Molecular weight and antitumour activity of Zymomonas mobilis levans.

Levans produced by several Zymomonas mobilis strains were classified by their viscosity average molecular weight and tested against sarcoma 180. Measurements of the samples' polydispersity were carried out to characterise the molecular weight distribution. The antitumour activities of levan samples were plotted against the viscosity average molecular weight and a maximum value of this activity was found at Mv = 210,000 (Mw = 456,900 and PD = 16.2). The results indicate that levan antitumour activities depend on the polysaccharide molecular weight and that a specific class of molecular weight may be responsible for this effect.