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Accueil > Thèses et HDR > Thèses en 2018

06/04/2018 - Alexiane GODAIN

par Laurent Krähenbühl - publié le , mis à jour le

Alexiane GODAIN soutient sa thèse le 06/04/2018 à 09h30.
Lieu : Amphi 202 (bâtiment W1), Ecole Centrale de Lyon, Ecully

Titre :
Etude de l’activité électrocatalytique des biofilms microbiens en fonction des forces d’adhésion pour l’optimisation des performances des biopiles microbiennes

Jury :

  • Pascal Simonet [Président]
  • Timothy Vogel, UCBL, Directeur de thèse
  • Wafa Achouak [Rapporteure]
  • Ian Head [Rapporteur]
  • Régine Basséguy)
  • Naoufel Haddour, ECL, et Pascal Fongarland, UCBL, encadrants (invités).

Résumé :
Microbial fuel cells (MFCs), as a potentially sustainable biotechnology, can directly convert organic matter into electricity by using bacterial biofilms as biocatalysts. In a political context where European legislation favors and imposes the revalorization of organic waste from industries, MFC seems an inexpensive and promising technology to meet this need. The aim of this thesis is to improve knowledge of the formation of electroactive biofilms on the anodic surface, and to understand the mechanisms involved in the competition between electroactive bacteria (EAB) and other bacteria. Special attention will be paid to shear force as a tool to control the formation of anodic biofilms. First, bacterial successions have been studied under stationary conditions and in standard laboratory configurations. The results show that the formation of the biofilm is divided in two stages. At first, non-specific EAB grow in all MFCs, producing or not electricity. Then, specific EAB become predominant only in MFCs producing electricity and is associated to an exponential increase of electricity. From these results, we hypothesize that inhibition of the first step should decrease the competition between nonspecific and specific EAB. We propose to use the shear stress to select specific EAB during the adhesion. First, MFCs with a shear stress flow chamber configuration were designed, constructed and set up. The results show that the proportion of specific EAB such as Geobacter was higher, up to 30.14% as opposed to a lower shear stress (less than 1%). Then, the effect of shear stress on microbial selection during biofilm growth was studied. These results confirm the previous conclusions : specific EAB are selected when shear stress is higher. This work demonstrates the major role of shear stress in biofilm formation and could be a way to control the selection of EAB. This factor should be taken into account in the architecture and implementation of the reactors.



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