Studies on Oxygen Transfer in Submerged Fermentations

The unsteady-state gas analysis method for the determination of oxygen transfer rate in shaken cultures was applied to the glutamic acid fermentation. This method was essentially based on the measurement of oxygen tension of gas phase in flasks. Major intentions of this application were to clarify the problems of oxygen transfer, to establish the measure of aeration effectiveness and to design the best aeration condition in the glutamic acid fermentation. Correlations of the fermentation to the level of dissolved oxygen, the rate of oxygen transfer, overall oxygen transfer coefficient and oxygen demand of cells were examined. As a measure of aeration effectiveness, the rate of oxygen transfer actually occurring in the fermentation seemed to be preferable, and was found to be above 7 × 10^?7 mol/ml-min for attaining the maximum productivity. Extremely high or low oxygen supply resulted in less productivity.