Asymmetric Hydrolysis of Ethyl Lactate by Enzymatic Catalysis

摘要：

The preparation of L-lactic acid through asymmetric hydrolysis of ethyl lactate using enzymatic catalysis was explored for the first time in this work. The effects of organic medium, enzyme sources, shaking rate, water content, ethyl lactate concentration, and temperature on the reaction were systematically examined. The effect of different factors on enantiomeric excess of L-lactic acid was investigated by adopting Response Surface Method and Plackett-Burman (PB) design based on the single factor experiments. The results showed that lipase Novozym 435 expressed both the highest catalytic activity and the highest enantioselectivity. The mixture of Tert-butanol and Isooctane (1:1 v/v) was the most suitable medium and the optimal reaction conditions were obtained: enzymatic concentration 0.82 gmol-1, shaking speed 200 rpm, temperature 60 , water content 1:5 and substrate concentration 0.27 g ℃ mL-1. A product enantiomeric excess (ee) of 94.38% and a yield of 28.69% were achieved after reacting for 16 h. The kinetics of lipase-catalyzed enantioselective hydrolysis of ethyl lactate was investigated, too. The experimental results indicated that: the reaction could be described in terms of the Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates.

关键词： ethyl lactate L- lactic acid lipase asymmetric hydrolysis organic medium Response Surface Method Introduction

作者: HUANG Zhihong LIU Xiaoyan GAO Jing LI Weijie ZHOU Liya

作者单位: School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China

会议类型: 国际会议

会议名称: 2009 International Symposium on Environmental Science and Technology(2009环境科学与技术国际会议)

会议地点: 上海

会议语种:英文

页码: 473-476

在线出版日期: 2009-06-02（万方平台首次上网日期，不代表论文的发表时间）