The production of enantiomerically pure 1-phenylethanol by enzymatic kinetic resolution method using response surface methodology

Authors: AYŞE BOZAN, RAHİME SONGÜR, ÜLKÜ MEHMETOĞLU

Abstract: As the enantiomers of 1-phenylethanol are valuable intermediates in several industries, the lipase catalyzed kinetic resolution of (R,S) -1-phenylethanol is a relevant research topic. In this study, the goal was to determine the optimum reaction parameters to produce enantiomerically pure 1-phenylethanol by lipase (Novozyme 435) catalyzed kinetic resolution using response surface methodology (RSM). Reactions were performed with 40-400 mM (R,S)-1-phenylethanol, 120-1200 mM vinyl acetate and 2-22 mg/ mL biocatalyst concentrations (BC$_{L}$), at 20-60 °C and with a stirring rate of 50-400 rpm for 5-120 min. The samples were analyzed using high performance liquid chromatography (HPLC) with a Chiralcel OB column. Optimum reaction parameters to reach 100% enantiomeric excess for the substrate (ee$_{s}$) were determined as follows: substrate concentration (C$_{s}$): 240 mM, BC$_{L}$: 11 mg/mL, at 42 °C with a reaction time of 75 min. Model validation was performed using these conditions and ee$_{s}$ was calculated as 100%, which indicates the predicted model was efficient and accurate. When compared to the literature, it was observed that the reaction time decreased significantly. This is an important result considering the industrial scale perspective.

Keywords: 1-phenylethanol, enzymatic kinetic resolution, chiral alcohol, Novozyme 435, response surface methodology

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