Structural characteristics and functional properties of a fucose containing prebiotic exopolysaccharide from Bifidobacterium breve NCIM 5671

Aim To evaluate the structure and functions of capsular exopolysaccharide (CPS) from Bifidobacterium breve NCIM 5671.Methods and results A CPS produced by the probiotic bacteria B. breve NCIM 5671 was isolated and subjected to characterization through GC analysis, which indicated the presence of rhamnose, fucose, galactose, and glucose in a molar ratio of 3:1:5:3. The average molecular weight of the CPS was determined to be similar to 8.5 x 105 Da. Further, NMR analysis revealed the probable CPS structure to be composed of major branched tetra- and penta-saccharide units alternately repeating and having both alpha- and beta-configuration sugar residues. CPS displayed an encouraging prebiotic score for some of the studied probiotic bacteria. Compared to standard inulin, CPS showed better resistance to digestibility against human GI tract in vitro. DPPH, total antioxidant, and ferric reducing assays carried out for CPS displayed decent antioxidant activity too.Conclusion This study indicates that the CPS from B. breve NCIM 5671 has the potential to be utilized as a prebiotic food supplement. It is a high-molecular-weight (similar to 8.5 x 105 Da) capsular heteropolysaccharide containing rhamnose, fucose, galactose, and glucose.