A Novel Microbacterium sp. for Asymmetric Reduction of Simple Aromatic Ketone and Its Key Reductase

A novel strain, Microbacterium sp., which can be used as a catalyst in the asymmetric reduction of simple aromatic ketones to produce chiral aromatic alcohols, was isolated from soil by microbial screening. Using acetophenone as a model substrate for asymmetric reduction, 82 % reaction yield with more than 99 % enantiomeric excess of (R)-1-phenylethanol were achieved under the optimal conditions. Furthermore, the key reductase responsible for the asymmetric reduction was purified from the newly isolated Microbacterium sp. through (NH4)2SO4 fractional precipitation, anion exchange chromatography and gel filtration chromatography. The purified reductase is a NADH-dependent aromatic ketone reductase. Gel filtration chromatography and SDS-PAGE results reveal that it is a homodimer with two 28-kDa subunits. The enzymatic properties of the reductase indicate that it is a highly efficient catalyst for the asymmetric reduction of simple aromatic ketone.