Background: The object of this experimental study is a new lipase screened from metagenomic libraries in the early stage of the laboratory and named it LIP 906. In order to improve the stability of the enzyme and develop and apply it as soon as possible, experiments use directed evolution and immobilization.
Results: A random mutation library was constructed by error-prone PCR technology, and finally a mutant lipase LIP 5-D with improved enzyme activity was screened out and then immobilized. Compared with the wild-type lipase LIP 906, the enzyme activity of the mutant enzyme LIP 5-D increased 4 times; the optimum reaction temperature was increased by 4 °C by mutation and 3 ℃ by immobilization; and the optimum reaction pH is changed from 7.8 to 7.5; temperature stability and pH stability has been improved. The mutant enzyme LIP 5-D can maintain a relative enzyme activity of about 70% at a temperature below 65 °C for 2 hours, and can also maintain a relative enzyme activity of about 60% at different pH 3 -10.
Conclusions: Error-prone PCR and immobilization improved the catalytic activity and stability of the enzyme, and promoted its development and application in many industries. The research on the properties and modification of the new lipase LIP906 provides a solid foundation for my next innovative research in application and environmental protection.