12 research outputs found
?-Fructofuranosidase activity in disaccharide transport mutants ofStreptococcus thermophilus
Influence of fermentation time, cryoprotectant and neutralization of cell concentrate on freeze-drying survival, storage stability, and acid and bile exposure of Bifidobacterium animalis ssp. lactis cells produced without milk-based ingredients
Glucose metabolism and internal pH of Lactococcus lactis subsp. lactis cells utilizing NMR spectroscopy
Exopolysaccharide-producing strains of thermophilic lactic acid bacteria cluster into groups according to their EPS structure
Aims: To compare galactose-negative strains of Streptococcus thermophilus and Lactobacillus delbrueckii subspecies bulgaricus isolated from fermented milk products and known to produce exopolysaccharides (EPSs).
Methods and Results: The structures of the EPSs were determined using nuclear magnetic resonance (NMR) and their genetic relationships determined using restriction endonuclease analysis (REA) and random amplification of polymorphic DNA (RAPD). Similar groupings were apparent by REA and RAPD, and each group produced an EPS with a particular subunit structure.
Conclusions: Although none of the strains assimilated galactose, all inserted a high proportion of galactose into their EPS when grown in skimmed milk, and fell into three distinct groups.
Significance and Impact of the Study: This information should help in an understanding of genetic exchanges in lactic acid bacteria