OXYGENATION OF INTENSIVE CELL-CULTURE SYSTEM

The abilities of various methods of oxygenation to meet the demands of high-cell-density culture were investigated using a spin filter perfu sion system in a bench-top bioreactor. Oxygen demand at high cell dens ity could not be met by sparging with air inside a spin filter (oxygen transfer values in this condition were comparable with those for surf ace aeration). Sparging with air outside a spin filter gave adequate o xygen transfer for the support of cell concentrations above 10(7) ml(- 1) in fully aerobic conditions but the addition of antifoam to control foaming caused blockage of the spinfilter mesh. Bubble-free aeration through immersed silicone tubing with pure oxygen gave similar oxygen transfer rates to that of sparging with air but without the problems o f bubble damage and fouling of the spin filter. A supra-optimal level of dissolved oxygen (478% air saturation) inhibited cell growth. Howev er, cells could recover from this stress and reach high density after reduction of the dissolved oxygen level to 50% air saturation.