Structural Analysis of EPS from Pedioccocus parvulus by NMR and molecular modeling

LUIS CALLE JIMÉNEZ; JAVIER CAÑADA; JESÚS JIMÉNEZ BARBERO; MARÍA LAURA WERNING,; PALOMA LÓPEZ

Sevilla

Otro; IV BIENAL DEL GERMN-I REUNION IBERICA DE RMN; 2008

Abstract A number of exopolysaccharides of β-glucan type play an important role in the rheology and texture of fermented foods and have also shown prebiotic properties. In addition, the (1→3)-β-D-glucans can promote antitumor and antimicrobial activity, by activating macrophages, other white blood cells or dendritic cells. It has been shown that the lactic acid bacteria Pedioccocus parvulus 2.6 synthesizes an extracellular exopolisaccharide with thickening properties, that has been characterized as a linear  (1-3) homopolymer of D-glucose substituted every two glucose residues by another -glucose unit on the 2 position. The NMR characterization and assignment1 of this -glucan and its rheological properties2 have been previously analysed. This exopolisaccharide has been produced and secreted (300 mg L-1) by an uncapsulated recombinant Lactococcus lactis strain. This bacteria expresses the P. parvulus glycosyltranferase responsible for the b-glucan biosynthesis3. We are now studying, by NMR and molecular modelling, the structure and conformation of this exopolysaccharide in water, in order to understand their physicochemical properties in structural terms.