A syntrophic, obligate two-member anaerobic consortium consisting of Syntrophomonas wolfei, which β-oxidizes saturated fatty acids (butyrate through octanoate) to acetate, and Methanospirillum hungatei, a hydrogen-utilizing methanogen. S. wolfei degrades butyrate only in coculture with H2-using bacteria, as it uses protons as the electron acceptor with H2 as the electron sink product. The removal of H2 by M. hungatei is thermodynamically essential for continued fatty acid oxidation by S. wolfei. This classic syntrophic relationship is fundamental to understanding methane production from fatty acids in anaerobic environments such as digesters, sediments, and the rumen.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Syntrophomonas wolfei | NCBITaxon:863 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SYNTROPHIC_PARTNER
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N/A |
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| Methanospirillum hungatei | NCBITaxon:2203 · TaxonMech · TraitMech |
SYNTROPHIC_PARTNER
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N/A |
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Butyrate Oxidation and H2 Production
SYNTROPHYS. wolfei oxidizes butyrate to acetate with hydrogen as an electron-sink product in the studied syntrophic cultures. Common electron acceptors did not support the tested butyrate metabolism. This is substrate- and assay-bounded dependence on a hydrogen-using partner, not a claim that every substrate requires coculture.
Source Taxon: Syntrophomonas wolfei
Target Taxon: Methanospirillum hungatei
Metabolites: butyrate (CHEBI:17968 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech)
Biological Processes:
- fatty acid beta-oxidation (GO:0006635 · PathwayMech)
- butyrate catabolic process (GO:0046359 · PathwayMech)
H2 produced by S. wolfei is consumed by M. hungatei for methanogenesis
Evidence
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PMID:16345745 - SUPPORT (IN_VITRO)"An anaerobic, nonphototrophic bacterium that beta-oxidizes saturated fatty acids (butyrate through octanoate) to acetate or acetate and propionate using protons as the electron acceptor"
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PMID:16345745 - SUPPORT (IN_VITRO)"Common electron acceptors are not utilized with butyrate as the electron donor"
Interspecies Hydrogen Transfer and Methanogenesis
SYNTROPHYM. hungatei is a documented hydrogen-using partner of S. wolfei. Hydrogen removal supports bacterial butyrate oxidation and methanogenesis. The abstract reports inhibition of growth and butyrate degradation by added hydrogen, but does not provide an exact permissive partial-pressure threshold or quantify competing carrier contributions.
Source Taxon: Methanospirillum hungatei
Target Taxon: Syntrophomonas wolfei
Metabolites: dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), methane (CHEBI:16183 · MediaIngredientMech · CMMMech)
Biological Processes:
- methanogenesis (GO:0015948 · PathwayMech)
DIRECTLY IMPLIED feedback: removal of hydrogen by the methanogenic partner relieves a constraint on S. wolfei butyrate oxidation. The 1981 abstract reports that added hydrogen stops growth and butyrate degradation; it does not specify a numerical permissive threshold or isolate hydrogen from all alternative carrier routes in this exact pairing.
Hydrogen transfer links S. wolfei butyrate oxidation to M. hungatei hydrogenotrophic methanogenesis.
Evidence
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PMID:16345745 - SUPPORT (IN_VITRO)"cocultures of S. wolfei with Desulfovibrio and Methanospirillum hungatei"
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PMID:16345745 - SUPPORT (IN_VITRO)"The addition of H(2) to the medium stopped growth and butyrate degradation by S. wolfei."
Syntrophic Butyrate-to-Methane Conversion
S. wolfei butyrate oxidation is coupled to hydrogen-consuming M. hungatei methanogenesis in the documented coculture. This is a community conversion endpoint, not an additional pairwise exchange; acetate is retained as an organic product.
Participating Taxa: Syntrophomonas wolfei, Methanospirillum hungatei
Metabolites: butyrate (CHEBI:17968 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), methane (CHEBI:16183 · MediaIngredientMech · CMMMech)
Biological Processes:
- fatty acid beta-oxidation (GO:0006635 · PathwayMech)
- methanogenesis (GO:0015948 · PathwayMech)
Evidence
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PMID:16345745 - SUPPORT (IN_VITRO)"cocultures of S. wolfei with Desulfovibrio and Methanospirillum hungatei"
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PMID:16345745 - SUPPORT (IN_VITRO)"Growth and degradation of fatty acids occur only in syntrophic association with H(2)-using bacteria"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN What quantitative carrier constraints apply to this exact butyrate coculture?
The accessible primary abstract supports the named partner and hydrogen-addition inhibition, but not the former less-than-10^-4-atm threshold. The existing feedback remains directly implied; no carrier-exclusive mechanism or universal obligacy is asserted. The older full-text XML endpoint failed, so detailed perturbation conditions remain unverified here.
Attaches to: ecological_interactions#Butyrate Oxidation and H2 Production, ecological_interactions#Interspecies Hydrogen Transfer and Methanogenesis
1 evidence item(s)
The addition of H(2) to the medium stopped growth and butyrate degradation by S. wolfei.
The reported hydrogen perturbation supports product-inhibition feedback; the abstract does not specify every assay condition or a numerical threshold.
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Anaerobic Conditions | Strict anaerobic | N/A |
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| Hydrogen Partial Pressure | Must be maintained below 10^-4 atm | N/A |
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| Generation Time | 84 hours | hours |
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Growth Media
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