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Simulation und Anwendung bioverfahrenstechnischer Kaskadenprozesse zur Behandlung von Abfallströmen
Citation Link: https://doi.org/10.15480/882.13691
Publikationstyp
Doctoral Thesis
Date Issued
2024
Sprache
German
Author(s)
Jürgensen, Nikolai
Advisor
Referee
Pörtner, Ralf
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2024-09-27
Institute
TORE-DOI
Citation
Technische Universität Hamburg (2024)
The use of fossil raw materials does not correspond to a sustainable economy, which is why existing resources must be utilised more efficiently and alternative energy sources such as hydrogen are needed. One approach is the microbial electrolysis cell (MEC), which uses exoelectrogenic microorganisms to convert biological waste streams into electrical energy, thus enabling the production of hydrogen. This work deals with the energetic and substantial utilisation of biobased waste such as beet silage and urine using two different process designs. The use of a MEC with a defined co-culture of Shewanella oneidensis and Geobacter sulfurreducens in combination with the biological degradation processes of a biogas plant for flexible biogas and hydrogen production was investigated in a process model. Furthermore, a process model was developed that shows the substantial utilisation of hydrogen and carbon dioxide by microbial organisms to produce platform chemicals. In addition, it was investigated whether urine can be used as a substrate source in a MEC with a defined co-culture.
The activity of the exoelectrogenic co-culture was investigated experimentally at different anode potentials. This made it possible to develop an electrode control at varying anode potentials in order to control the electron flow in a MEC. To describe the anaerobic degradation process based on beet silage, the mass-based ADM1 was used as a process model with which the biogas and organic acids produced could be simulated. By integrating the MEC into the biogas process, it was possible to demonstrate the control of biogas and hydrogen production in a process model based on electrode control. Furthermore, the utilisation of the gases produced, which could be converted into acetoin and 2,3-butanediol, was demonstrated in an autotrophic process model. In addition, the planktonic growth of S. oneidensis and G. sulfurreducens was analysed in sterile urine. The results showed that growth in urine is possible with the addition of a suitable electron donor and electron acceptor. Subsequently, the use of urine in two MEC designs was investigated and the anode community was analysed. A lower current density was measured in sterile urine than in the synthetic medium. In contrast, the current density could be increased in a flow-through system. Analysis of the anode community showed that G. sulfurreducens emerged as the dominant species in the long term and is important for the formation of a conductive biofilm, which is why an exoelectrogenic co-culture should be grown with urine or a waste stream in synthetic medium before use.
The activity of the exoelectrogenic co-culture was investigated experimentally at different anode potentials. This made it possible to develop an electrode control at varying anode potentials in order to control the electron flow in a MEC. To describe the anaerobic degradation process based on beet silage, the mass-based ADM1 was used as a process model with which the biogas and organic acids produced could be simulated. By integrating the MEC into the biogas process, it was possible to demonstrate the control of biogas and hydrogen production in a process model based on electrode control. Furthermore, the utilisation of the gases produced, which could be converted into acetoin and 2,3-butanediol, was demonstrated in an autotrophic process model. In addition, the planktonic growth of S. oneidensis and G. sulfurreducens was analysed in sterile urine. The results showed that growth in urine is possible with the addition of a suitable electron donor and electron acceptor. Subsequently, the use of urine in two MEC designs was investigated and the anode community was analysed. A lower current density was measured in sterile urine than in the synthetic medium. In contrast, the current density could be increased in a flow-through system. Analysis of the anode community showed that G. sulfurreducens emerged as the dominant species in the long term and is important for the formation of a conductive biofilm, which is why an exoelectrogenic co-culture should be grown with urine or a waste stream in synthetic medium before use.
DDC Class
660.6: Biotechnology
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