酱油曲霉产微生物絮凝剂MBFA_1的纯化及成分分析

Study on the purification and composition analysis of microbial flocculant MBFA_1

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。

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.