微生物絮凝剂ZS-7的纯化及其结构特征研究

采用透析、乙醇沉淀、凝胶过滤层析对微生物絮凝剂ZS-7进行了纯化.经鉴定纯化后的微生物絮凝剂ZS-7是一种新型的糖蛋白,其产量大约为0.98 g/L发酵液.ZS-7主要由多糖和蛋白质组成,含量分别为91.5%和8.4%.进一步的分析表明ZS-7中含有酸性多糖包括糖醛酸(16.4%)、丙酮酸(7.1%)和乙酸(0.5%).采用凝胶色谱法测得ZS-7的相对分子质量为6.89×104.红外光谱、X射线能谱图和核磁共振图谱说明糖蛋白絮凝剂ZS-7含有羟基、氨基、羧基、甲氧基和磺酸等功能性基团.单糖组成分析说明ZS-7主要由鼠李糖、甘露糖、葡萄糖和半乳糖组成,各单糖的摩尔比大致为:半乳糖∶葡萄糖∶甘露糖∶鼠李糖=142∶2.2∶4.5∶3.4.

Study on Structural Characterization and Purification of Bioflocculant ZS-7

The bioflocculant ZS-7 was purified to homogeneity by ethanol precipitation, dialysis and gel permeation chromatography (GPC). About 0.98 g of the purified bioflocculant could be recovered from 1L of fermentation broth. The purified bioflocculant was identified as a glycoprotein consisting of polysaccharide (91.5%) and protein (8.4%), with an approximate molecular weight of 6.89 x 10(4). The major component of ZS-7 is an acid polysaccharide including uronic (16.4%), pyruvic (7.1%) and acetic acids (0.5%). It consists of galactose, glucose, mannose and rhamnose in a molar ratio of 142 :2.2 : 4.5 : 3.4. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) and NMR spectrum of the bioflocculant indicate the presence of carboxyl, hydroxyl, amide, amino, methoxyl and sulfate groups.