The Dissolved Oxygen and Respiration Rates in Pellicle and Submerged Cultures of Corynebacterium diphtheriae

Abstract

Summary. The concentration of dissolved oxygen in submerged and static cultures of Corynebacterium diphtheriae was measured with a cathode ray polarograph. In a pellicle culture of the type frequently used for production of diphtheria toxin the concentration of dissolved oxygen in the medium below the pellicle fell sharply after the third or fourth day, and growth then proceeded in a medium which contained only minimal amounts of dissolved oxygen, in spite of the fact that only a cotton wool plug separated the atmosphere above the medium from the outside air.The measurement of dissolved oxygen in submerged cultures was applied to the determination of respiration rates in growing cultures. The respiration rate for the test organisms varied at different stages in the period of a submerged batch culture. The rate was greatest at the start of the logarithmic phase, and thereafter declined until a steady state was reached.