DETERMINATION OF THE MOLECULAR-WEIGHT DISTRIBUTION OF MICROBIAL EXOPOLYSACCHARIDES

A rapid method for the determination of the molecular-weight distribution of microbial exopolysaccharides (EPS) has been developed; it employs analytical centrifugation in a mixed salt gradient of NaCl and CsCl, and uses dextrans as molecular weight standards. The concurrent gradient centrifugation of the dextrans and the EPS under study resulted in the simplification and speeding up of the assay of molecular weights of EPS fractions. The method allows the analysis of native EPS with molecular weights ranging between 13.7 and 2000 kDa. The method has applications in both scientific-research and in industry concerned with EPS production.