Structural characterization and prebiotic activity evaluation of novel fucosylated disaccharides prepared from bacterial exopolysaccharides

The deoxyhexose sugar l-fucose and fucosylated oligosaccharides (FCO) are essential for various biological processes in human body and associated gut microbiota. Bacterial exopolysaccharides offer a promising new source for preparing functional oligosaccharides. Here, FCO were obtained through acidolysis of fucose-containing exopolysaccharides with a molecular weight of 5.9 × 10³ kDa, derived from Clavibacter michiganensis M2. Structural analysis revealed that the main disaccharide components of FCO exhibited a molecular weight of 326 Da and a monosaccharide composition of fucose, galactose, and glucose in a 3:1:2 ratio. Nuclear magnetic resonance indicated that the disaccharide fragments consisted of two backbones of α-Galp-(1 → 2)-α-Fucp and β-Glcp-(1 → 4)-β-Fucp, respectively. In vitro fermentation of FCO with human fecal cultures resulted in an increased abundance of Bifidobacterium and Bacteroides, and a reduction in Escherichia-Shigella and Fusobacterium. This research outlines a novel structural fucosylated oligosaccharide and its preparation method, suggesting its potential application as a promising new prebiotic.