Site-directed Mutagenesis on the Lipase Gene of Penicillium expansum FS1884 and the Activity Analysis of the Mutant

To increase the activity of Penicillium expansum FS1884 lipase (PEL),one-step site-directed mutagenesis method was used to introduce a mutation site of Met220Val into the lipase encoding gene. The recombinant vector of pPIC3.5K-M220V-PEL was constructed and transformed into Pichia pastoris GS115 by electroporation. The recombinant mutant was expressed in P. pastoris and can secret the mutant lipase of PEL-M220V-GS into the culture medium induced by Methanol. The specific activity of the mutant lipase was 3 099 U/mg,which was increased by 5% to that of wild type lipase PEL-GS.