Power to value-added products via electro-biotechnology: Production of bulk chemicals by combining electrochemical and biocatalytic steps in “one-pot” with “green” electricity

通过桥接电化学（Schäfer组，奥斯纳布吕克大学）和生物催化（Gröger组，比勒费尔德大学）的专业知识，该串联项目集中在开发一种新型的化学酶一锅级联工艺技术，包括有机分子的电化学功能化，然后是酶催化步骤，中间体然后转化为最终所需的目标分子。电化学和生物技术的这种类型的组合将使“正式”获得所谓的“梦想反应”，定义为化学转化，其中还没有（单一）催化剂存在。例如，在本项目中，将讨论（取代的）甲苯在形成（取代的）苄胺下的直接一锅胺化。利用仅利用O2（来自空气）和氨的优势，这种可持续的工艺技术在增值散装化学品和电力到产品工艺的新型制造路线方面，对于未来生物经济的应用也具有高度吸引力。这种一锅级联策略是基于甲苯的初始电化学氧化，导致苯甲醛，随后在形成苄胺的情况下进行酶促还原胺化。值得注意的是，作为第二电化学步骤，将进行原位形成的辅因子NAD+的氧化形式的还原，从而再生酶促还原胺化所需的辅因子NADH。因此，对于该方法，仅需要O2和NH3作为试剂和“绿色能源”（太阳能、风能）。然而，挑战将是优选在水中实现各个步骤以及实现这些步骤的相容性。

By bridging the expertises in electrochemistry (Schäfer group, Osnabrück University) and biocatalysis (Gröger group, Bielefeld University), this tandem project centers on the development of a novel type of chemoenzymatic one-pot cascade process technology consisting of an electrochemical functionalization of an organic molecule, followed by an enzyme-catalyzed step in which the intermediate is then converted into the final desired target molecule. Such types of combinations of electrochemistry and biotechnology will enable “formal” access to so-called “dream reactions”, defined as chemical transformations, for which no (single) catalyst exists yet. For instance, in this project a direct one-pot amination of (substituted) toluenes under formation of (substituted) benzylamines will be addressed. Taking advantage of utilizing solely O2 (from air) and ammonia, such a sustainable process technology would be also highly attractive for future applications in bioeconomy in terms of novel manufacturing routes for value-added bulk chemicals and power-to-product processes. Such a one-pot cascade strategy is based on an initial electrochemical oxidation of toluene(s) leading to benzaldehyde(s) and subsequent enzymatic reductive amination under formation of benzylamines. It is noteworthy that as a second electrochemical step, reduction of the in situ-formed oxidative form of the cofactor, NAD+, thus regenerating the cofactor NADH being needed for the enzymatic reductive amination, will be conducted. Thus, for this process only O2 and NH3 are needed as reagents and “green energy” (solar energy, wind energy). A challenge, however, will be to realize the individual steps preferably in water as well as to achieve compatibility of these steps.