Mutation breeding of Aspergillus niger 51-43 lipase with N+iron implantation and the enzyme properties

The Aspergillus niger 51-43 lipase was induced by N+iron implantation, for increasing the enzyme activity.The mutant L7 which was higher enzyme acticity and genetic stability was selected.The enzyme activity of this mutant from 19.28U/mL to 29.17U/mL, increased by 151.3%.The optimal pH and temperature of high-yield lipase strains L7 were 8.0 and 30℃ respectively.The lipase was highly stable in the pH range from 6.0 to 9.0 and at 50℃.Ca2+, Na+, and Mg2+ showed an advious activation to the enzyme, while Cu2+, Mn2+, Fe2+, Co2+ and Zn2+ inhibited its activity.