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Hessler T, Harrison ST, Banfield JF, Huddy RJ. Harnessing Fermentation May Enhance the Performance of Biological Sulfate-Reducing Bioreactors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2830-2846. [PMID: 38301118 PMCID: PMC10867827 DOI: 10.1021/acs.est.3c04187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 12/28/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024]
Abstract
Biological sulfate reduction (BSR) represents a promising strategy for bioremediation of sulfate-rich waste streams, yet the impact of metabolic interactions on performance is largely unexplored. Here, genome-resolved metagenomics was used to characterize 17 microbial communities in reactors treating synthetic sulfate-contaminated solutions. Reactors were supplemented with lactate or acetate and a small amount of fermentable substrate. Of the 163 genomes representing all the abundant bacteria, 130 encode 321 NiFe and FeFe hydrogenases and all genomes of the 22 sulfate-reducing microorganisms (SRM) encode genes for H2 uptake. We observed lactate oxidation solely in the first packed bed reactor zone, with propionate and acetate oxidation in the middle and predominantly acetate oxidation in the effluent zone. The energetics of these reactions are very different, yet sulfate reduction kinetics were unaffected by the type of electron donor available. We hypothesize that the comparable rates, despite the typically slow growth of SRM on acetate, are a result of the consumption of H2 generated by fermentation. This is supported by the sustained performance of a predominantly acetate-supplemented stirred tank reactor dominated by diverse fermentative bacteria encoding FeFe hydrogenase genes and SRM capable of acetate and hydrogen consumption and CO2 assimilation. Thus, addition of fermentable substrates to stimulate syntrophic relationships may improve the performance of BSR reactors supplemented with inexpensive acetate.
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Affiliation(s)
- Tomas Hessler
- The
Center for Bioprocess Engineering Research, University of Cape Town, Cape Town 7700, South Africa
- Department
of Chemical Engineering, University of Cape
Town, Cape Town 7700, South Africa
- The
Innovative Genomics Institute at the University of California, Berkeley, California CA94720, United
States
- The
Department of Earth and Planetary Science, University of California, Berkeley, California CA94720, United States
- Environmental
Genomics and Systems Biology Division, Lawrence
Berkeley National Laboratory, Berkeley, California CA94720, United States
| | - Susan T.L. Harrison
- The
Center for Bioprocess Engineering Research, University of Cape Town, Cape Town 7700, South Africa
- Department
of Chemical Engineering, University of Cape
Town, Cape Town 7700, South Africa
- The Future
Water Institute, University of Cape Town, Cape Town 7700, South Africa
| | - Jillian F. Banfield
- The
Innovative Genomics Institute at the University of California, Berkeley, California CA94720, United
States
- The
Department of Earth and Planetary Science, University of California, Berkeley, California CA94720, United States
- The
Department of Environmental Science, Policy and Management, University of California, Berkeley, California CA94720, United States
| | - Robert J. Huddy
- The
Center for Bioprocess Engineering Research, University of Cape Town, Cape Town 7700, South Africa
- Department
of Chemical Engineering, University of Cape
Town, Cape Town 7700, South Africa
- The Future
Water Institute, University of Cape Town, Cape Town 7700, South Africa
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