1 Final Report of GCEP Project Synthesis of Biofuels on Bioelectrodes

Microbial electrosynthesis of multi-carbon organic compounds is a promising novel technology for converting electricity into renewable organic molecules as well as for storing electrical energy. This project explored the breath of possible platform organisms to be used in this emerging technology and identified the potential as well as the limitations. Of the multiple microorganism and experimental settings tested, microbial electromethanogenesis is emerging as a strong technology platform, and we provided the first insights in the molecular mechanism of cathodic electron uptake as well as operation and resilience of the system. This project provided the basis for important follow-up studies on microbial electrosynthesis. Introduction Petroleum and other fossil hydrocarbons are primarily used as energy source for liquid (transportation) fuels as well as raw material for organic syntheses of commodity and fine chemicals. These uses represent the largest contribution to a net release of CO 2 and global warming. Development of novel and alternative energy technologies to reduce or eliminate net CO 2 release are urgently needed but often limited by their incompatibility with the current liquid hydrocarbon-based infrastructure (e.g. H 2 or electricity) in storage, transport, and use. Currently, solar and wind energy are the most promising sources for renewable energy, and, similarly as nuclear energy, produce electricity as the primary energy form. In the absence of better electricity and distribution technologies (e.g. battery), new approaches are needed to connect electrical energy to the infrastructure advantages of hydrocarbon fuels. This project explored ideas and examined the bottlenecks of a new technology linking electricity to synthesis of fuels and other useful chemicals at cathodes using microorganisms (Fig. 1).