Bacterial diversity and production of sulfide in microcosms containing uncompacted bentonites

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dc.contributor.authorGrigoryan, Alexander A.en_ZA
dc.contributor.authorJalique, Daphne R.en_ZA
dc.contributor.authorMedihala, Prabhakaraen_ZA
dc.contributor.authorStroes-Gascoyne, Simchaen_ZA
dc.contributor.authorWolfaardt, Gideon M.en_ZA
dc.contributor.authorMcKelvie, Jenniferen_ZA
dc.contributor.authorKorber, Darren R.en_ZA
dc.date.accessioned2019-09-30T09:43:09Z
dc.date.available2019-09-30T09:43:09Z
dc.date.issued2018
dc.descriptionCITATION: Grigoryan, A. A., et al. 2018. Bacterial diversity and production of sulfide in microcosms containing uncompacted bentonites. Heliyon, 4(8):e00722, doi:10.1016/j.heliyon.2018.e00722.en_ZA
dc.descriptionThe original publication is available at https://www.sciencedirect.comen_ZA
dc.description.abstractAims: This study examined the diversity and sulfide-producing activity of microorganisms in microcosms containing commercial clay products (e.g., MX-80, Canaprill and National Standard) similar to materials which are currently considered for use in the design specifications for deep geologic repositories (DGR) for spent nuclear fuel. Methods and results: In anoxic microcosms incubated for minimum of 60 days with 10 g l-¹ NaCl, sulfide production varied with temperature, electron donor and bentonite type. Maximum specific sulfide production rates of 0.189 d-¹, 0.549 d-¹ and 0.157 d-¹ occurred in lactate-fed MX-80, Canaprill and National Standard microcosms, respectively. In microcosms with 50 g l-¹ NaCl, sulfide production was inhibited. Denaturing gradient gel electrophoresis (DGGE) profiling of microcosms revealed the presence of bacterial classes Clostridia, Bacilli, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Sphingobacteriia and Erysipelotrichia. Spore-forming and non-spore-forming bacteria were confirmed in microcosms using high-throughput 16S rRNA gene sequencing. Sulfate-reducing bacteria of the genus Desulfosporosinus predominated in MX-80 microcosms; whereas, Desulfotomaculum and Desulfovibrio genera contributed to sulfate-reduction in National Standard and Canaprill microcosms. Conclusions: Commercial clays microcosms harbour a sparse bacterial population dominated by spore-forming microorganisms. Detected sulfate- and sulfur-reducing bacteria presumably contributed to sulfide accumulation in the different microcosm systems. Significance and impact of study The use of carbon-supplemented, clay-in-water microcosms offered insights into the bacterial diversity present in as-received clays, along with the types of metabolic and sulfidogenic reactions that might occur in regions of a DGR (e.g., interfaces between the bulk clay and host rock, cracks, fissures, etc.) that fail to attain target parameters necessary to inhibit microbial growth and activity.en_ZA
dc.description.urihttps://www.sciencedirect.com/science/article/pii/S2405844018314658?via%3Dihub
dc.description.versionPublisher's versionen_ZA
dc.format.extent28 pages : illustrationsen_ZA
dc.identifier.citationGrigoryan, A. A., et al. 2018. Bacterial diversity and production of sulfide in microcosms containing uncompacted bentonites. Heliyon, 4(8):e00722, doi:10.1016/j.heliyon.2018.e00722en_ZA
dc.identifier.issn2405-8440 (online)
dc.identifier.otherdoi:10.1016/j.heliyon.2018.e00722
dc.identifier.urihttp://hdl.handle.net/10019.1/106541
dc.language.isoen_ZAen_ZA
dc.rights.holderAuthors retain copyrighten_ZA
dc.subjectEnvironmental scienceen_ZA
dc.subjectCommercial clays microcosmsen_ZA
dc.subjectMicroorganisms in microcosmsen_ZA
dc.subjectBacterial diversity present in as-received claysen_ZA
dc.subjectBentonitesen_ZA
dc.titleBacterial diversity and production of sulfide in microcosms containing uncompacted bentonitesen_ZA
dc.typeArticleen_ZA
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