BIOT 248 |
| The transfer of oxygen and carbon dioxide gases to and from a cell culture broth are essential parameters to consider in the design and operation of a bioreactor. Sufficient oxygenation and regulation of carbon dioxide must be provided, while minimizing foaming and shear stress on the cells. Currently, the mass transfer rates in Centocor's GMP Pilot Plant 250 L bioreactors are adequate to support most processes in operation. However, new development processes with greater peak cell densities demand significant increases in mass transfer efficiency. In this work, we evaluated microspargers of varying surface area and pore size, and measured the corresponding mass transfer coefficients (kLa) as a function of gas flow rate and agitation speed for each microsparger. The resulting oxygen kLa values were not impacted by the microsparger pore sizes evaluated, however, significant increases were observed with greater surface area. The larger surface area microspargers effectively eliminated the saturation or “flooding” effect observed at high gas flow rates with the smaller microspargers. Based on these results, new microspargers with increased surface area were installed which provided oxygenation similar to the smaller microspargers at 2-4 times lower gas flow. The results of the mass transfer measurements and a subsequent bioreactor run will be discussed. |
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Poster Session
5:30 PM-7:30 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Biochemical Technology |