Influences of cellular components and redox potential of liquid concentrated culture of Lactobacillus bulgaricus on acid-producing activity and viability.

Acid-producing activity and viability of the liquid concentrated culture of Lactobacillus bulgaricus 1067 were markedly improved only when the cells were grown in a medium supplemented with Span 80 and then stored with .1% sodium ascorbate after addition of bubbling N2 into the culture. Oleic acid content of the cells increased from 17 to 38% to 39 to 54%, and the endothermic transition of the cell lipids shifted to a lower temperature when growth medium was supplemented with Span 80. During storage, the cells grown in the medium supplemented with Span 80 consumed a larger amount of lactose than those grown without Span 80. Also, the former cells had more ATP than the latter after storage at 5 degrees C for 14 d. Permeability of the cells for lactose might be improved by increased oleic acid content of the cellular components in which care the lactose incorporated into the cells would be utilized as the energy source during storage.