Microbial enantioselective reduction of ethyl-2-oxo-4-phenyl-butanoate

Different microorganisms (MOs) were used to carry out the enantioselective reduction of ethyl-2-oxo-4-phenylbutanoate to (S)-(+)-2-hydroxy-4-phenylbutanoate or (R)-(+)-2-hydroxy-4-phenylbutanoate. Commercially available Saccharomyces cerevisiae and Dekera sp. led to over 92% ee of (S)-(+)-2-hydroxy-4-phenylbutanoate. Kluyveromyces marxianus gave the opposite isomer with 32% ee (R). All reactions, except those with Hansenula sp., proceeded to greater than 90% conversion. This the first report on the use of Dekera sp., Hansenula sp. and K. marxianus in the reduction of α-ketoesters.