title: Production and partial characterization of exopolysaccharides produced by two Lactobacillus suebicus strains isolated from cider.
abstract: Many lactic acid bacteria synthesize extracellular polysaccharides (exopolysaccharides, EPSs) with a large variation in structure and potential functional properties. Although EPS production can produce detrimental effects in alcoholic beverages, these polymers play an important role in the rheological behavior and texture of fermented products. In this work, EPS production by two Lactobacillus suebicus strains, which were isolated from ropy ciders, was examined in a semidefined medium. The existence of priming glycosyltransferase encoding genes was detected by PCR. In addition, the preliminary characterization of the polymers was undertaken. Molecular masses were determined by size exclusion chromatography revealing the presence of two peaks, corresponding to polymers of high- and low-molecular-weight in all fractions. The composition of the EPS fractions was analyzed by gas chromatography-mass spectrometry after acid hydrolysis, revealing that they contained glucose, galactose, N-acetylglucosamine and phosphate, although in different ratios, suggesting that a mixture of polysaccharides is being synthesized. We also examined the influence of the sugar source (glucose, ribose, xylose, or arabinose) and pH conditions on growth and EPS production.
authors.affiliation: Departmento de Química Aplicada, Facultad de Ciencias Químicas, Universidad del País Vasco, Paseo Manuel de Lardizabal 3, 20018 San Sebastián, Spain.
authors.forename: Idoia
authors.initials: I
authors.lastname: Ibarburu
authors.affiliation: Departmento de Química Aplicada, Facultad de Ciencias Químicas, Universidad del País Vasco, Paseo Manuel de Lardizabal 3, 20018 San Sebastián, Spain.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Puertas
authors.affiliation: Departmento de Química Aplicada, Facultad de Ciencias Químicas, Universidad del País Vasco, Paseo Manuel de Lardizabal 3, 20018 San Sebastián, Spain.
authors.forename: Iñaki
authors.initials: I
authors.lastname: Berregi
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Profesor García González, 1, 41012 Sevilla, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez-Carvajal
authors.affiliation: Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Prieto
authors.affiliation: Departmento de Química Aplicada, Facultad de Ciencias Químicas, Universidad del País Vasco, Paseo Manuel de Lardizabal 3, 20018 San Sebastián, Spain. Electronic address: mariateresa.duenas@ehu.es.
authors.forename: Mª Teresa
authors.initials: MT
authors.lastname: Dueñas
mesh_terms: D000434:Alcoholic Beverages / Q000382:microbiology*; D005285:Fermentation; D005516:Food Microbiology; D007778:Lactobacillus / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry*
chemical_list: D011135:Polysaccharides, Bacterial
keywords: Exopolysaccharides; Heteropolysaccharides; Lactic acid bacteria; Lactobacillus suebicus