Uronic preparation from natural products

Bacterial polysaccharides represent a large variety of polymers biosynthesized by bacteria. Their chemical structures and also their physical properties in solution or in the solid state may vary widely. They often contain uronic acid and then become polyelectrolytes (190). Many new polysaccharides have been developed from bacteria for industrial purposes. Exocellular polysaccharides are produced on a large scale by the usual techniques of microbiology and fermentation. This procedure allows good control of the characteristics of the polymers and allows purification of the polysaccharides more easily than from other natural sources (191-194). Extension of such production also allows reducing the price and extends the range of applications. A good example remains the hyalmonan previously produced by extraction from animal somces but in which some fraction of proteins remained. Bacterial hyaluronan can be prepared in a very pme form (195). 

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