Growth and Metabolism of L Cells in a Chemically Defined Medium in a Controlled Environment Culture System

Abstract

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 p O 2 levels of l -cell cultures, grown at p H 6.9 ± 0.1, showed that dissolved O 2 tensions of ca. 9% were optimal for cell growth. At p O 2 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 × 10 6 cells/ml when grown for 4 days without medium renewal from inocula of ca. 10 6 cells/ml in a defined medium sparged with 5% CO 2 and maintained at 9% dissolved O 2 tension. The redox potentials of L-cell cultures reflected the p O 2 levels in the medium and ranged from −45 to +160 mv (versus calomel reference) for O 2 values ranging from 2 to 20% dissolved oxygen tension. Increased utilization of glucose per cell occurred in the presence of increased p O 2 , whereas minimal accumulation of ammonia occurred with a p O 2 value maintained at 9%.