Studies on Oxygen Transfer in Submerged Fermentations

Part VII. Glutamic Acid Fermentation under Controlled Pressure of Dissolved Oxygen by Means of Electrolysis of Water

Abstract

A system for the automatic control of oxygen pressure of gas- or liquid-phase in flasks was developed for shaken cultures. Electrolytic oxygen was utilized in this system and the control was performed by regulating the electric current passed through the electrolytic cell. Measurement of the quantity of electricity proved to give the rate of oxygen transfer.
No inhibitory effects of electrolytic oxygen were noticed without any purification procedure, and glutamic acid fermentation proceeded smoothly. In the glutamic acid fermentation under controlled pressure of dissolved oxygen, the critical level of dissolved oxygen for product formation was very low. This result was similar to that observed in the culture where dissolved oxygen was not controlled constant.