biostudies-literatureHolmes DEDOD | United States Army | RDECOM | ARO | Life Sciences Division, Army Research Officee0234421https://www.ebi.ac.uk/biostudies/studies/S-EPMC8546582biostudies-literatureUnknown12(5)Direct interspecies electron transfer (DIET) between bacteria and methanogenic archaea appears to be an important syntrophy in both natural and engineered methanogenic environments. However, the electrical connections on the outer surface of methanogens and the subsequent processing of electrons for carbon dioxide reduction to methane are poorly understood. Here, we report that the genetically tractable methanogen Methanosarcina acetivorans can grow via DIET in coculture with Geobacter metallireducens serving as the electron-donating partner. Comparison of gene expression patterns in <i>M. acetivorans</i> grown in coculture versus pure-culture growth on acetate revealed that transcripts for the outer-surface multiheme <i>c-</i>type cytochrome MmcA were higher during DIET-based growth. DelemBioMechanisms for Electron Uptake by Methanosarcina acetivorans during Direct Interspecies Electron Transfer.PMC8546582W911NF-17-1-0345Woodard TLovley DRHolmes DEZhou JUeki TfalseMechanisms for Electron Uptake by Methanosarcina acetivorans during Direct Interspecies Electron Transfer.Direct interspecies electron transfer (DIET) between bacteria and methanogenic archaea appears to be an important syntrophy in both natural and engineered methanogenic environments. However, the electrical connections on the outer surface of methanogens and the subsequent processing of electrons for carbon dioxide reduction to methane are poorly understood. Here, we report that the genetically tractable methanogen Methanosarcina acetivorans can grow via DIET in coculture with Geobacter metallireducens serving as the electron-donating partner. Comparison of gene expression patterns in <i>M. acetivorans</i> grown in coculture versus pure-culture growth on acetate revealed that transcripts for the outer-surface multiheme <i>c-</i>type cytochrome MmcA were higher during DIET-based growth. Dele2021-01-01T00:00:00Z2021 Oct2026-06-12T09:53:16.4Z2025-02-19T03:24:00.885ZS-EPMC85465823460745110.1128/mBio.02344-21