Highly enantioselective reduction of 2-hydroxy-1-phenylethanone to enantiopure (R)-phenyl-1,2-ethanediol using Saccharomyces cerevisiae of remarkable reaction stability.

Saccharomyces cerevisiae JUC15 was successfully obtained by target reaction-oriented screening, which reduced 2-hydroxy-1-phenylethanone (HPE) to (R)-phenyl-1,2-ethanediol ((R)-PED) of excellent enantiomeric excess (e.e. >99.9%). There was no significant decrease in the yield and optical purity of (R)-PED when the free cells were reused for 40 repeated cycles at 2gL(-1) substrate concentration. The strain used cheap sucrose for cofactor regeneration and worked over a considerably wider range of pH (4-9). The optimum substrate concentration was 8gL(-1), which was higher than any other biocatalysts reported so far. Interesting, when HPE concentration reached 20gL(-1) in reaction system, where 43.2% of the substrate was present in suspended solid form, the reaction still gave enantiopure (R)-PED in 71% yield. Last but not least, the product e.e. kept above 99.9% in all examined conditions. These results suggest the potential of this strain for the industrial production of optically active (R)-PED.