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Structural Characterization of Enzymatically Synthesized Dextran and Oligosaccharides from Leuconostoc mesenteroides NRRL B-1426 Dextransucrase

D. Kothari and A. Goyal*

Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; fax: 361-258-2249; E-mail: arungoyl@iitg.ernet.in

* To whom correspondence should be addressed.

Received April 3, 2013
Leuconostoc mesenteroides NRRL B-1426 dextransucrase synthesized a high molecular mass dextran (>2 × 106 Da) with ~85.5% α-(1→6) linear and ~14.5% α-(1→3) branched linkages. This high molecular mass dextran containing branched α-(1→3) linkages can be readily hydrolyzed for the production of enzyme-resistant isomalto-oligosaccharides. The acceptor specificity of dextransucrase for the transglycosylation reaction was studied using sixteen different acceptors. Among the sixteen acceptors used, isomaltose was found to be the best, having 89% efficiency followed by gentiobiose (64%), glucose (30%), cellobiose (25%), lactose (22.5%), melibiose (17%), and trehalose (2.3%) with reference to maltose, a known best acceptor. The β-linked disaccharide, gentiobiose, showed significant efficiency for oligosaccharide production that can be used as a potential prebiotic.
KEY WORDS: dextransucrase, dextran, Leuconostoc mesenteroides NRRL B-1426, acceptor, oligosaccharide

DOI: 10.1134/S0006297913100118