(467e) Improved Mixing and Mass Transfer Scale-Up: Design & Characterization for Cell Culture in Single Use Bioreactors
AIChE Annual Meeting
2013
2013 AIChE Annual Meeting
North American Mixing Forum
Applications of Multiphase Mixing
Wednesday, November 6, 2013 - 1:50pm to 2:10pm
Improved Mixing and Mass Transfer Scale-Up: Design & Characterization for Cell Culture in Single Use Bioreactors
An in-depth study of common direct sparge mechanism in stirred tank bioreactors revealed that increasing gas entrance kinetic energy and vessel liquid column height were variables that must be characterized in order improve sparge performance and create a more predictable system. Improving the sparge mechanism sufficient to generate a targeted ratio of oxygen to carbon dioxide mass transfer ratio improves process development knowledge and allows for much lower variability when preparing for large scale processing required for biomolecule manufacturing. The precision drilled hole sparge has been carefully designed to generate a relatively constant bubble size by providing enough pores to avoid “pore saturation” at normal flow rates (0.001 to 0.1VVM). This design addresses the needs of scalable O2 kLa and CO2 stripping when performing cell culture at dissolved oxygen (DO) set-points of 30-50% airs saturation, while avoiding high velocity jetting of gas into the culture, reduces micro bubble formation. This allows more consistent performance, better scaling, and reduced foam generation.
Numerous studies have shown that gas entrance velocities near and in excess of 30m/s are harmful to shear sensitive cultures. The new sparge design delivers velocities at less than half of this threshold across all designs at 0.1vvm.
Supporting data will include a design of experiments study. These methods include characterization of bioreactors from 50L to 2000L in single use disposable formats. Critical to this research were high speed camera analysis, a novel method for measuring CO2 stripping, and gauge R&R type studies that help to identify sources of experimental error.
The culmination of this study includes cell culture experiments growing Chinese hamster cells to produce recombinant protein at 50L, 250L, and 2000L scale.