Recent advances and perspectives on N2 fixation by microbial bioelectrochemical systems.
A. Rous, J. A. Behan, E. Desmond-Le Quéméner, N. Bernet, E. Trably, F. Gloaguen, F. Barrière, Bioelectrochemistry 2026, 168, 109123, DOI: 10.1016/j.bioelechem.2025.109123
This review covers recent advances in the fixing of dinitrogen in microbial bioelectrochemical systems (BES) where bacteria release or accept electron to/from electrodes for their respiratory metabolism, either directly or indirectly. We discuss how BES may be interesting platforms for producing ammonium or biomass from N2 fixation. The potential for N2-fixation in BES is first discussed with a focus on possible metabolism and different mechanism that may lead to an increase of fixed dinitrogen. We then review recent examples where dinitrogen is fixed at the cathodes of BES, either by pure cultures of hydrogenotrophic and/or diazotrophic bacteria using cathodic H2 or reduced redox mediators as the electron, or by mixed enriched consortia. A section is then devoted to the special case of nitrogen fixation at anodic microbial electrode where organic matter oxidation also occurs. Finally, a comparison of the reported current performance of nitrogen fixation in BES with other biotic (anerobic digestion) or abiotic (Haber-Bosch process, electrochemical N2 reduction) is provided together with a perspective on possible optimization and application of this emerging microbial electrochemical and technological process.