Process control during the suspension culture of a human melanoma cell line in a mechanically stirred loop bioreactor

Abstract A human melanoma cell line was cultivated for more than 5 months in a serum-free medium without macromolecular growth factors. A mechanically stirred loop bioreactor was used for the culture of the melanoma cells. The tip speed of the marine impellers was 1.5 m s −1 . This cell line was able to endure tip speeds of up to 3.5 m s −1 for a few hours without significant cell damage. By using process control it was possible to obtain growth rates and cell numbers close to those found in medium with serum. The pO 2 was controlled at 125 mbar and the pH at 7.15. The signal of an on-line fluorometer, although not caused by the cells, correlates with cell number. The partial pressure of CO 2 in the culture medium and the redox potential of the medium were monitored by on-line sensors.