Concentration regimes of solutions of levan polysaccharide from Bacillus sp.

The theological proper-ties of aqueous solutions of levan polysaccharide from Bacillus sp. were studied at 20.0 degrees C over a wide range of concentrations. At low concentrations the solutions were Newtonian, becoming shear thinning at higher concentrations. The intrinsic viscosity of this levan was found to be 0.14 dL/g, which is close to that of other levans. However, whereas other polysaccharides exhibit up to three concentrations regimes (dilute, semi-dilute, and concentrated) in a double logarithmic plot of the specific viscosity versus space occupancy, this levan exhibits four distinct concentration regions, at least three of which are linear. To the best of our knowledge, this is the first report of a solution of any kind exhibiting more than three distinct regions in this type of plot. (c) 2006 Elsevier Ltd. All rights reserved.