Scale-up strategy for bioreactors with Newtonian and non-Newtonian broths

In the scale-up of bioreactors one of the most commonly used criteria for aerobic processes is to keep the oxygen transfer coefficient constant. Nevertheless, the reproduction of the behaviour of a cell population at different scales is not dependent just on the oxygen transfer capability but rather on the oxygen transfer rate, that must be high enough to cope with the oxygen demand of the culture. In this work a strategy of scale-up is proposed based in geometric similarity, constant impeller tip speed, and constant oxygen transfer rate. The effects of the dissolved oxygen concentration, the scale-up ratio and the rheology of the broth are analysed.