Effective Production of (S)-α-Hydroxy ketones: An Reaction Engineering Approach
Effective Production of (S)-α-Hydroxy ketones: An Reaction Engineering Approach
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DOI：
10.1007/s11244-013-0237-5
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发表时间：
2014-03-01
影响因子：
3.6
通讯作者：
Rother, Doerte
中科院分区：
文献类型：
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作者：
Baraibar, Alvaro Gomez;von Lieres, Eric;Rother, Doerte
使用酶工程优化酶促反应可以显著提高生物催化剂的寿命和性能。反应优化是提高所需产物的产率和对映体过量（ee）的第二个有力工具。结合起来，一个有效的工具箱，生物催化过程的开发。先前的硫胺素二磷酸依赖性酶的合理酶工程通过廉价醛的碳化提供了获得不可用的（S）-羟基酮如苯丙酰基甲醇（PPC）的途径，但ee仅为中等（89%）并且产率低。在这项工作中，反应参数的强烈影响，性能以及（S）-选择性的巴氏醋酸杆菌丙酮酸脱羧酶变体催化的PPC的不对称合成的立体选择性进行了评估。通过结合适当的底物选择、反应和溶剂工程，产物的ee可以从89%提高到98%（S）-PPC。同时，比时空产率可以提高高达61倍，证明了合适的反应条件对催化剂产率和选择性的巨大影响。特别是避免有机共溶剂，用作底物溶解度增强剂，以及交换的供体醛由其相应的α-酮酸，这是脱羧醛之前由相同的酶，是必不可少的增强。在此成功优化的基础上，可以进一步表明，迭代多参数反应优化，特别是用于可视化的帕累托图的应用是有效工艺优化的宝贵工具。
The use of enzyme engineering for optimisation of an enzymatic reaction can significantly improve lifetime and performance of the biocatalyst. Reaction optimisation is a second powerful tool to enhance yield and enantiomeric excess (ee) of a desired product. In combination, an effective toolbox for biocatalytic process development is given. Previous rational enzyme engineering of thiamine diphosphate-dependent enzymes provided access to unavailable (S)-hydroxy ketones like phenylpropionylcarbinol (PPC) by carboligation of inexpensive aldehydes, but ee was only moderate (89 %) and yields low. In this work, the strong impact of reaction parameters of both, the performance as well as the stereoselectivity of the asymmetric synthesis of PPC catalysed by an (S)-selective Acetobacter pasteurianus pyruvate decarboxylase variant has been assessed. By combining appropriate substrate choice, reaction-, and solvent engineering the ee of the product could be improved from 89 % up to 98 % (S)-PPC. Simultaneously, specific space-time-yield could be increased up to 61-fold, proving the immense impact of suitable reaction condition on both, catalysts productivity and selectivity. Especially avoidance of organic co-solvents, used as substrate solubility enhancers, as well as the exchange of the donor aldehyde by its corresponding alpha-keto acid, which is decarboxylated to the aldehyde prior to carboligation by the same enzyme, were essential for the enhancement. On the basis of this successful optimisation it could be further shown, that iterative multi-parametric reaction optimisation and especially the application of Pareto charts for visualisation are valuable tools for effective process optimisation.