Enantiocomplementary reduction of 3-phenylthiopropan-2-one by Bacillus sp.: Effect of medium components

The enantioselectivity of the enzymes responsible for reduction of prochiral compound 3-phenylthiopropan-2-one was dependent on the concentration of yeast extract and glucose in the growth medium. Low concentrations of yeast extract (0.1–0.9% w/v) favored the formation of S-enantiomer (62% ee at 0.1% w/v yeast extract) of 3-phenylthiopropan-2-ol. However, R-enantiomer of the reduced product was formed when MSM was supplemented with yeast extract at a concentration of 1% (w/v) or more with a maximum ee of 85% at 2.0% (w/v) yeast extract supplement in the growth medium.