Isolation and characterization of an extracellular glucan produced by Leuconostoc garlicum PR

White and highly viscous extracellular polysaccharide composed of D-glucose residues has been isolated from culture medium of Leuconostoc garlicum PR by acetone precipitation followed by dialysis and freeze-drying. The crude biopolymer was recovered in the yield of 50 g/L of rich culture medium and showed an apparent molecular mass over 2 x 10(7). Chemical and spectroscopic studies revealed almost linear character of the bacterial biopolymer composed of alpha-1,6-linked D-glucopyranosyl backbone carrying a low content of branched points at C-2, C-3 and C-4. Moreover, a low content (similar to 2%) of alpha-1,4-linked D-glucopyranosyl residues has been determined in the extracellular biopolymer. (C) 2010 Elsevier Ltd. All rights reserved.