Mobilization of Selenite by Ralstonia metallidurans CH34 |
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Authors: | Murielle Roux, G raldine Sarret, Isabelle Pignot-Paintrand, Marc Fontecave, Jacques Coves |
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Affiliation: | Murielle Roux, Géraldine Sarret, Isabelle Pignot-Paintrand, Marc Fontecave, and Jacques Coves |
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Abstract: | Ralstonia metallidurans CH34 (formerly Alcaligenes eutrophus CH34) is a soil bacterium characteristic of metal-contaminated biotopes, as it is able to grow in the presence of a variety of heavy metals. R. metallidurans CH34 is reported now to resist up to 6 mM selenite and to reduce selenite to elemental red selenium as shown by extended X-ray absorption fine-structure analysis. Growth kinetics analysis suggests an adaptation of the cells to the selenite stress during the lag-phase period. Depending on the culture conditions, the medium can be completely depleted of selenite. Selenium accumulates essentially in the cytoplasm as judged from electron microscopy and energy-dispersive X-ray analysis. Elemental selenium, highly insoluble, represents a nontoxic storage form for the bacterium. The ability of R. metallidurans CH34 to reduce large amounts of selenite may be of interest for bioremediation processes targeting selenite-polluted sites. |
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