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Title

Structural characterization of the exocellular polysaccharides produced by Streptococcus thermophilus SFi39 and SFi12

Authors
Lemoine, Jérôme
Chirat, Frédéric
Wieruszeski, Jean-Michel
Strecker, Gérard
Published in Applied and Environmental Microbiology. 1997, vol. 63, no. 9, p. 3512-3518
Abstract We investigated the structures of the exopolysaccharides (EPSs) produced by Streptococcus thermophilus SFi39 and SFi12. Both polymers were found to have molecular masses of greater than 2 x 10(6) Da. The SFi39 EPS consisted of D-glucose and D-galactose in a molar ratio of 1:1, whereas the SFi12 EPS was composed of D-galactose, L-rhamnose, and D-glucose in a molar ratio of 3:2:1. Methylation analysis of and nuclear magnetic resonance spectra recorded from the native polysaccharide, as well as oligosaccharides released by partial acid hydrolysis, allowed the complete structural determination of the SFi39 EPS, which consists of the following tetrasaccharide repeating unit: [formula: see text] Similar spectra recorded only from the native polysaccharide were sufficient to allow the structural determination of the SFi12 EPS, which consists of the following hexasaccharide repeating unit: [formula: see text] This study shows that the texturizing properties of different S. thermophilus ropy strains are based on the production of EPSs exhibiting chemical similarities but structural differences.
Keywords Carbohydrate ConformationCarbohydrate SequenceMagnetic Resonance SpectroscopyMolecular Sequence DataMolecular StructureMolecular WeightPolysaccharidesBacterial/biosynthesis/chemistrySpecies SpecificityStreptococcus/chemistry/metabolism
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PMID: 9293002
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LEMOINE, Jérôme et al. Structural characterization of the exocellular polysaccharides produced by Streptococcus thermophilus SFi39 and SFi12. In: Applied and Environmental Microbiology, 1997, vol. 63, n° 9, p. 3512-3518. https://archive-ouverte.unige.ch/unige:82714

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