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Investigation and modeling of mechanical and surface-induced stress of pelleted filamentous microorganisms

Contact Person: Marcel Schrader
This project is part of the DFG SPP “DiSPBiotech” and it is handled in cooperation with the “Institute of Biochemical Engineering”. The aim is to investigate the correlation of the morphology and the productivity for filamentous microorganisms. The productivity can be influenced by different cultivation parameters, for example the pH-value, media composition, media additives, mechanical stress and the concentration of the inoculum. This project deals with the investigation of the effects on morphology and therefore on the productivity caused by addition of micro- (< 30 µm) and macro- (up to 5 mm) particles during the cultivation of Lechevalieria aerocolonigenes. Early results showed an increased concentration of the antibiotic product Rebeccamycin for both particle size ranges. Two reasons seem to be responsible for the increased productivity: physicochemical surface effects caused by the addition of microparticles and mechanical stress due to the addition of macroparticles to the cultivation medium. Through the combination of experiments and simulations, the mechanisms of disaggregation of the bioagglomerates as well as the fragmentation of the mycelia are investigated. At the “Institute for Particle Technology”, the intensity and number of mechanical stresses in the bioreactor should be predicted by using CFD-DEM-simulations. For the investigation of dispersity- and structure-changes due to mechanical stresses simulations of the bioagglomerates on a micro-scale are planned. An empiricalmechanistic model, which includes the pellet growth, pellet stress and the productivity, should be developed based on the results of the simulations and experiments. Furthermore, a fundamental understanding of physicochemical microorganism-particle interactions and their influence on the dispersity and structure of the pellets needs to be established. Later on, the focus lays on the determination of scaleup rules for the cultivation process and the consideration of the bioreactor geometry in the established models. Additionally population balances should describe the changes in dispersity and structure of the pellets as a function of the process parameters.

Team Members

Current Projects

Investigation and modeling of mechanical and surface-induced stress of pelleted filamentous microorganisms more

Micromechanical Properties of Filamentous Fungi more

Untersuchung der zellmechanischen Eigenschaften einzelner Mikroorganismen more

Finished Projects

Behavior of UV-absorbing metal oxide nanoparticles in porous media and their influence on soil bacteria more

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Einfluss der Zellaufschlussmethode auf die Expanded Bed Chromatographie mehr