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Rifle Aquifer Bioanode Extracellular Electron Transfer Community

Community ID CommunityMech:000241
Ecological State ENGINEERED
Environment microbial electrochemical cell anode biofilm
ENVO:01001405

An electroactive microbial community established and maintained for almost four years in microbial electrochemical cells (MXCs) inoculated with a well-studied aquifer near Rifle, CO. Anodes were poised mostly at -0.2 to -0.25 V vs SHE to mimic iron-oxide mineral redox potentials, with acetate as the sole carbon source. Genome-resolved metagenomics of two biofilm and 26 planktonic samples yielded 84 bacterial and 2 archaeal near-complete draft genomes. A novel Geobacter sp. with at least 72 putative multiheme c-type cytochromes dominated the electrode-attached community, while diverse other organisms (Actinobacteria, Ignavibacteria, Chloroflexi, Acidobacteria, Firmicutes, Beta- and Gammaproteobacteria) also encoded multiheme cytochromes, porin-cytochrome complexes, and electrically conductive pili (e-pili), identifying a small subset of Rifle aquifer organisms that may mediate mineral redox transformations.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
novel multiheme-cytochrome Geobacter sp. NCBITaxon:28231
PRIMARY_DEGRADER SYNTROPHIC_PARTNER
DOMINANT
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "A novel Geobacter sp. with at least 72 putative multiheme c-type cytochromes (MHCs) was the dominant electrode-attached organism"
EET-capable Rifle aquifer Actinobacteria NCBITaxon:201174
SYNTROPHIC_PARTNER
N/A
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "a diverse range of other electrode-associated organisms also harbored putative MHCs with at least 10 heme-binding motifs, as well as porin-cytochrome complexes and e-pili, including Actinobacteria"
EET-capable Rifle aquifer Ignavibacteria NCBITaxon:1648176
SYNTROPHIC_PARTNER
N/A
EET-capable Rifle aquifer Chloroflexi NCBITaxon:200795
SYNTROPHIC_PARTNER
N/A
EET-capable Rifle aquifer Acidobacteria NCBITaxon:57723
SYNTROPHIC_PARTNER
N/A
EET-capable Rifle aquifer Firmicutes NCBITaxon:1239
SYNTROPHIC_PARTNER
N/A
EET-capable Rifle aquifer Beta- and Gammaproteobacteria NCBITaxon:1224
SYNTROPHIC_PARTNER
N/A
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "Beta- and Gammaproteobacteria"

Ecological Interactions

Ecological interaction network for Rifle Aquifer Bioanode Extracellular Electron Transfer Community Bipartite graph where circle nodes represent taxa and colored rectangles represent ecological interactions (cross-feeding, mutualism, syntrophy, competition, commensalism).
Taxon
Cross-feeding
Mutualism
Syntrophy
Competition
Commensalism
Niche partitioning
Colonization facilitation
Strain competition
Predation

Acetate Oxidation Coupled to Anode Electron Donation

SYNTROPHY

Metabolites: acetate (CHEBI:30089)

Biological Processes:

Evidence

  • PMID:32849356 - SUPPORT (IN_VITRO)
    "using acetate as the sole carbon source"
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "putative MHCs with at least 10 heme-binding motifs, as well as porin-cytochrome complexes and e-pili"

Subset of Rifle Aquifer Organisms Mediates EET

NICHE_PARTITIONING

Evidence

  • PMID:32849356 - SUPPORT (IN_VITRO)
    "a small subset of the thousands of organisms previously detected in the Rifle aquifer that may have the potential to mediate mineral redox transformations"

External Resources

Name Repository Resource ID
Primary publication for the Rifle bioanode community
PubMed record for the Arbour et al. 2020 Frontiers in Microbiology paper. 		OTHER PMID:32849356
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "Diverse Microorganisms in Sediment and Groundwater Are Implicated in Extracellular Redox Processes Based on Genomic Analysis of Bioanode Communities"
DOI landing page
DOI link to the Frontiers in Microbiology paper. 		OTHER doi:10.3389/fmicb.2020.01694

Environmental Factors

Factor Value Unit
Anode redox potential -0.2 to -0.25 V vs SHE N/A
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "anodes poised mostly at -0.2 to -0.25 V vs. SHE, a range that mimics the redox potential of iron-oxide minerals"
Operating duration nearly 4 years of continuous operation N/A
  • PMID:32849356 - SUPPORT (IN_VITRO)
    "maintained for almost 4 years on anodes"