Master's thesis: Bioelectrocatalysis with acetogenic bacteria (PhD opportunity afterwards)

21.11.2024, Abschlussarbeiten, Bachelor- und Masterarbeiten

In our bioelectrochemical system (BES) we focus on the electrocatalytic CO2 reduction reaction to CO that can be converted as carbon source by acetogenic bacteria to acids and alcohols. Here, a state-of-art electrolysis cell (membrane-electrode-assembly = MEA) was coupled to a gasfermentation bioreactor to enable another Power-to-X process. Further improvements of the catalyst, BES and MEA are main objectives within the whole project.

Study background: Industrial Biotechnology, Chemical Engineering, Biotechnology/Biochemistry, Pharmaceutical Bioprocess Engineering

Project description:

Developing sustainable synthesis processes is a primary objective for the chemical industry since harsh process conditions and usage of fossil resources increase greenhouse gas emissions and the carbon footprint. Making use of CO2 as a feedstock to produce value-added organic chemicals is an attractive opportunity to realize a circular carbon economy. Moreover, electric energy generated by solar panels or wind power stations could be saved in stable chemical products. We combined both aspects in a novel bio-electrochemical system (BES) in which a PEM electrolysis cell is coupled to a standard stirred tank bioreactor. Precious group metal-free (PGM-free) catalysts consisting of atomically dispersed active metal sites in nitrogen-doped porous carbon matrix (M-N-C where M= Co, Ni, Zn etc.) enabled electrocatalytic CO2 reduction to CO (CO2RR) in an aqueous environment. The acetogenic bacterium Clostridium ragsdalei directly converts CO into organic acids and alcohols. Besides, the competing hydrogen evolution reaction (HER) delivers H2 as an additional electron carrier that can be consumed together with CO2. Bacteria are more flexible towards the stoichiometry of their substrates (CO, H2 and CO2), demonstrating an advantage over chemical synthesis processes that often require exact stoichiometries.

Possible objectives depending on your interests:

• New construction of membrane-electrode-assembly that allows CO2 gassing directly into the cathode (Chemical engineering, Bioprocess engineering) - M-N-C catalyst degradation study (all study programs) - (Mixotrophic) Electrofermentations with Clostridium ragsdalei (all study programs) - Study novel M-N-C catalysts in the single cell and BES in regards to selectivity, stability, total BES performance, different operation modes (all study programs)

More questions or interest in this topic?

Feel free to contact Irina Schwarz (irina.schwarz@tum.de) TUM Chair of Biochemical Engineering, Garching

Possibility of a PhD in Berlin afterwards (Dr. Tim-Patrick Fellinger): https://www.bam.de/Content/DE/Projekte/laufend/Ecat-Acetogens/ecat-acetogens.html

Kontakt: irina.schwarz@tum.de

Mehr Information

https://www.epe.ed.tum.de/biovt/forschung/gasfermentation/bioelektrokatalyse-mit-acetogenen-mikroorganismen/