TraitMech

TraitMech › METABOLISM

iron oxidation

traitmech:000107 · CLASS · REVIEWED

A metabolism in which an organism oxidizes ferrous iron (Fe2+) to ferric iron (Fe3+) to conserve energy, at acidic or circumneutral pH and under aerobic or anaerobic conditions.

Ferrous iron oxidation for energy

Evidence-backed causal sketch linking the iron-oxidation trait to oxidation of ferrous iron to ferric iron for energy conservation.

Ferrous iron oxidation for energy Interactive directed graph showing evidence-backed causal relationships for iron oxidation.

Edge evidence

  • iron oxidation oxidizes ferrous iron METPO:2000016

    Iron oxidizers oxidize ferrous iron as an electron donor.

    • DOI:10.1146/annurev.micro.112408.134208 Emerson et al. review iron-oxidizing bacteria that use Fe(II) for energy.
  • iron oxidation produces ferric iron METPO:2000202

    Ferrous-iron oxidation yields ferric iron.

    • DOI:10.1099/mic.0.045344-0 Hedrich et al. describe Fe(II) to Fe(III) oxidation by iron-oxidizing proteobacteria.
  • Cyc2 oxidizes ferrous iron METPO:2000016

    The outer-membrane cytochrome Cyc2 extracts electrons from extracellular Fe(II).

    • DOI:10.1128/mSystems.00720-23 "electrons are initially extracted from extracellular Fe(II) by the outer membrane cytochrome c Cyc2"; Cyc2 also validated in neutrophiles.
  • cbb3-type terminal oxidase supports growth in microaerobic conditions

    High-O2-affinity cbb3 oxidase enables FeOB growth under microaerobic conditions.

    • DOI:10.1128/AEM.00599-24 "These terminal oxidases have high affinity for oxygen and therefore are widely understood to be used under microaerobic conditions"; consistent with FeOB ecology.
  • cytochrome bd-type terminal oxidase supports growth in low-oxygen organic-rich niche

    High-O2-affinity cytochrome bd oxidase supports FeOB growth in low-oxygen, organic-rich niches.

    • DOI:10.1128/mSystems.00038-23 "cytochrome bd-type oxidases have a high affinity for oxygen ... can be more highly expressed ... under low-oxygen, organic-rich conditions".
  • nitrite and nitric oxide negatively regulates enzymatic iron oxidation

    Nitrite and NO bind hemes inhibiting cytochromes and abiotically oxidize Fe(II), competing with enzymatic iron oxidation.

    • DOI:10.1128/mSystems.00038-23 "they bind to hemes, inhibiting the activity of cytochromes, and also directly oxidize Fe(II), thus competing with enzymatic iron oxidation".
  • multiheme c-type cytochromes enables extracellular electron transfer RO:0002327

    FeOB multiheme cytochromes conduct electrons across long distances and broad redox potentials, enabling extracellular electron transfer.

    • DOI:10.1128/mSystems.00038-23 "MHCs efficiently conduct electrons across longer distances and function across a wide range of redox potentials ... which can expand the range of usable iron substrates".

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1146/annurev.micro.112408.134208

Parent traits (1)

Synonyms (1)

  • ferrous iron oxidation RELATED_SYNONYM · DOI:10.1146/annurev.micro.112408.134208

kg-microbe context

Matched 1 kg-microbe node via parent_proxy.

  • METPO:1000060 [-1.052, -1.766, -1.194, +0.291, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Curation history

  1. · PROPOSED_FROM_RESEARCH · claude

    Proposed candidate METABOLISM trait (iron oxidation); round 2, metal-cycle gap. Complements round-1 dissimilatory iron reduction.

  2. · CURATED_CAUSAL_GRAPH · claude

    Added evidence-backed causal graph (Fe(II) to Fe(III) oxidation) with CHEBI node groundings and METPO predicate groundings; promoted PROPOSED to REVIEWED.

  3. · ENRICH_CAUSAL_GRAPH · claude

    Added 5 evidence-backed generic edges (9 new nodes) from the deep-research report.

  4. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000016×1, RO:0002327×1).