The immobilization of α -amylase by ultrasonic treatment was studied. The results showed that the activity of immobilized α -amylase increased within a certain parameter range. By studying and optimizing the factors that can affect the activity of immobilized enzyme, such as ultrasonic power, ultrasonic frequency and ultrasonic time, the most appropriate ultrasonic parameters were: ultrasonic power of 40W and ultrasonic frequency of 15kHz.

α -amylase is widely distributed.

In animals (saliva, pancreas, etc.), plants (malt, turnip) and microorganisms. Almost all microbial enzymes are secreted. This enzyme takes Ca2+ as essential factor, as stabilizing factor and activating factor, and some amylases are Ca2+-independent. Amylase acts on both amylose and amylopectin, and randomly cuts off α-1,4- chains in sugar chains indiscriminately. Therefore, it is characterized by a sharp drop in the viscosity of the substrate solution and the disappearance of iodine reaction. In addition, there are a small amount of maltotriose and maltose in the final product when amylose is decomposed. Among them, the final product of fungal a- amylase hydrolysis of starch is mainly maltose without macromolecular limit dextrin, which is widely used in baking industry and maltose manufacturing industry. On the other hand, when amylopectin is decomposed, besides maltose, glucose and maltotriose, α-limit dextrin (also called α-dextrin) with α- 1 6- bond is also generated. Generally, the decomposition limit is 35-50% based on glucose, but in bacterial amylases, it is as high as 70% (glucose is finally dissociated);