Cellulase is the general name of a group of enzymes that catalyze the degradation of cellulose hydrolysis to produce glucose and low polymerization degree fiber, including three main components of dextran endonuclease, dextran exonuclease and cellobinase. It is not a single enzyme, but a multi-component enzyme system that plays a synergistic role.Cellulase is an off-white powder or liquid. In 1906, Seilliere discovered cellulase in the digestive juices of snails. Cellulase can hydrolyze the β-1, 4-glucoside bond in fiber to produce soluble polymer and D-glucose. Depending on the source of the enzyme, its relative molecular weight ranges from as low as 5,000 to as high as 400,000. The optimal pH value is 4.0 ~ 5.0.The optimum temperature is 40 ~ 60ºC. Some metal ions Mg2+, Cl2+ and neutral salts can activate this enzyme, and some other metal ions Ag2+, Cu2+, Mn2+, Hg2+ and dyes can inactivate this enzyme.