Abstract
The growth activities of CoA2, its precursors2 (PA, P-PA, PAC, P-PAC, PAT, P-PAT), and CE2 were determined for the strains of Bifidobacterium bifidum (Lactobacillus bifidus) isolated from the stools of breast-, bottle-, and mixed-fed infants. The activities of CoA and its precursors varied for each of the strains, while CE was active for most of the strains. The strains were divided into four groups. The first group was able to utilize PAT, P-PAT, and CoA, but none of the other precursors. The second group was able to utilize all of CoA and its precursors, while the third group neither of them, and the fourth group one or a few of them. However, these utilizabilities changed by subcultivation. These results indicate that the nutritional requirement of B. bifidum is complicated and that CE contains growth factors other than those hitherto recognized.