Continuous-flow culture of the ERK and L types of mammalian cells

Equipment used for the continuous-flow culture of animal cells included a 2 l fermenter and a new simplified apparatus with a 100 ml culture vessel. Steady-state growth was obtained with flow rates in the range 0.2 to 0.9 culture volumes per day. The maximum population density of L cells (1.5 million ml) was obtained with a flow rate of 0.4 culture volumes per day. The normal maximum population density in ERK cell cultures was 0.6 million/ml with a flow rate of 0.3 culture volumes per day. There was wide variation in the population density from culture to culture and at widely separated times (intervals of two or more weeks) in a continuous culture, other conditions being equal. Cultures were grown at different pH values maintained constant by automatic addition of HCl or NaOH. Maximum population densities of L cells were obtained in the pH range 6.8 to 7.5. In L cell cultures at high pH values the requirement for glucose increased.