Microbial communities in bentonite formations and their interactions with uranium

López-Fernández, Margarita; Fernández-Sanfrancisco, Omar; Moreno-García, Alberto; Martín-Sánchez, Inés; Sánchez-Castro, Iván; Merroun, Mohamed L.

doi:10.1016/j.apgeochem.2014.06.022

Cited by 55 publications

(51 citation statements)

References 60 publications

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“…0.6 ± 0.3% in Opalinus Clay [51], and 1-5% in Boom Clay [52]). The pH measured was 9.03, 7.82 [22] and 8.03, for superficial samples BI-2, BII-2 and BIV-2, respectively ( Table 3). The pH value for sample BI-3 was 9.16 and for sample BIV-3 was 8.32.…”

Section: Organic Carbon Content and Ph Measurementsmentioning

confidence: 99%

“…X-ray diffraction (XRD) characterization of the three bentonite sites was done as described in LopezFernandez et al [22]. Composition of the major elements of each sample was determined by X-ray fluorescence spectroscopy (XRF), on pressed pellets made of 1:10 lithium tetraborate dilution.…”

Section: Geochemical and Mineralogical Analysesmentioning

confidence: 99%

“…In each sampled site, the bentonites exhibit different characteristics, due to the type of rock undergoing alteration, or chemical composition for example [47]. The XRD semi-quantitative estimation of the mineralogical composition of the studied sites revealed that smectites (montmorillonites) are the dominant mineral phase, 84%, 71% and 96% in sites BI, BII [22] and BIV, respectively (Table 1). Moreover, feldspars were detected: Kfeldspar (sanidine) in site BII and plagioclase (albite) in sites BI and BIV.…”

Section: Sampling and Characterization Of The Bentonitesmentioning

confidence: 99%

“…Culture-dependent analysis of microbial diversity from these clay formations were presented in LopezFernandez et al [22]. Bacteria from different phyla were isolated, whereas representatives from Proteobacteria, Firmicutes and Actinobacteria were dominant.…”

Section: Introductionmentioning

confidence: 99%

“…Bacteria from different phyla were isolated, whereas representatives from Proteobacteria, Firmicutes and Actinobacteria were dominant. In addition, a pigmented yeast strain namely Rhodotorula mucilaginosa BII-R8 was also recovered [22]. Nevertheless, this approach is limited as a small percentage of natural microbial populations can be isolated and studied in the laboratory due to the limited knowledge about their nutrient requirements and other life-necessities [23][24].…”

Section: Introductionmentioning

confidence: 99%

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Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

López-Fernández

Cherkouk²,

Vílchez-Vargas

et al. 2015

Microb Ecol

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The long-term disposal of radioactive wastes in a deep geological repository is the accepted international solution for the treatment and management of these special residues. The microbial community of the selected host rocks and engineered barriers for the deep geological repository may affect the performance and the safety of the radioactive waste disposal. In this work the bacterial population of bentonite formations of Almeria (Spain), selected as reference material for bentonite engineered barriers in the disposal of radioactive wastes, was studied. 16S rRNA gene-based approaches were used to study the bacterial community of the bentonite samples by traditional clone libraries and Illumina-sequencing. By both techniques the bacterial diversity analysis revealed similar results, with phylotypes belonging to 14 different bacterial phyla:

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Section: Organic Carbon Content and Ph Measurementsmentioning

confidence: 99%

Section: Geochemical and Mineralogical Analysesmentioning

confidence: 99%

Section: Sampling and Characterization Of The Bentonitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

López-Fernández

Cherkouk²,

Vílchez-Vargas

et al. 2015

Microb Ecol

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Probing the viability of palladium‐challenged bacterial cells using flow cytometry

Omajali

Mikheenko²,

Overton

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND The ability of bacterial cells to retain membrane integrity and membrane potential when challenged with palladium (II) solution has not being examined previously, which would provide a platform towards the bio‐fabrication of a multifunctional tandem bio‐nanoparticles. This study investigates the use of flow cytometry coupled with fluorescent probes to determine membrane integrity and membrane potential of cells of Desulfovibrio desulfuricans and Bacillus benzeovorans challenged with 1 mmol L−1 of sodium tetrachloropalladate (II) (Na2PdCl4) solution at pH 2 followed by reduction of palladium (II) (Pd(II)) with formate to give 1 wt% loading of Pd(0) on the cells. RESULTS Fluorescently labelled active bacterial cells retained over 80% of membrane potential when challenged with Pd(II) solutions except for Bacillus benzeovorans (Bb) with about 32% retention. Cell viability was also seen to be variable and strain‐dependent while dead cells lack any membrane integrity. Since esterase activity is energy independent and unable to confirm the membrane potential of the bacterial cells, the dye 3,3′‐dihexyloxacarbocyanine iodide [DiO6(3)] was used to determine and confirm the membrane potential of the bacterial cells. CONCLUSION The results revealed that since fluorescently labelled bacterial cells containing Pd(0) can retain metabolic activity when analysed with flow cytometry, it provides the potential for combining chemical catalysis with biochemical activity in reactions that require metabolic synergy. © 2018 Society of Chemical Industry

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Clay‐associated microbial communities and their relevance for a nuclear waste repository in the Opalinus Clay rock formation

et al. 2023

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Microorganisms are known to be natural agents of biocorrosion and mineral transformation, thereby potentially affecting the safety of deep geological repositories used for high‐level nuclear waste storage. To better understand how resident microbial communities of the deep terrestrial biosphere may act on mineralogical and geochemical characteristics of insulating clays, we analyzed their structure and potential metabolic functions, as well as site‐specific mineralogy and element composition from the dedicated Mont Terri underground research laboratory, Switzerland. We found that the Opalinus Clay formation is mainly colonized by Alphaproteobacteria, Firmicutes, and Bacteroidota, which are known for corrosive biofilm formation. Potential iron‐reducing bacteria were predominant in comparison to methanogenic archaea and sulfate‐reducing bacteria. Despite microbial communities in Opalinus Clay being in majority homogenous, site‐specific mineralogy and geochemistry conditions have selected for subcommunities that display metabolic potential for mineral dissolution and transformation. Our findings indicate that the presence of a potentially low‐active mineral‐associated microbial community must be further studied to prevent effects on the repository's integrity over the long term.

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Microbial communities in bentonite formations and their interactions with uranium

Cited by 55 publications

References 60 publications

Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

Probing the viability of palladium‐challenged bacterial cells using flow cytometry

Clay‐associated microbial communities and their relevance for a nuclear waste repository in the Opalinus Clay rock formation

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