Microbial levan.

Levans are natural polymers of the sugar fructose found in many plants and microbial products. Like dextrans, they are formed as an undesirable by-product of sugar juice processing. On the other hand, levans, which can only be produced from sucrose, have potential industrial applications as thickeners and encapsulating agents and could provide additional, valuable products from sugarcane juice. A strain of B. polymyxa (NRRL B-18475) produced a high yield of polysaccharide when grown on sucrose solution. Hydrolysis and subsequent analyses showed the product to consist entirely of D-fructose. 13C-NMR and methylation analyses indicated the products to be a beta(2----6)-linked polymer of fructose, with 12% branching. The polysaccharide has a Mr of approximately 2 million and is readily soluble in water. Levan has not been utilized, but if developed, could be useful in food and other industrial applications.