I have studied on lactic acid bacteria (hereinafter LAB) involved in traditional fermented foods produced in East and South East Asian countries for 45 years. About 6,000 strains of LAB were collected during this studying.

At the time I began researching, in order to identify LAB, the following phenotypic characteristics were determined; cell form, cell arrangement, gram staining, motility, sugars fermentation, growth temperature and pH, optical form

of lactic acid, fermentation type (homo- and hetero-), litmus milk, and nitrate reduction. Therefore, it consisted of about 68 items of phenotypic characteristics per a strain of LAB. These phenotypic characteristics were consistently examined according to a text I wrote about 40 years ago. About 6,000 strains of LAB and databases consisting of these phenotypic characteristics are stored in the culture collection center of Tokyo University of Agriculture.

Several strains from LAB collection were supplied to food companies for the purpose of making a new drink with a comfortable flavor by removing the bad taste of raw materials. Two strains were noticed when several strains of LAB

were examined to eliminate the disgusting flavor of soybean steamed drain. Both of them were the same species

(Lactobacillus plantarum) and were isolated from one sample of Miang, fermented tea leaves produced in Thailand, but one (strain FP14-1) was optimal and the other (strain FP14-2) was the worst. It was also revealed that when the optimum strain FP14-1 is applied to a different raw material such as vegetable juice from the soybean steamed drain, it does not always give a good result.

It was noted that individual strain-characteristics that cannot be understood only from the phenotypes exist in plural strains belonging to one species.

In this paper, it presumed that new LAB can be isolated by clarifying the cause of the individual-strain characteristics.

It also indicated that when improving drinks and foods using from various plant raw materials are made by fermenting with LAB, the selection of individual strain-characteristics of them are important.

The human gut microbiome includes commensal bacteria from genus Bifidobacterium, which primarily colonizes the region from the small intestine to the colon. This region has a mucus layer composed mainly of mucin glycoproteins.

In addition to providing a habitat for the microbiota, the mucus is also a potential glycan source. Therefore, interaction with mucus could provide a competitive advantage for Bifidobacterium within the gut ecosystem. In this review, we first outline the role of Bifidobacterium extracellular proteins in bacterium-mucus interactions, and then we focus on extracellular glycoside hydrolases and a recently discovered pilus-mediated colonization process unique to Bifidobacterium.

The human gut microbiota has a profound influence on our health and disease. Recent studies have indicated that the gut microbiota development during infancy has effect on subsequent host’s physiology. The infant gut microbiota, therefore, has attracted a great deal of attention. This review summarizes our study about process of the gut microbiota development during early infancy and its influence on the infant gut environment. In addition, we refer to the key factors that play the important role on building mutually beneficial relationships between human and bifidobacteria that is the most prevalent in the infant gut.

The gut microbiota is an important contributor to the worldwide prevalence of metabolic syndrome (MS), which includes obesity and diabetes.　The present study investigated the effects of probiotic Bifidobacterium treatment on MS in mouse and human. Using an animal model, the anti-MS effects exerted by B. animalis subsp. lactis GCL2505, a highly proliferative Bifidobacterium strain in the gut, and B. longum subsp. longum JCM 1217^T were comparatively examined. GCL2505 treatment reduced visceral fat accumulation and improved glucose tolerance, whereas JCM 1217^T had no effect on these parameters. Gut microbial analysis revealed that GCL2505 exerted stronger effects on the overall bacterial structure of the gut microbiota than JCM 1217^T, including enrichment of the genus Bifidobacterium. The levels of acetate and glucagon-like peptide-1 were increased by GCL2505 treatment in both the gut and plasma, but not by JCM 1217^T treatment. Human clinical studies demonstrated that consumption of GCL2505 improved abdominal visceral fat accumulation. These findings indicated that GCL2505, a highly viable and proliferative probiotic, improves MS by modulating gut microbiota, which results in the elevation of SCFAs, especially acetate.