A defined laboratory coculture in which the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 and the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens cycle electrons through magnetite. The system demonstrates that mixed-valence magnetite can act as a recyclable electron donor and electron acceptor, effectively functioning as a naturally occurring biogeochemical battery under changing light and redox conditions. This community is DOE-relevant because mineral-mediated electron flow shapes subsurface elemental cycling and can influence contaminant fate in sediments, aquifers, and engineered remediation settings.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Rhodopseudomonas palustris TIE-1 | NCBITaxon:395960 |
PRIMARY_PRODUCER
CROSS_FEEDER
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ABUNDANT |
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| Geobacter sulfurreducens | NCBITaxon:35554 |
CROSS_FEEDER
SYNTROPHIC_PARTNER
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ABUNDANT |
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Ecological Interactions
Magnetite-Mediated Electron Sharing
CROSS_FEEDINGSource Taxon: Rhodopseudomonas palustris TIE-1
Target Taxon: Geobacter sulfurreducens
Metabolites: magnetite (CHEBI:50821), Fe(II) (CHEBI:29033), Fe(III) (CHEBI:29034)
Biological Processes:
- oxidation-reduction process (GO:0055114)
- iron ion transport (GO:0006826)
Evidence
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PMID:25814583 - SUPPORT (IN_VITRO)"sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms"
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PMID:25814583 - SUPPORT (IN_VITRO)"bioavailable as electron sinks and electron sources"
Phototrophic Magnetite Fe(II) Oxidation
NICHE_PARTITIONINGSource Taxon: Rhodopseudomonas palustris TIE-1
Metabolites: magnetite (CHEBI:50821), Fe(II) (CHEBI:29033)
Biological Processes:
- photosynthesis (GO:0015979)
- oxidation-reduction process (GO:0055114)
Evidence
-
PMID:25814583 - SUPPORT (IN_VITRO)"Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy"
Anaerobic Magnetite Fe(III) Reduction
NICHE_PARTITIONINGSource Taxon: Geobacter sulfurreducens
Metabolites: magnetite (CHEBI:50821), Fe(III) (CHEBI:29034), Fe(II) (CHEBI:29033)
Biological Processes:
- oxidation-reduction process (GO:0055114)
- iron ion transport (GO:0006826)
Evidence
-
PMID:25814583 - SUPPORT (IN_VITRO)"reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens"
Biogeochemical Battery Function
SYNTROPHYMetabolites: magnetite (CHEBI:50821)
Biological Processes:
- oxidation-reduction process (GO:0055114)
Evidence
-
PMID:25814583 - SUPPORT (IN_VITRO)"effectively rendering magnetite a naturally occurring battery"
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doi:10.1126/science.aaa4834 - SUPPORT (IN_VITRO)"magnetite, which contains both Fe(II) and Fe(III), can serve as both an electron acceptor and donor"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
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Magnetite redox cycling primary publication
Primary Science publication reporting magnetic and spectroscopic measurements of reversible magnetite redox cycling by R. palustris TIE-1 and G. sulfurreducens cocultures. |
PHENOTYPE | OTHER | PMID:25814583 |
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
DOE BER Science Highlight - Microbes Use Tiny Magnets as Batteries
DOE Biological and Environmental Research highlight describing the subsurface electron-flow relevance of the R. palustris TIE-1 and G. sulfurreducens magnetite battery study. |
OTHER | BER-2015-microbes-use-tiny-magnets |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Magnetite nanoparticles | mixed-valence Fe3O4 mineral substrate | N/A |
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| Light energy | required for phototrophic Fe(II) oxidation by TIE-1 | N/A |
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| Changing redox conditions | varying environmental conditions | N/A |
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