Studies On Extraction Technology Of Extra-cellular Polvsaccharides(EPS) From Fermentation Cordyceps Sinensis

Polysaccharides are important active ingredients in Cordyceps sinensis, also named Dong Chong Xia Cao, which is one of the most valuable medicinal fungi and has been used for over 2000 years in traditional Chinese medicine. In our study, a convenient system of extraction and purification of polysaccharides from fermentation Cordyceps sinensis filtrate has been established. And we also studied the theoretical basis for industrial applications.Firstly, based on the classical phenol-sulphuric acid method, we established the analytical system of polysaccharides. It was concluded that the compound could be quantified easily by spectrophotometric method at 486nm and the linear regression equation was y=0.0105x-0.0133 in the range of 0-107 μg/ml. The colored complex remained stable in 3 hours. The relative standard deviation (RSD) of absorbance and purity was 0.01% and 0.44% respectively, and the average recovery was 99.26% in 6 times of repetitious experiments.The influences of the conditions of nanofiltration and ethanol precipitation for preparation of polysaccharides were investigated. Results indicated that the optimal conditions for separate starches were as follows:pH>5, the volumetric ratio of enzyme and filtrate 4 μl/L, reaction temperature 25℃, reaction time 40min. Comparing various kinds of resins, We chose the type CT151 of resin for separate the pigment and protein. The optimized reaction conditions were as follows: concentration of polysaccharides 2mg/ml, the ratio of polysaccharides and resin 72: 1(mg/g), temperature 20℃, time 60 min. After the pilot scale experiment, under the operating conditions we obtained the polysaccharides with the yield of 1.5 g/L and the purity was above 50% at the same time.Secondly, we adopted the cellulose chromatograph to purify EPS and obtained three constituents:a single polysaccharide EPS1, polysaccharides mixture with a small amount of pigment and protein EPS2, polysaccharides contains numerous pigment EPS3. The weight-average molecular weights of the three types of polysaccharides were 5642,21811and 27371 respectively after analyses.