影响右旋糖酐比旋度因素的研究

比旋度是右旋糖酐产品的一个重要指标,右旋糖酐生产过程中的蔗糖、果糖、葡萄糖等糖类小分子物质的存在直接影响右旋糖酐产品的比旋度。通过不同分离纯化,不同水解方法等工艺过程来探究影响右旋糖酐产品比旋度的各种因素。同一右旋糖酐水解溶液应用乙醇沉淀法分离纯化时,随着乙醇浓度的增加,比旋度下降;多级乙醇沉淀分离纯化右旋糖酐时,高乙醇浓度高分离得到的右旋糖酐比旋度大于低乙醇浓度的右旋糖酐;粗酐和膜处理右旋糖酐发酵液水解制备的产品品质优于发酵直接水解制备的产品,粗酐和膜处理右旋糖酐发酵液水解液乙醇分级沉淀分离纯化产品比旋度分别为+192.4和+191.9,均达到国家标准,水解液膜分离和乙醇一次性沉淀组合分离纯化产品平均比旋度+194.7,有望达到国际最高标准(+195.0),发酵液直接水解液乙醇分级纯化和乙醇再次沉淀组合分离纯化产品比旋度达到国家标准+190;右旋糖酐的酶解产品品质优于盐酸水解产品品质,产品比旋度+196.6,达到国际最高标准;75%的乙醇洗涤沉淀可以提高产品比旋度,多次洗涤效果更好。

Study on Factors Affecting Specific Rotation of Dextran

The specific rotation is an important index of dextran products. The sugar small molecules such as sucrose, fructose, glucose directly affect the specific rotation of dextran products in the process of dextran production.The influence of dextran product specific rotation of various factors was explored through different separations and purifications, different hydrolysis methods and other technological processes.When the same dextran hydrolysate was separated and purified by ethanol precipitation, the specific rotation decreased with the increase of ethanol concentration. In multistage of ethanol precipitation fractionation, the specific rotation of dextran with high ethanol concentration was higher than that of dextran with low etyanol concertration. The quality of the product prepared by hydrolysis of crude anhydride and membrane treatment fermentation broth was better than that of products prepared by hydrolysis of fermentation byoth. The specific rotation of crude anhydride and membrane treatment fermentation broth hydolysate with ethanol fractionation were +192.4 and +191.9, which met the national standards. The average specific rotation of hydrolysate separated by membrane separation and ethanol one time precipitation was +194.7, which was expected to meet the international standard (+195.0). The specific rotation of the product separated and purified by the combination of ethanol fractionation and ethanol precipitation in direct hydrolysis of fermentation broth reached the national standard +190. The enzymatic hydrolysis product of dextran was better than that of hydrochloric acid hydrolysate, and its specific rotation was +196.6, which reached the international standard. 75% ethanol washing precipitation could improve the specific rotation of the product, and the effect of many times washing was better.