A defined starch-fed microbial fuel cell community pairing the exoelectrogen Shewanella oneidensis MR-1 with the starch-fermenting lactic acid producer Streptococcus bovis 148. The system was tested in two configurations: two-step fermentation, where S. bovis first converted starch to lactic acid before S. oneidensis generated electricity, and parallel fermentation, where cultivation and fermentation by both organisms occurred simultaneously. The community is relevant to DOE bioenergy and bioelectrochemical systems because it couples conversion of a polymeric biomass substrate to lactate cross-feeding and extracellular electron transfer in a microbial fuel cell.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Shewanella oneidensis MR-1 | NCBITaxon:211586 · TaxonMech · TraitMech |
CROSS_FEEDER
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ABUNDANT |
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| Streptococcus bovis 148 — ontology label: Streptococcus equinus | NCBITaxon:1335 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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.
Starch-Derived Lactate Provisioning
CROSS_FEEDINGStreptococcus bovis 148 produces lactic acid from starch that Shewanella oneidensis MR-1 can use for electricity generation. The reported two-step EGT configuration uses fermented broth after removal of the fermenter, whereas the parallel EGP configuration contains simultaneous cultivation. The retained one-way metabolite provisioning covers these distinct configurations; it does not imply a live two-member electricity-generation phase in EGT or a reciprocal benefit.
Source Taxon: Streptococcus bovis 148
Target Taxon: Shewanella oneidensis MR-1
Metabolites: starch (CHEBI:28017 · MediaIngredientMech · CMMMech), lactate (CHEBI:24996 · MediaIngredientMech · CMMMech)
Biological Processes:
- fermentation (GO:0006113 · PathwayMech)
Starch-derived lactic acid supplies the substrate used by S. oneidensis MR-1 for current generation. In EGT this is a sequential fermented-broth handoff after fermenter removal; EGP couples conversion and electricity generation during simultaneous cultivation. Neither configuration supports a reverse metabolite transfer to S. bovis.
Evidence
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PMID:28434977 - SUPPORT (IN_VITRO)"Streptococcus bovis 148 metabolizes starch and produces lactic acid"
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PMID:28434977 - SUPPORT (IN_VITRO)"starch was first converted to lactic acid by S. bovis 148"
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PMID:28434977 - SUPPORT (IN_VITRO)"The S. bovis 148 were then removed by centrifugation, and the fermented broth was preserved for electricity generation by S. oneidensis MR-1."
Lactate-Fed Current Generation
Shewanella oneidensis MR-1 generates current from starch-derived lactic acid. The reported 1.8, 2.4 and 2.8 mA maxima belong to successive terms of the two-step EGT broth experiment, not to the simultaneous coculture. The parallel EGP configuration also coupled starch-to-lactate conversion with electricity generation. This electrical outcome does not represent reverse cross-feeding from Shewanella to Streptococcus.
Participating Taxa: Shewanella oneidensis MR-1
Metabolites: lactate (CHEBI:24996 · MediaIngredientMech · CMMMech)
Evidence
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PMID:28434977 - SUPPORT (IN_VITRO)"Shewanella oneidensis MR-1 generates electricity from lactic acid"
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PMID:28434977 - SUPPORT (IN_VITRO)"maximum currents at each term were 1.8, 2.4, and 2.8 mA"
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PMID:28434977 - SUPPORT (IN_VITRO)"cultivation and subsequent fermentation processes of S. bovis 148 and S. oneidensis MR-1 were performed simultaneously"
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PMID:28434977 - SUPPORT (IN_VITRO)"starch was also converted into lactic acid with electricity generation"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which inferences depend on sequential broth use versus simultaneous coculture?
The fresh primary abstract and complete committed cache distinguish EGT fermenter removal from EGP simultaneous cultivation. The current endpoint is attributed to Shewanella, not to a reverse benefit or metabolite transfer. Full main text was not independently verified, so the graph does not equate the configurations or infer reciprocal fitness. The duplicate workflow node is removed while its positive result and evidence remain.
Attaches to: ecological_interactions#Starch-Derived Lactate Provisioning, ecological_interactions#Lactate-Fed Current Generation
1 evidence item(s)
The S. bovis 148 were then removed by centrifugation, and the fermented broth was preserved for electricity generation by S. oneidensis MR-1.
Distinguishes the sequential broth experiment from live simultaneous coculture.
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Exact-system primary publication - starch-fueled two-organism MFC
Primary publication reporting starch-fueled microbial fuel cells using S. oneidensis MR-1 and S. bovis 148. |
OTHER | PMID:28434977 |
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DOI landing page - Journal of Bioscience and Bioengineering article
DOI landing page for the exact-system starch-fed microbial fuel cell article. |
OTHER | doi:10.1016/j.jbiosc.2017.03.016 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Starch substrate | starch | N/A |
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| Lactic acid intermediate | lactic acid produced from starch | N/A |
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| Parallel fermentation mode | simultaneous cultivation and fermentation | N/A |
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Growth Media
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