Enantioselective properties of extracellular lipase from Serratia marcescens ES-2 for kinetic resolution of (S)-flurbiprofen

Serratia marcescens ES-2 excreting a catalytic lipase for the enantioselective hydrolysis of (R,S)-flurbiprofen ethyl ester to (S)-flurbiprofen was newly screened, and the excreted lipase was purified by a three-step procedure. The molecular mass was measured to be 64.9 kDa, a relatively high value among known bacterial lipases, and the optimal temperature was determined to be 37 °C. The enantioselectivity was significantly enhanced by the inorganic ion Ca2+ and surfactant Triton X-207, yet seriously inhibited by EDTA and SDS. The kinetic resolution of 50 mM (R,S)-flurbiprofen ethyl ester to optically pure (S)-flurbiprofen was carried out using 100 U lipase/mmol (R,S)-flurbiprofen ethyl ester in an aqueous phase reaction system supplemented with 10 mM Ca2+ and 1% Triton X-207. A high conversion, corresponding to an enantiomeric excess of 98.5% and conversion yield of 45.1%, was achieved after 24 h, along with a very high E-value of 332. An enantioselective lipase from S. marcescens ES-2 seems to be practically applicable for the production of optically active (S)-flurbiprofen.