. Dextran obtained by CMG713 is of viscosity 14.58 cp. High viscosity of dextran has suggested that it has long chain of α (1→6) linkage in the main chain. α (1→6) linked polysaccharides, this represents a class of very flexible and extended polymer. The average molecular weight of native dextran produced by L. mesenteroides NRRL B512F had been investigated and the values for average molecular weight were determined in the