high-efficiency cellulose hydrolysis with well-coordinated synergy for bioethanol production (Liu et al. 2018).
Alkali-stable GH11 endo-β-1,4 xylanase (XynB) from Bacillus subtilis strain CAM 21: application in hydrolysis of agro-industrial wastes, fruit/vegetable peels and weeds
Published in Preparative Biochemistry & Biotechnology, 2021
Endo-xylanases are classified under GH family 5, 8, 10, 11 and 30.[2] GH11 endo-xylanases exhibit highly conserved catalytic domain architecture and primary sequence leading to similar substrate selectivity and catalytic mechanism.[2] However, many GH11 endo-xylanases display significant differences in their biochemical characteristics (sensitivity to inhibitors, catalytic efficiency, pH and temperature optima, or stability at high temperatures) due to subtle structural differences and variations in gene sequence.[2] GH11 endo-xylanases are one of best characterized glycoside hydrolases and useful in many industrial applications due to their high substrate specificity, catalytic rate and small size (∼20 kDa). However, high cost of production, low titers and multi-step purification protocols of native GH11 endo-xylanases poses a persistent challenge toward their feasibility in industrial processes. For optimal industrial utilization, it is quintessential to reduce the bio-processing cost by over-expression and designing simple, efficient and robust purification strategies.[6–9]
Bioethanol production from Codium tomentosum residue
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Kalavathy Gengiah, Grace Lydia Phoebe Moses, Gurunathan Baskar
Bioethanol production consists of various stages: pretreatment, enzymatic hydrolysis, and fermentation. The first process in bioethanol production is the pretreatment of algal biomass where the algal cell wall is broken down to release the fermentable sugar by hydrolyzing the carbohydrate into monomers (Chia et al. 2018). Pretreated biomass is subjected to cellulase enzyme produced from Trichoderma reesei. Cellulase, recognized for accomplishing benefits of biomass utilization. It is responsible for the cleavage of the β–1, 4–glycosidic linkages in cellulose. They are individuals of the glycoside hydrolase families that hydrolyze polysaccharides. Cellulase has the ability to disintegrate the cellulose existing on the cell wall of algae residue into glucose by enzymatic hydrolysis (Hiroki et al. 2019). Saccharomyces cerevisiae ferments the carbohydrate to ethanol.
Lignocellulose derived functional oligosaccharides: production, properties, and health benefits
Published in Preparative Biochemistry and Biotechnology, 2019
Latika Bhatia, Ashutosh Sharma, Rakesh K. Bachheti, Anuj K. Chandel
Glucuronoxylan is the major hemicellulose in corn stover. Oligosaccharides (acetyl and feruloyl esters containing XOS) are the products of glucuronoxylan yielded as a result of dilute acid-pretreatment corn fiber.[39] Oligosaccharides with 6 carbon were also found in the sample after hydrolysis and fermentation. Glycoside hydrolases (GHs) cause breakdown of natural polysaccharides to yield mono- and oligosaccharides.[25] Oxidized oligosaccharides and native oligosaccharides containing reducing ends are the outcomes of lytic polysaccharide monooxygenases (LPMOs).[85] AOS can be obtained by the specific enzymatic breakdown of arabinose containing carbohydrate polymers. Arabinan degrading enzymes are categorized into 6 classes viz. α-l-Arabinofuranosidase (EC 3.2.1.55), (not active with polymer), α-l-Arabinofuranosidase (active with polymers), α-l-Arabinofuranohydrolase (specific for arabinoxylans), exo-α-l-Arabinanase, (not active with p-nitrophenyl-α-l-arabinofuranoside), β-l-Arabinopyranosidase and endo-1, 5-α-l-Arabinanase (EC 3.2.1.99).[30] Oligosaccharides may inhibit the enzymatic inhibition during hydrolysis. To overcome this, Xue and coworkers[86] used activated charcoal process followed by size exclusion chromatography to remove these compounds to improve the amenability of cellulases.