Using a water-immiscible ionic liquid to improve biocatalytic anti-prelog stereoselective reduction of acetyltrimethylsilane with immobilized Candida parapsilosis CCTCC M203011 cells

ORGN 791

Pan Wang, klistine1985@126.com, Wen-Yong Lou, wylou@scut.edu.cn, and Min-Hua Zong, btmhzong@scut.edu.cn. Laboratory of Applied Biocatalysis, South China University of Technology, Wushan Street 381#, Tianhe, Guangzhou, 510640, China
The biocatalytic anti−Prelog stereoselective reduction of acetyltrimethylsilane to enantiopure (R)−1−trimethylsilylethanol was successfully conducted in a biphasic water−immiscible ionic liquid (IL)/buffer system using immobilized Candida parapsilosis CCTCC M203011 cells. Of all the tested ILs, the best result was observed with BMIMPF6, which exhibited not only good biocompatibility with the cells but also excellent solvent properties for the toxic substrate and product. To better understand the bioreduction, several crucial influential variables were also examined. The optimum volume ratio of buffer to BMIMPF6, buffer pH, reaction temperature and substrate concentration were 8/1, 6.0, 30C and 120mM, respectively. Under the optimized conditions, the maximum yield and the product e.e. were as high as 97.1% and >99%, respectively, which are much higher than the corresponding values with the aqueous system or the biphasic n−hexane/buffer system. Additionally, the immobilized cells displayed a better operational stability in BMIMPF6−based biphasic system.