β-1,3-Glucan biodegradation and utilization: Enzyme discovery, engineering, and industrial applications.

β-1,3-Glucans are structurally diverse polysaccharides widely distributed in marine algae, fungi, and plants, and their enzymatic depolymerization is important for carbon turnover, biomass processing, and polysaccharide valorization. β-1,3-Glucanases are diverse glycoside hydrolases (GHs) that cleave β-1,3-glycosidic linkages and enable the biological transformation and industrial utilization of these polymers. These enzymes provide a mechanistic and technological bridge between β-1,3-glucan metabolism in nature and the development of sustainable processes for biomass valorization and functional product generation. This review summarizes recent advances in β-1,3-glucan enzymatic bioconversion by integrating GH family classification, structural diversity, catalytic mechanisms, enzyme discovery, molecular engineering, production optimization, and emerging applications. Particular attention is given to how variations in fold architecture, active-site organization, and carbohydrate-binding modules (CBMs) collectively determine substrate recognition, catalytic mode, and product specificity toward structurally distinct β-1,3-glucans such as laminarin, curdlan, callose, and fungal cell-wall glucans. For an application-oriented perspective, we further discuss how sequence-guided discovery, structure-based engineering, and heterologous production can be integrated to improve thermostability, catalytic efficiency, substrate adaptability, product control, and scalable enzyme production. Applications in agriculture, fermentation processing, biomass refining, functional oligosaccharide production, and environmental management are also discussed. Finally, we outline remaining challenges and emerging opportunities, particularly regarding the molecular basis of substrate recognition and product specificity, as well as artificial intelligence (AI) assisted predictive design of customized β-1,3-glucanases for next-generation polysaccharide biotechnology.