Isolation of a Bacillus strain producing ketone reductase with high substrate tolerance

Target reaction-oriented screening from soil samples yielded a ketone reductase-producing Bacillus sp., strain ECU0013, which exhibits excellent stereoselectivity, high substrate tolerance and is capable of regenerating the required cofactor with glucose as a co-substrate. Whole-cells catalyzed the asymmetric reduction of 2-chloro-1-phenylethanone (50 mM) to (R)-2-chloro-1-phenylethanol with a 93.3% conversion rate and 99% e.e. (enantiomeric excess). A variety of ketones were enantioselectively reduced by resting cells, giving corresponding chiral alcohols with good to excellent e.e. values. These results suggest the potential of this strain for the industrial production of chiral halogenated aromatic alcohols.