Growth and Metabolism of L Cells in a Chemically Defined Medium in a Controlled Environment Culture System: I. Effects of O2 Tension on L-Cell Cultures

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Six water-jacketed 500-ml Bellco spinner flasks were equipped to monitor and control environmental variables to study their effects on the growth and metabolism of mammalian cells. Studies with automated control of pO2 levels of l-cell cultures, grown at pH 6.9 ± 0.1, showed that dissolved O2 tensions of ca. 9% were optimal for cell growth. At pO2 values of 5 and 20%, maximum cell yields as well as growth rates were reduced by approximately 20%. Peak yields of L-cell cultures exceeded 5 × 106 cells/ml when grown for 4 days without medium renewal from inocula of ca. 106 cells/ml in a defined medium sparged with 5% CO2 and maintained at 9% dissolved O2 tension. The redox potentials of L-cell cultures reflected the pO2 levels in the medium and ranged from −45 to +160 mv (versus calomel reference) for O2 values ranging from 2 to 20% dissolved oxygen tension. Increased utilization of glucose per cell occurred in the presence of increased pO2, whereas minimal accumulation of ammonia occurred with a pO2 value maintained at 9%.

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