摘要
对嗜热链球菌CH9胞外多糖进行分离纯化,经DEAE-52离子交换柱及Sephadex G-100凝胶柱得到单一组分,利用高效液相色谱(HPLC)测其分子质量,结果表明:EPS1a为中性多糖,分子质量为1.8×106u;EPS2a、EPS3a为酸性多糖,分子质量分别为1.06×106、1.05×106u。经琼脂糖凝胶电泳及Sephadex G-100凝胶柱鉴定3种糖均为单一组分。紫外及红外光谱扫描结果显示:3种糖均具有多糖的特征吸收峰,且EPS2a、EPS3a可能为糖与蛋白的复合物。刚果红实验表明:EPS1a具有三股螺旋结构,而其他两种糖并未发现此现象。β消去实验证明:EPS1a、EPS3a为—O—连接,EPS2a为—N—连接。
Crude exopolysaccharides （EPS） isolated from the fermentation supernatant of Streptococcus thermophilus CH9 were fractionated by DEAE-52 column chromatography into EPS1, EPS2 and EPS3. Sephadex G-100 column chromatography was used to further ffactionate the three factions to harvest their respective major components named as EPSla, EPS2a and EPS3a, respectively. EPSla was a neutral polysaccharide with a molecular weight of 1.8×10^6 U, and EPS2a and EPS3a were acidic polysaccharides with a molecular weight of 1.06×10^6u and 1.05 × 10^6 u, respectively. Agarose gel electrophoresis analysis indicated that all these three polysaccharides consisted of a single component. UV and IR spectroscopic analyses showed that all of them had characteristic adsorption peaks of polysaccharide. EPS2a and EPS3a might be polysaccharide- protein complexes. Congo red test revealed that EPSla rather than EPS2a and EPS3a had a three-stranded helix structure. Beta elimination test demonstrated that EPS la and EPS3a were -O-linked, but EPS2a was a -N-linked polysaccharide.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2012年第19期107-112,共6页
Food Science
基金
天津科技大学引进人才科研启动基金项目(20080420)
关键词
嗜热链球菌
胞外多糖
分离纯化
结构分析
Streptococcus thermophilus CH9
exopolysacchurides
purification： structural characterization
