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Nitrate reducing bacterial activity in concrete cells of nuclear waste disposal

Alquier, Marjorie and Kassim, Caroline and Bertron, Alexandra and Rafrafi, Yan and Sablayrolles, Caroline and Albrecht, Achim and Erable, Benjamin Nitrate reducing bacterial activity in concrete cells of nuclear waste disposal. (2013) EPJ Web of Conferences, vol. 56 (n° 9). pp. 1-9. ISSN 2100-014X

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Official URL: http://dx.doi.org/10.1051/epjconf/20135601003

Abstract

Leaching experiments of solid matrices (bitumen and cement pastes) have been first implemented to define the physicochemical conditions that microorganisms are likely to meet at the bitumen-concrete interface (see the paper of Bertron et al.). Of course, as might be suspected, the cement matrix imposes highly alkaline pH conditions (10 < pH < 11). The screening of a range of anaerobic denitrifying bacterial strains led us to select Halomonas desiderata as a model bacterium capable of catalyzing the reaction of nitrate reduction in these extreme conditions of pH. The denitrifying activity of Halomonas desiderata was quantified in batch bioreactor in the presence of solid matrices and / or leachate from bitumen and cement matrices. Denitrification was relatively fast in the presence of cement matrix (< 100 hours) and 2 to 3 times slower in the presence of bituminous matrix. Overall, the presence of solid cement promoted the kinetics of denitrification. The observation of solid surfaces at the end of the experiment revealed the presence of a biofilm of Halomonas desiderata on the cement paste surface. These attached bacteria showed a denitrifying activity comparable to planktonic bacterial culture. On the other side, no colonization of bitumen could be highlighted as either by SEM or epifluorescence microscopy. Now, we are currently developing a continuous experimental bioreactor which should allow us a more rational understanding of the bitumen-cement-microbe interactions.

Item Type:Article
Additional Information:Thanks to EDP Sciences editor. The definitive version is avaialable at http://www.epj-conferences.org The original PDF can be found at EPJ Web of Conferences website: http://www.epj-conferences.org/articles/epjconf/abs/2013/17/epjconf_nucp2012_01003/epjconf_nucp2012_01003.html
HAL Id:hal-00875245
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Agence Nationale pour la Gestion des Déchets Radioactifs - ANDRA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
Université de Toulouse > Institut National des Sciences Appliquées de Toulouse - INSA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: Benjamin ERABLE
Deposited On:21 Oct 2013 09:29

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