A thermophilic, anaerobic, two-member laboratory coculture pairing Clostridium thermocellum ATCC 27405 with Caldicellulosiruptor bescii DSM 6725. The system was used to test whether low-ionic-strength defined medium with reduced nitrogen, sulfur, phosphate, and vitamin supplements could maintain both cellulolytic bacterial populations during conversion of cellulosic substrates relevant to consolidated bioprocessing.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Clostridium thermocellum ATCC 27405 — ontology label: Acetivibrio thermocellus ATCC 27405 | NCBITaxon:203119 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SECONDARY_FERMENTER
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N/A |
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| Caldicellulosiruptor bescii DSM 6725 | NCBITaxon:521460 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SECONDARY_FERMENTER
|
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.
Reduced-Nutrient Defined Cellulose-Xylan Medium
A low-ionic-strength defined medium with reduced nitrogen, sulfur, phosphate and vitamin supplements was developed after nutrient-response experiments. The primary abstract reports cellobiose, cellulose and acid-pretreated Populus fermentation and separately reports coculture maintenance on cellulose/xylan substrates. These statements do not establish that every substrate or nutrient-response experiment used the coculture. Medium development is cultivation context, not demonstrated partner-to-partner colonization facilitation.
Participating Taxa: Clostridium thermocellum ATCC 27405, Caldicellulosiruptor bescii DSM 6725
Metabolites: cellulose (CHEBI:18246 · MediaIngredientMech · CMMMech), xylan (CHEBI:37166 · MediaIngredientMech · CMMMech), sulfate (CHEBI:16189 · MediaIngredientMech · CMMMech)
Evidence
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PMID:23306120 - SUPPORT (IN_VITRO)"From these results, a low ionic strength, defined minimal nutrient medium with decreased nitrogen, sulfur, phosphate and vitamin supplements was developed "
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PMID:23306120 - SUPPORT (IN_VITRO)"fermentation of cellobiose, cellulose and acid-pretreated Populus"
Observed Co-Maintenance On Cellulose And Xylan
Both populations were reported to be maintained in cocultures on substrates containing cellulose and xylan in defined medium with sulfate and basal vitamins. This is an observed co-maintenance endpoint. The accessible exact-system abstract does not resolve the duration, population trajectories or perturbations needed to establish long-term stability, reciprocal benefit, colonization facilitation or a unique maintenance mechanism.
Participating Taxa: Clostridium thermocellum ATCC 27405, Caldicellulosiruptor bescii DSM 6725
Metabolites: cellulose (CHEBI:18246 · MediaIngredientMech · CMMMech), xylan (CHEBI:37166 · MediaIngredientMech · CMMMech)
Evidence
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PMID:23306120 - SUPPORT (IN_VITRO)"Both bacterial populations were maintained in co-cultures"
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PMID:23306120 - SUPPORT (IN_VITRO)"substrates containing cellulose and xylan"
Thermophilic Plant-Polysaccharide Conversion Capacity
Separate member-level evidence supports plant-polysaccharide conversion: C. thermocellum was grown on crystalline cellulose in the nutrient study, and C. bescii DSM 6725 was studied by genome analysis plus experimental transcriptomics and proteomics on polysaccharide substrates. Cellulose-responsive expression and cellulose/xylan-associated proteins are measured results, while functions of some hypothetical proteins remain inferred. These member assays do not demonstrate niche partitioning, interspecies substrate transfer or mediation of coculture maintenance.
Participating Taxa: Caldicellulosiruptor bescii DSM 6725, Clostridium thermocellum ATCC 27405
Metabolites: cellulose (CHEBI:18246 · MediaIngredientMech · CMMMech), xylan (CHEBI:37166 · MediaIngredientMech · CMMMech)
Biological Processes:
- cellulose catabolic process (GO:0030245 · PathwayMech)
- xylan catabolic process (GO:0045493 · PathwayMech)
Evidence
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PMID:23306120 - SUPPORT (IN_VITRO)"C. thermocellum was grown on crystalline cellulose"
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PMID:21227922 - SUPPORT (IN_VITRO)"overproduced on cellulose or xylan"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
| Clostridium thermocellum ATCC 27405 genome project | GENOMICS | NCBI_BIOPROJECT | PRJNA314 |
| Caldicellulosiruptor bescii DSM 6725 genome project | GENOMICS | NCBI_BIOPROJECT | PRJNA29407 |
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which exact-system population measurements and nutrient or substrate perturbations explain co-maintenance?
PMID:23306120 is abstract-bounded in this review; its full body was not obtained through the attempted public routes. The abstract reports maintenance, not its duration or an isolated ecological mechanism. PMID:21227922 contains empirical C. bescii molecular responses as well as genomic inference, but does not test this coculture. Full-method access and partner-resolved time courses are needed before claiming nutrient-reduction causality, stability or niche partitioning. The earlier removed capacity-to-maintenance arrow remains absent.
Attaches to: ecological_interactions#Reduced-Nutrient Defined Cellulose-Xylan Medium, ecological_interactions#Observed Co-Maintenance On Cellulose And Xylan, ecological_interactions#Thermophilic Plant-Polysaccharide Conversion Capacity
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
Exact-system primary publication - defined medium coculture
Primary publication describing the low-ionic-strength defined medium and the C. thermocellum ATCC 27405 / C. bescii DSM 6725 coculture on cellulose/xylan. |
OTHER | PMID:23306120 |
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C. bescii DSM 6725 biomass-conversion genome paper
Comparative genomics and transcriptomics source for C. bescii DSM 6725 plant-biomass and polysaccharide conversion capacity. |
OTHER | PMID:21227922 |
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| C. thermocellum ATCC 27405 BioProject | OTHER | PRJNA314 |
| C. bescii DSM 6725 BioProject | OTHER | PRJNA29407 |
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Reduced-nutrient defined medium | Low-ionic-strength defined medium with decreased nitrogen, sulfur, phosphate, and vitamins. | N/A |
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| Sulfate with ascorbate reductant | Sulfate assimilated in the presence of ascorbate. | N/A |
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| Mixed cellulose and xylan coculture substrate | filter paper cellulose plus xylan | N/A |
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Growth Media
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