FIG. 1.

Effect of aeration on the growth of L. delbrueckii subsp. bulgaricus (A), the lactate concentration (B), and the pH of the culture medium (C). Open circles, still cultures; solid circles, aerated cultures. The arrow shows the time at which aeration was started. MRS medium with 2% lactose was used. Growth was measured through changes in A₆₀₀. The lactate concentration and pH of the medium of the supernatant were determined after rapidly centrifuging the cells.