Abstract: This work aims to construct a co-expression system of S-imine reductase（S-IRED）and glucose dehydrogenase（GDH）in Escherichia coli Bl21,and to efficiently synthesize chiral secondary amine by regenerating coenzyme NADPH. A co-expression system with double promoters in a single plasmid was designed and constructed by seamless cloning. Whole cells of the recombinant strain were adapted as a catalyst to synthesize chiral secondary amine S-2-methylpyrrolidine（S-2MP）,and the effects of temperature,pH and organic solvent on the reaction were studied. As results,the recombinant co-expressed plasmid was successfully constructed and intracellular co-expression of S-IRED and GDH in E. coli was achieved. Using imine 2-methyl pyrroline（2MPN）as the model substrate and catalyzed by whole cells of the strain,S-2MP was synthesized;both the production rate and optical purity of chiral amine were higher than 95%. The optimal temperature and pH were 37℃ and 8 respectively. Methanol of <10% had a positive role in promoting the reaction. In sum,the construction of co-expression system in E. coli Bl21 allows in-situ regeneration of coenzyme NADPH,which reduces the synthesis cost of chiral amine catalyzed by imine reductase and provides a basis for further scale preparation of chiral amine.

Key words: imine reductase, glucose dehydrogenase, co-expression, chiral amine