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Clostridium-Saccharomyces Cellulose Ethanol Coculture

Community ID CommunityMech:000206
Ecological State ENGINEERED
Environment oxygen-controlled cellulose-fed laboratory bioreactor coculture
ENVO:01001405

A synthetic two-member cellulose-to-ethanol coculture pairing the cellulolytic mesophile Clostridium phytofermentans ISDg, currently represented in NCBI Taxonomy as Lachnoclostridium phytofermentans ISDg, with the engineered cellodextrin-fermenting yeast Saccharomyces cerevisiae cdt-1. The consortium is maintained by controlled oxygen delivery: the yeast removes inhibitory oxygen and receives soluble sugars released during C. phytofermentans cellulose hydrolysis. With added endoglucanase, the coculture produced approximately 22 g/L ethanol from 100 g/L alpha-cellulose. This system is relevant to DOE lignocellulosic biofuel and consolidated bioprocessing goals.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Clostridium phytofermentans ISDg NCBITaxon:357809
PRIMARY_DEGRADER SECONDARY_FERMENTER
ABUNDANT
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "C. phytofermentans and yeast"
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "soluble sugars released by C. phytofermentans hydrolysis"
Saccharomyces cerevisiae cdt-1 NCBITaxon:4932
CROSS_FEEDER SECONDARY_FERMENTER
ABUNDANT
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "Saccharomyces cerevisiae cdt-1"
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "Saccharomyces cerevisiae cdt-1"

Ecological Interactions

Ecological interaction network for Clostridium-Saccharomyces Cellulose Ethanol 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 Feeds Yeast Fermentation

CROSS_FEEDING

Source Taxon: Clostridium phytofermentans ISDg

Target Taxon: Saccharomyces cerevisiae cdt-1

Metabolites: cellulose (CHEBI:18246), glucose (CHEBI:17234), ethanol (CHEBI:16236)

Biological Processes:

Evidence

  • PMID:23628342 - SUPPORT (IN_VITRO)
    "soluble sugars released by C. phytofermentans hydrolysis"
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "produced approximately 22 g/L ethanol"

Oxygen Protection of Anaerobic Cellulolytic Partner

MUTUALISM

Source Taxon: Saccharomyces cerevisiae cdt-1

Target Taxon: Clostridium phytofermentans ISDg

Metabolites: oxygen (CHEBI:15379)

Biological Processes:

  • interspecies interaction between organisms (GO:0044419)

Evidence

  • PMID:23628342 - SUPPORT (IN_VITRO)
    "protect C. phytofermentans from introduced oxygen"
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "maintained by controlled oxygen transport"

Long-Term Symbiotic Population Maintenance

MUTUALISM

Source Taxon: Saccharomyces cerevisiae cdt-1

Target Taxon: Clostridium phytofermentans ISDg

Biological Processes:

  • interspecies interaction between organisms (GO:0044419)

Evidence

  • PMID:23628342 - SUPPORT (IN_VITRO)
    "maintenance of populations of 105 to 106 CFU/mL for 50 days"

External Resources

Name Repository Resource ID
Exact-system primary publication - cellulose-to-ethanol symbiotic coculture
Primary PubMed record for the C. phytofermentans and S. cerevisiae cdt-1 cellulose-to-ethanol coculture. 		OTHER PMID:23628342
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "C. phytofermentans and S. cerevisiae cdt-1"
Full-text open-access article
Full-text article with reactor design, culture conditions, and comparative mono- and coculture data. 		OTHER PMCID:PMC3653780
DOI landing page
DOI for the Biotechnology for Biofuels publication. 		OTHER doi:10.1186/1754-6834-6-59

Environmental Factors

Factor Value Unit
Controlled oxygen transfer approximately 8 micromol/L hour diffusive oxygen delivery N/A
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "controlled oxygen delivery by diffusion"
Semi-aerobic cellulose degradation filter paper and alpha-cellulose under semi-aerobic coculture conditions N/A
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "semi-aerobic conditions"
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "Only co-cultures were able to degrade filter paper"
Added endoglucanase added endoglucanase during high-cellulose fermentation N/A
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "improve with additional cellulase"
Ethanol titer approximately 22 g/L ethanol from 100 g/L alpha-cellulose N/A
  • PMID:23628342 - SUPPORT (IN_VITRO)
    "22 g/L ethanol from 100 g/L"

Growth Media

Oxygen-controlled alpha-cellulose ethanol coculture

Atmosphere MICROAEROBIC

Composition

Component Concentration Unit CHEBI
alpha-cellulose N/A N/A CHEBI:18246
oxygen N/A N/A CHEBI:15379
ethanol N/A N/A CHEBI:16236

Preparation notes: The coculture used alpha-cellulose as the feedstock and controlled diffusive oxygen delivery. The abstract supports the core substrate, oxygen-transfer, scale-up, and ethanol production conditions; detailed GS2 medium composition is left to the full-text resource.

Evidence

PMID:23628342

"semi-aerobic conditions"

PMID:23628342

"scaled up 500 mL bioreactors"