Cell Separator Operation within Temperature Ranges To Minimize Effects on Chinese Hamster Ovary Cell Perfusion Culture

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• 作者：Hans Drouin ; Joachim B. Ritter ; Volker M. Gorenflo ; Bruce D. Bowen ; James M. Piret
• 刊名：Biotechnology Progress
• 出版年：2007
• 出版时间：December 2007
• 年：2007
• 卷：23
• 期：6
• 页码：1473 - 1484
• 全文大小：356K
• 年卷期：v.23,no.6(December 2007)
• ISSN：1520-6033

文摘

A cell retention device that provides reliable high-separation efficiency with minimal negativeeffects on the cell culture is essential for robust perfusion culture processes. External separationdevices generally expose cells to periodic variations in temperature, most commonly temperaturesbelow 37 C, while the cells are outside the bioreactor. To examine this phenomenon, aliquotsof ~5% of a CHO cell culture were exposed to 60 s cyclic variations of temperature simulatingan acoustic separator environment. It was found that, for average exposure temperatures between31.5 and 38.5 C, there were no significant impacts on the rates of growth, glucose consumption,or t-PA production, defining an acceptable range of operating temperatures. These results weresubsequently confirmed in perfusion culture experiments for average exposure temperaturesbetween 31.6 and 38.1 C. A 2^5-1 central composite factorial design experiment was thenperformed to systematically evaluate the effects of different operating variables on the inlet andoutlet temperatures of a 10L acoustic separator. The power input, ambient temperature, as wellas the perfusion and recycle flow rates significantly influenced the temperature, while the cellconcentration did not. An empirical model was developed that predicted the temperature changesbetween the inlet and the outlet of the acoustic separator within ±0.5 C. A series of perfusionexperiments determined the ranges of the significant operational settings that maintained theacoustic separator inlet and outlet temperatures within the acceptable range. For example, theseobjectives were always met by using the manufacturer-recommended operational settings aslong as the recirculation flow rate was maintained above 15 L day^-1 and the ambient temperaturewas near 22 C.