Responses of Taxus cuspidata to hydrodynamics in bubble column bioreactors with different sparging nozzle sizes

Studying bioreactor hydrodynamics under growth conditions holds great significance in the scale-up of plant cell cultures. In this study, a 3D Laser Doppler Anemometer (LDA) system was used to measure liquid velocity fields in bubble columns with different nozzle sizes, and their hydrodynamic stresses were calculated by liquid velocity fluctuation components. The magnitude of axial normal Reynolds stress was higher compared to other directions, varying from 2.0 Pa to 7.2 Pa. The maximum axial normal stress took place near the gas–liquid interface, followed by the sparger where bubbles form and the bulk flow area where bubbles rise, suggesting from a hydrodynamic perspective that cell damage occurs mainly at the gas–liquid interface. Reynolds stresses at the gas–liquid interface increased with decreasing nozzle size of distributor. Taxus cuspidata cultured in bubble columns with larger nozzle sizes showed better performance with respect to cell growth and viability, which matched well with hydrodynamics fluctuation in bubble columns with different nozzle sizes. The correlation of cellular response with hydrodynamics may be helpful in optimizing bioreactor design and scale-up of plant cell culture.