A thermophilic two-member cellulosic biofuel coculture composed of Clostridium thermocellum JN4 and Thermoanaerobacterium thermosaccharolyticum GD17. The system improves overall cellulosic biofuel production efficiency relative to C. thermocellum alone, but later mechanistic work indicates that GD17 also competitively hampers C. thermocellum JN4 growth while using glucose and cellobiose released during cellulose degradation.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Clostridium thermocellum JN4 — ontology label: Acetivibrio thermocellus | NCBITaxon:1515 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SECONDARY_FERMENTER
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N/A |
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| Thermoanaerobacterium thermosaccharolyticum GD17 — ontology label: Thermoanaerobacterium thermosaccharolyticum | NCBITaxon:1517 · TaxonMech · TraitMech |
SECONDARY_FERMENTER
CROSS_FEEDER
|
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.
Enhanced Community Fermentation Products
The JN4-GD17 coculture produced more lactate, acetate and ethanol than JN4 alone in the reported cellulose experiments, without improved overall cellulose utilization. This is a community product outcome, not cellulose donation. Cellulose is the feedstock; soluble glucose and cellobiose are the proposed exchanged carbon.
Participating Taxa: Clostridium thermocellum JN4, Thermoanaerobacterium thermosaccharolyticum GD17
Metabolites: cellulose (CHEBI:18246 · MediaIngredientMech · CMMMech)
Biological Processes:
- cellulose catabolic process (GO:0030245 · PathwayMech)
- fermentation (GO:0006113 · PathwayMech)
Evidence
-
PMID:31551972 - SUPPORT (IN_VITRO)"coculture significantly improves overall cellulosic biofuel production efficiency"
GD17 Competitive Conversion of Released Sugars
GD17 consumed glucose and cellobiose and produced fermentation products faster than JN4 in separate monoculture assays. Low soluble sugars and altered cellulolytic-gene transcription in coculture support a resource-competition model. PARTIAL - these measurements do not directly partition partner carbon flux or establish reciprocal harm required by the COMPETITION enum.
Source Taxon: Thermoanaerobacterium thermosaccharolyticum GD17
Target Taxon: Clostridium thermocellum JN4
Metabolites: cellobiose (CHEBI:17057 · MediaIngredientMech · CMMMech), glucose (CHEBI:17234 · MediaIngredientMech · CMMMech)
Biological Processes:
- fermentation (GO:0006113 · PathwayMech)
PARTIAL - faster GD17 conversion of JN4-released soluble sugars can contribute to higher community fermentation output. Monoculture conversion assays and coculture product measurements support this model, but do not directly measure the partner-specific contribution.
Evidence
-
PMID:31551972 - PARTIAL (IN_VITRO)"strong competitive metabolic advantage of T. thermosaccharolyticum GD17 over C. thermocellum JN4"
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PMID:31551972 - SUPPORT (IN_VITRO)"conversion of glucose or cellobiose into final products"
GD17 Growth Inhibition of JN4
JN4 biomass estimated from total protein and genomic community proportions was lower in coculture; this is not a direct viable-cell count. Dextrin or sucrose addition favored GD17 and largely stopped cellulose use. PARTIAL - the positive perturbation supports community rebalancing, but also adds carbon and changes sampling time, so it does not selectively isolate growth suppression or prove reciprocal harm.
Source Taxon: Thermoanaerobacterium thermosaccharolyticum GD17
Target Taxon: Clostridium thermocellum JN4
Biological Processes:
- interspecies interaction between organisms (GO:0044419 · PathwayMech)
PARTIAL - reduced JN4 biomass and cellulose use can constrain the cellulose-derived contribution to community products. Stimulant-driven rebalancing supports this possibility, not a measured reduction of total fermentation products or a resolved carbon balance when extra substrate is supplied.
Evidence
-
PMID:31551972 - PARTIAL (IN_VITRO)"T. thermosaccharolyticum GD17 significantly hampers the growth of C. thermocellum JN4"
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PMID:31551972 - PARTIAL (IN_VITRO)"relieves the carbon catabolite repression of C. thermocellum JN4"
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PMID:31551972 - PARTIAL (IN_VITRO)"re-balanced cocultures largely stopped degrading cellulose"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN How do GD17 sugar conversion and JN4 suppression separately determine cellulose-derived product flux?
Monoculture rates, coculture products, sugar concentrations and transcription support the proposed model. Protein-based biomass estimates and added-substrate rebalancing are not selective viable-growth or flux measurements. Partner-resolved carbon tracing and matched-carbon perturbations would distinguish conversion benefit from suppression without assuming reciprocal harm.
Attaches to: ecological_interactions#Enhanced Community Fermentation Products, ecological_interactions#GD17 Competitive Conversion of Released Sugars, ecological_interactions#GD17 Growth Inhibition of JN4
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Exact-system mechanistic publication - JN4 and GD17 relationship
Primary open-access mechanistic study of the C. thermocellum JN4 and T. thermosaccharolyticum GD17 coculture. |
OTHER | PMID:31551972 |
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Exact-system hydrogenase publication - JN4 and GD17 hydrogen production mechanism
Follow-up exact-composition publication focused on why the JN4-GD17 coculture improves cellulosic hydrogen production. |
OTHER | PMID:27538932 |
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Exact-system original hydrogen publication - cellulose-to-hydrogen coculture
Original report of hydrogen production from cellulose by the C. thermocellum JN4 and T. thermosaccharolyticum GD17 coculture. |
OTHER | doi:10.1016/j.ijhydene.2008.04.004 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Cellulose-rich lignocellulosic substrate | cellulose | N/A |
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| Released sugar intermediates | glucose or cellobiose | N/A |
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Growth Media
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