文献类型：期刊文献

英文题名：Immobilization of Bacillus subtilis esterase by simple cross-linking for enzymatic resolution of dl-menthyl acetate

作者：Zheng, Gao-Wei[1]; Yu, Hui-Lei[1]; Li, Chun-Xiu[1]; Pan, Jiang[1]; Xu, Jian-He[1]

机构：[1] Laboratory of Biocatalysis and Bioprocessing, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China

年份：2011

卷号：70

期号：3-4

起止页码：138

外文期刊名：Journal of Molecular Catalysis B: Enzymatic

收录：EI(收录号：20111613919255)

语种：英文

外文关键词：Bacteriology - Monoterpenes - Nitrogen compounds - Cloning - Esters - Enzyme immobilization

摘要：A recombinant esterase (EC 3.1.1.1) cloned from Bacillus subtilis 0554 (BSE) was carrier-freely immobilized with the method of cross-linked enzyme aggregates. The conditions for preparing the cross-linked aggregates of BSE (CLA-BSE) were optimized, including the type and concentration of precipitants, and the concentration of cross-linker, and a simple and efficient procedure for preparing CLA-BSE was developed, consisting of a precipitation step with 0.5 g mL-1 (NH4)2SO4 and a cross-linking step with 60 mM glutaraldehyde for a period of 3 h as the cross-linking time. As a result, about 70% of the initial free BSE activity was incorporated into the CLA-BSE. The thermal stabilities of the immobilized enzyme at 30 °C and 50 °C were >360 and 14 times those of free BSE, respectively. More importantly, the operational stability of CLA-BSE was also considerably improved. In the kinetic resolution of dl-menthyl acetate to produce l-menthol with CLA-BSE gave eep > 94% at conversion of >40% and the CLA-BSE could be reused for 10 times with only about 8% reduction in activity. Therefore, the new biocatalyst immobilized through the methodology of CLEAs could significantly decrease the manufacturing cost of l-menthol and would be more beneficial for its practical applications. ? 2011 Elsevier B.V. All rights reserved.