High yields from microcarrier cultures by medium perfusion.

A culture perfusion system is described for the growth of anchorage-dependent cells on microcarriers. The critical component of this system is a column separator, which removes medium while allowing the microcarriers to remain in the culture. Amino acids and ammonia were analysed during cell growth of the perfusion culture. None of the amino acids was completely utilized. The accumulation of ammonia to 2.3 mM was observed and may be responsible for, or coincident with, events limiting further cell growth. It is suggested that oxygen deprivation and growth inhibitor accumulation, rather than nutrient depletion, are the major factors in limiting even higher cell yields.