Engineered two-member co-culture pairing the succinic-acid producer Corynebacterium glutamicum (including an ldhA-deleted, lactate-deficient strain K1) with the electroactive bacterium Shewanella oneidensis to enhance anaerobic succinic acid biosynthesis through interspecies interactions. Co-cultivation raised succinic acid yield markedly over monoculture without altering glucose consumption, and supplementation with riboflavin (the most effective of five screened redox-active additives) further improved production. Transcriptomics showed co-culture reprogrammed C. glutamicum metabolism, reinforcing its electron transport system and redistributing carbon flux toward the reductive TCA pathway.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Corynebacterium glutamicum (ldhA-deleted strain K1) — ontology label: Corynebacterium glutamicum | NCBITaxon:1718 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
|
N/A |
|
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| Shewanella oneidensis | NCBITaxon:70863 · TaxonMech · TraitMech |
ELECTROGEN
ELECTRON_DONOR
|
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.
Riboflavin-Supplemented Coculture Response
The complete abstract reports that externally supplied riboflavin was the most effective of five screened redox-active additives, with 0.1 mM supplementation further improving coculture production. This supports an additive response, not demonstrated Shewanella secretion, directed interspecies electron transfer or thermodynamic syntrophy. Parent-strain and K1 experiments must be distinguished; the abstract does not resolve every additive/transcript assay to K1.
Participating Taxa: Corynebacterium glutamicum (ldhA-deleted strain K1), Shewanella oneidensis
Metabolites: riboflavin (CHEBI:17015 · MediaIngredientMech · CMMMech)
Biological Processes:
- electron transport chain (GO:0022900 · PathwayMech)
HYPOTHESIZED - altered coculture redox conditions could contribute to the Corynebacterium transcript response. Additive screening and the transcriptomic interpretation support this candidate link, but the accessible abstract does not selectively establish riboflavin-dependent electron transfer as its cause.
Evidence
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PMID:42203120 - SUPPORT (IN_VITRO)"Screening of five redox-active compounds identified riboflavin as the most effective additive, and supplementation with 0.1 mM riboflavin further improved production performance."
Corynebacterium Coculture Transcript Response
Coculture changed C. glutamicum transcript profiles, interpreted by the authors as enhanced electron transport, redistribution toward the reductive TCA pathway and suppression of succinic-acid-consuming pathways. This is transcript-based metabolic interpretation, not directly traced carbon or electron flux. The canonical entry includes K1; the abstract does not identify the strain used for every transcript comparison.
Source Taxon: Corynebacterium glutamicum (ldhA-deleted strain K1)
Metabolites: succinic acid (CHEBI:15741 · MediaIngredientMech · CMMMech)
Biological Processes:
- tricarboxylic acid cycle (GO:0006099 · PathwayMech)
PARTIAL - the transcript-based interpretation is consistent with metabolic changes contributing to increased succinic acid yield. Positive coculture, riboflavin and ldhA-deletion outcomes support the production strategy, but do not selectively establish this transcript response or inferred flux redistribution as the mediator of each yield comparison.
Evidence
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PMID:42203120 - PARTIAL (IN_VITRO)"Transcriptomic analysis revealed that co-culture induced global metabolic reprogramming in C. glutamicum, including reinforcement of the electron transport system, redistribution of carbon flux toward the reductive TCA pathway"
Enhanced Succinic Acid Production
The abstract reports an optimized parent-strain coculture yield of 0.169 g/g, 45.65% above monoculture without markedly changing glucose consumption. Separately, ldhA deletion abolished lactate formation in K1; its coculture reached 0.686 g/g and showed up to 23.4% higher yield during extended fermentation than monoculture. These positive interventions do not establish thermodynamic syntrophy or assign the parent-strain result to K1.
Participating Taxa: Corynebacterium glutamicum (ldhA-deleted strain K1), Shewanella oneidensis
Metabolites: succinic acid (CHEBI:15741 · MediaIngredientMech · CMMMech)
Evidence
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PMID:42203120 - SUPPORT (IN_VITRO)"The engineered strain maintained enhanced succinic acid production in the co-culture system, reaching a yield of 0.686 g/g"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which redox and metabolic changes mediate the strain-specific succinate yield improvements?
Only the complete primary abstract was accessible; publisher full-body access returned 403. Direct electron/carbon flux, mediator-specific perturbations and exact strain/condition assignments are needed to resolve the two proposed arrows. Riboflavin is externally supplied, not proven to be secreted by Shewanella. Preserve the positive parent-strain and K1 treatment outcomes without conflating them. Top-level description and donor-role metadata require separate followup #1354.
Attaches to: ecological_interactions#Riboflavin-Supplemented Coculture Response, ecological_interactions#Corynebacterium Coculture Transcript Response, ecological_interactions#Enhanced Succinic Acid Production
Growth Media
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