Endogenous oxygen uptake and polysaccharide accumulation in Bifidobacterium.

To study the behavior of Bifidobacterium toward oxygen, oxygen uptake was investigated in detail. The cells of Bifidobacterial strains absorbed considerable amounts of oxygen. The exogenous oxygen uptake activity changed depending upon the period of incubation. Bifidobacterial cells also had high endogenous oxygen uptake, which was, in B. longum strains, as high as about 80% of the exogenous oxygen uptake activity. Bifidobacterial cells accumulated considerable amounts of polysaccharide, which was associated with cellular growth. By incubating the cultivated cells in a glucose-free medium, the endogenous oxygen uptake activity was decreased with a decrease of intracellular polysaccharide. Therefore it was postulated that the high endogenous oxygen uptake activity of Bifidobacterium was owing to the metabolism of intracellular polysaccharide. The enzymatic activity, which was involved in the mechanism of oxygen uptake, was also investigated.