文献类型：期刊文献

英文题名：Bioproduction of chiral mandelate by enantioselective deacylation of α-acetoxyphenylacetic acid using whole cells of newly isolated Pseudomonas sp ECU1011

作者：Ju, Xin[1];Yu, Hui-Lei[1];Pan, Jiang[1];Wei, Dong-Zhi[1];Xu, Jian-He[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2010

卷号：86

期号：1

起止页码：83

外文期刊名：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录：;EI(收录号：20100812732978);WOS:【SCI-EXPANDED(收录号:WOS:000274543200009)】；

基金：This research was financially supported by the National Natural Science Foundation of China (grant nos. 20506037 and 20773038), the Ministry of Science and Technology (grant nos. 2007AA02Z225 and 2009CB724704), and the China National Special Fund for State Key Laboratory of Bioreactor Engineering (grant no. 2060204).

语种：英文

外文关键词：Microbial esterase; Pseudomonas sp.; Enantioselective deacylation; alpha-Acetoxyphenylacetic acid; Enantiopure mandelic acid

摘要：Substrate-directed screening was carried out to find bacteria that could deacylate O-acetylated mandelic acid from environmental samples. From more than 200 soil isolates, we identified for the first time that Pseudomonas sp. ECU1011 biocatalytically deacylated (S)-alpha-acetoxyphenylacetic acid with high enantioselectivity (E > 200), yielding (S)-mandelic acid with 98.1% enantiomeric excess (ee) at a 45.5% conversion rate. The catalytic deacylation of (S)-alpha-acetoxyphenylacetic acid by the resting cell was optimized using a single-factor method to yield temperature and pH optima of 30A degrees C and 6.5, respectively. These optima help to reduce the nonselective spontaneous hydrolysis of the racemic substrate. It was found that substrate concentrations up to 60 mM could be used. 2-Propanol was used as a moderate cosolvent to help the substrate disperse in the aqueous phase. Under optimized reaction conditions, the ee of the residual (R)-alpha-acetoxyphenylacetic acid could be improved further, to greater than 99%, at a 60% conversion rate. Furthermore, using this newly isolated strain of Pseudomonas sp. ECU1011, three kinds of optically pure analogs of (S)-mandelic acid and (R)-alpha-acetoxyphenylacetic acid were successfully prepared at high enantiomeric purity.