Comparison of a Production Process in a Membrane-Aerated Stirred Tank and up to 1000-L Airlift Bioreactors Using BHK-21 Cells and Chemically Defined Protein-Free Medium

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• 作者：Friedemann Hesse ; Maria Ebel ; Nadine Konisch ; Reinhard Sterlinski ; Wolfgang Kessler ; and Roland Wagner
• 刊名：Biotechnology Progress
• 出版年：2003
• 出版时间：June 2003
• 年：2003
• 卷：19
• 期：3
• 页码：833 - 843
• 全文大小：1393K
• 年卷期：v.19,no.3(June 2003)
• ISSN：1520-6033

文摘

The applicability of a protein-free medium for the production of recombinant humaninterleukin-2 with baby hamster kidney cells in airlift bioreactors was investigated.For this purpose, a BHK-21 cell line, adapted to grow and produce in protein-freeSMIF7 medium without forming spheroids in membrane-aerated bubble-free bioreactors, was used as the producer cell line. First, cultivation of the cells was establishedat a 20-L scale using an internal loop airlift bioreactor system. During the culturingprocess the medium formulation was optimized according to the specific requirementsassociated with cultivation of mammalian cells under protein-free conditions in abubble-aerated system. The effects of the addition of an antifoam agent on growth,viability, productivity, metabolic rates, and release of lactate dehydrogenase wereinvestigated. Although it was possible to establish cultivation and production at a20-L scale without the use of antifoaming substances, the addition of 0.002% silicon-oil-based antifoaming reagent improved the cultivation system by completely preventing foam formation. This reduced the release of lactate dehydrogenase activity to thelevel found in bubble-free aerated stirred tank membrane bioreactors and led to areduction in generation doubling times by about 5 h (17%). Using the optimizedmedium formulation, cells were cultivated at a 1000-L scale, resulting in a cultureperformance comparable to the 20-L airlift bioreactor. For comparison, cultivationswith protein-containing SMIF7 medium were carried out at 20- and 1000-L scales.The application of protein supplements did not lead to a significant improvement inthe cultivation conditions. The results were also compared with experiments performedin a bubble-free aerated stirred tank membrane bioreactor to evaluate the influenceof bubbles on the investigated culture parameters. The data implied a higher metabolicactivity of the cells in airlift bioreactors with a 150% higher glucose consumption rate.The results of this study clearly demonstrate the applicability of a protein-freechemically defined medium for the production of recombinant proteins with BHK cellsin airlift bioreactors.