High-Level Expression and Engineering of Candida antarctica Lipase B in a Non-Methanol-Induced Pichia pastoris System

The efficient expression and excellent thermal stability of Candida antarctica lipase B (CALB) are crucial for its industrial production. In this study, through genetic engineering and rational design, while preserving the superior catalytic properties of CALB, we optimized the induction pathway using glycerol as the sole carbon source; moreover, the thermal stability sites of CALB were predicted and optimized. The results revealed that the level of CALB expression in this expression system reached 2.27 g/L under the condition of a 5 L fermenter. The Tm value of the CALB-Q231F increased by 10 °C. Moreover, after thermal inactivation at 80 °C for 1 h, the retention rate of esterification enzymatic activity over 24 h was 2.99 times that of wild-type (WT) CALB, whereas the retention rate of hydrolytic enzymatic activity was 2.23 times that of WT CALB. In this study, a non-methanol-induced Pichia pastoris expression system was successfully designed and constructed; a non-methanol-induced CALB-producing strain, X33-pGAPZ(Mα) A-CalB-Q231F, with high thermal stability and a high expression level was obtained, which can be used for the development of industrial enzymes.