Fatty acid composition of Bifidobacterium and Lactobacillus strains.

Normal C(14), C(16), and C(18) saturated acids and C(16) and C(18) monoenoic acids are the main fatty acids of nine strains of Bifidobacterium. Their lactobacillic acid content was less than 5%. Lactobacillus strains contained the same fatty acids as main compounds except for octadecanoic acid, which was present only in very low amounts. Eight of nine Lactobacillus strains contained in the stationary phase more than 15% lactobacillic acid. No correlation was observed between the fatty acid composition and other physiological characteristics used in the literature for classification of strains of one genus. Aging of the culture, which involved a decrease of the pH, caused a lengthening of the chain length of the fatty acids of B. bifidum var. pennsylvanicus but only a conversion of octadecenoic to lactobacillic acid in the lactobacilli. Lowering of the temperature of cultivation decreased the chain length of the fatty acids of B. bifidum var. pennsylvanicus. L. lactis did not show any influence of the temperature on the chain length of the fatty acids. The percentage of unsaturated acids was temperature independent in both organisms.