Preparation And Structural Analysis Of High Molecular Weight Schizophyllan

The exopolysaccharide produced by Schizophyllum commune was selected, and the culture medium and conditions of SPG (Schizophyllan) fermentation was optimized. The progress of isolation, purification of SPG from fermentation broth was studied. The structure of the purified SPG was analyzed.1) The optimal culture and fermentation conditions selected by single factors experiment was following :Glucose is the optimal carbon source and its fitting concentration of glucose was 15%; yeast extract was the optimal nitrogen source and its fitting concentration was 0.8 % ,and the fitting concentration of NH4NO3 was 0.2 % ; phosphate K2HP04 could promote the SPG yield and its fitting concentration was 0.3%;the fitting concentration of MgSO4 was 0.1%;the optimal charge quantity was 100~125 ml culture medium in 500 ml flask, and the optimum temperature was 26~30℃; and shaker rotation speed, 180 rpm; initial pH, 6.5; fermentation time was 132 h. Pao-di as surfactant could modify dissolved oxygen in the fermentation broth and promotion SPG production. The average production of SPG could reach 38.1 g/L.2) The optimized culture medium also used for the batch culture in a stirred-tank fermentor with the impeller speed of 450 rpm after 300 rpm for 48 h.3) The protein was removed by Enzyme-Sevag method after the fermentation broth was decolorized by activated carbon. Then the crude SPG was precipitated with volume anhydrous ethanol in method of ethanol precipitation. The semi-purified SPG1 was purified from this product by column chromatography on Sephadex G-200. The purified SPG1 was identified by the Sephadex G-200, and the ultraviolet spectrum showed that the SPG1 was a unique, homogenous component and its relative molecular weight was 436 kDa.4) The result of GC showed the monosaccharide component sample was glucose. From the result of FT-IR, periodate oxidation, Smith degradation and 13C-NMR analysis, it was concluded that SPG1 has aβ-(1-3)-D-linked glucopyranosyl backbone with a singleβ–D-glucopyranosyl group at O-6.