In recent years the biopharmaceutical industry has significantly increased the demands it makes on bioreactor systems. Efficient and reproducible production of active pharmaceuticals of high quality and in large quantities is of highest priority. However, bioprocessing is a complex topic. Numerous factors affect growth of cells in culture but are difficult to determine and interpret reliably. One of the most relevant performance parameters is the volumetric mass transfer coefficient (kLa). It describes the efficiency of gas transfer (e.g., oxygen) from…