Kazumoto Kinoshita

Studies on Oxygen Transfer in Submerged Fermentations: Part IV. Determination of Oxygen Transfer Rate and Respiration Rate in Shaken Cultures Using Oxygen Analyzers

The application of oxygen analyzer to the determination of oxygen transfer rate in shaken flasks was intended in order to obtain the similar advantages already realized in fermentation tanks. The difficulty of this intension was that in shaken flasks the determination of the partial pressure of gas-phase oxygen in flasks did not give the oxygen transfer rate but supplied only the data on the equilibrium condition. By separating the oxygen transfer sequences, however, oxygen transfer coefficient of cotton plugs, overall oxygen transfer coefficient of gas-liquid interface and respiration rate of cells were evlauated with the oxygen analyzer. This unsteady-state gas analysis method had some distinctive characters, especially no necessity of determining dissolved oxygen, and oxygen transfer problems in shaken flasks could be discussed based on this method.

Studies on Oxygen Transfer in Submerged Fermentations:Part III. A Comparative Study of the Sulfite and the Biological Systems in Relation to their Behavior to Oxygen

Using gas analysis method, comparative studies were made between sulfite solutions and the biological systems in relation to their behavior to oxygen. It was found that sulfite oxidation method did not always give a maximum rate of oxygen transfer that could take place into the growing cell suspensions. Sulfite solution was different from the biological systems in some respects especially in KLa values, and these differences might be due to the variation of the sizes of air bubbles. For a measure of a eration effectiveness, oxygen transfer rate in biological systems seemed to be preferable.