A defined seven-member marine bacterial SynCom assembled from the fucoidan degraders F12, F40, F56, F94, V25, V69, and V4 to quantify complementary fucose- and rare-sugar-monomer degradation of Fucus vesiculosus fucoidan. Sichert et al. constructed all 127 possible non-empty combinations of these degraders at equal OD600 in MBL medium with 0.2% fucoidan, measured total and monomer-specific degradation by liquid chromatography mass spectrometry, and resolved a functionally synergistic community landscape in which specialized degrader combinations reached up to 97.1% total degradation.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Algibacter sp. AS12 | NCBITaxon:3135773 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| Algibacter lectus AS40 — ontology label: Algibacter lectus | NCBITaxon:221126 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| Mariniflexile sp. AS56 | NCBITaxon:3063957 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| Zobellia laminariae AS94 — ontology label: Zobellia laminariae | NCBITaxon:248906 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
|
N/A |
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| Luteolibacter sp. AS25 | NCBITaxon:3135776 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| Roseibacillus persicicus AS69 — ontology label: Roseibacillus persicicus | NCBITaxon:454148 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| Lentimonas sp. CC4 | NCBITaxon:2676099 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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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.
Complementary fucoidan monomer degradation
Across the seven-degrader panel, V4/V25 preferentially degrade fucose, F12/F40/F94 rare sugars, and V69/F56 act as generalists. Genomic predictions were compared with experimental LC-MS monomer depletion. Monomer degradation combines cleavage of fucoidan-bound sugars and uptake, not measured CO2 mineralization. Cell-free residual-fucoidan and purified-enzyme assays support complementary substrate accessibility without requiring contact or small-molecule cross-feeding. Six of nine tested soluble enzymes had detectable activity; this does not establish each enzyme as necessary in every community. Participants identify the panel, not seven obligatory partners in every assay. G88 and the algal substrate producer are not members.
Participating Taxa: Algibacter sp. AS12, Algibacter lectus AS40, Mariniflexile sp. AS56, Zobellia laminariae AS94, Luteolibacter sp. AS25, Roseibacillus persicicus AS69, Lentimonas sp. CC4
Biological Processes:
- carbohydrate catabolic process (GO:0016052 · PathwayMech)
Evidence
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PMID:42649294 - SUPPORT (IN_VITRO)"V69 and F56 function as generalists, whereas V4, V25 and G88 are fucose-specialists and F12, F40 and F94 are rare-sugar specialists."
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PMID:42649294 - SUPPORT (IN_VITRO)"access to complementary substrate fractions--rather than enzyme count--limits fucoidan degradation, such that complete breakdown emerges from interactions among metabolically complementary degraders."
Seven-degrader synergistic function landscape
All 127 nonempty combinations of the seven listed degraders were assayed, not a single invariant seven-member community. The reported maximum 97.1% monomer degradation occurred in the five-member F40/F56/V69/F94/V4 subset. Functional synergism, reported for 80% of interactions relative to the resource-partitioning null, is distinct from reciprocal fitness benefit; pairwise outcomes include commensalism, amensalism and competition. The mutualistic V69/G88 pair lies outside this panel. Initial OD600 was 0.01 per strain, so total inoculum varied with richness. These endpoint assays do not isolate a richness-only effect or establish ocean carbon-sequestration rates. The model is fitted prediction, not independent enzyme-necessity evidence.
