Objectif "Most toxic metals and radionuclides can be naturally rendered insoluble-immobile by bacterial reduction, which may be exploited for bioremediation purposes at waste repository sites. Some bacteria (e.g. iron or sulphate respirers) are receiving intense attention as their envelope-located electron transport chain can carry out such reductions. However, this process is subject to inhibition by nitrate and oxygen, usually present at waste sites. It also involves 1 e- transfer reactions generating reactive oxygen species which poison the cells and hamper remediation, and the reduced species are released outside the cells, where re-oxidation may occur rapidly. An alternative ""safe"" bacterial pathway for reduction of metals-radionuclides has been discovered recently at the host laboratory (Dr. AC Matin). It involves proteins from the widely distributed ChrR enzyme family, performing 2 e- (4 e-) transfer processes strongly reducing oxidative stress, and leads to sequestering of reduced species. Strengthening this pathway should lessen metal toxicity and increase bioremediation capabilities. The objectives of this multidisciplinary project are (1) to assess this reduction process in bioreactors simulating waste sites conditions, using an engineered strain producing a highly improved ChrR, by analysing the oxidation state and distribution of reduced products; (2) as minor mutations of ChrR led to its increased efficiency, to test the hypothesis that improved ChrR activity is naturally present at US waste sites, where bacteria have been exposed to metals for over 50 years; (3) to test if the intra-cellular reduced products are indeed less amenable to re-oxidation than extra-cellular ones; and (4) to use the skills gained for the identification of new cytoplasmic enzymes with safe metal reduction mechanisms in uranyl-rich soils from Bessines (France), where bacterial communities with effective means of safe enzymatic reduction of uranyl are likely to have naturally evolved." Champ scientifique engineering and technologyenvironmental biotechnologybioremediation Mots‑clés Environmental sciences bacterial remediation metal sequestration naturally improved enzymes nuclear waste sites other radioactive sites safe reduction pathways Programme(s) FP7-PEOPLE - Specific programme "People" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Thème(s) PEOPLE-2007-4-1.IOF - Marie Curie Action: "International Outgoing Fellowships for Career Development" Appel à propositions FP7-PEOPLE-2007-4-1-IOF Voir d’autres projets de cet appel Régime de financement MC-IOF - International Outgoing Fellowships (IOF) Coordinateur COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES Contribution de l’UE € 239 736,50 Adresse RUE LEBLANC 25 75015 PARIS 15 France Voir sur la carte Région Ile-de-France Ile-de-France Paris Type d’activité Research Organisations Contact administratif Catherine Berthomieu (Dr.) Liens Contacter l’organisation Opens in new window Site web Opens in new window Coût total Aucune donnée
