A methane-fed, nitrogen-limited microbial fuel-cell enrichment that couples anaerobic methane oxidation, extracellular electron transfer, current generation, and biological nitrogen fixation through a reported division of labor. The six genera recorded here are the functional groups named by the source, not a claim that the enrichment contains only six taxa.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Methanobacterium | NCBITaxon:2160 · TaxonMech · TraitMech |
SYNTROPHIC_PARTNER
|
N/A |
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| Geobacter | NCBITaxon:28231 · TaxonMech · TraitMech |
ELECTROGEN
SYNTROPHIC_PARTNER
|
N/A |
|
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| Desulfovibrio | NCBITaxon:872 · TaxonMech · TraitMech |
ELECTROGEN
SYNTROPHIC_PARTNER
|
N/A |
|
|||
| Sulfurivermis | NCBITaxon:2034504 · TaxonMech · TraitMech |
SYNTROPHIC_PARTNER
|
N/A |
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| Desulfobulbus | NCBITaxon:893 · TaxonMech · TraitMech |
SYNTROPHIC_PARTNER
|
N/A |
|
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| Azoarcus | NCBITaxon:12960 · TaxonMech · TraitMech |
SYNTROPHIC_PARTNER
|
N/A |
|
|||
Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Methane-Fed Syntrophic Division of Labor
The methane-fed, nitrogen-limited enrichment generated current and fixed nitrogen. DNA-SIP/sequencing supported the authors' division-of-labor interpretation: Methanobacterium for methane oxidation, Geobacter/Desulfovibrio for EET and Sulfurivermis/Desulfobulbus/Azoarcus for diazotrophy. These six reported functional groups are not a complete roster or a defined six-isolate test. The abstract does not resolve obligatory reciprocal dependence, exact partner exchanges or quantitative pathway shares.
Participating Taxa: Methanobacterium, Geobacter, Desulfovibrio, Sulfurivermis, Desulfobulbus, Azoarcus
Metabolites: methane (CHEBI:16183 · MediaIngredientMech · CMMMech), ammonium (CHEBI:28938 · MediaIngredientMech · CMMMech)
Evidence
-
PMID:42551599 - SUPPORT (IN_VITRO)"concurrent electrogenesis and BNF via a syntrophic division of labor mechanism"
Reported Extracellular Electron-Transfer Guild
DNA-SIP combined with sequencing assigned Geobacter and Desulfovibrio to EET in the enriched methane-fed fuel cell. Retain this reported functional assignment, not direct evidence that every member expresses the same cytochromes, that either genus is individually necessary, or that a measured limited-resource niche was partitioned. Taxon-resolved pathway and inhibitor-control details are unavailable at abstract scope.
Participating Taxa: Geobacter, Desulfovibrio
PARTIAL - the assigned EET guild could contribute to the cytochrome c-associated current pathway. Community electrochemistry and inhibitor results support that pathway, but the accessible abstract does not isolate each genus' contribution or establish an exclusive partner-to-electrode route.
Evidence
-
PMID:42551599 - SUPPORT (IN_VITRO)"Geobacter and Desulfovibrio specialized in EET"
Core Diazotroph Specialization
Sulfurivermis, Desulfobulbus and Azoarcus were reported as core diazotrophs based on DNA-SIP/sequencing. This preserves the study's assignment without equating community-level isotope incorporation with separately measured fixation by each genus or experimental proof of niche partitioning.
Participating Taxa: Sulfurivermis, Desulfobulbus, Azoarcus
Biological Processes:
- nitrogen fixation (GO:0009399 · PathwayMech)
PARTIAL - activity of the assigned diazotroph guild could account for fixed nitrogen accumulating in the medium. The 15N2 result demonstrates positive fixation at enrichment level, but contributions of individual genera, release routes and subsequent cross-feeding are not quantified in the abstract.
Evidence
-
PMID:42551599 - SUPPORT (IN_VITRO)"Sulfurivermis, Desulfobulbus and Azoarcus acted as the core diazotrophs"
Nitrogen Fixation to Ammonium Accumulation
The whole enrichment incorporated supplied 15N2: reported 15N abundances reached 13.55% in biomass and 7.15% in aqueous ammonium. Ammonium accumulated to 0.22 +/- 0.01 mg/L over 30 days. These positive isotope results support biological nitrogen fixation, not merely ammonium accumulation. Participants denote the reported enrichment subset, not six individually proven fixers; the three assigned diazotrophs are distinguished in the guild node. Net accumulation does not equal gross fixation or resolved donor-to-recipient transfer.
Participating Taxa: Methanobacterium, Geobacter, Desulfovibrio, Sulfurivermis, Desulfobulbus, Azoarcus
Metabolites: dinitrogen (CHEBI:17997 · MediaIngredientMech · CMMMech), ammonium (CHEBI:28938 · MediaIngredientMech · CMMMech)
Biological Processes:
- nitrogen fixation (GO:0009399 · PathwayMech)
Evidence
-
PMID:42551599 - PARTIAL (IN_VITRO)"Sulfurivermis, Desulfobulbus and Azoarcus acted as the core diazotrophs"
-
PMID:42551599 - SUPPORT (IN_VITRO)"ammonium in the medium accumulated to 0.22 ± 0.01 mg/L over a 30-day operation"
Cytochrome c-Mediated Electrogenesis
The enrichment reached 1.17 +/- 0.18 mA peak current with 78.1% Coulombic efficiency. Electrochemical and inhibitor assays identified cytochrome c-mediated electron transfer as the dominant pathway, and Raman spectroscopy detected 15N incorporation into cytochrome c. Preserve these positive whole-system results; labeled cytochrome synthesis does not itself demonstrate that newly fixed nitrogen caused increased current, nor assign the entire pathway to the two EET genera. The abstract does not establish an exclusive route or identify all relevant controls.
Participating Taxa: Methanobacterium, Geobacter, Desulfovibrio, Sulfurivermis, Desulfobulbus, Azoarcus
Biological Processes:
- electron transport chain (GO:0022900 · PathwayMech)
Evidence
-
PMID:42551599 - SUPPORT (IN_VITRO)"electrochemical analyses and inhibitor assays identified cytochrome c-mediated electron transfer as the dominant pathway for electrogenesis"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN How are methane oxidation, fixed nitrogen and cytochrome current causally distributed among members?
Positive isotope, current and inhibitor results are retained; both guild-to-endpoint arrows remain PARTIAL. Whole-enrichment endpoints are distinct from DNA-SIP functional assignments. Label incorporation into cytochrome is not a selective test that nitrogen fixation improves current. Full Methods, inhibitor specificity, cross-feeding controls and exact taxon fluxes were unavailable: public publisher links failed, and only the primary abstract was read. #1598 bounds existing nodes/arrows; #1600 retains non-graph roles and protocol uncertainty. No new methane or nitrogen-to-current arrow is asserted.
Attaches to: ecological_interactions#Methane-Fed Syntrophic Division of Labor, ecological_interactions#Reported Extracellular Electron-Transfer Guild, ecological_interactions#Core Diazotroph Specialization, ecological_interactions#Nitrogen Fixation to Ammonium Accumulation, ecological_interactions#Cytochrome c-Mediated Electrogenesis
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
Primary publication - methane-driven MFC electrogenesis and nitrogen fixation
Primary DNA-SIP, nitrogen-15 SIP, spectroscopy, electrochemistry, and sequencing study of the consortium. |
OTHER | PMID:42551599 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Carbon and nitrogen regime | methane-fed and nitrogen-limited | N/A |
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| Operation duration | 30 | days |
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Growth Media
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