Influence of very small bubbles on kLa measurement in viscous microbiological cultures



In gas–liquid dispersions based on viscous non-Newtonian fluids, numerous very small bubbles are formed due to their high residence times in contacting devices such as bubble columns. The influence of these small bubbles on the measurement of the volumetric mass transfer coefficient in the contactor by the dynamic CO2 gas analysis method is discussed. It is found that their effect on this measuring technique is insignificant compared to that when using the conventional dissolved-oxygen technique.