Electron Transfer at Microbe–Mineral Interfaces: From Molecular Mechanisms to Ecosystem-Scale Biogeochemical Cycling and Remediation

Microbe–mineral electron transfer (MMET) drives key microbial processes and biogeochemical cycling, but linking these microscopic interactions to ecosystem-scale dynamics remains a major challenge. MMET couples intracellular metabolism to extracellular mineral transformations. The resulting changes in mineral redox state and reactivity can, in turn, influence microbial energy conservation and metabolism. MMET flux could therefore provide a quantitative link between nanometer-scale electron exchange and larger-scale biogeochemical processes. In energy-limited and contaminated environments, electroactive microorganisms may transfer electrons to or acquire electrons from redox-active minerals, depending on their metabolic capabilities and local redox conditions. These interactions can support energy conservation, mitigate toxic stress, and generate localized zones of high biogeochemical activity. As their effects accumulate across space and time, microscale electron transfer may influence ecosystem-scale elemental cycling, microbial community succession, organic carbon stabilization, and contaminant fate. Building on established modeling approaches, we suggest that integrating individual-based models (IBMs) with genome-scale metabolic models (GSMMs) could translate spatially heterogeneous, genome-informed microbial responses into collective MMET fluxes across scales while accounting for key thermodynamic and kinetic constraints. More broadly, progress requires characterizing electroactive microbial diversity and mechanisms, engineering microbe–mineral interfaces through computational design and synthetic biology, and translating MMET principles into scalable environmental applications.