Design and Simulation of a Multiphase Continuous Bioreactor

This research investigates a novel continuous bioreactor with significant improvement in gas-liquid transport phenomena leading to high cell survival rate, enhanced growth rate, and overall high productivity.  This bioreactor is an automated, horizontally-rotating bioreactor consisting of an outer cylindrical shell and a core with adjustable rotating velocities operated in continuous mode.  The under filled bioreactor provides a multiphase environment for the cell line beneficial for improving the gas-liquid transport phenomena.  In addition, a spiroid tube is attached to the inside of the bioreactor at optimized position so that to increase gas-liquid contact area and thus improve oxygen transfer.

Computational fluid dynamics (CFD) simulations were performed to determine the range of flow patterns possible in this bioreactor.  The simulations were conducted in multiphase environment at different operating conditions to determine the appropriate rotational cylinders’ velocities, suitable inlet fluid velocities and optimized spiroid position based on the oxygen transfer performance, the shear stress on the cells and other factors.  Specific oxygen transfer coefficients both for the bioreactor and spiroid tube at specific operating conditions were also calculated to assist the analysis and optimize performance.  Using simulation results reactor scale-up was investigated to allow the bioreactor to operate with maximum production rates.  Experiments were conducted for selected operating conditions to verify the simulation results. 

Key words:  multiphase computational fluid dynamics, continuous bioreactor, oxygen transport phenomena, scale-up