有机溶剂/缓冲液双相体系中固定化Acetobacter sp.CCTCC M209061细胞催化1-(4-甲氧基)-苯基乙醇不对称氧化反应  

Biocatalytic Asymmetric Oxidation of Racemic 1-(4-Methoxyphenyl) Ethanol Using Immobilized Acetobacter sp.CCTCC M209061 Cells in Organic Solvent-containing Biphasic System

作　　者：程景[1] 娄文勇[1,2] 宗敏华[2] 

机构地区：[1]华南理工大学轻工与食品学院应用生物催化实验室,广州510640 [2]华南理工大学制浆造纸工程国家重点实验室,广州510640

出　　处：《高等学校化学学报》2014年第7期1529-1535,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21222606,21376096);广东省自然科学基金重点项目(批准号:S2013020013049);华南理工大学中央高校基本科研业务费(批准号:2013ZG0003);全国百篇优秀博士论文作者资助项目(批准号:201504)资助~~

摘　　要：在有机溶剂/缓冲液双相体系中,利用固定化醋酸杆菌Acetobacter sp.CCTCC M209061细胞高对映体选择性地催化1-(4-甲氧基)-苯基乙醇(MOPE)的不对称氧化反应,成功地拆分外消旋MOPE得到对映体纯(S)-MOPE.与游离细胞相比,固定化细胞催化反应速度有所降低,但其稳定性(包括操作稳定性、热稳定性和储藏稳定性)明显提高.固定化细胞连续使用10批次(每批次12 h)后,仍能保留其初始催化活性的58%以上,而游离细胞仅保留约20%的相对活性.在所考察的不同有机溶剂中,正己烷不仅能较好地溶解底物,而且对细胞的生物相容性相对较好,因而提高了反应底物浓度、反应初速度、对映体回收率及残留底物e.e.值,是反应体系中最适宜的有机相.该反应的最适宜正己烷体积分数为60%,辅底物为50 mmol/L丙酮,底物浓度为40 mmol/L,缓冲液pH=6.5,反应温度为30℃;在此条件下,反应初速度为80.4μmol/min,反应12 h后,对映体回收率和残留底物e.e.值分别为51.0%和99.9%,明显好于水单相反应体系.The resolution of racemic 1-（ 4-methoxyphenyl ） ethanol （ MOPE ） to enantiopure （ S ） -MOPE through highly enantioselective oxidation of MOPE with immobilized Acetobacter sp. CCTCC M209061 cells was successfully conducted in organic solvent-containing biphasic system. In spite of exhibiting relatively slower reaction rate than free cells, immobilized cells of Acetobacter sp. CCTCC M209061 showed much higher stability, including operational stability, thermal stability and storage stability. The immobilized cells still retained more than 58% of its original catalytic activity after being repeatedly used for 10 batches（ 12 h per batch）, and the free cells maintained only around 20% of relative activity. Among various organic solvents examined, use of n-hexane as the second phase in a two-phase system enhanced the concentration of substrate, the initial reaction rate, the enantiomer recovery and the residual substrate e. e. , resulting from its excellent ability to dissolve MOPE and good biocompatibility with Acetobacter sp. CCTCC M209061 cells. As a result, n-hexane was selected as the most suitable organic phase for the reaction. For the biocatalytic oxidation of MOPE carried out in n-hexane-based biphasic system, the optimum volume fraction of n-hexane, co-substrate and its concentration, substrate concentration, buffer pH and reaction temperature were 60%, 50 mmol/L acetone, 40 mmol/L, 6.5 and 30℃, respectively. Under the above-described optimized reaction conditions, the initial reaction rate was 80. 4 μmol/min, the enantiomer recovery and the residual substrate e. e. reached 51.0% and 99.9% at reaction time of 12 h, respectively, which were better than the results obtained in aqueous monophasic system.

关 键 词：固定化Acetobacter SP CCTCC M209061细胞 1-(4一甲氧基)一苯基乙醇 4-甲氧基苯乙酮 有机溶剂 缓冲液双相体系 不对称氧化 

分 类 号：O643[理学—物理化学]