P36: Biophysical characterization of a cube-shaped single-use bioreactor

Since the recent shifts towards single-use bioreactor (SUB) technology in cell culture processes, fundamental bioreactor design changes, including shape and agitation method, have been introduced.  Thus, in several of these innovative SUB’s, the effects of these changes are on hydrodynamics properties, mixing and gas exchange are not well understood. This work has focused on the mixing and carbon dioxide (CO₂) stripping capabilities in a cube-shaped SUB equipped with a rotating paddle.

Mixing was examined using conductivity as the parameter for analyzing the bioreactor’s ability to suspend and evenly distribute.  CO₂stripping experiments were performed using an optical probe in a 10-L bioreactor working with 5 g/L microcarriers in distilled water. The paddle was equipped with a macrosparger, agitated between 20 and 100 rpm and aeration rates between 0.33 and 1 vvm were used.

We found that aeration and agitation rates did not affect the mixing significantly, as the mixing time ranged between 2.3 and 3 minutes, and increasing the aeration by 100 % resulted in only a 7% decrease in mixing time. It was also shown that although agitation rate does not impact CO₂ removal, but that increasing aeration rate from 0.33 vvm to 1 vvm lead to a two-fold increase in CO₂ removal rate. The CO₂ stripping rates ranged from 2.8 to 9.3 mmHg/min.