中文摘要：

液体培养发菜细胞,发菜细胞经去藻体、浓缩、透析、脱蛋白、醇沉、DEAE-52离子交换柱层析分级、Sephadex-100葡聚糖凝胶柱分级处理得到发菜胞外精多糖。以硫酸根的取代度为指标,在单因素试验的基础上,利用Box-Behnken设计进行响应面试验,建立因素与响应值之间的数学模型,确定适宜的发菜胞外多糖硫酸化条件。结果表明,发菜胞外多糖硫酸化修饰最佳条件为反应温度71℃、反应时间3 h、氯磺酸-吡啶体积比1∶7,在此条件下,硫酸化取代度为5.05。红外光谱检测表明,硫酸基团已与多糖分子结合。

英文摘要：

A purified exopolydsaccharide was obtained from the cell-free culture broth of Nostoc flagelliforme cells by concentration,dialysis,deproteinization,alcohol precipitation and sequential column chromatographies on DEAE-52 cellulose and Sephadex-100.By combined use of one-factor-at-a-time method and Box-Behnken response surface methodology,the optimum sulfation conditions for maximum degree of substitution（DS） of sulfate groups in the polydsaccharide（5.05） were obtained as follows： reaction temperature,71 ℃; reaction time,3 h; and chlorosulfonic acid-pyridine ratio,1：7（V/V）.The infrared spectroscopy analysis showed the binding of sulfuric acid groups to the polysaccharide molecule.