identifier: traitmech:000106 label: sulfur oxidation definition: A metabolism in which an organism oxidizes reduced inorganic sulfur compounds (sulfide, elemental sulfur, thiosulfate) to sulfate, conserving energy and often supporting chemolithotrophic growth. definition_source: DOI:10.1111/j.1574-6976.2009.00187.x trait_category: METABOLISM term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000060 synonyms: - synonym_text: sulfide oxidation synonym_type: NARROW_SYNONYM source: DOI:10.1111/j.1574-6976.2009.00187.x evidence: - reference: DOI:10.1111/j.1574-6976.2009.00187.x notes: Ghosh & Dam review the biochemistry and molecular biology of lithotrophic sulfur oxidation across bacteria and archaea. - reference: DOI:10.1128/AEM.67.7.2873-2882.2001 notes: Friedrich et al. describe a common mechanism for bacterial oxidation of reduced inorganic sulfur compounds (the Sox system). canonical_examples: - taxon_id: NCBITaxon:36861 taxon_label: Thiobacillus denitrificans note: "Obligately chemolithoautotrophic sulfur-compound oxidizer with a sequenced genome anchoring sulfur-oxidation pathways. Beggiatoa is a historic morphological exemplar." reference: https://pmc.ncbi.nlm.nih.gov/articles/PMC1367237/ causal_graphs: - graph_id: sulfur_oxidation_sox title: Lithotrophic sulfur oxidation to sulfate description: Evidence-backed causal sketch linking sulfur-oxidizing enzyme systems to oxidation of reduced sulfur compounds to sulfate. nodes: - node_id: sulfur_oxidation_trait label: sulfur oxidation node_type: TRAIT grounding: traitmech:000106 description: Capacity to oxidize reduced inorganic sulfur to sulfate. - node_id: sox_system label: Sox enzyme system node_type: GENE_OR_PROTEIN description: Sulfur-oxidizing multienzyme system. - node_id: hydrogen_sulfide label: hydrogen sulfide node_type: CHEMICAL grounding: CHEBI:16136 description: Reduced inorganic sulfur substrate. - node_id: sulfate label: sulfate node_type: CHEMICAL grounding: CHEBI:16189 description: Oxidized sulfur end product. - node_id: sqr_enzyme label: sulfide:quinone oxidoreductase (SQR) node_type: GENE_OR_PROTEIN description: Membrane flavoprotein oxidizing sulfide to sulfane sulfur/polysulfide. - node_id: sulfane_sulfur label: sulfane sulfur node_type: CHEMICAL grounding: CHEBI:15037 description: Sulfane sulfur / S0 / polysulfide intermediate. - node_id: pdo_enzyme label: persulfide dioxygenase (PDO) node_type: GENE_OR_PROTEIN description: Oxidizes glutathione persulfide to sulfite using O2. - node_id: glutathione_persulfide label: glutathione persulfide (GSSH) node_type: CHEMICAL description: Persulfide substrate of persulfide dioxygenase. - node_id: sulfite label: sulfite node_type: CHEMICAL grounding: CHEBI:16526 description: Sulfite intermediate in sulfur oxidation. - node_id: thiosulfate label: thiosulfate node_type: CHEMICAL grounding: CHEBI:30087 description: Thiosulfate intermediate substrate of the Sox system. - node_id: tsda_enzyme label: thiosulfate dehydrogenase (TsdA) node_type: GENE_OR_PROTEIN description: Oxidizes thiosulfate to tetrathionate. - node_id: tetrathionate label: tetrathionate node_type: CHEMICAL grounding: CHEBI:30926 description: Tetrathionate intermediate in the S4 intermediate pathway. - node_id: teth_enzyme label: tetrathionate hydrolase (TetH) node_type: GENE_OR_PROTEIN description: Hydrolyzes/disproportionates tetrathionate to S0, thiosulfate and sulfate. edges: - subject: sox_system predicate: enables object: sulfur_oxidation_trait description: The Sox system enables lithotrophic sulfur oxidation. evidence: - reference: DOI:10.1128/AEM.67.7.2873-2882.2001 notes: Friedrich et al. describe the Sox system as a common sulfur-oxidation mechanism. predicate_id: RO:0002327 - subject: sulfur_oxidation_trait predicate: oxidizes object: hydrogen_sulfide description: Sulfur oxidizers oxidize reduced sulfur compounds such as sulfide. evidence: - reference: DOI:10.1111/j.1574-6976.2009.00187.x notes: Ghosh & Dam review lithotrophic oxidation of reduced inorganic sulfur. predicate_id: METPO:2000016 - subject: sulfur_oxidation_trait predicate: produces object: sulfate description: Complete sulfur oxidation produces sulfate. evidence: - reference: DOI:10.1111/j.1574-6976.2009.00187.x notes: Supports sulfate as the oxidized end product. predicate_id: METPO:2000202 - subject: sqr_enzyme predicate: oxidizes object: hydrogen_sulfide description: SQR oxidizes sulfide to sulfane sulfur (S0/polysulfide). evidence: - reference: DOI:10.3390/ijms252010962 notes: SQR oxidizing sulfide to sulfane sulfur (S0/polysulfide). predicate_id: METPO:2000016 - subject: sqr_enzyme predicate: produces object: sulfane_sulfur description: SQR produces sulfane sulfur/polysulfide from sulfide. evidence: - reference: DOI:10.3390/ijms252010962 notes: SQR oxidizing sulfide to sulfane sulfur (S0/polysulfide). predicate_id: METPO:2000202 - subject: pdo_enzyme predicate: oxidizes object: glutathione_persulfide description: PDO oxidizes glutathione persulfide (GSSH). evidence: - reference: DOI:10.3390/ijms252010962 notes: PDO oxidizes glutathione persulfide (GSSH); O2-dependent. predicate_id: METPO:2000016 - subject: pdo_enzyme predicate: produces object: sulfite description: Persulfide dioxygenase produces sulfite (GSSH + O2 + H2O -> GSH + SO3(2-)). evidence: - reference: DOI:10.3390/ijms252010962 notes: GSSH + O2 + H2O -> GSH + SO3(2-) + 2H+; oxygen-dependent. predicate_id: METPO:2000202 - subject: sulfite predicate: reacts to form object: thiosulfate description: Sulfite reacts with sulfane sulfur to form thiosulfate (non-enzymatic). evidence: - reference: DOI:10.3390/ijms252010962 notes: The generated sulfite can react with sulfane sulfur to form thiosulfate. - subject: sox_system predicate: oxidizes object: thiosulfate description: Thiosulfate is oxidized to sulfate via the Sox system. evidence: - reference: DOI:10.3390/ijms252010962 notes: Thiosulfate is then oxidized to sulfate via the Sox-system. predicate_id: METPO:2000016 - subject: tsda_enzyme predicate: oxidizes object: thiosulfate description: TsdA oxidizes thiosulfate to tetrathionate (S2O32- to S4O62-). evidence: - reference: DOI:10.3389/fmicb.2024.1426584 notes: tsdA (S2O32- to S4O62-). predicate_id: METPO:2000016 - subject: tsda_enzyme predicate: produces object: tetrathionate description: TsdA produces tetrathionate from thiosulfate. evidence: - reference: DOI:10.3389/fmicb.2024.1426584 notes: tsdA (S2O32- to S4O62-). predicate_id: METPO:2000202 - subject: teth_enzyme predicate: oxidizes object: tetrathionate description: TetH disproportionates/hydrolyzes tetrathionate to S0, thiosulfate and sulfate. evidence: - reference: DOI:10.3389/fmicb.2024.1426584 notes: Tetrathionate generated by tsdA can be disproportionated by tetH to yield S0, thiosulfate and sulfate. predicate_id: METPO:2000016 curation_history: - timestamp: '2026-06-08T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate METABOLISM trait (sulfur oxidation); round 2, sulfur-cycle gap. llm_assisted: true - timestamp: '2026-06-08T12:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (Sox-mediated sulfur oxidation to sulfate) with CHEBI node groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 9 evidence-backed generic edges (9 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:12Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 8 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000016×5, METPO:2000202×3). llm_assisted: true