Participating Taxa: Algibacter sp. AS12, Algibacter lectus AS40, Mariniflexile sp. AS56, Zobellia laminariae AS94, Luteolibacter sp. AS25, Roseibacillus persicicus AS69, Lentimonas sp. CC4
Biological Processes:
- carbohydrate catabolic process (GO:0016052 · PathwayMech)
Evidence
-
PMID:42649294 - SUPPORT (IN_VITRO)"Total degradation increased with community richness, ranging from 4% to a maximum of 97.1% in the 5-member community F40, F56, V69, F94 and V4"
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PMID:42649294 - SUPPORT (COMPUTATIONAL)"even when approaching near-complete degradation, 80% of interactions were still synergistic beyond what would be expected from simple resource partitioning"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
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Fucoidan degrader genome BioProject
NCBI BioProject carrying genome assemblies and sequencing data for the fucoidan-degrader study. |
GENOMICS | NCBI_BIOPROJECT | PRJNA996876 |
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Panorama Public LC-MS dataset
Panorama Public raw LC-MS dataset used to quantify fucoidan-bound monomer depletion. |
METABOLOMICS | OTHER | doi:10.6069/r2z3-7b10 |
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Global fucoidan-degrader analysis Zenodo dataset
Zenodo dataset for global ocean metagenome analysis and fucoidan-degrader annotations. |
METAGENOMICS | ZENODO | zenodo.19591477 |
Knowledge gaps & discussions (3)
KNOWLEDGE_GAP OPEN Should the context-dependent Pseudocolwellia degrader G88/AS88 be represented in a companion pairwise-coculture record?
G88 was an experimentally validated fucoidan degrader from the same strain collection, but the full 127-community landscape explicitly excluded G88 and used the seven degraders F12, F40, F56, F94, V25, V69, and V4.
Attaches to: engineering_design, ecological_interactions#Seven-degrader synergistic function landscape
2 evidence item(s)
The only exception was G88, which increased degradation when paired with V69, but acted as an exploiter when paired with V4 and V25.
Supports treating G88 as pairwise context-dependent instead of silently adding it to the seven-degrader panel.
seven degraders F12, F40, F56, F94, V25, V69 and V4
Names the exact full-combinatorial panel that excluded G88.
KNOWLEDGE_GAP RESOLVED Does the article's prose label for Lentimonas sp. CC4 resolve to V4 or V43?
Publisher HTML inspected on 2026-10-06 shows V4 immediately followed by a superscript link to reference 3, not strain V43. The selected-text cache flattened this citation into V43. Table 2 selected rows and combinatorial Methods consistently use V4 for Lentimonas sp. CC4. Preserve the historical question and original cache, but do not treat the rendering artifact as a biological alias. The decision ledger retains the source HTML hash and exact DOM fragment.
Attaches to: taxonomy#Lentimonas sp. CC4
2 evidence item(s)
Lentimonas sp. CC4 | Verruco4 | V4 | degrader
Supports the Supplementary Table 2 mapping from LCC_4 to V4.
seven degraders F12, F40, F56, F94, V25, V69 and V4
Supports the V4 code in the full-combinatorial Methods section.
KNOWLEDGE_GAP OPEN How should complementary substrate accessibility connect to panel-level degradation without overstating partner benefit?
Full public primary main body and Methods read. Cell-free residual substrate and six active purified enzymes support complementary accessibility; no universal contact requirement, small-molecule exchange or reciprocal benefit follows. Depletion combines cleavage and uptake, not CO2 mineralization. Preserve the five-member maximum, G88 exclusion, variable total inoculum and experimental/model distinction. The Results describe fitting one-, two- and three-member communities while Methods more generally reference the 127-community data; code and raw data were not audited, so no independent train/test verification is claimed. New structure is pending #1465 after the one-community Edison dry run; specific credit authorization requested, no job or spend. Two corrected existing nodes and zero arrows are not a completed causal expansion. Figure images and original supplements were not inspected.
Attaches to: ecological_interactions#Complementary fucoidan monomer degradation, ecological_interactions#Seven-degrader synergistic function landscape
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Nature article DOI
DOI for the Nature article describing synergistic fucoidan degradation by marine bacterial SynComs. |
OTHER | doi:10.1038/s41586-026-10980-z |
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Sichert2025_Fucoidan GitHub workflow
GitHub repository with the reproducible LC-MS degradation and model-fitting workflow. |
GITHUB | EnvSysMicroLAB/Sichert2025_Fucoidan |
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Global ocean fucoidan-degrader GitHub analysis
GitHub repository with global ocean fucoidan-degrader distribution analysis code. |
GITHUB | tpriest0/Global_ocean_microbial_fucoidan_degrader_analysis |
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