CHEMICAL CHARACTERIZATION OF EXOCELLULAR POLYSACCHARIDE FROM LACTOBACILLUS-DELBRUECKII SUBSP BULGARICUS OLL1073R-1

The chemical structure of exocellular polysaccharide produced through Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 in 10% skim mil k was examined. The exocellular polysaccharide was divided into neutra l and acidic polysaccharides by anion-exchange chromatography. Sugar a nalysis and H-1-NMR spectroscopy revealed that the neutral and acidic polysaccharides were composed of pentasaccharide repeating units conta ining galactose (Gal) and glucose (Glc) in the molar ratio of 3:2, and the apparent molecular weight were 1.2x10(6) Da and 1.1x10(6) Da, res pectively. A slight amount (0.1%) of phosphorus was contained in the a cidic polysaccharide. On the base of methylation analysis, it was foun d that neutral polysaccharide consisted of 2,3,4,6-tetra-O-methyl-1,5- di-O-acetyl galactitol, 2,3,6-tri-O-methyl-1,4,5-tri-O-acetyl galactit ol, 3,4,6-tri-O-methyl-1,2,5-tri-O-acetyl glucitol, 2,4,6-tri-O-methyl -1,3,5-tri-O-acetyl glucitol, and 2,6-di-O-methyl-1,3,4,5-tetra-O-acet yl galactitol in the molar ratio of 1.0:0.7:0.8:1.3:0.9, and indicated that it was branched with Gal.