A de novo constructed, continuous-flow, hydrogen-producing coculture pairing Caldicellulosiruptor saccharolyticus DSM 8903 with the strain reported as Caldicellulosiruptor kristjanssonii DSM 12137. The system was designed to test whether two extreme thermophilic sugar-fermenting Caldicellulosiruptor strains could stably coexist while converting glucose and xylose, major lignocellulosic hydrolysate sugars, to hydrogen-rich fermentation products.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Caldicellulosiruptor saccharolyticus DSM 8903 | NCBITaxon:351627 · TaxonMech · TraitMech |
SECONDARY_FERMENTER
CROSS_FEEDER
|
N/A |
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| Caldicellulosiruptor kristjanssonii DSM 12137 — ontology label: Caldicellulosiruptor acetigenus I77R1B | NCBITaxon:632335 · 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.
Stable Chemostat Coexistence
Both strains persisted across dilution rates, including glucose-only limitation. Coexistence does not establish niche partitioning or show that stability causes enhanced hydrogen yield.
Participating Taxa: Caldicellulosiruptor saccharolyticus DSM 8903, Caldicellulosiruptor kristjanssonii DSM 12137
Metabolites: glucose (CHEBI:17234 · MediaIngredientMech · CMMMech), xylose (CHEBI:18222 · MediaIngredientMech · CMMMech)
Biological Processes:
- interspecies interaction between organisms (GO:0044419 · PathwayMech)
Evidence
-
PMID:21192828 - SUPPORT (IN_VITRO)"co-culture exhibited a remarkable stability over a period of 70 days"
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PMID:21192828 - SUPPORT (IN_VITRO)"The two strains retained their ability to stably coexist"
C. saccharolyticus Growth-Supernatant Enhancement
C. saccharolyticus supernatant shortened C. kristjanssonii lag and increased maximum biomass about 18% in batch culture. Maximum specific growth rate did not significantly change. This growth response is not a direct colonization assay; the active material and secretion-versus-lysis origin remain unknown.
Source Taxon: Caldicellulosiruptor saccharolyticus DSM 8903
Target Taxon: Caldicellulosiruptor kristjanssonii DSM 12137
Biological Processes:
- interspecies interaction between organisms (GO:0044419 · PathwayMech)
HYPOTHESIZED - growth stimulation could help maintain coexistence. The model assumes rate and biomass-yield enhancement; the batch assay supports only part of that mechanism, not its necessity in the chemostat.
Evidence
-
PMID:21192828 - PARTIAL (IN_VITRO)"enhance the growth of C. kristjanssonii"
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PMID:21192828 - SUPPORT (IN_VITRO)"increasing its maximum biomass concentration by ca. 18%"
Enhanced Glucose-Limited Hydrogen Yield
Glucose-limited coculture hydrogen yield exceeded both monocultures, reaching 3.7 mol/mol glucose at dilution 0.06/h. Yield is not volumetric productivity or evidence of reciprocal fitness benefit; the mixed-sugar experiments are a different condition.
Participating Taxa: Caldicellulosiruptor saccharolyticus DSM 8903, Caldicellulosiruptor kristjanssonii DSM 12137
Metabolites: hydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), glucose (CHEBI:17234 · MediaIngredientMech · CMMMech), xylose (CHEBI:18222 · MediaIngredientMech · CMMMech)
Biological Processes:
- fermentation (GO:0006113 · PathwayMech)
Evidence
-
PMID:21192828 - SUPPORT (IN_VITRO)"from glucose and xylose"
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PMID:21192828 - SUPPORT (IN_VITRO)"H2 yields on glucose exceeded those of either organism alone"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
|
C. saccharolyticus DSM 8903 genome BioProject
Genome project for C. saccharolyticus DSM 8903, one member of the coculture. |
GENOMICS | NCBI_BIOPROJECT | PRJNA13466 |
|
C. kristjanssonii DSM 12137 genome BioProject
Genome project for the strain reported as C. kristjanssonii DSM 12137. |
GENOMICS | NCBI_BIOPROJECT | PRJNA41727 |
|
Coculture fermentation supplementary tables
Supplementary fermentation tables for product yields, sugar consumption, and carbon/electron recoveries. |
PHENOTYPE | OTHER | PMID:21192828-supplement-2 |
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Does the unidentified stimulatory material mediate coexistence under continuous operation?
PMID:21192828 provides a model and batch-supernatant test, not molecular necessity. Retain the proposed direction as hypothetical; do not infer a named signal, altruism or reciprocal fitness.
Attaches to: ecological_interactions#Stable Chemostat Coexistence, ecological_interactions#C. saccharolyticus Growth-Supernatant Enhancement, ecological_interactions#Enhanced Glucose-Limited Hydrogen Yield
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
Exact-system primary publication - stable Caldicellulosiruptor coculture
Primary open-access study of the DSM 8903 and DSM 12137 hydrogen-producing coculture in continuous culture. |
OTHER | PMID:21192828 |
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Earlier exact-pair mixed-sugar coculture publication
Earlier publication evaluating C. saccharolyticus and C. kristjanssonii in coculture during mixed-sugar hydrogen production. |
OTHER | doi:10.1016/j.ijhydene.2008.07.092 |
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Extreme thermophilic cultivation | extreme thermophiles | N/A |
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| Mixed lignocellulosic sugars | glucose and xylose | N/A |
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| Glucose-limited high-yield condition | 3.7 | mol H2 per mol glucose |
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Growth Media
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