Overcoming the thermodynamic limitation in asymmetric hydrogen transfer reactions catalyzed by whole cells
Overcoming the thermodynamic limitation in asymmetric hydrogen transfer reactions catalyzed by whole cells
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DOI：
10.1002/bit.21014
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发表时间：
2006-09-05
影响因子：
3.8
通讯作者：
Liese, Andreas
中科院分区：
文献类型：
--
作者：
Goldberg, Katja;Edegger, Klaus;Liese, Andreas
将过表达来自红色红球菌DSM 44541的醇脱氢酶（ADH-“A”）的大肠杆菌的完整冻干细胞用于酮到仲醇的不对称还原。所需的烟酰胺辅因子（NADH）的再循环是在偶联底物过程中实现的。在反应过程中，酮被还原成醇，氢供体2-丙醇被一种酶氧化成丙酮。这导致所有四种组分之间的热力学平衡，从而确定可实现的最大转化率。为了克服这一限制，开发了用于全细胞应用的原位产物去除技术（ISPR）。在该方法中，最易挥发的化合物通过气流从反应容器中分离，导致平衡向所需仲醇移动。汽提过程是克服生物催化反应中热力学限制的一种简单有效的方法。采用这种方法，选定的生物转化的转化率增加到完全。(c)2006 Wiley Periodicals，Inc.
Whole lyophilized cells of an Escherichia coli overexpressing the alcohol dehydrogenase (ADH-'A') from Rhodococcus ruber DSM 44541 were used for the asymmetric reduction of ketones to secondary alcohols. The recycling of the required nicotinamide cofactor (NADH) was achieved in a coupled-substrate process. In the course of the reaction the ketone is reduced to the alcohol and the hydrogen donor 2-propanol is oxidized to acetone by one enzyme. This leads to a thermodynamic equilibrium between all four components determining the maximum achievable conversion. To overcome this limitation an in situ product removal technique (ISPR) for the application with whole cells was developed. In this method the most volatile compound is separated from the reaction vessel by an airflow resulting in a shift of the equilibrium towards the desired secondary alcohol. The so-called stripping process represents a simple and efficient method to overcome the thermodynamic limitation in biocatalytic reactions. Employing this method, the conversion of selected biotransformations was increased up to completeness. (c) 2006 Wiley Periodicals, Inc.