Lehrstuhl für Technische Mikrobiologie, Technische Universität München (TUM), Freising, Germany.
Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Carbohydr Polym. 2018 Dec 15;202:236-245. doi: 10.1016/j.carbpol.2018.08.115. Epub 2018 Sep 1.
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 M ∼2 × 10 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.
微生物胞外多糖（EPS），如黄原胶，被广泛用作各种工业领域的天然生物聚合物。在食品中，通过启动培养物原位形成 EPS，可以制造具有改善的质地和营养特性的“清洁标签”产品。我们对植物乳杆菌 TMW 1.1478 产生的细胞表面相关 EPS 进行了结构分析，该菌是发酵食品中很有前途的启动培养物。色谱分析和 NMR 实验表明，主要成分是由葡萄糖、鼠李糖和半乳糖组成的乙酰化七聚体重复单元，而大分子 HePS 结构的分析表明，表观分子量 M∼2×10，均方根（RMS）半径约为 60nm。基因分析使 EPS 生物合成簇的鉴定成为可能，其模块化组织支持化学鉴定的新型 EPS 结构。所得结果拓宽了对植物乳杆菌利用活化糖核苷酸形成复杂 EPS 的理解。
