Levans: I. Fractionation, solution viscosity, and chemical analysis of levan produced by Streptococcus salivarius.

Levan produced by Streptococcus salivarius was fractionated into a series of 20 fractions of varying molecular weight. The range of intrinsic viscosities of the fractions was 0.07 to 0.18 dl/gm in water and 0.20 to 0.29 dl/gm in dimethyl sulfoxide. The molecular weight of the unfractionated leval determined by light scattering was 31.5 times 10-6. Small amounts of fatty acids and protein were found associated with levan.