Thiocyanate and Organic Carbon Inputs Drive Convergent Selection for Specific Autotrophic Afipia and Thiobacillus Strains Within Complex Microbiomes.

Autor: Huddy RJ; Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.; Future Water Institute, University of Cape Town, Cape Town, South Africa., Sachdeva R; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, United States., Kadzinga F; Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.; Future Water Institute, University of Cape Town, Cape Town, South Africa., Kantor RS; Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, United States., Harrison STL; Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.; Future Water Institute, University of Cape Town, Cape Town, South Africa., Banfield JF; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, United States.; Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, United States.; Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, United States.; School of Earth Sciences, University of Melbourne, Melbourne, VIC, Australia.
Jazyk: angličtina
Zdroj: Frontiers in microbiology [Front Microbiol] 2021 Apr 08; Vol. 12, pp. 643368. Date of Electronic Publication: 2021 Apr 08 (Print Publication: 2021).
DOI: 10.3389/fmicb.2021.643368
Abstrakt: Thiocyanate (SCN - ) contamination threatens aquatic ecosystems and pollutes vital freshwater supplies. SCN - -degrading microbial consortia are commercially adapted for remediation, but the impact of organic amendments on selection within SCN - -degrading microbial communities has not been investigated. Here, we tested whether specific strains capable of degrading SCN - could be reproducibly selected for based on SCN - loading and the presence or absence of added organic carbon. Complex microbial communities derived from those used to treat SCN - -contaminated water were exposed to systematically increased input SCN concentrations in molasses-amended and -unamended reactors and in reactors switched to unamended conditions after establishing the active SCN - -degrading consortium. Five experiments were conducted over 790 days, and genome-resolved metagenomics was used to resolve community composition at the strain level. A single Thiobacillus strain proliferated in all reactors at high loadings. Despite the presence of many Rhizobiales strains, a single Afipia variant dominated the molasses-free reactor at moderately high loadings. This strain is predicted to break down SCN - using a novel thiocyanate desulfurase, oxidize resulting reduced sulfur, degrade product cyanate to ammonia and CO 2 via cyanate hydratase, and fix CO 2 via the Calvin-Benson-Bassham cycle. Removal of molasses from input feed solutions reproducibly led to dominance of this strain. Although sustained by autotrophy, reactors without molasses did not stably degrade SCN - at high loading rates, perhaps due to loss of biofilm-associated niche diversity. Overall, convergence in environmental conditions led to convergence in the strain composition, although reactor history also impacted the trajectory of community compositional change.
Competing Interests: JB is a founder of Metagenomi. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2021 Huddy, Sachdeva, Kadzinga, Kantor, Harrison and Banfield.)
Databáze: MEDLINE
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