Enzyme and reaction engineering of unspecific peroxygenase driven hydroxylation of butane (BUPOx)

Holtmann教授和Liese教授的这一联合建议旨在深入了解工艺参数对短链烷烃氧基官能化生物催化效率的影响和相互作用。以新近出现的酶系催化丁烷不对称羟基化合成2-丁醇为例，对非特异性过氧化物酶(UPO)进行了详细的跨学科过程研究。在第一次鼓泡塔实验中，两组的共同初步研究已经证明了反应体系的可行性，同时有必要进行更详细的调查，以掌握观察到的拮抗效果。首先，将对一种模型酶AaeUPO进行鉴定。特别令人感兴趣的是关于过氧化氢进料速度和丁烷气态进料的放气效应的稳定性。为了提高相关的选择性，将把筛选新的UPO变体(对映体选择性)与反应工程结合起来，重点放在通过萃取原位去除产物(过程选择性)。由于UPO显示的底物范围很广，为了同时找到不是底物的合适溶剂，有必要进行“反向”底物筛选。最后，有希望的UPO变体将被固定在集成在反应器中的气体扩散电极上。通过这种方法，在克服UPO催化羟基化的限制因素方面，产生了新的基础知识。

This joint proposal of the working groups of Prof. Holtmann and Prof. Liese aims at the profound understanding of the influences and interactions of process parameters on the biocatalytic efficiency of the oxy functionalization of short chain alkanes. On the example of the asymmetric hydroxylation of butane to 2-butanol catalyzed by the recently emerging enzyme group, the unspecific peroxidases (UPO) detailed interdisciplinary process studies are carried out. The feasibility of the reaction system was already demonstrated in common preliminary research by the two groups in first bubble column experiments and at the same time the necessity for more detailed investigations to grasp the observed antagonistic effects. At first a model enzyme, the AaeUPO, will be characterized. Of particular interest is the stability regarding hydrogen peroxide feed rate and gassing effects from gaseous butane feed. To improve relevant selectivities a screening for new UPO variants (enantioselectivity) will be combined with reaction engineering, focusing on in situ product removal by extraction (process selectivity). As UPOs display a broad substrate scope, a “reversed” substrate screening is necessary to find suitable solvents that are not substrates at the same time. Lastly, promising UPO variants will be immobilized on a gas diffusion electrode that is integrated in the reactor. By this means new fundamental knowledge is generated in terms of overcoming limiting factors for hydroxylations catalyzed by UPOs.