Glycoside hydrolases in the biodegradation of lignocellulosic biomass

Composition of Lignocellulose Hydrolysate in Different Biorefinery Strategies: Nutrients and Inhibitors

“…Saccharification is a key step in the biotransformation process of lignocellulose, aiming at breaking down complex polysaccharides of cellulose and hemicellulose into fermentable oligosaccharides and monosaccharides through enzymatic hydrolysis [12]. These oligosaccharides and monosaccharides are primary nutrients for subsequent microbial fermentation, providing carbon sources and energy for the production of ethanol, biofuels, or other chemicals [40,136].…”

“…The cellulase system primarily includes the following three types of enzymes: endoglucanases (EGs), which break down the crystalline structure of cellulose microfibrils to release individual polysaccharide chains and reduce the polymerization degree [57]; exoglucanases, or cellobiohydrolases (CBHs), that cut cellulose from the free ends of polysaccharides, mainly releasing cellobiose; and βglucosidases, which can further hydrolyze cellobiose and other oligosaccharides to produce individual glucose molecules. These enzymes work together to break down celluloses into glucose units [12]. Unlike celluloses, the structure of hemicelluloses is very complex and requires a wider variety of enzymes for complete degradation, mainly including xylanases, arabinoxylanases, mannanases, β-xylosidases, and esterases [12,138].…”

“…These enzymes work together to break down celluloses into glucose units [12]. Unlike celluloses, the structure of hemicelluloses is very complex and requires a wider variety of enzymes for complete degradation, mainly including xylanases, arabinoxylanases, mannanases, β-xylosidases, and esterases [12,138]. These enzymes work synergistically and degrade polysaccharides specifically according to the chemical composition and different linkages in hemicelluloses, releasing sugar monomers such as xyloses and mannoses [13].…”

“…Lignocellulosic biomass is a tightly interwoven matrix, and pretreatment is a required step for breaking this highly complex structure with a recalcitrant nature by various chemical, physical, physicochemical, and biological methods [11]. Then, the saccharification of cellulose and hemicellulose polymers is achieved by enzymatic hydrolysis with cellulases and hemicellulases [12,13]. In addition to cellulose and hemicellulose, lignin is also one major component of lignocellulose, as a network phenolic polymer providing structural reinforcement and resilience [14].…”