Highly efficient inoculum propagation in perfusion culture using WAVE Bioreactor™ systems

Introduction A perfusion-based process was developed to increase the split ratio during the scale-up of CHO-STM cell cultures. Fedbatch cultures were inoculated with cells propagated in either batch or perfusion cultures. All cultures were grown in disposable CellbagTM bioreactors using the WAVE Bioreactor system. Cell concentrations of 4.8 × 10 cells/mL were achieved in the perfusion culture, whereas the final cell concentration in the batch culture was 5.1 × 10 cells/ mL. The higher cell concentration of the perfusion culture allowed for a more than six-fold increase of the split ratio to about 1:30. The method described here, can reduce the number of required expansion steps and eliminate the need for one or two bioreactors in the seed train. Singleuse bioreactors at benchtop scale can be used for direct inoculation of production bioreactors. Alternatively, high biomass concentrations accumulated in perfusion culture can be used to seed production vessels at increased cell concentrations. Thus, the process time in these bioreactors, which often is the bottleneck in plant throughput, can be shortened.