Abstract: The purified microbial flocculant MBFA₁ was obtained by centrifugation，ethanol precipitation，dialysis，gel permeation chromatography（GPC）and freezing-drying. The composition，content，molecular weight and structure of the microbial flocculant were analyzed by UV，IR，GPC and GC-MS. The results demonstrated that purified MBFA₁ was lemon yellow solid mainly composed of polysaccharides. The content of polysaccharides was 91.2% and protein was 0.59%. The elemental analysis showed that 33.41% of carbon，7.69% of hydrogen，9.63% of nitrogen and 0.39% of sulphur were present in MBFA₁. The mean molecular weight of MBFA₁ was about 1.38×10⁴ determined by GPC. Ultraviolet spectrum revealed that the absorption peak appeared at 199nm in MBFA₁，which may be characteristic of polysaccharides. IR showed that functional groups，such as hydroxyl，amino，carboxyl，hydrogen bond and sulfate，which were beneficial to flocculation，were contained in the structure of MBFA₁. GC-MS indicated that D-glucose dominated the monosaccharide composition，and a small amount of D-arabinose and D-mannose were also present in it with a molar ratio of about 100.7∶1∶8.2.

Key words: microbial flocculant, Aspergillus sojae, purification, composition

摘要： 经离心、乙醇沉淀、透析、凝胶过滤层析及冷冻干燥后获得纯化的微生物絮凝剂MBFA1，并利用紫外、红外、凝胶渗透色谱、气质色谱进行絮凝剂的组分、含量、分子量和结构的分析。结果表明，纯化后的MBFA1为淡黄色，主要成分为多糖类物质，其中多糖含量为91.2%，蛋白质为0.59%。元素分析显示MBFA1中C、H、N、S的含量分别为33.41%、7.69%、9.63%和0.39%。采用凝胶色谱法测得MBFA1的重均相对分子质量约为1.38×104。紫外光谱显示，MBFA1在199 nm处出现了吸收峰值，为多糖的特征峰。红外光谱显示MBFA1中含有羟基、氨基、羧基、氢键、硫酸根等对絮凝有利的基团。GC-MS分析MBFA1主要的单糖构成为D-葡萄糖，并含有少量的D-阿拉伯糖及D-甘露糖，其摩尔比约为100.7∶1∶8.2。

关键词: 微生物絮凝剂, 酱油曲霉, 纯化, 成分