Improved production of ethyl-(R)-2-hydroxy-4-phenylbutyrate with pretreated Saccharomyces cerevisiae in water/organic solvent two-liquid phase systems |
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Authors: | Yu-Gang Shi Hong-Ping Wu Feng Li Xue-Qin Zuo |
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Institution: | School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu, People's Republic of China |
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Abstract: | Baker's yeast pretreated with α-phenacyl chloride was employed to improve the enantioselectivity of the asymmetric reduction of ethyl-2-oxo-4-phenylbutyrate (EOPB) to ethyl-(R)-2-hydroxy-4-phenylbutyrate ((R)-EHPB) and maintain a high activity of the yeast. A water/organic solvent two-liquid phase system was also introduced to overcome the strong substrate and product inhibition of the enzyme; the highest catalytic activity and enantioselectivity were obtained in a water/benzene two-liquid phase system. When the reduction was catalyzed with pretreated yeast (300 mg mL?1 buffer) in the water/benzene two-liquid phase system (Vaq/Vben=20:40), 41.9% molar conversion of EOPB and 87.5% e.e. of (R)-EHPB were obtained in 48 h, using pH 8.0 phosphate buffer with 1.5% (v/v) of ethanol added as a co-substrate at 30°C, even with an initial EOPB concentration of 400 mM and a final EHPB concentration as high as 167.7 mM. |
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Keywords: | Asymmetric reduction two-liquid phase system baker's yeast ethyl-(R)-2-hydroxy-4-phenylbutyrate |
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