Please use this identifier to cite or link to this item: http://buratest.brunel.ac.uk/handle/2438/8793
Title: Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses
Authors: Merroun, ML
Nedelkova, M
Ojeda, JJ
Reitz, T
López Fernández, M
Arias, JM
Romero-González, M
Selenska-Pobell, S
Keywords: Uranium biomineralization;Potentiometric titration;XAS;TEM/EDX;Acid phosphatase
Issue Date: 2011
Publisher: Elsevier
Citation: Journal of Hazardous Materials, 197, 1 - 10, 2011
Abstract: This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U–bacterial interaction experiments were performed at low pH values (2.0–4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase.
Description: This is the post-print version of the final paper published in Journal of Hazardous Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.
URI: http://www.sciencedirect.com/science/article/pii/S0304389411011496
http://bura.brunel.ac.uk/handle/2438/8793
DOI: http://dx.doi.org/10.1016/j.jhazmat.2011.09.049
ISSN: 0304-3894
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