@misc{10481/63619,
year = {2020},
url = {http://hdl.handle.net/10481/63619},
abstract = {The deep geological repository (DGR) system is widely accepted as the solution for the disposal of
radioactive wastes in the future. This concept is based on several natural and engineered barriers such as
bentonite clays, which will encase the metal containers holding the radioactive waste. Microorganisms
living therein can influence the mobility of the radionuclides (e.g. selenium, uranium, etc.) present in such
residues. In this work the bentonite isolate Stenotrophomonas bentonitica is shown to reduce selenite
(SeIV) to elemental Se (Se0
) nanostructures (amorphous and trigonal) and to volatile methylated Se−II
species. Electron microscopy (HAADF-STEM) analysis of purified Se nanostructures supported the
transformation process from amorphous to trigonal Se, proposed in previous studies. Infrared spectroscopy
(ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) revealed the presence of amine rich organic
matter, covering the nanostructures, suggesting the role of proteins in their synthesis and transformation.
In addition, X-ray absorption spectroscopy (XAS) of SeNPs associated to the cells confirmed the formation
of different Se0 structures (amorphous and crystalline). Finally, the reduction of SeIV to volatile methylated
species (DMDSe and DMSeS) was detected using a gas chromatography-mass spectrometry (GC-MS)
system. The oxidation state and molecular coordination of Se in the purified Se nanostructures as well as
the volatile Se species, by means of microscopic, spectroscopic, and gas chromatographic techniques,
indicated their lower mobility and chemo-toxicity. This study thus highlights the potential environmental
significance of microbial processes for the mobility and toxicity of selenium in future repositories, which in
turn contribute to their safe implementation.},
organization = {Euratom research and training programme 2014-2018 	
661880},
organization = {University of Granada},
publisher = {Royal Society of Chemistry},
title = {Chemical and structural characterization of SeIV biotransformations by Stenotrophomonas bentonitica into Se0 nanostructures and volatiles Se species},
doi = {10.1039/d0en00507j},
author = {Ruiz Fresneda, Miguel Ángel and Merroun, Mohamed Larbi},
}