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Syntrophobacter-Methanospirillum Syntrophic Consortium

Community ID CommunityMech:000069
Ecological State STABLE
Environment anaerobic environment — ontology label: active anaerobic enrichment culturing unit
ENVO:01001825 · HabitatMech ↗

A syntrophic, obligate two-member anaerobic consortium consisting of Syntrophobacter fumaroxidans, which oxidizes propionate to acetate, and Methanospirillum hungatei, a hydrogen and formate-utilizing methanogen. S. fumaroxidans degrades propionate via the methylmalonyl-CoA pathway only in coculture with H2/formate-using archaea, as it uses protons as the electron acceptor with H2 and formate as electron sink products. The removal of H2 and formate by M. hungatei is thermodynamically essential for continued propionate oxidation by S. fumaroxidans. This syntrophic relationship is fundamental to understanding methane production from propionate in anaerobic environments such as digesters, sediments, and wastewater treatment systems, playing a critical role in biogeochemical cycling.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Syntrophobacter fumaroxidans NCBITaxon:119484 · TaxonMech · TraitMech
PRIMARY_DEGRADER SYNTROPHIC_PARTNER
N/A
  • PMID:9828440 - SUPPORT (IN_VITRO)
    "The name Syntrophobacter fumaroxidans is proposed; strain MPOBT (= DSM 10017T) is the type strain."
Methanospirillum hungatei NCBITaxon:2203 · TaxonMech · TraitMech
SYNTROPHIC_PARTNER
N/A
  • PMID:9828440 - SUPPORT (IN_VITRO)
    "It oxidized propionate syntrophically in co-culture with the hydrogen- and formate-utilizing Methanospirillum hungateii, and was able to oxidize propionate and other organic compounds in pure culture with sulfate or fumarate as the electron acceptor"

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.

Ecological interaction network for Syntrophobacter-Methanospirillum Syntrophic Consortium Bipartite graph where circles represent taxa and non-circular symbols represent interactions, with distinct shapes and colours for syntrophy. Rare or untyped interactions share the Other symbol; exact curated types remain in the interaction details.
Taxon
Syntrophy
Other

Propionate Oxidation and H2/Formate Production

SYNTROPHY

S. fumaroxidans oxidizes propionate in syntrophy with M. hungatei, releasing reducing equivalents through hydrogen and/or formate. The methylmalonyl-CoA pathway produces acetate and inorganic carbon. Partner consumption maintains low hydrogen partial pressure and formate concentration; these are different physical quantities. This is the tested methanogenic growth context, not universal partner dependence: sulfate or fumarate can support axenic growth. PARTIAL: comparative protein abundance and homology support proposed Fdh1/Hox confurcation and Fdh2/Hyn reverse-electron-transport roles, not direct demonstration of every enzyme assignment or the fraction of electrons carried by each route in this pair.

Source Taxon: Syntrophobacter fumaroxidans

Target Taxon: Methanospirillum hungatei

Metabolites: propionate (CHEBI:17272 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech)

Biological Processes:

Downstream Effects:
→ Interspecies Electron Transfer and Methanogenesis

DIRECTLY IMPLIED: reducing equivalents released during bacterial propionate oxidation supply M. hungatei through hydrogen and/or formate for methanogenesis. The evidence does not quantify their separate fluxes in this pair.

Evidence

  • PMID:29611893 - SUPPORT (IN_VITRO)
    "We performed a proteome analysis of S. fumaroxidans growing with propionate axenically with sulfate or fumarate, and in syntrophy with Methanospirillum hungatei, Methanobacterium formicicum or Desulfovibrio desulfuricans"
  • PMID:29611893 - PARTIAL (IN_VITRO)
    "a very plausible candidate for a confurcating-type of formate dehydrogenase"
  • PMID:29611893 - PARTIAL (IN_VITRO)
    "Hox is most probably a confurcating hydrogenase involved in energy conservation"

Interspecies Electron Transfer and Methanogenesis

SYNTROPHY

M. hungatei acts as the hydrogen/formate-using methanogenic partner of S. fumaroxidans. Carrier consumption supports methane formation and relieves the thermodynamic constraint on propionate oxidation. Low hydrogen partial pressure and low formate concentration are distinct constraints; formate is not a gas pressure. The comparative proteome suggests an important formate route but does not independently quantify exact-pair carrier partitioning.

