title: Characterization of glucansucrase and dextran from Weissella sp. TN610 with potential as safe food additives.
abstract: Pear-derived Weissella sp. TN610 produced extracellular glycosyltransferase activity responsible for the synthesis of soluble exopolysaccharide from sucrose. Acid and dextranase-catalyzed hydrolysis revealed that the synthesized polymer was a glucan. According to (1)H and (13)C NMR analysis, the glucan produced by TN610 was a linear dextran made of 96% α-(1→6) and 4% α-(1→3) linkages. Zymogram analysis confirmed the presence of a unique glucansucrase of approximately 180 kDa in the cell-free supernatant from TN610. The crude enzyme, optimally active at 37°C and pH 5, has promising potential for application as a food additive since it catalyzes dextran synthesis in sucrose-supplemented milk, allowing its solidification. A 4257-bp product corresponding to the mature glucansucrase gene was amplified by PCR from TN610. It encoded a polypeptide of 1418 residues having a calculated molecular mass of 156.089 kDa and exhibiting 96% and 95% identity with glucansucrases from Lactobacillus fermentum Kg3 and Weissella cibaria CMU, respectively.
authors.affiliation: Laboratoire de Microorganismes et de Biomolécules (LMB), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP 1177 3018 Sfax, Tunisie.
authors.forename: Wacim
authors.initials: W
authors.lastname: Bejar
authors.forename: Valérie
authors.initials: V
authors.lastname: Gabriel
authors.forename: Myriam
authors.initials: M
authors.lastname: Amari
authors.forename: Sandrine
authors.initials: S
authors.lastname: Morel
authors.forename: Monia
authors.initials: M
authors.lastname: Mezghani
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Maguin
authors.forename: Catherine
authors.initials: C
authors.lastname: Fontagné-Faucher
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.forename: Hichem
authors.initials: H
authors.lastname: Chouayekh
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D005503:Food Additives / Q000737:chemistry*; D016695:Glycosyltransferases / Q000737:chemistry*; D058836:Weissella / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D003911:Dextrans; D005503:Food Additives; D016695:Glycosyltransferases; C033837:alternansucrase