A defined anaerobic synthetic coculture that combines a lactate-producing Acetobacterium woodii mutant with Clostridium drakei to convert CO2 and H2 into longer-chain products. A. woodii fixes CO2 with H2 and is engineered to release lactate, which C. drakei uses as an intermediate for chain elongation to caproic acid. The system is DOE-relevant because it couples microbial CO2 valorization with in situ water electrolysis or CO2/H2 gas feeding for production of value chemicals.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Acetobacterium woodii | NCBITaxon:33952 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
CROSS_FEEDER
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ABUNDANT |
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| Clostridium drakei | NCBITaxon:332101 · TaxonMech · TraitMech |
SECONDARY_FERMENTER
CROSS_FEEDER
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ABUNDANT |
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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.
Acetogenic Lactate Production from CO2 and H2
CROSS_FEEDINGRecombinant A. woodii fixes CO2 with H2 and is engineered to route carbon toward lactate, creating the intermediate consumed by C. drakei.
Source Taxon: Acetobacterium woodii
Target Taxon: Clostridium drakei
Metabolites: carbon dioxide (CHEBI:16526 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), lactate (CHEBI:24996 · MediaIngredientMech · CMMMech)
Biological Processes:
- carbon fixation (GO:0015977 · PathwayMech)
- fermentation (GO:0006113 · PathwayMech)
A. woodii converts CO2 and H2 into lactate, the intermediate that C. drakei consumes for chain elongation to caproic acid in the coculture.
Evidence
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PMID:36619880 - SUPPORT (IN_VITRO)"Acetobacterium woodii is known to produce mainly acetate from CO2 and H2"
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PMID:36619880 - SUPPORT (IN_VITRO)"production of caproic acid from CO2 and H2 via the intermediate lactic acid"
Lactate-Mediated Chain Elongation to Caproic Acid
CROSS_FEEDINGC. drakei consumes lactate-derived carbon in the coculture and carries out chain elongation to caproic acid.
Participating Taxa: Acetobacterium woodii, Clostridium drakei
Metabolites: lactate (CHEBI:24996 · MediaIngredientMech · CMMMech), hexanoate (CHEBI:30776 · MediaIngredientMech · CMMMech)
Biological Processes:
- fermentation (GO:0006113 · PathwayMech)
Evidence
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PMID:36619880 - SUPPORT (IN_VITRO)"longer-chained products such as caproic acid"
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PMID:36619880 - SUPPORT (IN_VITRO)"production of caproic acid from CO2 and H2 via the intermediate lactic acid"
Electrolysis-Generated Hydrogen Supply
In situ water electrolysis supplies H2 to support autotrophic coculture operation, with hydrogen limitation identified as a process constraint.
Participating Taxa: Acetobacterium woodii
Metabolites: dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech)
In situ electrolysis supplies the H2 electron donor used with CO2 by the recombinant A. woodii strain to form lactate for the chain-elongating partner.
Evidence
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PMID:36619880 - SUPPORT (IN_VITRO)"supplied using an All-in-One electrode for in situ water electrolysis"
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PMID:36619880 - SUPPORT (IN_VITRO)"Hydrogen limitation was identified in the AiO process"
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Exact-system primary publication - in situ electrolysis CO2/H2 coculture
Primary publication establishing the A. woodii and C. drakei synthetic coculture for caproic acid production from CO2 and in situ generated H2 through lactic acid. |
OTHER | PMID:36619880 |
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Exact-system publication - lactate-mediated mixotrophic cocultivation
Follow-up publication on lactate-mediated mixotrophic cocultivation of the same A. woodii and C. drakei species pair. |
OTHER | doi:10.3389/fbioe.2023.1212044 |
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Exact-system publication - CO2/H2 bioreactor optimization
Bioreactor optimization publication for the same lactate-mediated A. woodii mutant and C. drakei coculture using CO2/H2 gas mixture as substrate. |
OTHER | doi:10.1186/s12934-024-02481-3 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Gas substrate | CO2 and H2 | N/A |
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| Hydrogen delivery mode | All-in-One electrode or direct H2 sparging | N/A |
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| Hydrogen limitation | process-limiting under All-in-One electrode operation | N/A |
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Growth Media
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