Study On Extracting And Purifying Chinese Traditional Medicine Polysaccharide By Membrane Separation

The industrialization and large-scale clinical application of Chinese traditional medicine polysaccharide are restricted by the comparatively high production costs which results from the complexity and time-consuming process of traditional technology used in separating polysaccharide from natural products.For this problem,seeking for some new separation methods to extract Chinese traditional medicine polysaccharide has became the hotspot of separation engineering reseach.This paper utilized membrane separation into Chinese traditional medicine polysaccharide extraction.The separation process employed the combination of ultrafiltration membrane and nanofiltration membrane to purify oligosaccharides from Rehmannia glutinosa, a process we never noticed in the literatures before.Microfiltration were confirmed as the pretreatment before ultrafiltration through comparing microfiltration with centrifugation. After the selection of content determination of polysaccharide, membrane and membrane module,as well as the optimization of operating conditions, we successfully discovered the pressure of 0.275Mpa,temperature of 36℃,as well as concentration of 0.013g/mL were the optimal conditions of ultrafiltration,and the pressure of 1.03Mpa～1.24Mpa,temperature of 20℃～45℃,as well as volume concentration of 3～6 were the most oppropriate conditions of nanofiltration. Then the gel filtration was employed to determine the molecular weight of oligosaccharides,phenol-sulphate acid method and coomassie brilliant fluka G-250 method were employed to determine the purity of Rehmannia glutinosa oligosaccharides. The result indicated that, the molecular weight of rehmannia glutinosa oligosaccharides were 692Dal and 5777Dal, the removal rate of protein got to 94.15% ; the decolorization ratio , salt rejection rate and ash removal rate were 92.31% ,72.8% , 88.7% ; the purity and yield got to 93.3% and 46.63% .A mathematical model had been developed to portray the traits of the ultrafiltration procedures of polysaccharides extraction from Indigowoad root,with the calculating datas and experimental datas tallied. As a result of a comparison in terms of principles, production process, quality and costs between membrane separation and traditional ones, membrane separation displayed tremendous advantages over ethanol precipitation process in the following aspects, the simplification of process, improvement of product quality, and reduction of environmental contamination, which indicated its glorious future in the industrial utilization.