ABSTRACT
This chapter focuses on the manipulation of cell metabolism using the measurement of on-line sensors such as pH and dissolved oxygen probes. It discusses the unique features of monitoring and controlling pH and dissolved oxygen in cell culture processes, since the accurate measurement and control of these parameters is essential for the estimation of process variables. The control of chemical and physical parameters in animal cell reactors is similar to that in microbial fermentations. Animal cell processes, despite their close resemblance to conventional microbial fermentation, have some unique features; three are probably most directly related to the development of instrumentation for on-line monitoring and control: a large time constant for growth and metabolism, a slow response to control action, a more stringent requirement for the chemical environment. Because of these features, the control actions usually taken to control physical and chemical variables also show some variation from those for microbial processes.
