Structural characterization of the surface-associated heteropolysaccharide of Lactobacillus plantarum TMW 1.1478 and genetic analysis of its putative biosynthesis cluster

• Published in: Carbohydrate polymers Vol. 202; pp. 236 - 245
• Main Authors: Prechtl, Roman M., Wefers, Daniel, Jakob, Frank, Vogel, Rudi F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.12.2018
• Subjects: Biosynthesis; Carbohydrate Conformation; DNA, Bacterial - genetics; Gene cluster; Heteropolysaccharide; Kinetics; Lactobacillus plantarum; Lactobacillus plantarum - chemistry; Lactobacillus plantarum - cytology; Lactobacillus plantarum - growth & development; Methylation analysis; NMR spectroscopy; Polysaccharides - biosynthesis; Polysaccharides - chemistry; Polysaccharides - genetics; Surface Properties; Gene cluster; Biosynthesis; Lactobacillus plantarum; NMR spectroscopy; Heteropolysaccharide; Methylation analysis
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2018.08.115

[Display omitted] •L. plantarum TMW 1.1478 produces a cell-wall associated heteropolysaccharide (HePS).•The HePS displays an average Mr of 2 × 106 and an RMS radius of 60 nm.•The acetylated, heptameric repeating unit contains glucose, rhamnose and galactose.•Identification of the HePS biosynthesis cluster suggests a Wzy-dependent synthesis.•The modular organization of the cluster confirms its molecular structure. Microbial exopolysaccharides (EPS) like xanthan are widely exploited as natural biopolymers in diverse industrial sectors. In foods, in-situ EPS formation by starter cultures allows the manufacturing of “clean labeled” products with improved textural and nutritional properties. We performed structural analyses of the cell surface-associated EPS produced by Lactobacillus plantarum TMW 1.1478, which is a promising starter culture for fermented foods. Chromatographic analyses and NMR experiments suggested an acetylated heptameric repeating unit comprised of glucose, rhamnose and galactose as major components, whereas analysis of the macromolecular HePS structure suggested an apparent molecular mass of Mr ∼2 × 106 and a root mean square (RMS) radius of ca. 60 nm. Genetic analyses enabled the identification of the respective EPS biosynthesis cluster, and its modular organization supports the chemically identified, novel EPS structure. The obtained results broaden the understanding of complex EPS formation from activated sugar nucleotides by Lactobacillus plantarum.