Source Taxon: Methanospirillum hungatei

Target Taxon: Syntrophobacter fumaroxidans

Metabolites: dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech), methane (CHEBI:16183 · MediaIngredientMech · CMMMech)

Biological Processes:

Downstream Effects:
→ Propionate Oxidation and H2/Formate Production

DIRECTLY IMPLIED feedback: hydrogen/formate consumption by M. hungatei lowers hydrogen partial pressure and formate concentration, enabling continued propionate oxidation. This retains the thermodynamic cooperation inferred from syntrophic versus electron-acceptor-supported axenic growth; it is not a selective carrier-removal assay in this exact pair.

→ Syntrophic Propionate-to-Methane Conversion

Methanogenic consumption of bacterially supplied reducing equivalents couples propionate oxidation to methane production. Cooperation is reciprocal, but the carrier transfer described here is bacterial-to-methanogen, not bidirectional donation.

Evidence

  • PMID:29611893 - SUPPORT (IN_VITRO)
    "We performed a proteome analysis of S. fumaroxidans growing with propionate axenically with sulfate or fumarate, and in syntrophy with Methanospirillum hungatei, Methanobacterium formicicum or Desulfovibrio desulfuricans"
  • PMID:29611893 - SUPPORT (IN_VITRO)
    "During syntrophic growth, S. fumaroxidans needs to transfer electrons via hydrogen and/or formate to a syntrophic partner."
  • PMID:29611893 - PARTIAL (IN_VITRO)
    "It has long been speculated that formate plays a more important role than hydrogen as an electron carrier"

Syntrophic Propionate-to-Methane Conversion

The S. fumaroxidans-M. hungatei coculture joins propionate oxidation to methanogenesis. This community conversion is the outcome of the two existing partner processes, not a third pairwise exchange. Acetate remains a bacterial product, so this does not assert complete mineralization of propionate carbon to methane.

Participating Taxa: Syntrophobacter fumaroxidans, Methanospirillum hungatei

Metabolites: propionate (CHEBI:17272 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech), methane (CHEBI:16183 · MediaIngredientMech · CMMMech)

Biological Processes:

Evidence

  • PMID:29611893 - SUPPORT (IN_VITRO)
    "We performed a proteome analysis of S. fumaroxidans growing with propionate axenically with sulfate or fumarate, and in syntrophy with Methanospirillum hungatei, Methanobacterium formicicum or Desulfovibrio desulfuricans"

Knowledge gaps & discussions (1)

KNOWLEDGE_GAP OPEN What are the separate carrier fluxes and enzyme contributions in this exact pairing?

Comparative proteomics supports candidate energy-conservation and electron-transfer roles. It does not resolve exact carrier fractions or selectively demonstrate all enzyme assignments. Existing metabolic feedback is retained with that boundary.

Attaches to: ecological_interactions#Propionate Oxidation and H2/Formate Production, ecological_interactions#Interspecies Electron Transfer and Methanogenesis

1 evidence item(s)
IN_VITRO PARTIAL PMID:29611893

It has long been speculated that formate plays a more important role than hydrogen as an electron carrier

The main text explicitly frames relative carrier importance as a mechanistic interpretation rather than a measured exact-pair flux.

Environmental Factors

Factor Value Unit
Anaerobic Conditions Strict anaerobic N/A
  • PMID:9828440 - SUPPORT (IN_VITRO)
    "A syntrophic propionate-oxidizing bacterium, strain MPOBT, was isolated from a culture enriched from anaerobic granular sludge"
Hydrogen and Formate Partial Pressure Must be maintained at low levels N/A
  • PMID:29611893 - SUPPORT (IN_VITRO)
    "fumaroxidans mainly used formate for electron release and that different confurcating mechanisms were used in its sulfidogenic metabolism"
Ecological Relevance Biogeochemical cycling N/A
  • PMID:9828440 - SUPPORT (IN_VITRO)
    "A syntrophic propionate-oxidizing bacterium, strain MPOBT, was isolated from a culture enriched from anaerobic granular sludge"

