A defined anaerobic syntrophic coculture pairing Dehalococcoides mccartyi strain 195 with Desulfovibrio vulgaris Hildenborough. In this laboratory model for chlorinated-solvent groundwater bioremediation, D. vulgaris Hildenborough ferments lactate and supplies hydrogen and acetate that support strain 195 growth and reductive dechlorination. The system is DOE-relevant because it resolves metabolite exchange and stress responses that affect organohalide-respiring communities used for in situ trichloroethene bioremediation.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Dehalococcoides mccartyi strain 195 — ontology label: Dehalococcoides mccartyi 195 | NCBITaxon:243164 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SYNTROPHIC_PARTNER
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DOMINANT |
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| Desulfovibrio vulgaris Hildenborough — ontology label: Nitratidesulfovibrio vulgaris str. Hildenborough | NCBITaxon:882 · TaxonMech · TraitMech |
SECONDARY_FERMENTER
SYNTROPHIC_PARTNER
CROSS_FEEDER
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COMMON |
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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.
Lactate Fermentation Supports Dehalococcoides Growth
SYNTROPHYDvH fermentation of lactate supplies hydrogen as electron donor and acetate for strain-195 growth in the syntrophic coculture. Hydrogen consumption by the dechlorinator supports fermentative energetics. This does not establish that DvH supplies every required cofactor; later cobalamin-free tests required an additional corrinoid source or cobalamin amendment.
Source Taxon: Desulfovibrio vulgaris Hildenborough
Target Taxon: Dehalococcoides mccartyi strain 195
Metabolites: lactate (CHEBI:24996 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech)
Biological Processes:
- lactate catabolic process (GO:1903457 · PathwayMech)
- anaerobic respiration (GO:0009061 · PathwayMech)
DvH-derived hydrogen and acetate support strain-195 growth and reductive dechlorination in the tested coculture. The faster dechlorination comparison does not isolate every proposed ancillary benefit; proton translocation, amino-acid supply and corrinoid-related effects are not separately demonstrated by this arrow.
Evidence
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PMID:21881617 - SUPPORT (IN_VITRO)"using lactate as the sole energy and carbon source"
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PMID:21881617 - SUPPORT (IN_VITRO)"capabilities of DVH to ferment lactate to provide H(2) and acetate for growth"
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PMID:24463969 - PARTIAL (IN_VITRO)"Only the triculture exhibited sustainable dechlorination and cell growth"
Enhanced TCE Dechlorination By Syntrophic Support
Strain 195 showed faster reductive dechlorination and greater cell yield in DvH coculture than in isolation. The approximately threefold comparison concerns maximum dechlorination rate, not every growth endpoint. This is the recipient dechlorinator phenotype, not a second DvH-to-Dhc195 metabolite-transfer event.
Source Taxon: Dehalococcoides mccartyi strain 195
Metabolites: trichloroethene (CHEBI:16602 · MediaIngredientMech · CMMMech), chloroethene (CHEBI:28509 · MediaIngredientMech · CMMMech), ethene (CHEBI:18153 · MediaIngredientMech · CMMMech), dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech)
Biological Processes:
- anaerobic respiration (GO:0009061 · PathwayMech)
Evidence
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PMID:21881617 - SUPPORT (IN_VITRO)"maximum dechlorination rates of DE195 were enhanced by approximately three times"
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PMID:21881617 - SUPPORT (IN_VITRO)"Cell yield of DE195 was enhanced in the co-culture"
Sulfide-Associated Inhibition Of Dechlorination
In the electron-acceptor-limited DvH/195 coculture, sulfate reduction at high initial sulfate generated sulfide and inhibited strain-195 dechlorination and growth. This is conditional sulfide-associated inhibition, not a general effect of sulfate itself or demonstrated hydrogen starvation. Donor-limited butyrate-triculture and enrichment outcomes are separate experiments.
Source Taxon: Desulfovibrio vulgaris Hildenborough
Target Taxon: Dehalococcoides mccartyi strain 195
Metabolites: sulfate (CHEBI:16189 · MediaIngredientMech · CMMMech), hydrogen sulfide (CHEBI:16136 · MediaIngredientMech · CMMMech), trichloroethene (CHEBI:16602 · MediaIngredientMech · CMMMech)
Biological Processes:
- sulfate reduction (GO:0019420 · PathwayMech)
- anaerobic respiration (GO:0009061 · PathwayMech)
Under the tested high-sulfate, electron-donor-excess conditions, accumulated sulfide suppresses strain-195 dechlorination despite available hydrogen. Electron allocation to sulfate reduction is not sufficient evidence that hydrogen competition caused this inhibition. The arrow qualifies the recipient phenotype under this perturbation, not its unperturbed coculture rate.
Evidence
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PMID:28159790 - SUPPORT (IN_VITRO)"high sulfate concentrations (5 mM) inhibited reductive dechlorination due to the toxicity of generated sulfide"
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PMID:28159790 - SUPPORT (IN_VITRO)"sulfide at 5 mM exhibited inhibitory effects"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
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GSE26815 strain 195 syntrophic coculture transcriptomes
GEO microarray dataset for strain 195 grown in isolation, DvH/195 coculture, and related triculture conditions. |
METATRANSCRIPTOMICS | OTHER | GSE26815 |
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PRJNA136009 strain 195 syntrophic growth BioProject
NCBI BioProject linked to the GSE26815 syntrophic growth transcriptomic study. |
OTHER | NCBI_BIOPROJECT | PRJNA136009 |
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which ancillary partner benefits and sulfide-sensitive processes explain strain-195 performance?
Keep measured fermentation support and conditional inhibition distinct. The 2012 full body was unavailable; ancillary benefits remain potential. The 2017 primary body distinguishes donor-excess cocultures from donor-limited tricultures and shows inhibition despite hydrogen availability. Its abstract and Results differ on the DvH sulfide threshold. Expression changes do not by themselves identify the inhibited enzyme. Broader field concentrations and mechanisms are not established by these laboratory comparisons. Non-graph follow-up: #1385.
Attaches to: ecological_interactions#Lactate Fermentation Supports Dehalococcoides Growth, ecological_interactions#Enhanced TCE Dechlorination By Syntrophic Support, ecological_interactions#Sulfide-Associated Inhibition Of Dechlorination
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
Exact-system primary publication - DvH/195 sustainable syntrophy
Primary study reporting D. mccartyi strain 195 grown with D. vulgaris Hildenborough as a sustainable syntrophic coculture. |
OTHER | PMID:21881617 |
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Exact-system isotope-fractionation publication - Dhc195/DvH coculture
Follow-up isotope-fractionation study that included the same Dhc195 and DvH syntrophic coculture composition. |
OTHER | PMID:24015929 |
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Exact-system corrinoid publication - Dhc195/DvH lactate coculture
Corrinoid-salvaging study that constructed Dhc195/DvH cocultures and related consortia in cobalamin-free or amended media. |
OTHER | PMID:24463969 |
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Exact-system perturbation publication - sulfate effects on DvH/195 consortia
Sulfate and sulfide perturbation study including D. mccartyi 195, D. vulgaris Hildenborough, and DvH/195 constructed consortia. |
OTHER | PMID:28159790 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Lactate-fed anaerobic condition | lactate as sole energy and carbon source | N/A |
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| Trichloroethene electron acceptor | TCE-amended dechlorinating culture | N/A |
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| Sulfate and sulfide exposure | sulfate up to 5 mM and sulfide at 5 mM | N/A |
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Growth Media
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