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

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。

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 combinedwith 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 ofαandβtype glycosidic bonds.In conclusion,this study provides theoretical basis for further study and application of the biological activity of exopolysaccharides produced by strain NM18.