Abstract: This study aimed to comparatively analyze the common and unique glycoside hydrolase (GH) family genes in Bifidobacterium. On this basis, a rapid method for isolating target Bifidobacterium strains from infant fecal samples was developed. The GH family genes of four bifidobacterial taxa, including B. breve, B. longum subsp. longum, B. bifidum and B. longum subsp. infantis, were compared, revealing that there were common and unique patterns in the GH family genes among these species, which could serve as molecular markers for the isolation and identification of Bifidobacterium strains. Based on colony polymerase chain reaction (PCR) and nucleic acid electrophoresis, a rapid method for the isolation and identification of the aforementioned bifidobacterial strains were successfully developed and applied to the isolation of B. bifidum. This method is characterized by not only high efficiency of isolation but also low costs. The results of this study contribute to a better understanding of the diversity of Bifidobacterium, thereby laying a foundation for future probiotic research and development.

Key words: comparative genomics; glycoside hydrolase; Bifidobacterium; isolation and identification