Department of Biotechnology, Indian Institute of Technology, Kharagpur-721302, West Bengal, India.
J Nat Prod. 2011 Aug 26;74(8):1692-7. doi: 10.1021/np1008448. Epub 2011 Jul 29.
An exopolysaccharide (EPS) was isolated from Bacillus coagulans RK-02 and purified by size exclusion chromatography. The purified, homogeneous EPS had an average molecular weight of ∼3 × 10⁴ Da by comparison with FITC-labeled dextran standards. In vivo evaluations showed that, like other reported polysaccharides, this EPS displayed significant antioxidant activity. FTIR spectroscopy analysis showed the presence of hydroxy, carboxy, and α-glycosidic linkages and a mannose residue. GC analysis indicated that the EPS was a heteropolymer composed of glucose, mannose, galactose, glucosamine, and fucose as monomeric constituent units. Partial elucidation of the structure of the carbohydrate biopolymer based on GC-MS and NMR analysis showed the presence of two unique sets of tetrasaccharide repeating units that have 1→3 and 1→6 glycosidic linkages. This is also the first report of a Gram-positive bacterial polysaccharide with both fucose as a sugar monomer and 1→3 and 1→6 glycosidic linkages in the molecular backbone.
从凝结芽孢杆菌 RK-02 中分离出一种胞外多糖 (EPS)，并通过大小排阻色谱法进行纯化。通过与 FITC 标记的葡聚糖标准品比较，纯化的均一 EPS 的平均分子量约为 3×10⁴ Da。体内评价表明，与其他报道的多糖一样，该 EPS 表现出显著的抗氧化活性。傅里叶变换红外光谱分析表明存在羟基、羧基和α-糖苷键以及甘露糖残基。GC 分析表明，EPS 是一种由葡萄糖、甘露糖、半乳糖、葡糖胺和岩藻糖作为单体组成单元组成的杂多糖。基于 GC-MS 和 NMR 分析对碳水化合物生物聚合物结构的部分阐明表明，存在两组独特的四糖重复单元，具有 1→3 和 1→6 糖苷键。这也是首次报道革兰氏阳性细菌多糖具有岩藻糖作为糖单体和分子主链中的 1→3 和 1→6 糖苷键。
