Biodiversity of exopolysaccharides produced from sucrose by sourdough lactic acid bacteria.
The distribution and diversity of natural exopolysaccharides (EPS) produced from sucrose by thirty heterofermentative lactic acid bacteria strains from French traditional sourdoughs was investigated. The EPS production was found to be related to glucansucrase and fructansucrase extracellular activities. Depending on the strain, soluble and/or cell-associated glycansucrases were secreted. Structural characterization of the polymers by 1H and 13C NMR spectroscopy analysis further demonstrated a high diversity of EPS structures. Notably, we detected strains that synthesize glucans showing amazing variations in the amount of alpha-(1-->2), alpha-(1-->3) and alpha-(1-->6) linkages. The representation of Leuconostoc strains which produce putative alternan polymers and alpha-(1-->2) branched polymers was particularly high. The existence of glucan- and fructansucrase encoding genes was also confirmed by PCR detection. Sourdough was thus demonstrated to be a very attractive biotope for the isolation of lactic acid bacteria producing novel polymers which could find interesting applications such as texturing agent or prebiotics.
Laboratoire de Biologie appliquée à l'Agroalimentaire et à l'Environnement, Institut Universitaire de Technologie-Université Paul Sabatier, 24 rue d'Embaquès, F-32000 Auch, France.
Marie-Sophie
MS
Bounaix
Valérie
V
Gabriel
Sandrine
S
Morel
Hervé
H
Robert
Philippe
P
Rabier
Magali
M
Remaud-Siméon
Bruno
B
Gabriel
Catherine
C
Fontagné-Faucher
D044822:Biodiversity; D001939:Bread / Q000382:microbiology*; D002236:Carbohydrate Conformation; D004269:DNA, Bacterial / Q000032:analysis; D005285:Fermentation; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D007934:Leuconostoc / Q000201:enzymology / Q000378:metabolism*; D056584:Leuconostocaceae / Q000201:enzymology / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D016133:Polymerase Chain Reaction; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D013395:Sucrose / Q000378:metabolism*
D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D013395:Sucrose; D016695:Glycosyltransferases; C033837:alternansucrase