8 research outputs found

    Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

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    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

    Soot volume fraction from extinction in JP-8 and heptane pool fires

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    Total extinction measurements from a multiple beam experiment using a 10mW laser diode are presented and compared to calculate soot volume fraction in heavily sooting pool fires from a 150 mm diameter pan of Jet Propulsion fuel 8 (JP-8) and heptane. Trends in attenuation are critiqued for the two fuels, and estimates of the axi-symmetrical distribution of soot are established.Tara L. Henriksen, Gus Nathan, Zeyad Alwahabi, Jennifer Spinti, Eric Eddings, Phillip J. Smit
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