According to statistics, amylase accounts for 25% of the enzyme preparation market and is a very important industrial enzyme. There are several types of amylases, namely alpha amylase, β-amylase, glucoamylase, and isoamylase. Among them, when alpha amylase decomposes amylose, the product is mainly glucose, and a small amount of maltotriose and maltose, when decomposing amylopectin, in addition to generating maltose, glucose, and maltotriose, it also generates a-dextrin with a-1, 6-bonds in the branched part. In the processing of noodle products, for example, adding fungal alpha amylase to the steamed bread we often eat can enhance the reproductive ability of yeast and shorten the fermentation time of bread dough. The alpha amylases currently produced mainly include: fungal alpha amylase, medium-temperature alpha amylase, and high-temperature alpha amylase.
Among them, the fungal alpha amylase is an endo-amylase, and its optimum action temperature is about 55°C, and it will be inactivated when it exceeds 60°C. It can quickly hydrolyze the α-1,4 glucosidic bonds in gelatinized starch, amylose and amylopectin aqueous solution to produce soluble dextrin and a small amount of maltose and glucose; the medium temperature alpha amylase is produced by submerged fermentation of Bacillus subtilis strain , is an endo-amylase with an optimum action temperature of 70-80°C; high-temperature-resistant alpha amylase is made from Bacillus licheniformis through liquid fermentation, and its optimum action temperature is 95-105°C.
(1) Food processing
As a safe and efficient improver in the noodle industry, it can improve the quality of bread. Alpha-amylase has liquefaction and saccharification effects and is often used as a sweetener in the beverage industry. In cold drinks, the viscosity of cold drinks is reduced, and the fluidity is increased to ensure the taste of high-starch cold drinks. As a new type of liquefying enzyme preparation, high-temperature alpha amylase is widely used in the fermentation industry, and its thermal stability is determined by the thermal stability of the protein itself, so it is widely used in the alcohol and beer brewing industries.
(2) Feed industry
Adding exogenous alpha amylase in the diet can help young animals digest and utilize starch, and its growth performance and feed conversion rate are very beneficial. Addition of live alpha amylase-producing Escherichia coli cultures to broiler diets can act as antibiotic growth promoters, improve intestinal morphology, and improve production performance.
(3) Washing industry
Because starch is cheap, easy to obtain, and easy to remove, it is used as a layer of protective material to prevent yarn breakage in modern fiber manufacturing processes, and then treated with alpha amylase to selectively remove starch slurry and Without harming the yarn fiber, it can also degrade starch into dextrin, which is easily soluble in water, making it easy to wash off.
(4) Pharmaceutical industry
Since Aspergillus niger alpha amylase has acid resistance, it can be used to manufacture drugs to help digestion, and to develop acid-resistant alpha amylase suitable for the acidic environment of the stomach for the preparation of digestive aids.
(5) Paper industry
Amylase is mainly used in the paper industry to improve the viscosity and concentration of starch in paper coatings. Paste is a good paper coating, which can improve the hardness and strength of paper and enhance the rubability of paper. However, the natural starch concentration is too high for paper sizing, so it can be adjusted by partially degrading starch with alpha amylase.