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Clostridium-Thermoanaerobacter Cellulosic Bioethanol Coculture

Community ID CommunityMech:000168
Ecological State ENGINEERED
Environment anaerobic laboratory bioreactor
ENVO:01001405

A thermophilic, anaerobic, two-member laboratory coculture for consolidated cellulosic bioethanol production. The cellulolytic Clostridium thermocellum LQRI member hydrolyzes and ferments cellulose, while the non-cellulolytic Thermoanaerobacter pseudethanolicus strain X514 partner improves ethanol production from cellulose-derived fermentation intermediates. The system is DOE-relevant because it uses a defined coculture to increase ethanolic fermentation of recalcitrant cellulosic material under batch and cyclic fed-batch bioprocess conditions.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Clostridium thermocellum LQRI NCBITaxon:572545
PRIMARY_DEGRADER SECONDARY_FERMENTER
N/A
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "cellulolytic Clostridium thermocellum LQRI"
  • PMID:21868218 - SUPPORT (IN_VITRO)
    "Co-cultures of cellulolytic Clostridium thermocellum"
Thermoanaerobacter pseudethanolicus strain X514 NCBITaxon:399726
SECONDARY_FERMENTER CROSS_FEEDER
N/A
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "saccharolytic Thermoanaerobacter pseudethanolicus strain X514"
  • PMID:21868218 - SUPPORT (IN_VITRO)
    "non-cellulolytic Thermoanaerobacter strains (X514 and 39E)"

Ecological Interactions

Ecological interaction network for Clostridium-Thermoanaerobacter Cellulosic Bioethanol Coculture Bipartite graph where circle nodes represent taxa and colored rectangles represent ecological interactions (cross-feeding, mutualism, syntrophy, competition, commensalism).
Taxon
Cross-feeding
Mutualism
Syntrophy
Competition
Commensalism
Niche partitioning
Colonization facilitation
Strain competition
Predation

Cellulose Hydrolysis Supporting Coculture Fermentation

CROSS_FEEDING

Source Taxon: Clostridium thermocellum LQRI

Target Taxon: Thermoanaerobacter pseudethanolicus strain X514

Metabolites: cellulose (CHEBI:18246), ethanol (CHEBI:16236)

Biological Processes:

Evidence

  • PMID:23275517 - SUPPORT (IN_VITRO)
    "improve bioethanol production from the fermentation of recalcitrant cellulosic materials"
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "tested in the semicontinuous fermentor as a model system"

X514-Enhanced Ethanolic Fermentation

CROSS_FEEDING

Source Taxon: Thermoanaerobacter pseudethanolicus strain X514

Target Taxon: Clostridium thermocellum LQRI

Metabolites: ethanol (CHEBI:16236)

Biological Processes:

Evidence

  • PMID:21868218 - SUPPORT (IN_VITRO)
    "improved ethanol production by 194-440%"
  • PMID:21868218 - SUPPORT (IN_VITRO)
    "Strain X514 enhanced ethanolic fermentation much more effectively"

Vitamin B12-Linked Fermentation Robustness

COMMENSALISM

Source Taxon: Thermoanaerobacter pseudethanolicus strain X514

Target Taxon: Clostridium thermocellum LQRI

Metabolites: cobalamin (CHEBI:30411)

Biological Processes:

Evidence

  • PMID:21868218 - SUPPORT (IN_VITRO)
    "complete vitamin B(12) biosynthesis pathway"
  • PMID:21868218 - SUPPORT (IN_VITRO)
    "improved ethanol production in strain 39E by 203%"

External Resources

Name Repository Resource ID
Mechanisms of enhanced cellulosic bioethanol fermentation by co-cultivation
Primary publication reporting C. thermocellum cocultures with Thermoanaerobacter X514 and 39E, including X514-linked ethanol enhancement and vitamin B12 pathway analysis. 		OTHER PMID:21868218
  • PMID:21868218 - SUPPORT (IN_VITRO)
    "Co-cultures of cellulolytic Clostridium thermocellum"
Continuous cellulosic bioethanol fermentation by cyclic fed-batch cocultivation
Primary publication reporting the exact C. thermocellum LQRI and Thermoanaerobacter pseudethanolicus X514 coculture in cyclic fed-batch cellulose fermentation. 		OTHER PMID:23275517
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "Clostridium thermocellum LQRI and saccharolytic Thermoanaerobacter pseudethanolicus strain X514"

Environmental Factors

Factor Value Unit
Initial cellulose concentration 40 to 80 g liter(-1) cellulose N/A
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "Initial cellulose concentration and pH were identified as the key process parameters"
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "initial cellulose concentration of 80 g liter(-1)"
pH control pH 6.5 to 6.8 N/A
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "pH controlled at 6.5 to 6.8"
  • PMID:23275517 - SUPPORT (IN_VITRO)
    "ethanol produced with pH control was 4.5-fold higher"

Growth Media

Cellulose-fed anaerobic cyclic fed-batch coculture medium

pH 6.5 to 6.8
Atmosphere ANAEROBIC

Composition

Component Concentration Unit CHEBI
cellulose 40 to 80 g/L CHEBI:18246

Preparation notes: Semicontinuous cyclic fed-batch fermentor configuration using cellulose as the recalcitrant substrate; the PubMed abstract reports cellulose loading and controlled pH but not a full medium recipe.

Evidence

PMID:23275517

"semicontinuous cyclic fed-batch fermentor configuration"

PMID:23275517

"bioethanol production reaching 474 mM in 96 h"