Abstract

Yang Li, Yang Ping and Wang Manying*

In this study, the plasmid pPIC9K-CSN was transformed into Pichia pastoris strain GS115 by electroporation and the high expression transformants with G418 resistance were obtained. The expression conditions for CSN in P. pastoris, such as the expression time, pH value and methanol concentration in the BMMY were optimized. The maximum activity of CSN is about 100 mg/L under optimized condition (96 h of 0.5% methanol induction). The Chitosanase exhibited a molecular mass of approximately 25 kDa on 12% SDS–PAGE. The results showed that the coding sequence of CSN was successfully obtained and inserted into P. pastoris GS115 vector. This study would provide a new opportunity for largescale expression and purification of CSN, which might facilitate studies on the biological activity of CSN.