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

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 Co2+ and Ca2+ ions. Glycerol and Tween 80 enhanced enzyme stability, and its half-life at 30 degrees C increased from 10 h to 74h and 59h, respectively. The H-1 and C-13 NMR spectral analysis of the produced dextran confirmed the presence of main chain alpha-(1 -> 6) linkages with only 3.0% of alpha-(1 -> 3) branching, of which some were elongated. An HPSEC analysis in DMSO revealed a high molecular weight of 1.8 x 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. (C) 2013 Elsevier Ltd. All rights reserved.