Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2009
Publication Date: 4/2/2009
Citation: Leathers, T.D., Nunnally, M.S., Cote, G.L. 2009. Alternan research at the National Center for Agricultural Utilization Research [abstract]. The 2nd Thai-American Symposium on Plant Biomass, Biotechnology and Agriculture. p. S1.
Technical Abstract: The Northern Regional Research Laboratory (later the National Center for Agricultural Utilization Research, or NCAUR) began operations on December 16, 1940. By the late 1940’s, Dr. Allene Jeanes was leading a team in an extensive research program on dextrans. Dextrans are glucan polysaccharides that possess a backbone structure in which a-(1,6) linkages predominate. In a survey of 96 bacterial isolates, Jeanes and coworkers found that some strains produced unusual polysaccharides in addition to dextran. Alternan is a glucan produced by rare strains of Leuconostoc mesenteroides, with a distinctive backbone structure of alternating a-(1,6) and a-(1,3) linkages. The unique structural and physical properties of alternan have created a good deal of interest in alternan and its derivatives. In recent years, improved strains for production of alternan were developed at NCAUR. Novel Bacillus sp. strains were discovered that produce an endoglucanase that attacks alternan. The principal product of this alternanase is a unique cyclic tetrasaccharide. Penicillium sp. strains were isolated that modify alternan to a lower molecular weight form that more closely mimics gum arabic. Recently, it was discovered that dextranase is responsible for this modification. Oligosaccharides based on alternan were produced enzymatically using acceptor reactions. These alternanoligosaccharides are potential second generation prebiotics. Alternan technology developed at NCAUR was transferred to Cargill, leading to the development of sucromalt, a low-glycemic index sweetener that appears in the popular Glucerna line of diabetic foods.