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.

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 pO(2) levels of l-cell cultures, grown at pH 6.9 +/- 0.1, showed that dissolved O(2) tensions of ca. 9% were optimal for cell growth. At pO(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 x 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 pO(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 pO(2), whereas minimal accumulation of ammonia occurred with a pO(2) value maintained at 9%.