Structural characterization of the exopolysaccharide produced by Lactobacillus acidophilus LMG9433

The exopolysaccharide produced by Lactobacillus acidophilus LMG9433 in a semi-defined medium was found to be a charged heteropolymer, with a composition of d-glucose, d-galactose, d-glucuronic acid, and 2-acetamido-2-deoxy-d-glucose in molar ratios of 2:1:1:1. By means of methylation analysis, uronic acid degradation, de-N-acetylation/deamination, partial acid hydrolysis, and 1D/2D NMR studies the polysaccharide was demonstrated to consist of repeating units with the following structure: .