DEATH RATE IN A SMALL AIRLIFT-LOOP REACTOR OF VERO CELLS GROWN ON SOLID MICROCARRIERS AND IN MACROPOROUS MICROCARRIERS

The death rate of Vero cells grown on Cytodex-3 microcarriers was stud ied as a function of the gas flow rate in a small air-lift loop reacto r. The death rate may be described by first-order death-rate kinetics. The first-order death-rate constant as calculated from the decrease i n viable cells, the increase in dead cells and the increase in LDH act ivity is linear proportional to the gas flow rate, with a specific hyp othetical killing volume in which all cells are killed of about 2 . 10 (-3) m(3) liquid per m(3) of air bubbles. In addition, an experiment w as conducted in the same air-lift reactor with Vero cells grown inside porous Asahi microcarriers. The specific hypothetical killing volume calculated from this experiment has a value of 3 . 10(-4) m(3) liquid per m(3) of air bubbles, which shows that the porous microcarriers wer e at least in part able to protect the cells against the detrimental h ydrodynamic forces generated by the bubbles.