Bioreactor Characterization
Bioreactor scaling: a comprehensive view is key
Reliable bioreactor design calls for a process-based scaling approach, focusing on the performance of the system. But how does this work in practice?
One of the primary challenges when establishing a biopharmaceutical production is ensuring the proper transfer of the process. This becomes especially crucial when working with living microorganisms, as obtaining critical process parameters is essential for productive and profitable production. To assist customers with the process transfer and optimize potential processes, ZETA examines the performance of bioreactors and makes detailed information available in a series of whitepapers.
Process-based upscaling
The process-based scale-up approach proposed by ZETA involves a deep understanding of the process itself. Predictive bioreactor characterization provides a highly valuable source of data, which is required for the development of scale-up strategies. Reliable methods for measuring performance parameters (heat transfer rate, mixing time, oxygen transfer rate etc) are key to ensure that the optimal conditions are fulfilled.
Is vvm a reliable parameter?
One of ZETA’s detailed studies centered on the challenges of scaling the gassing rate across different bioreactor scales. The volumetric gassing rate vvm – very commonly used as scaling parameter – was called into question. The conclusion: relying solely on this parameter would certainly produce erroneous results in scaling! This shows once more that optimal scaling requires a comprehensive view on the highly complex system.
Impeller geometry
The focus of a further study in the area of process-based scaling lay on the geometry of mixing impellers. Using CFD simulations and experiments, an impeller design with very good scaling characteristics was developed. With this hydrofoil geometry, relationships between power inputs, turbulences and mixing times could be transferred to all scales.
