Weissella confusa Cab3 dextransucrase: properties and in vitro synthesis of dextran and glucooligosaccharides

Abstract

Food-derived Weissella spp. have gained attention during recent years as efficient dextran producers. Weissella confusa Cab3 dextransucrase (WcCab3-DSR) was isolated applying PEG fractionation and used for in vitro synthesis of dextran and glucooligosaccharides. WcCab3-DSR had a molar mass of 178 kDa and was activated by Co(2+) and Ca(2+) ions. Glycerol and Tween 80 enhanced enzyme stability, and its half-life at 30°C increased from 10h to 74 h and 59 h, respectively. The (1)H and (13)C NMR spectral analysis of the produced dextran confirmed the presence of main chain α-(1→6) linkages with only 3.0% of α-(1→3) branching, of which some were elongated. An HPSEC analysis in DMSO revealed a high molecular weight of 1.8 × 10(7)g/mol. Glucooligosaccarides produced through the acceptor reaction with maltose, were analyzed with HPAEC-PAD and ESI-MS/MS. They were a homologous series of isomaltooligosaccharides with reducing end maltose units. To the best of our knowledge, this is a first report on native W. confusa dextransucrase.

Keywords: Dextran; Dextransucrase; Glucooligosaccharides; Weissella confusa.