Frontiers of Chemical Science and Engineering
Expression and characterization of a CALB-type lipase from
. The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, China.. Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
A lipase from SRZ2 (SRL) with 73% amino acid sequence identity to lipase B (CALB) was cloned and overexpressed in . The recombinant SRL showed a preference for short-chain -nitrophenyl esters. It achieved maximum activity at pH 8.0 and 65°C for -nitrophenyl hexanoate (C6) with and / values of 0.14 mmol∙L and 1712 min ∙mmol∙L at 30°C, respectively. SRL displayed excellent thermostability and pH stability, retaining more than 79% of its initial activity after incubation at 60°C for 72 h and 75% at pH 3 to 11 for 72 h. It also maintained most of its activity in the presence of inhibitors and detergents except sodium dodecyl sulfate, and it tolerated organic solvents. SRL was covalently immobilized and successfully used for ethyl hexanoate synthesis in cyclohexane or in a solvent-free system with a high conversion yield (>95%). Furthermore, high conversion yield was also achieved for the synthesis of various short-chain flavor esters when high substrate concentrations of 2 mol∙L were applied. This study indicated that a CALB-type lipase from SRZ2 showed great potential in organic ester synthesis.