Cellulase (β-1,4-glucan-4-glucanohydrolase) is a general term for a group of enzymes that degrade cellulose to produce glucose. It is not a single enzyme, but a multi-component synergistic effect. Enzyme system is a kind of compound enzyme, mainly composed of exo-β-glucanase, endo-β-glucanase and β-glucosidase, as well as high-activity xylanase. Acts on cellulose and products derived from cellulose. Microbial cellulase is of great significance in converting insoluble cellulose into glucose and destroying cell walls in fruit and vegetable juice to improve the yield of juice.