Glucose‐based optimization of CHO‐cell perfusion cultures

Abstract

Perfusion cultures of CHO cells producing t-PA were performed using acoustic filter cell retention. A robust off-line glucose analysis and predictive control protocol was developed to maintain the process within approximately 0.5 mM of the glucose set point, without the need for a more fallible on-line sensor. Glucose usage (the difference between the inlet and reactor glucose concentrations) provided an easily measured indicator of overall medium utilization for mapping acceptable ranges of operation, including the edge of failure. Earlier onset of perfusion with a ramping glucose set point (1.5 mM/d) resulted in improved growth and consistency during the perfusion culture start-up. At steady state, the t-PA concentration variability increased gradually with increasing glucose usage up to approximately 22 mM, then up to 24 mM the variability increased threefold. Peak t-PA concentrations of over 90 mg/L were obtained by controlling at a glucose usage of approximately 24 mM, but these t-PA levels were not sustainable for more than 3 days. A consistent t-PA concentration of 40 mg/L was obtained at a glucose usage of 21.5 mM.

Optimizing capacity utilization by large scale 3000 L perfusion in seed train bioreactors

“…Cell‐specific perfusion rates were between 2.3 and 2.8 pL/(cell h) and within values reported in literature during cultivation 25. The cell densities and viabilities achieved were comparable to those described for several retention devices using CHO cells in the literature at significantly smaller scales 15, 18, 22–36. A decline in viability from 99 to 90% was observed during the course of the culture.…”

Perfusion Processes

“…The control of the perfusion rate can be based on the consumption of a main substrate present in the medium such as the glucose (Dowd et al 2001;Wang et al 2002;Meuwly et al 2006). From daily glucose concentration measurement, the perfusion rate is increased or decreased in order to maintain the residual glucose concentration constant in the culture.…”

Kinetics independent multivariable robust control of animal cell cultures

“…Additionally, the perfusion operation of a biorector is naturally a multivariable process, whose performance depends on both inputs: the dilution/perfusion rate and the bleed rate. However, it has been controlled for a long time in a suboptimal way as a single input single output system [4], [7]. Recently, the potential of using the bleed flow (see Fig.…”