Structural studies on exopolysaccharides produced by three different propionibacteria strains

Abstract

The exopolysaccharides produced by three propionibacteria strains, Propionibacterium freudenreichii 109, Propionibacterium freudenreichii 111, and Propionibacterium thoenii 126, grown on whey-based media, were found to be charged heteropolymers, composed of D-glucose, D-mannose, and D-glucuronic acid in molar ratios of 2:2:1. By means of methylation analysis, mass spectrometry, partial acid hydrolysis, and 1D/2D NMR (1H and 13C) studies, it was determined that all three exopolysaccharides contain the same branched, pentasaccharide repeating unit: β-D-GlcpA α-D-Glcp 1 1 ↓ ↓ 6 6 →3) -α-D-Manp-(1→3) -α-D-Manp-(1→3) -α-D-Glcp-(1→