Structural characterization of an exopolysaccharide produced by Lactobacillus plantarum Ts

Abstract

Abstract An exopolysaccharide (EPS) was isolated from Lactobacillus plantarum Ts and purified by size exclusion chromatography train. L. plantarum showed the highest production (9.4 ± 0.8 g/l) of EPS. Furthermore, L. plantarum was cultured in medium with volume of 5 L and the EPS was extracted by ethanol precipitation. By HPLS analysis demonstrated, that the EPS has two fractions - polymer and olygomer. The molecular mass of the EPS from both fractions is respectively 8.3x104 Da for the greater pic and 5.0x102 Da. Fourier transform infrared spectroscopy analysis showed the presence of hydroxyl and carboxyl groups and glycosidic linkages. TLC analysis indicated that the EPS was a heteropolymer composed of fructose, and sucrose as monomeric constituent units. The strain L. plantarum and pathogenic E. coli 3398, St. aureus 745, B. subtilis 6633, S. typhimurium 3591, L. monocytogenes 863 and E. aerogenes 3691 were tested for their growth utilizing the EPS from L. plantarum as the sole carbon source for its possible use as a prebiotic. L. plantarum exhibited growth in the EPS supplied medium compared with sucrose as carbon source, whereas the pathogenic strains did not grow in the EPS-supplied medium. In vitro evaluations showed that, like other reported polysaccharides, this EPS displayed significant prebiotics properties.