INVESTIGADORES
HEBERT Elvira Maria
congresos y reuniones científicas
Título:
Diversity of exopolysaccharide-producing lactic acid bacteria strains and their biopolymer
Autor/es:
MOZZI, F; VANINGELGEM, F.; HEBERT, E.M.; VAN DER MEULEN, R.; FONT DE VALDEZ, G.; DE VUYST, L.
Lugar:
Egmond aan Zee, Netherlands
Reunión:
Simposio; EIGTH SYMPOSIUM ON LACTIC ACID BACTERIA. GENETICS, METABOLISM AND APPLICATIONS; 2005
Institución organizadora:
Federation of European Microbiological Societies (FEMS)
Resumen:
Exopolysaccharides (EPS) from lactic acid bacteria (LAB) play an important role in the texture of fermented foods. To explore the diversity of the EPS-producing LAB and their polysaccharides, thirty-two strains [Lactobacillus delbrueckii subsp. bulgaricus (10), L. delbrueckii subsp. lactis (1), Streptococcus thermophilus (8), L. helveticus (1), L. paracasei (5), L. casei (3), L. rhamnosus (1), Enterococcus faecalis (2), and E. faecium (1)] were evaluated for their EPS-producing ability in milk, and screened for ropiness (R), capsular polysaccharide (CPS) and oligosaccharide (EOS) formation. All EPS produced were characterised. A PCR screening using primers coding for six different eps genes was performed. In this study, thermophilic strains were higher EPS producers than mesophilic ones. The ability to form CPS or ropy cultures by thermophilic LAB was variable, these properties being more widespread among mesophilic strains. Although L. delbrueckii subsp. bulgaricus CRL861 and L. paracasei CRL686 and CRL208 scarcely synthesized EPS, their cultures were R+. This phenotype seemed to be related to the polymer size, as most of the high-molecular-mass EPS-producing strains were R+. The EPS were mainly composed of galactose and glucose, and to a lesser extent rhamnose, galactosamine and glucosamine. L. delbrueckii subsp. bulgaricus CRL406 and CRL142 secreted polysaccharides composed of galactose. For the first time, EPS from Enterococcus strains were isolated and characterised. EOS of 10 monomers were found for L. casei group strains and two L. delbrueckii subsp. bulgaricus strains. The eps-genetic screening showed that most of these LAB were positive with at least one set of eps primers.
