Highly enantioselective reduction of acetophenone by locally isolated Alternaria alternata using ram horn peptone

Enantiomerically pure compounds are important building blocks in the synthesis of natural products. In this study, the reduction of acetophenone to the (S)-isomer of 1-phenylalcohol with a high enantiomeric excess (ee) by locally isolated Alternaria alternata using ram horn peptone (RHP) was investigated. Ten strains of A. alternata were isolated from different plant samples. These isolates were evaluated for the reduction of acetophenone (ACP) to 1-phenylethanol (PEA). Glucose, yeast extract and RHP in a shake flask and fermenter for growth of A. alternata cultures were used. A. alternata EBK-4 isolate was found to be an effective biocatalyst for the enantiomeric bioreduction of acetophenone. Conversions of up to 100% with excellent enantiomeric excesses (>99%) were obtained. Production of PEA was achieved via a fermenter. The yield was calculated as 86%. This is the first report on the enantioselective reduction of ACP by A. alternata using ram horn peptone from waste material.