33 research outputs found
Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine
Remediation of former uranium mining sites represents one of the biggest challenges worldwide
that have to be solved in this century. During the last years, the search of alternative
strategies involving environmentally sustainable treatments has started. Bioremediation,
the use of microorganisms to clean up polluted sites in the environment, is considered one
the best alternative. By means of culture-dependent methods, we isolated an indigenous
yeast strain, KS5 (Rhodosporidium toruloides), directly from the flooding water of a former
uranium mining site and investigated its interactions with uranium. Our results highlight
distinct adaptive mechanisms towards high uranium concentrations on the one hand, and
complex interaction mechanisms on the other. The cells of the strain KS5 exhibit high a
uranium tolerance, being able to grow at 6 mM, and also a high ability to accumulate this
radionuclide (350 mg uranium/g dry biomass, 48 h). The removal of uranium by KS5 displays
a temperature- and cell viability-dependent process, indicating that metabolic activity
could be involved. By STEM (scanning transmission electron microscopy) investigations,
we observed that uranium was removed by two mechanisms, active bioaccumulation and
inactive biosorption. This study highlights the potential of KS5 as a representative of indigenous
species within the flooding water of a former uranium mine, which may play a key role
in bioremediation of uranium contaminated sites.This work was supported by the
Bundesministerium fĂĽr Bildung und Forschung
grand nÂş 02NUK030F (TransAqua). Further support
took place by the ERDF-co-financed Grants
CGL2012-36505 and 315 CGL2014-59616R,
Ministerio de Ciencia e InnovaciĂłn, Spain