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Masterarbeit: Performance of acidophilic electrogenic bacteria in microbial electrolysis cells

The current treatment of waste water requires a high consumption of energy in order to remove all the organic compounds. However, the chemical energy stored in the bonds of these compounds keeps normally unused. At the moment, only a part of this energy is recovered by anaerobic digestion process, obtaining as product methane-rich biogas. A breakthrough concept poses the utilization of the chemical energy contained in the organic matter of waste water for the production of high valuable compounds, such as hydrogen, in a microbial electrolysis cell (MEC), while reducing the corresponding concentration of organic acids. Up to now, mainly Geobacter sulfurreducens is used as electrogenic bacteria, oxidizing organic acids to CO2 releasing electrons and protons in the process. This type of bacteria shows a proper operation under pH values from 5.8 to 7.3, but most of the MEC plants developed until now suffer anolyte acidification problems with the corresponding reduction in the efficiency. This acidification is caused by the increase in the hydronium concentration in the medium due to the oxidation of organic acids.

In this context, the proposed Master Project aims to identify acidophilic electrogenic bacteria that may operate efficiently under low pH conditions, so that the acidification problem in the anodes of MECs becomes an advantage for this type of bacteria. For it, 4 long-term experiments (4 weeks each one) will be carried out to compare the electrochemical results obtained with the pure strain of the acidophilic bacteria, Acidiphilium cryptum, with those of a mix culture previously characterized. From electrochemical point of view, the efficiency will be evaluated based on chronoamperometry, cyclic voltammetry and polarization curve experiments. The control of the experiments will require the measurement of pH, optical density at 600 nm, Chemical Oxygen Demand (COD), organic acids and conductivity, while the exact composition will be determined by High Performance Liquid Chromatography (HPLC). Additionally, the quality of the obtained biofilms will be assessed by fluorescence microscopy, qPCR and scanning electron microscope. Therefore, we are looking for a highly motivated students, willing to work in the field of bio-electrochemistry and to contribute in the development of microbial electrolysis cells.
Candidates with background in biology and electrochemistry will be preferred.

Language:      

English

Starting date:  

September 1st, 2021

Period of time:  

6 months

Supervisors:   

Prof. Dr.-Ing habil. Sven Kerzenmacher – kerzenmacherprotect me ?!uni-bremenprotect me ?!.de

Dr. Guillaume Pillot – pillotprotect me ?!uvt.uni-bremenprotect me ?!.de

Dr. Óscar Santiago Carretero - santiagoprotect me ?!uni-bremenprotect me ?!.de

www.uvt.uni-bremen.de