Microbial polysaccharides--a comparison with eukaryotic polymers.

Many microorganisms secrete exopolysaccharides, most of which are composed of monosaccharides widely found in non-microbial sources. Bacterial polysaccharides are frequently acylated or may contain phosphate esters but, with the exception of cyanobacterial material, appear to lack sulphate. They may contain a number of unusual or methylated sugars. The majority of microbial exopolysaccharides are composed of repeating units ranging in size from disaccharides to heptasaccharides. Some of these polymers are either identical to, or very similar to, polysaccharides found in eukaryotic tissues. In the microorganism, however, the function of the material is very different to that in the eukaryote.