B群链球菌荚膜多糖抗原的分离纯化工艺研究

The isolation and purification of the capsular polysaccharide from group B streptococcus

目的为提高荚膜多糖抗原得率，降低荚膜多糖中残余蛋白质含量和核酸含量，提高荚膜多糖抗原纯度．优化B群链球菌荚膜多糖的提取纯化工艺条件。方法研究pH值，沉淀核酸和荚膜多糖的乙醇浓度，乙醇沉淀多糖所需的温度和时间；比较蛋白酶K法、sevag法和冷酚抽提法去除荚膜多糖中杂蛋白质的效果。结果建立起25％乙醇沉淀去核酸。冷酚抽提法去蛋白质分离纯化荚膜多糖，55％乙醇沉淀多糖的方法。3批GBSⅢ发酵液中获得的荚膜多糖的唾液酸含量为12．4％～14.8％；分配系数（Kav）≤0．5的多糖回收率达90％以上；荚膜多糖得率为0．021～0．027g/L，抗原纯度较高。结论从发酵液中提取纯化荚膜多糖抗原的工艺是可行有效的。

Purpose In order to develop an economic and effective method for isolation and purification of the capsular polysaccharide（CPS） from group B streptococcus（GBS）. Methods The following experiment were conducteds： pH control of fermentation, the concentration of ethanol for CPS extraction and nucleic acid precipitation, the temperature and time of ethanol precipitation and the times of protein extraction with cold phenol. Results The CPS of type Ⅲ GBS was obtained, then the guantitative determination of residue protein and nucleic acid was performed and the guantitative determination of sialic acid and yield rate as Kav ≤ 0.5 in CPS was conducted. Conclusion Results have shown that the purification process is effective and feasible for scale up.