A two-member photosynthetic synthetic consortium pairing acetate-secreting Synechocystis sp. PCC 6803 WT_PKPa_RBS_BsPta_Δacs with a Pseudomonas taiwanensis VLB120 derivative engineered with the TPC4 1-butanol pathway under the Pem7 promoter. The coculture was grown for 42 days in illuminated CoBG11 with repeated medium replacement, added bicarbonate, and pH adjustment. The system tests whether Synechocystis can route light- and CO2-derived carbon through extracellular acetate toward heterotrophic production of the bulk chemical 1-butanol.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
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| Synechocystis sp. PCC 6803 WT_PKPa_RBS_BsPta_Δacs — ontology label: Synechocystis sp. PCC 6803 | NCBITaxon:1148 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
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DOMINANT |
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| Pseudomonas taiwanensis VLB120 Pem7_ButOH — ontology label: Pseudomonas taiwanensis | NCBITaxon:470150 · TaxonMech · TraitMech |
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.
Photosynthetic Acetate Supply To Pseudomonas
CROSS_FEEDINGThe engineered Synechocystis partner supplies photosynthetic organic carbon to P. taiwanensis in the acetate-designed coculture. The heterotroph grows on acetate in separate assays, and coculture acetate levels are lower than in axenic Synechocystis. PARTIAL: these observations support acetate consumption but do not isotope-resolve its flux or exclude other cyanobacterial exudates as carbon sources. CO2 is the photosynthetic substrate, not the exchanged organic molecule.
Source Taxon: Synechocystis sp. PCC 6803 WT_PKPa_RBS_BsPta_Δacs
Target Taxon: Pseudomonas taiwanensis VLB120 Pem7_ButOH
Metabolites: carbon dioxide (CHEBI:16526 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech)
Biological Processes:
- photosynthesis (GO:0015979 · PathwayMech)
- acetate metabolic process (GO:0006083 · PathwayMech)
HYPOTHESIZED/PARTIAL: photosynthetically supplied acetate is a supported candidate carbon route to the observed Pseudomonas 1-butanol output. The experiment does not resolve the fraction of product carbon derived from acetate rather than other cyanobacterial exudates; production detection is not a quantified acetate-to-product flux.
Evidence
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PMID:42726284 - SUPPORT (IN_VITRO)"where no additional carbon source was used"
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PMID:42726284 - PARTIAL (IN_VITRO)"acetate levels remained lower than in the axenic Synechocystis culture"
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PMID:42726284 - PARTIAL (IN_VITRO)"we cannot conclude that the heterotrophic bacteria used acetate as the only source of carbon"
Acetate-Coupled 1-Butanol Production
The engineered P. taiwanensis partner produced measurable 1-butanol during the 42-day, periodically replenished coculture. Titers fluctuated and reached a plateau; this does not establish uniformly high productivity. The earlier acetate-adaptation assays improved heterotroph growth without increasing 1-butanol production above pre-adaptation levels. This is a community production endpoint, not a second pairwise exchange. Product-carbon attribution to acetate remains unresolved.
Participating Taxa: Synechocystis sp. PCC 6803 WT_PKPa_RBS_BsPta_Δacs, Pseudomonas taiwanensis VLB120 Pem7_ButOH
Metabolites: acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), butan-1-ol (CHEBI:28885 · MediaIngredientMech · CMMMech)
Biological Processes:
- acetate metabolic process (GO:0006083 · PathwayMech)
Evidence
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PMID:42726284 - SUPPORT (IN_VITRO)"1-butanol production was detected in the two co-cultures"
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PMID:42726284 - SUPPORT (IN_VITRO)"the production was not stable in the systems but it clearly reached a plateau"
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PMID:42726284 - SUPPORT (IN_VITRO)"1-butanol production did not exceed the levels prior to adaptation"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN What fraction of Pseudomonas carbon in the coculture came from Synechocystis-derived acetate rather than extracellular polysaccharides or other cyanobacterial exudates?
The paper reports lower acetate levels in the P. taiwanensis coculture than in axenic Synechocystis and uses acetate as the designed exchange metabolite, but it did not isotope-resolve Pseudomonas carbon uptake.
Attaches to: ecological_interactions#Photosynthetic Acetate Supply To Pseudomonas
1 evidence item(s)
we cannot conclude that the heterotrophic bacteria used acetate as the only source of carbon
Records the authors' caveat that other cyanobacterial carbon pools may have contributed to heterotroph growth.
External Resources
| Name | Repository | Resource ID |
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Primary publication DOI
Version-of-record publication describing two acetate-based Synechocystis synthetic consortia, including the P. taiwanensis VLB120 acetate-to- 1-butanol coculture curated here. |
OTHER | doi:10.1007/s00253-026-14029-z |
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Environmental Factors
| Factor | Value | Unit |
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| Illumination | 65 umol photons m^-2 s^-1 | N/A |
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| Temperature | 30 | C |
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| Periodic pH adjustment | pH 7 at 10% medium replacement | N/A |
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Growth Media
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