Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 6, 1999
Publication Date: N/A
Technical Abstract: Several species of bacteria synthesize extracellular fructans and glucans from sucrose. These products include dextran (a soluble alpha- 1,6-D-glucan), mutan (an insoluble alpha-1,3-D-glucan), alternan (alternating alpha-1,3-1,6-D-glucan), and levan (beta-2,6-D-fructan). Dozens of permutations and combinations of these structures are known. Although these polymers represent a variety of properties and potential applications, only the dextran from Leuconostoc mesenteroides NRRL B-512F has been commercialized. Produced by fermentation from sucrose, it is a moderately viscous, water-soluble polymer. Its main industrial uses are in photographic emulsions and in the aluminum refining process. Derivatives are also used in medicine, and its crosslinked form is sold under the trade name Sephadex. Uses of the other polysaccharides in this group are mostly speculative at this point. Levan, a fructose polymer, has been proposed as a dietary supplement but lacks any particular advantage over similar such polymers. Mutan and related D-glucans from various bacteria are water-insoluble and have been proposed for various applications, but no current uses are known. Branched oligosaccharides produced by the same glucansucrases responsible for the synthesis of branched dextrans have found some small markets in Europe as ingredients in cosmetics. One promising glucan under investigation in our laboratory is alternan. This low- viscosity polysaccharide may be useful as a bulking agent in artificially sweetened foods. Alternan can also be used as a wet-end additive to enhance the dry strength of paper.