内蒙古酸马奶中植物乳植杆菌NM18胞外多糖的结构特征

Structural Characteristics of Exopolysaccharide from Lactiplantibacillus plantarum NM18 of Koumiss in Inner Mongolia

摘要:

胞外多糖（Exopolysaccharides，EPS）是具有不同糖残基的高分子聚合物，其在医药、食品、环境等不同领域都有广泛应用。该研究对植物乳植杆菌NM18所产胞外多糖采用乙醇沉淀、阴离子交换法和凝胶过滤层析法进行纯化得到6种组分（EPS-1A、EPS-1B、EPS-2、EPS-3、EPS-4和EPS-5），并对其一级结构进行鉴定。组分EPS-1A、EPS-1B、EPS-2均由甘露糖、葡萄糖和半乳糖组成；组分EPS-3由甘露糖、葡萄糖、半乳糖、鼠李糖、岩藻糖和N-乙酰葡萄糖胺组成；组分EPS-4由甘露糖、葡萄糖、半乳糖、N-乙酰葡萄糖胺组成；组分EPS-5由甘露糖，半乳糖和N-乙酰葡萄糖胺组成，含有微量的岩藻糖及阿洛糖。组分EPS-1A、EPS-1B和EPS-2的甲基化反应结合GC-MS分析表明，组分EPS-1A和EPS-1B糖链主要由→3)-D-Glcp-(1→,→6)-D-Galp-(1→,→4)-D-Glcp-(1→和→6)-D-Manp-(1→组成，末端为Glcp-(1→；组分EPS-2糖链主要由→6)-D-Galp-(1→和→6)-D-Manp-(1→组成，末端为D-Glcp-(1→。组分EPS-1A、EPS-1B和EPS-2的糖苷键构型为α型和β型的混合物。综上，该研究将会为菌株NM18所产胞外多糖的生物活性研究及应用提供理论依据。

Abstract:

Exopolysaccharides (EPSs) are macromolecules with different sugar residues and are widely used in medicine, food, environment, and other fields. In this study, six components (EPS-1A, EPS-1B, EPS-2, EPS-3, EPS-4, and EPS-5) of the exopolysaccharides produced by Lactiplantibacillus plantarum NM18 were purified using ethanol precipitation, anion exchange method, and gel filtration chromatography, and their primary structures were identified. Components EPS-1A, EPS-1B, and EPS-2 comprised mannose, glucose, and galactose. Component EPS-3 comprised mannose, glucose, galactose, rhamnose, trehalose, and N-acetyl-D-glucosamine. Component EPS-4 comprised mannose, glucose, galactose, and N-Acetyl-D-glucosamine. Component EPS-5 comprised mannose, galactose, and N-acetyl-D-glucosamine, and contained trace amounts of fucose and allose. The methylation reaction of EPS-1A, EPS-1B, and EPS-2 combined with GC-MS analysis showed that EPS-1A and EPS-1B carbohydrate chains mainly comprised →3)-D-Glcp-(1→,→6)-D-Galp-(1→,→4)-D-Glcp-(1→ and →6)-D-Manp-(1→, with the terminus being Glcp-(1→. The EPS-2 carbohydrate chains mainly comprised →6)-D-Galp-(1→ and →6)-D-Manp-(1→, with the terminus being D-Glcp-(1→. Components EPS-1A, EPS-1B, and EPS-2 have a mixture of α and β type glycosidic bonds. In conclusion, this study provides theoretical basis for further study and application of the biological activity of exopolysaccharides produced by strain NM18