title: Characterization of glucan-producing Leuconostoc strains isolated from sourdough.
abstract: Sourdough was previously demonstrated to be a fruitful biotope for isolation of lactic acid bacteria producing exopolysaccharides and more accurately diverse glycan polymers which have interesting applications as texturing agents or prebiotics. Characterization of polymers by (1)H and (13)C NMR spectroscopy analysis demonstrated that these strains could synthesize glucans of high structural variety and containing different amounts of α-(1→2), α-(1→3) and α-(1→6) linkages. In this study, fifteen glucan-producing Leuconostoc mesenteroides and L. citreum strains from sourdoughs were characterized according to carbohydrate fermentation, rep-PCR fingerprinting using (GTG)(5) primers and glycansucrase activity (soluble or cell-associated). Enzyme characterization using SDS-PAGE and in situ polymer production after incubation with sucrose correlated with synthesis of classical or α-(1→2) branched dextrans, alternan and levan. In addition, the presence of genes coding for alternansucrase was detected by PCR and partially characterized by sequence analysis. We thus provide new information on the biodiversity of glucan production by sourdough Leuconostoc strains.
authors.affiliation: Laboratoire de Biologie appliquée à l'Agroalimentaire et à l'Environnement (LBAE), Institut Universitaire de Technologie-Université Paul Sabatier, 24 rue d'Embaquès, F-32000 Auch, France.
authors.forename: Marie-Sophie
authors.initials: MS
authors.lastname: Bounaix
authors.forename: Valérie
authors.initials: V
authors.lastname: Gabriel
authors.forename: Hervé
authors.initials: H
authors.lastname: Robert
authors.forename: Sandrine
authors.initials: S
authors.lastname: Morel
authors.forename: Magali
authors.initials: M
authors.lastname: Remaud-Siméon
authors.forename: Bruno
authors.initials: B
authors.lastname: Gabriel
authors.forename: Catherine
authors.initials: C
authors.lastname: Fontagné-Faucher
mesh_terms: D000595:Amino Acid Sequence; D001939:Bread / Q000382:microbiology*; D050260:Carbohydrate Metabolism; D016172:DNA Fingerprinting; D005285:Fermentation; D005936:Glucans / Q000096:biosynthesis; D016695:Glycosyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007934:Leuconostoc / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D005936:Glucans; D016695:Glycosyltransferases; C033837:alternansucrase