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United States Department of Agriculture

Agricultural Research Service

Title: A Novel Modified Alternan

Authors
item Leathers, Timothy
item Nunnally, Melinda
item Cote, Gregory

Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 2, 2001
Publication Date: N/A

Technical Abstract: Alternan is a unique glucan produced by rare strains of Leuconostoc mesenteroides, with a backbone structure of alternating alpha-(1-6) and alpha-(1-3)-D-glucosidic linkages. Native alternan has an apparent molecular weight average of 10**6 - 10**7. Derivatives of alternan with reduced molecular weights exhibit potentially useful properties. Ultrasonication breaks apart alternan, changing its rheological properties to more closely resemble those of gum arabic. However, ultrasonication is a relatively expensive process that would be difficult to carry out on an industrial scale. Arthrobacter globiformis produces an isomaltodextranase that attacks alternan to produce a "limit alternan" with properties similar to those of oligosaccharides of maltodextrin. Alternan is resistant to endodextranases; however, Bacillus sp. isolates were recently described that produce an endoglucanase specific for alternan. The principal product tof this alternanase is a unique cyclic tetrasaccharide. In order to exten the useful range of alternan derivatives, soil samples were screened for new microorganisms that could partially degrade or modify alternan. A novel modified alternan was produced and partially characterized.

Last Modified: 8/30/2014
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