Computational fluid dynamics as a tool for bioreactor characterization

Stefanie Brüning, doctoral thesis Technische Universität München, 2012

Development times of bioprocesses can be reduced by downscaling and parallel operation of bioreactors. However, many of the process variables needed for a successful scale-up cannot be measured in miniaturized bioreactors. Thus, the objective of this work was to assess which of these process variables could be estimated by means of computational fluid dynamics using the examples of different milliliter-scale stirred-tank bioreactors. For most cases, it was possible to simulate energy dissipations and distributions in good agreement with reference data and also the interface between gas and liquid phase which is crucial for gas-liquid mass transfer in bioprocesses. The homogenization of reaction media containing solids was taken as an example to show that the development time of new stirrers can be shortened substantially by applying computational fluid dynamics. Additionally, mixing times for these systems could be predicted well.

Publications

• Brüning S, Weuster-Botz D (2014): CFD analysis of interphase mass transfer and energy dissipation in a milliliter-scale stirred-tank reactor for filamentous microorganisms. Chem Eng Res Des 92: 240-248.
• Riedlberger P, Brüning S, Weuster-Botz D (2013): Characterization of stirrers for screening studies of enzymatic biomass hydrolyses on a milliliter-scale. Bioproc Biosys Eng 36: 927-935.