Production of polysaccharide with <i>Xanthomonas campestris</i>

Abstract

Abstract Industrially important polysaccharides are now primarily obtained from plant sources. One exception is the exocellular bacterial polysaccharide, dextran. A survey at the Northern Laboratory revealed that many other microbial polysaccharides could be synthesized by the action of micro‐organisms on starch‐derived saccharides. Previous publications from this laboratory describe the production of the microbial polymer, phosphomannan, synthesized by the yeast Hansenula holstii . This paper describes the production of another polysaccharide, synthesized by the bacterium Xanthomonas campestris NRRL B‐1459. Fermentation of media containing 3 per cent dextrose, seeded with 5 per cent inoculum of X. campestris NRRL B‐1459 and cultured aerobically at 28°C, is complete in 96 h. A light tan polymer is recovered in yields of 50 per cent, based on commercial dextrose, from the viscous fermentation broth by precipitation with methanol in the presence of an electrolyte. The viscosities of aqueous re‐solutions containing 1 and 2 per cent of the polymer were 3,000 cP and 11,000 cP respectively.