@misc{10481/70605,
year = {2021},
month = {7},
url = {http://hdl.handle.net/10481/70605},
abstract = {Uranium-containing effluents generated by nuclear energy industry must be efficiently remediated before release
to the environment. Currently, numerous microbial-based strategies are being developed for this purpose. In
particular, the bacterial strain Stenotrophomonas sp. Br8, isolated from U mill tailings porewaters, has been
already shown to efficiently precipitate U(VI) as stable U phosphates mediated by phosphatase activity. However,
the upscaling of this strategy should overcome some constraints regarding cell exposure to harsh environmental
conditions. In the present study, the immobilization of Br8 biomass in an inorganic matrix was
optimized to provide protection to the cells as well as to make the process more convenient for real-scale utilization.
The use of biocompatible, highly porous alginate beads for Br8 cells immobilization resulted the best
alternative when investigating by a multidisciplinary approach (High-Angle Annular Dark-Field Scanning
Transmission Electron Microscopy (HAADF-STEM), Environmental Scanning Electron Microscopy (ESEM),
Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance, etc.) several consolidated entrapment
methods. This biomaterial was applied to complex real U mining porewaters (containing 47 mg/L U) in
presence of an organic phosphate source (glycerol-2-phosphate) to produce reactive free orthophosphates
through Br8 phosphatase activity. Uranium immobilization rates around 98 % were observed after one cycle of
72 h. In terms of U removal ability as a function of biomass, Br8-doped alginate beads were determined to
remove up to 1199.5 mg U/g dry biomass over two treatment cycles. Additionally, optimized conditions for
storing Br8-doped beads and for a correct application were assessed. Results for U accumulation kinetics and
HAADF-STEM/ESEM analyses revealed that U removal by the immobilized cells is a biphasic process combining
a first passive U sorption onto bead and/or cell surfaces and a second slow active biomineralization. This work
provides new practical insights into the biological and physico-chemical parameters governing a high-efficient U
bioremediation process based on the phosphatase activity of immobilized bacterial cells when applied to complex
mining waters under laboratory conditions.},
organization = {ORANO Mining (France)	3022 OTRI-UGR},
organization = {Universidad de Granada/CBUA},
publisher = {Elsevier},
keywords = {Mining waters},
keywords = {Bioremediation},
keywords = {Biomineralization},
keywords = {Uranium},
keywords = {Bacteria immobilization},
keywords = {Alginate beads},
title = {Uranium removal from complex mining waters by alginate beads doped with cells of Stenotrophomonas sp. Br8: Novel perspectives for metal bioremediation},
doi = {10.1016/j.jenvman.2021.113411},
author = {Sánchez Castro, Iván and Martínez Rodríguez, Pablo and Abad Ortega, María del Mar and Descostes, Michael and Merroun, Mohamed Larbi},
}