title: Application of culture-dependent and culture-independent methods for the identification of Lactobacillus kefiranofaciens in microbial consortia present in kefir grains.
abstract: The biological and technological characteristics of kefiran as well as its importance in grain integrity led us to analyze the microbial kefir grain consortium with focus on Lactobacillus kefiranofaciens. The presence of L. kefiranofaciens in the nine kefir grains studied was demonstrated by denaturing gradient gel electrophoresis. By culture dependent methods applying a methodology focused on the search of this species, 22 isolates with typical morphology were obtained and identified applying a combination of SDS-PAGE of whole cell proteins, (GTG)5-PCR and sequence analysis of the housekeeping gene encoding the α-subunit of bacterial phenylalanyl-tRNA synthase (pheS). This polyphasic approach allowed the reliable identification of 11 L. kefiranofaciens, 5 Lactobacillus paracasei, 4 Lactobacillus kefiri and 2 Lactobacillus parakefiri isolates. Isolated L. kefiranofaciens strains produced polysaccharide in strain-dependent concentrations and EPS produced by them also differed in the degree of polymerization. The isolation and accurate identification of L. kefiranofaciens is relevant taking into account the important role of this microorganism in the grain ecosystem as well as its potential application as starter in food fermentations.
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) (CONICET-Facultad de Ciencias Exactas, UNLP), La Plata 1900, Argentina.
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Hamet
authors.forename: Alejandra
authors.initials: A
authors.lastname: Londero
authors.forename: Micaela
authors.initials: M
authors.lastname: Medrano
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Vercammen
authors.forename: Koenraad
authors.initials: K
authors.lastname: Van Hoorde
authors.forename: Graciela L
authors.initials: GL
authors.lastname: Garrote
authors.forename: Geert
authors.initials: G
authors.lastname: Huys
authors.forename: Peter
authors.initials: P
authors.lastname: Vandamme
authors.forename: Analía G
authors.initials: AG
authors.lastname: Abraham
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods*; D015169:Colony Count, Microbial; D043302:Cultured Milk Products / Q000737:chemistry / Q000382:microbiology*; D058645:Denaturing Gradient Gel Electrophoresis; D004591:Electrophoresis, Polyacrylamide Gel; D007778:Lactobacillus / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D059013:Microbial Consortia; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction
keywords: Exopolysaccharide; Kefir; Kefiran; Lactobacillus kefiranofaciens