Growth Media

Anaerobic bicarbonate-buffered mineral medium for syntrophic propionate oxidation (CultureMech:000423)

View in CultureMech →

pH 7.2
Temperature 37 degrees Celsius
Atmosphere ANAEROBIC

Composition

Component Concentration Unit CHEBI
Propionate (sodium salt) · MediaIngredientMech 10 mM CHEBI:132106
Sodium bicarbonate · MediaIngredientMech 30 mM CHEBI:32139
Ammonium chloride · MediaIngredientMech 20 mM CHEBI:31206
Sodium phosphate buffer · MediaIngredientMech 2.8 mM CHEBI:37585
Potassium phosphate buffer · MediaIngredientMech 3.5 mM CHEBI:131527
Magnesium chloride · MediaIngredientMech 1 mM CHEBI:6636
Calcium chloride · MediaIngredientMech 0.5 mM CHEBI:3312
Sodium sulfide · MediaIngredientMech 1 mM CHEBI:76209
L-Cysteine hydrochloride · MediaIngredientMech 1 mM CHEBI:91247
Resazurin · MediaIngredientMech 0.5 mg/L CHEBI:8806
Trace element solution SL-10 · MediaIngredientMech 1 mL/L N/A
Vitamin solution · MediaIngredientMech 1 mL/L N/A
Yeast extract · MediaIngredientMech 0.2 g/L N/A
KNO3 · MediaIngredientMech 0.25 G_PER_L N/A
KH2PO4 · MediaIngredientMech 0.1 G_PER_L N/A
MgSO4 x 7 H2O · MediaIngredientMech 0.05 G_PER_L N/A
CaCl2 x 2 H2O · MediaIngredientMech 0.01 G_PER_L N/A
EDTA · MediaIngredientMech 5 G_PER_L N/A
CuCl2 x 5 H2O · MediaIngredientMech 0.1 G_PER_L N/A
FeSO4 x 7 H2O · MediaIngredientMech 2 G_PER_L N/A
ZnSO4 x 7 H2O · MediaIngredientMech 0.1 G_PER_L N/A
NiCl2 x 6 H2O · MediaIngredientMech 0.02 G_PER_L N/A
CoCl2 x 6 H2O · MediaIngredientMech 0.2 G_PER_L N/A
Na2MoO4 · MediaIngredientMech 0.03 G_PER_L N/A
MnCl2 x 4 H2O · MediaIngredientMech 0.03 G_PER_L N/A

Preparation notes: Medium prepared under strict anaerobic conditions using modified Hungate technique. Medium boiled and cooled under N2/CO2 atmosphere, dispensed anaerobically into serum bottles or tubes, sealed with butyl rubber stoppers, and autoclaved. Reducing agents (Na2S and cysteine) added from sterile anaerobic stock solutions after autoclaving to establish low redox potential. Final pH adjusted to 7.2. Resazurin used as redox indicator (colorless when reduced). S. fumaroxidans uses both H2 and formate as electron carriers for interspecies electron transfer to M. hungatei, with formate being the preferential carrier during syntrophic propionate oxidation.

Evidence

PMID:9828440

"It oxidized propionate syntrophically in co-culture with the hydrogen- and formate-utilizing Methanospirillum hungateii, and was able to oxidize propionate and other organic compounds in pure culture with sulfate or fumarate as the electron acceptor"

PMID:29611893

"fumaroxidans mainly used formate for electron release and that different confurcating mechanisms were used in its sulfidogenic metabolism"

Cross-Mech Suite Links

Explore related entities across the CultureBotAI X-Mech knowledge bases:

HabitatMech: anaerobic environment ↗ TaxonMech: Syntrophobacter fumaroxidans ↗ TraitMech: Syntrophobacter fumaroxidans ↗ TaxonMech: Methanospirillum hungatei ↗ TraitMech: Methanospirillum hungatei ↗ CMMMech (Critical Minerals & REE) ↗ CultureMech Growth Media ↗ PathwayMech Pathways ↗