文摘
Objectives The Tyr52 residue of d-lactate dehydrogenase (d-LDH) from Lactobacillus pentosus was replaced with small hydrophobic residues and overexpressed in E. coli BL21 (DE3) to enhance 3-phenyllactic acid (PLA) synthesis by whole-cell catalyst. Results Escherichia coli pET-28a-d-ldh produced 12.2?g PLA l? in 3?h, with a molar conversion rate of 61?%, while E. coli pET-28a-d-ldh Y52V produced 15.6?g PLA l?, with a molar conversion rate of 77?%. This study demonstrates the feasibility of using engineered E. coli for PLA production from phenylpyruvate (PPA) and showed that site-directed mutagenesis of d-ldh markedly improved PLA yield and substrate conversion rate. Conclusion This biocatalytic system is a promising platform for PLA production from PPA.