Classification and Mechanism of Cellulase

Cellulase is a general term for enzymes with the ability to degrade cellulose. They work together to break down cellulose. All microorganisms that can use crystalline cellulose can secrete cellulases to a greater or lesser degree. These enzymes have different specificities and modes of action. Different cellulases can more effectively degrade cellulose with complex structure. Cellulase mainly comes from fungi and bacteria, and fungal cellulase production is relatively high (20g / L).

1. Classification of cellulases

1. Endoglucanase: It can arbitrarily break β-1,4 glycosidic bonds inside the cellulase molecule.

1. Exoglucanase or cellobiosidase: It can sequentially cleave β-1,4 glycosidic bonds from the non-reducing end of fiber molecules to release cellobiose molecules.

1. β-glucosidase: It can break down cellobiose and other low molecular fiber dextrin into glucose.

Irwin et al. Found in 1993 that virtually any enzyme cannot lyse crystalline cellulose alone when decomposing crystalline cellulose. Only the three enzymes coexist and cooperate to complete the hydrolysis process.

a. Mechanism of Cellulase

1. While cellulase can improve the decomposition of cellulose and hemicellulose, it can promote the dissolution of plant cell walls to dissolve more soluble substances in plant cells and degrade the non-digestible macromolecular polysaccharides, proteins and lipids into small molecules are beneficial to the digestion and absorption of the gastrointestinal tract of animals.

1. Cellulase preparations can activate the secretion of endogenous enzymes and supplement the deficiency of endogenous enzymes. And adjust the endogenous enzymes to ensure the normal digestion and absorption of animals, in order to play a role in preventing disease and promoting growth.

1. Eliminate anti-nutritional factors and promote healthy growth of organisms. After the hemicellulose and pectin are partially dissolved in water, a viscous solution will be produced, which will increase the viscosity of digestion and cause obstacles to endogenous enzymes. The addition of cellulase can reduce the viscosity, increase the diffusion of endogenous enzymes, and increase the contact between enzymes and nutrients. Area to promote good digestion of feed.

1. The cellulase preparation itself is a multi-enzyme complex consisting of protease, amylase, pectinase, and cellulase. In this multi-enzyme complex system, the product of one enzyme can become another enzyme. Substrate, so that digestion in the digestive tract can proceed smoothly. In other words, in addition to directly degrading cellulose and promoting its decomposition into low-molecular compounds that are easily digested and absorbed by animals, cellulase also works with other enzymes to improve the decomposition and digestion of feed nutrients by cows.

1. Cellulase also has the function of maintaining the small intestinal villi morphology and promoting the absorption of nutrients.

b. Applications

Food industry: Cellulase is used for peeling in the processing of soybean paste, which greatly reduces the cost while improving product quality. The use of cellulase can also improve the baking and nutritional quality of the noodle products and extend the shelf life. Fruit and vegetables contain a lot of cellulose. If you use traditional methods to process fruits and vegetables, it will destroy the taste and loss of nutrition. However, if treated with cellulase, the plant tissue will be softened and good for absorbing by the body. Therefore, the use of food-grade enzyme preparations for the effective degradation of fruits can increase the yield of juices, improve the color of the products and increase the stability.

Brewing industry: Cellulase is used in beer fermentation. Addition of cellulase to a small amount of barley germination can effectively degrade β-1,3-glycosidic bonds and β-1,4-glycosidic bonds, thus aiding the germination of barley. In addition, cellulase can also degrade distiller's grains and increase beer filtration efficiency. The cellulase acts directly on the plant cell wall and can increase the reaction speed during vinegar fermentation, and the output of the main product also increases.

Feed industry: Cellulase can be used for saccharification of various cellulosic raw materials. When the amount of cellulase added is 0.1% to 0.3%, it can decompose structurally complex cellulose for the production of protein feed and increase the source of feed. Cellulase can degrade cellulose that is not easily digested in feed into sugar and bacterial protein, which improves the utilization rate and value of feed and utilization. At the same time, it can increase the appetite of animals and promote the growth and development.

Other industries: The proper treatment of pulp with cellulase can increase the production of microfibers and improve the water retention, and may increase the paper's tensile strength. Fabrics with the treatment of cellulase has the characteristics of smoothness, clear pattern, good drape, and strong hygroscopicity