Promotion of the Asymmetric Reduction of Prochiral Ketone with Recombinant E. coli Through Strengthening Intracellular NADPH Supply by Modifying EMP and Introducing NAD Kinase

Abstract The intracellular NADPH insufficient supply is the main bottleneck to the synthesis of chiral alcohols by asymmetric reduction with whole-cell catalysis. Herein, we provide a novel strategy to strengthen intracellular NADPH supply through introducing an NADP + -dependent glyceraldehyde 3-phosphate dehydrogenase ( gap B from Bacillus subtilis 168) into the Embden-Meyerhof pathway and a NAD kinase ( yfj B from E. coli MG1655) to further enhance the NADP(H) pool. A recombinant E. coli ( E. coli BL21 (DE3)/pETDuet-1- gap B- yue D&pET28a- yfj B) was constructed to co-express gap B and yfj B with a carbonyl reductase gene yue D together. The result showed that the intracellular NADPH amount increased by 134.4% with the strategy. To the model reaction (asymmetric reduction of acetophenone to S -phenyl ethanol), the yield was 3.7-fold with this strategy compared to the control. This provides a technological route for strengthening the intracellular NADPH supply in E. coli for biocatalysis and biosynthesis. Graphic Abstract