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Shewanella loihica PV-4 electroactive biofilms (EABs) grown in potentiostat-controlled electrochemical cells.

Epifanio, Monica (2016) Shewanella loihica PV-4 electroactive biofilms (EABs) grown in potentiostat-controlled electrochemical cells. PhD thesis, Dublin City University.

S.loihica PV-4 is a biofilm forming bacterium with an incredible respiratory versatility under anoxic conditions. It can indeed use various number of electron acceptors, such as heavy metals and solid substrates like an electrode surface., thus finding its application in diverse field like bioremediation and bio-energy production. S.loihica PV-4 can form electro-active biofilms on solid electrodes, an dthe electron transfer between the electrode surface and the m.o. can occur through two main mechanism. One, called direct electron transfer (DET), involves a network of c-type cytochromes localized in the periplasm and outer membrane of Shewanella sp. The other, named mediated electron transfer (MET), involves the release of soluble redox-active electron shuttles that transfer electrons from cell-associated reductases to the electron acceptor. Despite all members of the Shewenella spp. genus have the presence of c-type cytochromes, the number and the order of their genes varies, and this might affect their ability to reduce external insoluble substrates. In this study, improved electron transfer rate characterization in S. loihica PV-4 biofilms in potentiostat-controlled three-electrode cells was achieved. Different electrode materials were used, as well as chemical (carbon nanotube coating and atmospheric air plasma treatments) and physical (surface abrasion) treatment of the electrode, under various growth and inoculum conditions. Results confirm that carbon nanotube surface-modified electrodes improve the electron transfer rate in thin biofilms (<5 µm), but are not feasible for power production in microbial fuel cells, where the biofilm thickness is much greater. Atmospheric air plasma treatment is a feasible option to increase power output in bioelectrochemical systems. However, the effects of plasma pre-treatment are mixed, and the interplay between DET and MET must be considered when designing optimal electrode pre-treatment.
Item Type:Thesis (PhD)
Date of Award:March 2016
Supervisor(s):O'Connor, Brendan and Marsili, Enrico
Subjects:Biological Sciences > Biotechnology
Biological Sciences > Biochemistry
Physical Sciences > Electrochemistry
Biological Sciences > Enzymology
Biological Sciences > Biosensors
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Biotechnology
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:20944
Deposited On:12 Apr 2016 09:51 by Brendan O'connor . Last Modified 28 Jul 2021 15:07

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