文献类型：期刊文献

英文题名：Efficient production of (R)-(-)-mandelic acid with highly substrate/product tolerant and enantioselective nitrilase of recombinant Alcaligenes sp.

作者：Zhang, Zhi-Jun[1]; Xu, Jian-He[1]; He, Yu-Cai[1]; Ouyang, Li-Ming[1]; Liu, You-Yan[2]; Imanaka, Tadayuki[1,3]

机构：[1] Laboratory of Biocatalysis and Bioprocessing, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China; [2] College of Chemistry and Chemical Engineering, Guangxi University, Nanning, Guangxi 530004, China; [3] Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan

年份：2010

卷号：45

期号：6

起止页码：887

外文期刊名：Process Biochemistry

收录：EI(收录号：20101612858217)

语种：英文

外文关键词：Escherichia coli - Cloning - Enantioselectivity - Organic acids

摘要：For efficient production of (R)-(-)-mandelic acid, a nitrilase gene from Alcaligenes sp. ECU0401 was cloned and overexpressed in Escherichia coli. After simple optimization of the culture conditions, the biocatalyst production was greatly increased from 500 to 7000 U/l. The recombinant E. coli whole cells showed strong tolerance against a high substrate concentration of up to 200 mM, and the concentration of (R)-(-)-mandelic acid after only 4 h of transformation reached 197 mM with an enantiomeric excess (eep) of 99%. In a fed-batch reaction with 600 mM mandelonitrile as the substrate, the cumulative production of (R)-(-)-mandelic acid after 17.5 h of conversion reached 520 mM. The recombinant E. coli cells could also be repeatedly used in the biotransformation, retaining 40% of the initial activity after 10 batches of reaction. The highly substrate/product tolerable and enantioselective nature of this recombinant nitrilase suggests that it is of great potential for the practical production of optically pure (R)-(-)-mandelic acid. ? 2010 Elsevier Ltd. All rights reserved.