title: Ammonia inhibition of hybridomas propagated in batch, fed-batch, and continuous culture.
abstract: The nature and temporal development of ammonia inhbition were investigated in batch, fed-batch, and continuous cultures. Significant inhibition was observed when cells were inoculated in serum-containing or chemically defined medium containing more than 2 mM of ammonia. In contrast, no inhibition was observed at greater than 10 mM when the ammonia concentration was gradually increased over the span of a batch culture by feeding ammonium chloride. Strong growth inhibition was observed after each of five step changes (2.8 --> 3.7 --> 4.0 --> 4.9 --> 7.7 --> 13.5 mM) in continuous culture. Following a period of adaptation at each higher value, the viable cell density stabilized at a new lower value. The lowering in viable cell density was caused by an increase in specific death rate and a decreased cell yield on glucose, glutamine, and oxygen. Increased ammonia concentration had little or no effect on the steady-state specific growth kinetics or specific antibody productivity. (c) 1994 John Wiley & Sons, Inc.
authors.affiliation: Department of Chemical Engineering, University of Queensland, Queensland 4072, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Newland
authors.forename: M N
authors.initials: MN
authors.lastname: Kamal
authors.forename: P F
authors.initials: PF
authors.lastname: Greenfield
authors.forename: L K
authors.initials: LK
authors.lastname: Nielsen