Integrated electromicrobial conversion of CO2 to higher alcohols.

One of the major challenges in using electrical energy is the efficiency in its storage. Current methods, such as chemical batteries, hydraulic pumping, and water splitting, suffer from low energy density or incompatibility with current transportation infrastructure. Here, we report a method to store electrical energy as chemical energy in higher alcohols, which can be used as liquid transportation fuels. We genetically engineered a lithoautotrophic microorganism, Ralstonia eutropha H16, to produce isobutanol and 3-methyl-1-butanol in an electro-bioreactor using CO(2) as the sole carbon source and electricity as the sole energy input. The process integrates electrochemical formate production and biological CO(2) fixation and higher alcohol synthesis, opening the possibility of electricity-driven bioconversion of CO(2) to commercial chemicals.