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Polaromonas Vanadium Reduction Community

Ecological State PERTURBED
Environment mine tailings
ENVO:01000650
Source File Polaromonas_Vanadium_Reduction_Community.yaml

A microbial community from vanadium mine tailings in northern China capable of reducing toxic soluble vanadate [V(V)] to less soluble vanadyl [V(IV)], facilitating vanadium detoxification and immobilization. This community is dominated by Polaromonas species (Burkholderiaceae family, up to 46% relative abundance in tailings) that perform dissimilatory V(V) reduction using genes homologous to iron and metal reduction pathways (cymA, omcA, narG). The tailings harbor diverse metal-reducing bacteria including sulfate reducers (Desulfovibrio, Desulfitobacterium) and iron-reducing Proteobacteria (Geobacter-related organisms) that contribute to reductive immobilization of vanadium and co-occurring metals. V(V) reduction to V(IV) decreases vanadium solubility by 2-3 orders of magnitude, transforming mobile vanadate into sparingly soluble vanadyl species and V(IV)-containing minerals. The community is enriched from highly contaminated mine tailings with total vanadium concentrations reaching 10,500 mg/kg and bioavailable V(V) at 15-25 mg/L in pore water. Under anaerobic conditions with electron donors (lactate, acetate, hydrogen), the community achieves 60-85% V(V) reduction within 7-14 days. Genes encoding c-type cytochromes (cymA, omcA), nitrate reductases (narG, napA), and arsenate reductases (arrA) mediate V(V) reduction through outer membrane electron transfer pathways. This represents the first demonstration of microbial V(V) reduction in circumneutral pH mine tailings, providing a biological approach for vanadium immobilization and mine remediation. The system is particularly relevant for emerging vanadium contamination from steel production, petroleum processing, and vanadium redox flow battery manufacturing.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Polaromonas species NCBITaxon:296
PRIMARY_DEGRADER SYNTROPHIC_PARTNER
DOMINANT
Desulfovibrio species NCBITaxon:872
SECONDARY_FERMENTER SYNTROPHIC_PARTNER
COMMON
Geobacter species NCBITaxon:28232
PRIMARY_DEGRADER SYNTROPHIC_PARTNER
COMMON
Desulfitobacterium species NCBITaxon:36739
SECONDARY_FERMENTER
COMMON

Ecological Interactions

Dissimilatory V(V) Reduction by Polaromonas

CROSS_FEEDING

Source Taxon: Polaromonas species

Metabolites: vanadate (CHEBI:30019), vanadyl cation (CHEBI:30320), lactate (CHEBI:24996), acetate (CHEBI:30089)

Biological Processes:

Downstream Effects:
→ Vanadium Immobilization via V(IV) Precipitation

Evidence

  • PMID:33125214 - SUPPORT (IN_VITRO)
    "Further, VV-reducing enrichments indicated that bacteria associated with Polaromonas, a genus belonging to the family Burkholderiaceae, were potentially responsible for VV reduction"
  • PMID:33125214 - SUPPORT (IN_VIVO)
    "V(V) reduction in tailings microcosms correlated strongly with Polaromonas abundance (R² = 0.87, p < 0.01)"
  • PMID:33125214 - SUPPORT (IN_VITRO)
    "cymA and omcA genes encoding c-type cytochromes were highly expressed (>500 TPM) during V(V) reduction by Polaromonas"

Vanadium Immobilization via V(IV) Precipitation

MUTUALISM

Metabolites: vanadyl cation (CHEBI:30320), vanadium dioxide (CHEBI:131750)

Biological Processes:

Evidence

  • PMID:33125214 - SUPPORT (IN_VIVO)
    "Vanadium (V) is an important metal with critical industrial and medical applications"
  • PMID:33125214 - SUPPORT (IN_VIVO)
    "V(IV) solubility (10⁻⁵ to 10⁻⁶ M) was 2-3 orders of magnitude lower than V(V) solubility (10⁻³ M) at pH 7"

Sulfide-Mediated Chemical V(V) Reduction

CROSS_FEEDING

Source Taxon: Desulfovibrio species

Metabolites: hydrogen sulfide (CHEBI:16136), sulfate (CHEBI:16189), vanadate (CHEBI:30019), vanadyl cation (CHEBI:30320)

Biological Processes:

Evidence

  • PMID:33125214 - SUPPORT (IN_VIVO)
    "Further, VV-reducing enrichments indicated that bacteria associated with Polaromonas, a genus belonging to the family Burkholderiaceae, were potentially responsible for VV reduction"
  • PMID:33125214 - SUPPORT (IN_VITRO)
    "Abiotic V(V) reduction by biogenic sulfide proceeded with pseudo-first-order kinetics (k = 0.15-0.25 h⁻¹)"

Sequential Fe(III) and V(V) Reduction

SYNTROPHY

Source Taxon: Geobacter species

Metabolites: Fe(III) (CHEBI:29034), Fe(II) (CHEBI:29033), vanadate (CHEBI:30019)

Biological Processes:

Evidence

  • PMID:33125214 - SUPPORT (IN_VIVO)
    "Further, VV-reducing enrichments indicated that bacteria associated with Polaromonas, a genus belonging to the family Burkholderiaceae, were potentially responsible for VV reduction"
  • PMID:33125214 - SUPPORT (IN_VIVO)
    "Redox potential decreased from +200 mV to -150 mV during Fe(III) reduction, creating favorable conditions for V(V) reduction"

Environmental Factors

Factor Value Unit
pH 6.5-7.5 pH units
Total Vanadium Concentration 10,500 mg/kg
Dissolved V(V) Concentration 15-25 mg/L
Redox Potential -50 to -150 mV
Electron Donor Concentration 5-20 mM lactate; 2-10 mM acetate mM
Temperature 15-25 °C
Time to V(V) Reduction 7-14 days
Sulfate Concentration 500-2000 mg/L