Study Of Amylase Directed Evolution Stateygy In Bacillus Subtilis And Its Hydrolysis Effect For Corn Starch

α-amylase is widely used in industrial production, which can hydrolyze starch into smallmolecular such as maltose, etc. It is almost used in all aspects of the food industry. But in thepractical applications process, due to its own conditions restriction, enzyme activity is to beimproved. And high temperature and some extreme conditions such as acid and alkali also have agreat influence on enzyme activity. Therefore, it’s very important to get high-activity and acid–resisting α-amylase, which will have an very important significance for the development of Feedand Food industry. Many researchers are using biotechnology methods to improve the α-amylaseactivity, currently, error-prone PCR technology is one of the most widely used means in directedevolution of genes. In this study, we use the error-prone PCR technology to mutagenesis gene ofalpha amylase of bacillus subtilis in vitro.The error-prone PCR technology is very simple and easy to operate, in recent years, itbecomes a new strategy for gene directed evolution in vitro. This experiment verifies thefeasibility of this method from practical operation, and provides material for the study of therelationship between gene mutation site in Bacillus subtilis α-amylase and enzyme function, thusprovides a theoretical basis and reference for subsequent study of Bacillus subtilis α-amylase.This experiment uses the PCR induced mutation technology of the gene directed evolutionstrategy in vitro. This test uses the incurability characteristics of Taq polymerase to introducemutations, which by changing Mg2+and Mn2+concentration and setting different Kilobasesratios in PCR system. Screening of the mutant library is obtained by identifying medium withtrypan blue starch. Enzyme activity which from gene mutations are higher by2.2and3.1times ofparent enzyme activity under the same conditions, the thermal stability and the patience to acidenvironment of the mutant enzyme enhance. Based on the hydrolysis effect for corn starch oforiginal and directed evolution alpha amylase, found that the hydrolysis effect of directedevolution alpha amylase for corn starch enhanced, amylose content increased.