Improvement of the Optimum Temperature of Penicillium expansum Lipase by Site-directed Mutagenesis / 微生物学通报

ABSTRACT

In order to improve the optimum temperature of lipases, The Penicillum expansum lipase (PEL) gene was mutated by site-directed mutagenesis using overlap extension PCR technique. The recombinant plasmid pPIC3.5K-lip-E83V containing matant gene was expressed in Pichia pastoris GS115. The comparison experiments of the mutant PEL-E83V-GS with the wild-type PEL-GS showed that the optimum temperature of the mutant (45℃) was higher by 5℃ than that of the wild type. The thermostability of the mutant was similar to the wild type. The enzymatic activity of the mutant was 188 U/mL at 37 ℃, which was 80% that of the wild type at the same conditions. The hydrophobic interaction may be enhanced in the surface region by the hydrophilic amino acid, Glu substituted with the hydrophobic amino acid, Val, and be responsible for the improvement of optimum temperature.