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Thiocyanate-Degrading Afipia and Thiobacillus Bioreactor Community

Community ID CommunityMech:000239
Ecological State ENGINEERED
Environment thiocyanate-fed laboratory bioreactor
ENVO:01001405

A laboratory bioreactor microbial community derived from consortia used to treat thiocyanate-contaminated water, perturbed by systematically increased SCN- input loading and the presence or absence of molasses as organic carbon. Five experiments over 790 days with genome-resolved metagenomics showed that a single Thiobacillus strain proliferated in all reactors at high SCN- loading, while a single Afipia variant dominated the molasses- free reactor at moderate loadings. The Afipia variant is predicted to degrade SCN- via a novel thiocyanate desulfurase, oxidize the resulting reduced sulfur, degrade the cyanate product to ammonia and CO2 via cyanate hydratase, and fix CO2 via the Calvin-Benson-Bassham cycle. Removal of molasses reproducibly selects for this autotrophic strain, although molasses-free reactors did not sustain high-loading SCN- degradation, possibly due to loss of biofilm-associated niche diversity.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Thiobacillus thiocyanate-degrader strain NCBITaxon:919
PRIMARY_DEGRADER PRIMARY_PRODUCER
DOMINANT
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "A single Thiobacillus strain proliferated in all reactors at high loadings"
Afipia thiocyanate-degrader variant NCBITaxon:1033
PRIMARY_DEGRADER PRIMARY_PRODUCER
DOMINANT
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "a single Afipia variant dominated the molasses-free reactor at moderately high loadings"
Rhizobiales background strains NCBITaxon:356
CROSS_FEEDER
N/A
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "Despite the presence of many Rhizobiales strains"

Ecological Interactions

Ecological interaction network for Thiocyanate-Degrading Afipia and Thiobacillus Bioreactor Community Bipartite graph where circle nodes represent taxa and colored rectangles represent ecological interactions (cross-feeding, mutualism, syntrophy, competition, commensalism).
Taxon
Cross-feeding
Mutualism
Syntrophy
Competition
Commensalism
Niche partitioning
Colonization facilitation
Strain competition
Predation

Thiocyanate Degradation and Autotrophic CO2 Fixation by Afipia

CROSS_FEEDING

Metabolites: thiocyanate (CHEBI:18022), cyanate (CHEBI:29195), ammonia (CHEBI:16134), carbon dioxide (CHEBI:16526)

Biological Processes:

Evidence

  • PMID:33897653 - SUPPORT (IN_VITRO)
    "predicted to break down SCN- using a novel thiocyanate desulfurase, oxidize resulting reduced sulfur, degrade product cyanate to ammonia and CO2 via cyanate hydratase, and fix CO2 via the Calvin-Benson-Bassham cycle"

Molasses Removal Selects for Afipia

COMPETITION

Evidence

  • PMID:33897653 - SUPPORT (IN_VITRO)
    "Removal of molasses from input feed solutions reproducibly led to dominance of this strain"

Loss of Biofilm Niche Diversity Without Molasses

NICHE_PARTITIONING

Evidence

  • PMID:33897653 - SUPPORT (IN_VITRO)
    "reactors without molasses did not stably degrade SCN- at high loading rates, perhaps due to loss of biofilm-associated niche diversity"

External Resources

Name Repository Resource ID
Primary publication for the Afipia/Thiobacillus thiocyanate community
PubMed record for the Huddy et al. 2021 Frontiers in Microbiology paper. 		OTHER PMID:33897653
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "Thiocyanate and Organic Carbon Inputs Drive Convergent Selection for Specific Autotrophic Afipia and Thiobacillus Strains"
DOI landing page
DOI link to the Frontiers in Microbiology paper. 		OTHER doi:10.3389/fmicb.2021.643368

Environmental Factors

Factor Value Unit
Thiocyanate loading systematically increased SCN- input concentration N/A
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "systematically increased input SCN concentrations"
Molasses amendment molasses-amended vs molasses-free N/A
  • PMID:33897653 - SUPPORT (IN_VITRO)
    "molasses-amended and -unamended reactors"