GEOC 16 |
| Laure Avoscan1, Richard N Collins1, Géraldine Sarret2, Marie Carriere1, Jacques Covès3, and Barbara Gouget1. (1) Laboratoire Pierre Süe, Commissariat à l'énergie atomique, CEA/SACLAY, Gif sur Yvette, France, (2) Groupe de Géochimie de l'Environnement LGIT/IRIGM, Université Joseph Fourier, BP 53 F38041, Grenoble, France, (3) Laboratoire des protéines membranaires, Institut de biologie Structurale CNRS-CEA-UJF, 41 rue jules horowitz, 38027, Grenoble, France |
| The bacteria Ralstonia metallidurans CH34 is a facultative aerobe that has been shown to reduce selenite (SeO32-), by an intracellular process to elemental selenium (monoclinic form) (Roux et al., 2001). In soils, however, Se is principally found as selenate (SeO42-) as well as selenite. Therefore, the present study examined the kinetics of selenite and selenate uptake, and transformation, by R. metallidurans CH34. The speciation of these oxyanions was followed by two complementary analytical techniques, Se K-edgeXANES spectroscopy and HPLC-ICP-MS. It was observed that selenate was reduced into selenite and then organic selenium such as the amino acid Se-methionine, but not into elemental selenium. It was also found that the reduction of selenite to elemental Se progressed via organic intermediates. These results report a fundamental microbiological process that potentially influences the biogeochemical fate of Se in soils. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
1:25 PM-5:05 PM, Sunday, March 28, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |