Estimation of Cell Density and Protein Production from Glucose and Lactate Measurement

Recombinant CHO-K1 cells expressing human soluble thrombomodulin (rsTM) were cultured in a repeated batch system and a continuous culture system including a fluidized bed reactor. A procedure for estimating cell density and protein production was established using experimental glucose and lactate measurements from repeated batch cultures. In this procedure, cell density is estimated from the glucose consumption rate, and the specific protein (rsTM) production rate is estimated from the ratio of lactate production/glucose consumption (ΔL/ΔG). Cell density and protein productivity in repeated batch cultures were well estimated by this procedure. Since there is a large advantage for establishing a control scheme for protein production by estimation from glucose and lactate measurements, this procedure was applied to a continuous culture.