Structural analysis of the exopolysaccharides produced by Lactobacillus spp. G-77

The exopolysaccharide produced by a ropy strain of Lactobacillus spp. G-77 in a semi-defined medium, was found to be a mixture of two homopolymers composed of d-Glc. The two polysaccharides were separated and, on the basis of monosaccharide and methylation analyses, 1H, 13C, 1D and 2D NMR experiments, one of the polysaccharides was shown to be a 2-substituted-(1–3)-β-d-glucan, identical to that described for the EPS from Pediococcus damnosus 2.6 (M.T. Dueñas-Chasco, M.A. Rodrı́guez-Carvajal, P. Tejero-Mateo, G. Franco-Rodrı́guez, J.L. Espartero, A. Irastorza-Iribar, and A.M. Gil-Serrano, Carbohydr. Res., 303 (1997) 453–458), and the other polysaccharide was shown to consist of repeating units with the following structure