Effect of aeration intensity on the biochemical composition of baker's yeast. I. Factors affecting the type of metabolism

Efforts were made to eliminate the influence of other factors as far as possible in order to obtain reliable results on the effects of oxygen on the growth of baker's yeast. A cultivation method is presented which permits the study of the effects of aeration intensity under conditions where the influence of catabolite repression is eliminated. A completely synthetic medium with glucose as the only carbon and energy source is also described. The capacity of yeast to perform aerobic metabolism varies when cultivated under different intensities of aeration. A clear maximum is observed for growth with 10% oxygen in the aerating gas mixture. Under conditions where catabolite repression does not function yeast has the potential for oxidative metabolism even under oxygen‐limited growth. The main agent controlling the ability of yeast to support growth using only the oxidative metabolism is the available oxygen. At high oxygen tensions the metabolism is disturbed.