Highly enantioselective oxidation of α-hydroxyacids bearing a substituent with an aryl group: co-production of optically active α-hydroxyacids and α-ketoacids.

A novel and simple methodology for co-obtaining of enantiomerically pure α-hydroxyacids and α-ketoacids was developed by enantioselective oxidation of α-hydroxyacids bearing a substituent with an aryl group using α-hydroxyacid dehydrogenase (α-HADH). A high-throughput method was firstly established for screening of enantioselective α-HADHs. Sinorhizobium sp. ZJB1 101 with high activity and excellent enantioselectivity of α-HADH for oxidation of α-hydroxyacids bearing a substituent with an aryl group was isolated and identified. This strain has potential for co-production of (R)-α-hydroxyacids and α-ketoacids in near theoretical yields, while no consecutive oxidation of α-ketoacids was observed. The green conversion system appears promising for potential applications in industry.