Zheng Jianyong, Lan Xing, Huang Lijuan, Zhang Yinjun, Wang Zhao
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China.
Chirality. 2018 Jul;30(7):907-912. doi: 10.1002/chir.22863. Epub 2018 Apr 20.
D-alanine is widely used in medicine, food, additives, cosmetics, and other consumer items. Esterase derived from Bacillus cereus WZZ001 exhibits high hydrolytic activity and stereoselectivity. In this study, we expressed the esterase gene in Escherichia coli BL21 (DE3). We analyzed the biocatalytic resolution of N-acetyl-DL-alanine methyl ester by immobilized whole E. coli BL21 (DE3) cells, which were prepared through embedding and cross-linking. We analyzed biocatalytic resolution under the optimal conditions of pH of 7.0, temperature of 40°C and substrate concentration of at 700 mM with an enantiomeric excess of 99.99% and e.e. of 99.50%. The immobilized recombinant B. cereus esterase E. coli BL21 (DE3) cells exhibited excellent reusability and retained 86.04% of their initial activity after 15 cycles of repeated reactions. The immobilized cells are efficient and stable biocatalysts for the preparation of N-acetyl-D-alanine methyl esters.
D-丙氨酸广泛应用于医药、食品、添加剂、化妆品及其他消费品中。蜡样芽孢杆菌WZZ001来源的酯酶具有较高的水解活性和立体选择性。在本研究中，我们在大肠杆菌BL21(DE3)中表达了该酯酶基因。我们分析了通过包埋和交联制备的固定化大肠杆菌BL21(DE3)全细胞对N-乙酰-DL-丙氨酸甲酯的生物催化拆分。我们在pH为7.0、温度为40℃、底物浓度为700 mM的最佳条件下分析了生物催化拆分，对映体过量率为99.99%，对映体过量值为99.50%。固定化重组蜡样芽孢杆菌酯酶大肠杆菌BL21(DE3)细胞表现出优异的重复使用性，在15次重复反应循环后仍保留其初始活性的86.04%。固定化细胞是制备N-乙酰-D-丙氨酸甲酯的高效且稳定的生物催化剂。
