Efficient anti-Prelog enantioselective reduction of acetyltrimethylsilane to (R)-1-trimethylsilylethanol by immobilized Candida parapsilosis CCTCC M203011 cells in ionic liquid-based biphasic systems

Microbial Cell Factories

Research

Pan Wang¹  Jing Cheng¹  Min-Hua Zong¹  Bo-Bo Zhang²  Wen-Yong Lou³ 

[1] Laboratory of Applied Biocatalysis, College of Light Industry and Food Sciences, South China University of Technology, 510640, Guangzhou, China;State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 510640, Guangzhou, China;Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China;State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 510640, Guangzhou, China;Laboratory of Applied Biocatalysis, College of Light Industry and Food Sciences, South China University of Technology, 510640, Guangzhou, China;

关键词: Immobilize Cell;    Alginate Bead;    Calcium Alginate;    Initial Reaction Rate;    Biphasic System;   

DOI  :  10.1186/1475-2859-11-108

 received in 2012-04-23, accepted in 2012-06-27,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundBiocatalytic asymmetric reductions with whole cells can offer high enantioselectivity, environmentally benign processes and energy-effective operations and thus are of great interest. The application of whole cell-mediated bioreduction is often restricted if substrate and product have low water solubility and/or high toxicity to the biocatalyst. Many studies have shown that a biphasic system is often useful in this instance. Hence, we developed efficient biphasic reaction systems with biocompatible water-immiscible ionic liquids (ILs), to improve the biocatalytic anti-Prelog enantioselective reduction of acetyltrimethylsilane (ATMS) to (R)-1-trimethylsilylethanol {(R)-1-TMSE}, which is key synthon for a large number of silicon-containing drugs, using immobilized Candida parapsilosis CCTCC M203011 cells as the biocatalyst.ResultsIt was found that the substrate ATMS and the product 1-TMSE exerted pronounced toxicity to immobilized Candida parapsilosis CCTCC M203011 cells. The biocompatible water-immiscible ILs can be applied as a substrate reservoir and in situ extractant for the product, thus greatly enhancing the efficiency of the biocatalytic process and the operational stability of the cells as compared to the IL-free aqueous system. Various ILs exerted significant but different effects on the bioreduction and the performances of biocatalysts were closely related to the kinds and combination of cation and anion of ILs. Among all the water-immiscible ILs investigated, the best results were observed in 1-butyl-3-methylimidazolium hexafluorophosphate (C4mim·PF6)/buffer biphasic system. Furthermore, it was shown that the optimum substrate concentration, volume ratio of buffer to IL, buffer pH, reaction temperature and shaking rate for the bioreduction were 120 mM, 8/1 (v/v), 6.0, 30°C and 180 r/min, respectively. Under these optimized conditions, the initial reaction rate, the maximum yield and the product e.e. were 8.1 μ mol/min gcwm, 98.6% and >99%, respectively. The efficient whole-cell biocatalytic process was shown to be feasible on a 450-mL scale. Moreover, the immobilized cells remained around 87% of their initial activity even after being used repeatedly for 8 batches in the C4mim·PF6/buffer biphasic system, exhibiting excellent operational stability.ConclusionsFor the first time, we have successfully utilized immobilized Candida parapsilosis CCTCC M203011 cells, for efficiently catalyzing anti-Prelog enantioselective reduction of ATMS to enantiopure (R)-1-TMSE in the C4mim·PF6/buffer biphasic system. The substantially improved biocatalytic process appears to be effective and competitive on a preparative scale.

【 授权许可】

Unknown   
© Zhang et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.