Light-powered bioelectrochemical conversion of CO2 for the synthesis of value-added chemicals based on gas-diffusion electrodes and enzyme cascades

近年来，CO2的（生物）电化学转化为增值化学品得到了极大的关注。相关的经济上可行的和可持续的系统将减少全球CO2量，并规避与使用化石燃料进行碳基化学品生产相关的缺点。在这个项目中，我们将开发新的氧化还原聚合物，允许扭曲的氧化还原蛋白质甲酸脱氢酶（FDH），可逆地催化CO2的相互转化为甲酸使用气体扩散电极。然后，该活性CO2还原层将与酶级联耦合，其中C1前体甲酸盐进一步转化为增值的化学甲醇。整个酶级联将被固定在电极表面，以确保该方法对技术相关系统的适用性。开发的CO2还原生物阴极然后将耦合到光电化学电池中的高电流密度聚合物/光系统II基生物阳极，该光电化学电池允许从CO2作为唯一的碳原料太阳能驱动生产甲醇。所提出的系统的优点是明显的：（i）使用3D结构的氧化还原聚合物将通过同时为生物催化剂提供合适的亲水环境而使大量生物催化剂布线到电极表面;（ii）气体扩散电极的实施将克服质量传输限制，以及（iii）使用光来为甲醇的生产提供动力将导致可持续的和生态友好的整个制造过程。

The (bio)electrochemical conversion of CO2 to value added chemicals has gained great attention during recent years. Related economically viable and sustainable systems would decrease the global CO2 volume and circumvent drawbacks that are coupled to the use of fossil fuels for carbon base chemical production. In this project we will develop new redox polymers that allow for the wring of the redox protein formate dehydrogenase (FDH) that catalyses reversibly the interconversion of CO2 to formate using gas diffusion electrodes. This active CO2 reduction layer will then be coupled to enzyme cascades in which the C1 precursor formate is further converted into the value-added chemical methanol. The entire enzyme cascade will be immobilized at the electrode surface to ensure applicability of the approach towards technical relevant systems. The developed CO2 reducing biocathode will then be coupled to a high current density polymer/photo-system II-based bioanode in a photoelectrochemical cell that allows for solar-driven production of methanol from CO2 acting as the only carbon feedstock. The advantages of the proposed system are obvious: (i) the use of a 3D-structured redox polymer will enable the wiring of a high number of biocatalyst to the electrode surface by simultaneously providing a suitable hydrophilic environment for the biocatalyst; (ii) the implementation of gas diffusion electrodes will overcome mass transport limitations and (iii) the use of light to power the production of methanol will lead to a sustainable and eco-friendly overall manufacturing process.