Renewable electricity–driven microbial electrosynthesis for high-value CO2 valorization: recent trends

Abstract Microbial electrosynthesis (MES) employs electroactive, self-replicating biocatalysts at the cathode of a bioelectrochemical system to reduce CO₂ and synthesize acetate and other volatile fatty acids, as well as intracellular products such as polyhydroxybutyrate (PHB) and single cell protein (SCP). Interest in MES is growing because it provides a platform to convert renewable electricity into valuable chemical intermediates for the future electrified society. Recent advances in electrode materials, reactor configurations, and strain improvement using synthetic biology have improved titers, rates, and selectivity of MES. This review summarizes recent trends in CO 2 conversion to volatile fatty acids and longer chain products, the use of MES for biogas upgrading, and the production of PHB and SCP from CO 2 derived intermediates. Recent reports show acetate production with coulombic efficiencies often exceeding 90% and titers up to 29.4 g/L in continuous thermophilic H 2 mediated MES, alongside biogas upgrading to 95% CH 4 with methane production rate 8.8 L CH 4 /m 2 cat/day using biogas from an operating anaerobic digestion plant. Overall, MES provides a promising platform for recycling and valorizing greenhouse gases (GHGs) into useful chemicals, supporting future sustainable process development.