Pii: 0032-9592(93)85012-5

The scale-up of stirred tank bioreactors from 0.02 m3 to a 03 m-’ commercial plant is discussed for hybridoma suspension cultures. Schemes for dissolved oxygen control with sparged air in serum containing media are described, as well as mechanical breakage offoam in small and large bioreactors. Porous metal spargers (180-200 x lo6 m) were found to produce foams which were hard to control. Aeration with larger (2 0001 m) multihole spargers is recommended. Combined cell damage due to foam formation and control, and possible damage at mechanical seals or submerged bearings, were found to have no measurable effect on cell growth relative to roller bottle production. Hybn’domas are shown to withstand significant impeller tip speed (> 1 m s-r) and&id turbulence as evidenced by impeller Reynolds numbers in excess of 10s. The size ofthe energy-dissipating terminal eddies was calculated to be greater than ten-fold that of the hybridoma cells. The specific fluid turnover rate was employed as the scale-up criterion.