A defined four-member actinobacterial consortium assembled from Streptomyces sp. SPA2, Streptomyces rochei IT, Streptomyces variabilis Herb, and Streptomyces griseoincarnatus SC for laboratory glyphosate biodegradation. The strains were mixed at a 1:1:1:1 ratio after separate ISP2 pre-culture and OD590 normalization, then incubated in mineral salt medium with glyphosate as the only carbon source. In 15-day 30 C shake-flask assays, RH1 removed glyphosate across 1-200 mg/L initial concentrations, reached 92.06% glyphosate removal and 91.03% total organic carbon reduction at 50 mg/L, and outperformed the matching single-strain treatments at that concentration. Higher glyphosate doses inhibited consortium growth and degradation, and the Haldane-Andrews model was the best fit to the initial-concentration growth-rate response.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Streptomyces sp. SPA2 — ontology label: Streptomyces sp. | NCBITaxon:1931 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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DOMINANT |
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| Streptomyces rochei IT — ontology label: Streptomyces rochei | NCBITaxon:1928 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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DOMINANT |
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| Streptomyces variabilis Herb — ontology label: Streptomyces variabilis | NCBITaxon:67372 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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DOMINANT |
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| Streptomyces griseoincarnatus SC — ontology label: Streptomyces griseoincarnatus | NCBITaxon:29305 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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DOMINANT |
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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.
RH1 glyphosate biodegradation
The four Streptomyces members were compatible in the antagonism assay and, as the RH1 mixed culture, degraded glyphosate at all tested initial concentrations. At 50 mg/L glyphosate, RH1 exceeded the previously reported single-strain removal and TOC-reduction rates. Pairwise exchange metabolites and glyphosate-catabolic genes were not directly resolved. Compatibility and greater aggregate performance do not establish reciprocal fitness benefits among the four members.
Metabolites: glyphosate (CHEBI:27744 · MediaIngredientMech · CMMMech)
Biological Processes:
- xenobiotic metabolic process (GO:0006805 · PathwayMech)
Evidence
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PMID:42582159 - SUPPORT (IN_VITRO)"The antagonism test of strains Herb, IT, SC, and SPA2 showed a negative result, which explains that these actinobacterial strains could be cultured together to form the consortium RH1."
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PMID:42582159 - SUPPORT (IN_VITRO)"The consortium RH1 degraded 92.06% of the initial glyphosate concentration (50 mg/L) within 15 days under optimal conditions (Temperature 30 °C, pH 7.2, and inoculum volume 4%)."
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PMID:42582159 - SUPPORT (IN_VITRO)"This rate of biodegradation is maximal compared to the single strains Herb, IT, SC, and SPA2, which degraded 78.36%, 48.82%, 73.56%, and 68.22% respectively, at the same conditions"
RH1 total organic carbon reduction
At 50 mg/L initial glyphosate, RH1 showed a 91.03% decrease in measured total organic carbon after 15 days. TOC was measured after centrifugation and filtration. This positive processed-sample endpoint does not distinguish mineralization from biomass incorporation or other carbon partitioning, and does not independently establish a direct glyphosate-transformation-to-TOC causal link.
Metabolites: glyphosate (CHEBI:27744 · MediaIngredientMech · CMMMech)
Evidence
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PMID:42582159 - SUPPORT (IN_VITRO)"The results of the reduction of total organic carbon by the actinobacteria consortium RH1, using glyphosate as the sole carbon source at a concentration of 50 mg/L, showed that the consortium was able to eliminate 91.03% of the total organic carbon during a 15-day incubation period."
Knowledge gaps & discussions (2)
KNOWLEDGE_GAP OPEN Which genes and intermediate metabolites mediate glyphosate catabolism by the RH1 consortium?
The paper explains that glyphosate degradation can proceed through the AMPA and sarcosine pathways and proposes phnJ, dadA, and soxA as future molecular targets; the authors state that functional genes were not directly characterized in this study. The RH1 record therefore asserts only the observed degradation, TOC, ATR-FTIR, and kinetic endpoints.
Attaches to: ecological_interactions#RH1 glyphosate biodegradation
1 evidence item(s)
Although functional genes were not directly characterized in this study, the observed biodegradation behavior strongly indicates the involvement of conserved phosphonate-degrading genetic systems, warranting future molecular analyses targeting genes such as phnJ, dadA, and soxA.
Supports leaving the proposed glyphosate-pathway genes as an open mechanistic gap.
KNOWLEDGE_GAP OPEN How are member fitness benefits and glyphosate-derived carbon partitioned in RH1?
The negative antagonism test demonstrates compatibility, not MUTUALISM. The single-strain comparisons cite earlier work, and consortium-level growth/removal does not measure each member benefit. Glyphosate removal, ATR-FTIR changes and TOC decline remain positive observations, but centrifuged/filtered TOC does not resolve mineralization versus biomass or other partitioning. The stoichiometric reaction is predicted, not an empirical carbon balance. The direct arrow between the two outcome nodes is removed while both endpoints and the existing unresolved-gene discussion are preserved.
Attaches to: ecological_interactions#RH1 glyphosate biodegradation, ecological_interactions#RH1 total organic carbon reduction
1 evidence item(s)
After 15 days of incubation, samples were centrifuged, filtered, and diluted before analysis
Methods 2.4 delimit the measured TOC fraction; this preparation does not itself resolve the missing carbon fate.
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Primary publication - RH1 glyphosate biodegradation
Primary open-access Frontiers study of RH1 glyphosate biodegradation and kinetics. |
OTHER | PMID:42582159 |
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Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Initial glyphosate concentration range | 1, 10, 25, 50, 100, and 200 | mg/L |
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| High-glyphosate substrate inhibition | 54.11% at 100 mg/L; 37.08% at 200 mg/L | N/A |
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| Maximum tested 50 mg/L glyphosate removal | 92.06 | percent |
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| Haldane-Andrews growth model fit | R2 0.976, F 65.49, P 0.00074 | N/A |
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Growth Media
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