Structural characterization of the extracellular polysaccharide produced by Bifidobacterium longum JBL05

The extracellular polysaccharide produced by Bifidobacterium longum JBL05 was found to be composed of d-galactopyranosyl, d-glucopyranosyl and l-rhamnopyranosyl residues in the molar ratio of 4:2:1. Methylation analysis coupled with GC–MS, and both 1D and 2D NMR spectroscopy showed that the polysaccharide has a heptasaccharide repeating unit with the following structure: