@misc{10481/72108,
year = {2021},
month = {11},
url = {http://hdl.handle.net/10481/72108},
abstract = {Uranium (U) is the most hazardous radionuclide in nuclear waste and its harmful effects depend on its mobility
and bioavailability. Microorganisms can affect the speciation of radionuclides and their migration in Deep
Geological Repositories (DGR) for high level radioactive waste (HLW) storage. Consequently, a better understanding
of microbe-radionuclide interactions within a DGR concept is essential for a safe storage. With that in
mind, bentonite microcosms amended with uranyl nitrate and glycerol-2-phosphate were incubated for six
months under anoxic conditions. Post-incubation 16S rRNA gene sequencing revealed high microbial diversities
including glycerol oxidizers such as Clostridium and Desulfovibrio and nitrate reducers (Limnobacter and Brevundimonas).
In addition, uranium-reducing bacteria (Desulfovibrio and Pseudomonas) were highly enriched in
glycerol-2-phosphate‑uranium amended microcosms. These bacteria may contribute to uranium immobilization
through enzymatic reduction and/or biomineralization. Scanning electron microscopy of colored spots on the
surface of the bentonite in the microcosms indicated the probable formation of Mn(IV) oxides likely through the
activity of Mn(II)-oxidizing microbes. This could affect the biogeochemical cycle of U(VI) by concentrating and
immobilizing this element in the bentonites. Finally, X-ray diffraction determined a high structural stability of
bentonites. The outputs of this study help to predict the impact of microbial activity (e.g. smectite alteration,
metal corrosion, and radionuclides mobilization) on the long-term performance of a DGR and to develop
appropriate waste treatments, remediation, and management strategies.},
organization = {European Commission	CGL2014-59616-R},
organization = {German Research Foundation (DFG)	FPU 14/04263},
publisher = {Elsevier},
keywords = {Bacterial diversity},
keywords = {DGR},
keywords = {Radionuclides},
keywords = {G2P},
keywords = {Bioreduction},
keywords = {Immobilization},
title = {Impact of anoxic conditions, uranium(VI) and organic phosphate substrate on the biogeochemical potential of the indigenous bacterial community of bentonite},
doi = {10.1016/j.clay.2021.106331},
author = {Povedano Priego, Cristina and Jroundi, Fadwa and Morales Hidalgo, Mar and Martín Sánchez, Inés and Huertas Puerta, Francisco Javier and Merroun, Mohamed Larbi},
}