Isolation and characterisation of a ropy Lactobacillus strain producing the exopolysaccharide kefiran

A capsular-polysaccharide-producing strain, LM-17, was isolated from kefir grains and was identified as a slime-forming, rod-shaped Lactobacillus. Acc ording to H-1- and C-13-NMR spectral data, the exopolysaccharide produced b y the isolated bacterial strain is identical to the glucogalactan extracted from kefir grains and therefore known as kefiran. The kefiran produced was characterised by means of viscosity, optical rotatory power, circular dich roism and IR spectral measurements. A batch procedure was set up for the cu lture and extraction of the exopolysaccharide in laboratory conditions, res ulting in a yield of 2 g/l purified kefiran from the culture supernatant of the LM-17 strain.