Integrated Electromicrobial Conversion of CO ₂ to Higher Alcohols

TLDR

Storing electrical energy efficiently is difficult; existing methods such as batteries, hydraulic pumping, and water splitting have low energy density or are incompatible with current transportation infrastructure. The authors propose a method to store electrical energy as chemical energy in higher alcohols that can serve as liquid transportation fuels. They genetically engineered the lithoautotrophic bacterium *Ralstonia eutropha* H16 to produce isobutanol and 3‑methyl‑1‑butanol in an electro‑bioreactor using CO₂ as the sole carbon source and electricity as the sole energy input. The integrated process couples electrochemical formate production with biological CO₂ fixation and higher‑alcohol synthesis, demonstrating a pathway for electricity‑driven conversion of CO₂ into commercial chemicals.

Abstract

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.