A synthetic, light-driven two-member phototroph-heterotroph consortium pairing sucrose-exporting Synechococcus elongatus PCC 7942 cscB with the halotolerant polyhydroxybutyrate producer Halomonas boliviensis LC1. The cyanobacterium fixes carbon dioxide under illumination and exports sucrose, while H. boliviensis consumes the cyanobacterial sucrose and accumulates the bioplastic precursor polyhydroxybutyrate. The system is relevant to DOE carbon utilization and bioproduct goals because it couples photosynthetic carbon fixation to heterotrophic biopolymer production in a modular synthetic coculture.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Synechococcus elongatus PCC 7942 cscB — ontology label: Synechococcus elongatus | NCBITaxon:32046 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
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DOMINANT |
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| Halomonas boliviensis LC1 — ontology label: Vreelandella boliviensis LC1 | NCBITaxon:1072583 · TaxonMech · TraitMech |
CROSS_FEEDER
PRIMARY_DEGRADER
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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.
Photosynthetic Sucrose Transfer To Halomonas
CROSS_FEEDINGThe study reports that sucrose secreted by S. elongatus CscB directly supports H. boliviensis in the light-driven consortium. CO2 is the photosynthetic substrate, not the exchanged organic carbon. The primary Introduction identifies the heterotroph as LC1 (DSM 15516), supporting the canonical strain-specific attribution. Complete medium inputs remain unverified.
Source Taxon: Synechococcus elongatus PCC 7942 cscB
Target Taxon: Halomonas boliviensis LC1
Metabolites: carbon dioxide (CHEBI:16526 · MediaIngredientMech · CMMMech), sucrose (CHEBI:17992 · MediaIngredientMech · CMMMech)
Biological Processes:
- photosynthesis (GO:0015979 · PathwayMech)
- sucrose biosynthetic process (GO:0005986 · PathwayMech)
Photosynthetically supplied sucrose supports the PHB-producing Halomonas partner. This preserves the source-supported carbon-to-product route without asserting that the abstract proves exclusion of every external organic input or a quantitative carbon balance.
Evidence
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PMID:29061492 - SUPPORT (IN_VITRO)"sucrose secreted by S. elongatus CscB directly supports the bacterium Halomonas boliviensis"
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PMID:29061492 - SUPPORT (IN_VITRO)"Halomonas boliviensis LC1 (DSM 15516)"
Light-Driven Biopolymer Production
The light-driven consortium accumulated PHB in H. boliviensis. The primary abstract reports up to 31% of heterotroph dry weight as PHB and productive coculture persistence for over five months. This is a community production endpoint, not an additional pairwise exchange or direct photosynthesis by Halomonas. LC1 identity is supported by the primary Introduction; exact assay details await full Methods.
Participating Taxa: Synechococcus elongatus PCC 7942 cscB, Halomonas boliviensis LC1
Metabolites: poly(3-hydroxybutyrate) (CHEBI:53389 · MediaIngredientMech · CMMMech)
Evidence
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PMID:29061492 - SUPPORT (IN_VITRO)"Consortial H. boliviensis accumulate up to 31% of their dry-weight as PHB"
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PMID:29061492 - SUPPORT (IN_VITRO)"cultures were continuously productive for over 5 months"
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PMID:29061492 - SUPPORT (IN_VITRO)"Halomonas boliviensis LC1 (DSM 15516)"
Alginate-Partitioned Coculture Stabilization
Alginate encapsulation of S. elongatus CscB increased sucrose export and improved coculture stability in the primary abstract. This is an abiotic partitioning intervention, not organism-driven colonization facilitation. The source supports these positive effects but the abstract does not isolate how much of PHB output is mediated by export versus other effects.
Participating Taxa: Synechococcus elongatus PCC 7942 cscB, Halomonas boliviensis LC1
Metabolites: sucrose (CHEBI:17992 · MediaIngredientMech · CMMMech)
HYPOTHESIZED/PARTIAL: alginate-enhanced sucrose export and stability could sustain carbon delivery to the PHB producer. The abstract reports these benefits and PHB production but does not separate their causal contributions to productivity.
Evidence
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PMID:29061492 - SUPPORT (IN_VITRO)"alginate encapsulation of S. elongatus CscB enhances sucrose-export rates"
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PMID:29061492 - SUPPORT (IN_VITRO)"enhances the co-culture stability"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which full primary methods establish medium inputs and the contribution of encapsulation to PHB output?
The publisher-indexed Introduction now establishes LC1 (DSM 15516) as the coculture heterotroph. It also reports growth without supplemental carbon sources, but the accessible section previews do not provide complete medium accounting or isolate encapsulation-mediated PHB output. Direct publisher retrieval failed; full Methods, Table 1 and supplements remain unaudited. Issue #1860 remains open for these methods and mediation limits, not for the resolved LC1 identity.
Attaches to: ecological_interactions#Photosynthetic Sucrose Transfer To Halomonas, ecological_interactions#Light-Driven Biopolymer Production, ecological_interactions#Alginate-Partitioned Coculture Stabilization
1 evidence item(s)
enhances the co-culture stability
The stability finding does not resolve the remaining medium and mediation details.
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Exact-system primary publication - Synechococcus/Halomonas PHB coculture
Primary publication reporting the S. elongatus cscB and H. boliviensis light-driven PHB-producing synthetic coculture. |
OTHER | doi:10.1016/j.ymben.2017.10.009 |
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Environmental Factors
| Factor | Value | Unit |
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| Illumination | light-driven culture | N/A |
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| No external organic carbon input | cyanobacterial sucrose as organic carbon source | N/A |
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Growth Media
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