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United States Department of Agriculture

Agricultural Research Service

Title: Some Structural Features of An Insoluble Glucan from An Unusual Mutant of Leuconostoc Mesenteroides

item Ahlgren, Jeffrey
item Cote, Gregory
item Nicholson, James
item Smith, Michael

Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 1998
Publication Date: N/A

Technical Abstract: Leuconostoc mesenteroides strain NRRL B-1355 produces two soluble extracellular alpha-D-glucans from sucrose, namely, alternan and dextran. An unusual mutant strain derived from B-1355 has recently been isolated which produces practically no soluble polysaccharide but significant amounts of an insoluble polysaccharide. Acid hydrolysis shows it to be a D-glucan. FTIR analysis indicates a lack of contiguous alpha(1-3) linkages. Methylation analysis shows it to contain linear (1-3) and (1-6) linkages as well as (1-2) and (1-3) branch linkages. The insoluble glucan was partially digestible by endodextranase, giving rise to a series of oligosaccharides, a high- molecular weight soluble fraction, and an insoluble residue. Endo- alternanase had no discernable activity against the glucan. Treatment of the dextranase-limit fractions with an alpha(1-2) debranching enzyme led to further dextranase susceptibility. These results, in conjunction with methylation and NMR analysis of the various dextranase-treated fractions, indicate a strong similarity to Leuconostoc mesenteroides strain NRRL B-1299 dextran.

Last Modified: 4/22/2015
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