Electrogenic bacteria, such as Geobacter sulfurreducens or Shewanella oneidensis, are being a subject of great interest in recent years due to their potential to be used in different bio-electrochemical devices. The emergence of technologies such as microbial electrolysis cells, microbial fuel cells or microbial electrosynthesis reactors have boosted the study of this kind of bacteria. Even so, there are still gaps in the knowledge of the mechanisms used by these bacteria for the transport of electrons and of the influence of the mass transport – specially with regard to the study of mixed cultures. In this context, a powerful technique to study these phenomena as well as the growth of the biofilms or the influence of different conditions on the performance is cyclic voltammetry.
The proposed Master Project/Master Thesis aims to study in depth the use of cyclic voltammetries for the characterization of electroactive biofilms, both from an experimental and theoretical approach. For it, cyclic voltammograms will be recorded at different scan rates with acetate and butyrate as substrates, using Geobacter sulfurreducens as electrogenic bacteria model for the experiments. The control of the experiments will require the measurement of pH, optical density at 600 nm (to determine the growth of bacteria in the planktonic phase) and conductivity, while the exact composition of the medium and the consumption of the substrate will be determined by High Performance Liquid Chromatography (HPLC). In the same way, the quality of the biofilms will be evaluated by fluorescence microscopy and qPCR. Additionally, the resulting cyclic voltammograms will be analyzed using MATLAB/Python based on previously reported bio-electrochemical models, including the mass transport influence. By determining the parameters of the model, the mechanisms underlying the oxidation of the substrate can be ascertained and the information that can be obtained based on the test parameters can be determined.
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Prof. Dr.-Ing habil. Sven Kerzenmacher – kerzenmacherprotect me ?!uni-bremenprotect me ?!.de
Dr. Óscar Santiago Carretero - santiagoprotect me ?!uni-bremenprotect me ?!.de
Dr. Guillaume Pillot – pillotprotect me ?!uvt.uni-bremenprotect me ?!.de