摘要
以面包酵母细胞不对称还原苯乙酮合成S-α-苯乙醇为模型反应,研究了水-有机溶剂两相体系促进面包酵母细胞催化芳香酮的不对称还原情况。首先研究了适合于活性细胞催化的两相溶剂体系,实验表明合适的有机溶剂为logP>3的溶剂,这与有机相中的酶催化对溶剂的要求相一致。在所选用的溶剂中,正辛烷获得的效果最好。在此基础上进一步考察了两相之间的比率、辅助溶剂、底物浓度以及水相体系的pH等对反应的影响。实验表明两相之间的比率和辅助溶剂对反应有显著的影响,合理改变这些因素可以改善底物在两相之间的分配进而促进反应的进行。反应对底物浓度的敏感性较单相水相体系反应要小得多,而pH对反应的影响与水相中反应相同。在有机溶剂与水相体积比为1:4、添加1%乙醇以及底物浓度为30mmol·L-1时,产物得率可达到45%左右,这较在水相中反应有显著的提高。
Optically active aromatic alcohols are one of the most important chiral building blocks for many single enantiopure pharmaceuticals, and asymmetric reduction of the corresponding prochiral keton to chiral alcohol by active yeast cell is one of the most promising routes for their preparation. Since the substrate and product of this process are toxic to the cell, the space-time production of this process is low. In order to promote the asymmetric reduction reaction, the application of aqueous-organic solvent biphasic reaction system was studied; the asymmetric reduction of acetophenone （ACP） to chiral α-phenylethyl alcohol （PEA） catalyzed by Saccharomyces cerevisiae was chosen as the model reaction. At first, the appropriate organic solvent used for this reaction was studied, and then the effects of volume ratio of organic solvent phase to aqueous phase, cosolvent used, substrate concentration and aqueous phase pH on the asymmetric reduction were investigated in detail. As the same requirement required for the solvent of enzymatic biocatalysis in organic solvent medium, the logP of the appropriate organic solvent chosen for the biphasic system should also be more than 3. The experiment results indicate that the asymmetric reduction reaction could be remarkably improved when n-octane was applied as the organic phase, and the greatest yield of 45% could be obtained with the volume ratio of 1：4 for organic to aqueous phase, adding 1% alcohol ethanol as the cosolvent and substrate concentration of 30 mmol.L-1. Compared with the same asymmetric reduction reacted in single aqueous phase, the proposed measure of using biphasic solvent system provides a practicable technique route to improve those reactions with substrate and product inhibitions.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2009年第3期450-454,共5页
Journal of Chemical Engineering of Chinese Universities
基金
湖北省自然科学基金(2008CDB354)
武汉市青年科技晨光计划(200750731288)
武汉科技大学科学研究基金(2005XY15)
关键词
生物催化
不对称还原
手性醇
S-α-苯乙醇
水-有机溶剂两相体系
面包酵母细胞
biocatalysis
asymmetric reduction
chiral alcohol
S-α-phenylethyl alcohol
aqueous-organic solvent biphasic system
Saccharomyces cerevisiae
