ERA-Chemistry - Enzymatic Carboxylation in Ionic Liquids

以重碳酸盐为二氧化碳来源的各种脱羧酶催化芳烃的酶促羧化反应，是一种非常有前景的生物合成工具，可以替代通常要求苛刻反应条件的经典化学方法(Kolbe-Schmitt)。尽管现有的酶具有完美的区域选择性，但从热力学上讲，向所需的生物合成羧化方向是不利的，因此不完全转化阻碍了这一方向，这是该项目最艰巨的挑战之一。将研究使用新型工具通过反应萃取原位去除产物的生物催化过程的工程以及离子液体的使用。此外，将评估以产物I为酶II的底物的两个酶反应的级联系统。总体而言，这些战略旨在实现均衡向完全转换的转变。这项建议的另一个主要研究重点将是生物催化剂的工程设计和包括突变体在内的候选酶的底物范围的评估，因为从工业应用的角度来看，后者对于生物催化方法至关重要。

The enzymatic carboxylation of aromatics catalysed by various decarboxylases, using bicarbonate as CO2 source, represents a very promising biosynthetic tool as 'green' alternative to classic chemical (Kolbe-Schmitt) methods which often require harsh reaction conditions. Despite the perfect regio-selectivity of the available enzymes, the direction towards desired biosynthetic carboxylation is thermodynamically disfavored and therefore impeded by incomplete conversion, which represents one of the most demanding challenges within this project. Engineering of the biocatalytic process using novel tools for in-situ product removal by reactive extraction as well as the use of ionic liquids will be investigated. Furthermore, a cascade systems of two enzymatic reaction in which product I is the substrate of enzyme II will be evaluated. Overall, these strategies aim at the shift of the equilibrium towards full conversion. A further main research focus of this proposal will be the engineering of the biocatalysts and the evaluation of the substrate scope of the enzyme candidates including mutants since the latter is of crucial importance for a biocatalytic approach in view of industrial application.