Exopolysaccharide-producing strains of thermophilic lactic acid bacteria cluster into groups according to their EPS structure.
OBJECTIVE
To compare galactose-negative strains of Streptococcus thermophilus and Lactobacillus delbrueckii subspecies bulgaricus isolated from fermented milk products and known to produce exopolysaccharides (EPSs).


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.


CONCLUSIONS
This information should help in an understanding of genetic exchanges in lactic acid bacteria.
Marshall
V M
VM
Centre for Biomolecular Sciences, University of Huddersfield, UK. v.m.marshall@hud.ac.uk
Laws
A P
AP
Gu
Y
Y
Levander
F
F
Rådström
P
P
De Vuyst
L
L
Degeest
B
B
Vaningelgem
F
F
Dunn
H
H
Elvin
M
M
D002240:Carbohydrate Sequence; D005690:Galactose / Q000378:metabolism; D005838:Genotype; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000235:genetics / Q000378:metabolism*; D008968:Molecular Conformation; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000145:classification; D013291:Streptococcus / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic
D011135:Polysaccharides, Bacterial; C098632:exopolysaccharide, Streptococcus; D019344:Lactic Acid; D005690:Galactose