关键词: 胞外多糖, 双歧杆菌, 基因簇

Abstract:

Bifidobacterium has been accepted as an important probiotic bacterium with its health benefit on the host, its
exopolysaccharides (EPS) also have antioxidant and immune modulating function for humans. In this work, we identified an
exopolysaccharide producing strain as Bifidobacterium animalis subsp. lactis RH by physiological, biochemical, 16S rRNA
and tuf analysis. The specific primers of wzx, wzy, wzz and so on were designed according to the conservative gene sequences
of Bifidobacterium animalis subsp. lactis AD011 from GenBank. And we acquired 12 gene sequences such as repeat unit
transporter(Wzx) and repeat unit polymerase(Wzy). Functional prediction analysis of open reading frames (ORF) indicates
that these 12 genes encode the amino acid sequences of the proteins involved in polysaccharide chain length determination,
polymerization and transport. The results of this research may lay a foundation for further understanding of the EPS
biosynthetic pathway of Bifidobacterium and the underlying mechanism.

Key words: exopolysaccharide, Bifidobacterium, gene cluster