Study On Extraction And Purification Of Polysaccharide From Sargassum Fusiforme

Sargassum jusiforme(Harv.) Setchel is one of the plentiful brown seaweeds in east China sea. Its various biological activities (antitumoral, anticoagulant, antiviral, antioxdative, hypoglycemic and so on) have been reported in the literature. To make best use of the precious marine resources, the methods of extraction and purification of polysaccharide (SFP) from Sargassum fusiforme were studied in this paper.Three methods for extraction of SFP are discussed. The conditions of extracting SFP by boiling water, acid water and cellulase were investigated, result shows the optimum extraction temperature of enzymatic treatment is 50℃ optimum time is 3hr, optimum pH value is 3.0, add cellulase (16000U/g ) 8%, pectinase (20000U/g) 4%. The optimum extraction temperature of boiling water treatment is 102℃, optimum time is 3hr, weight of material: weight of water=l :40. Enzyme and high temperature extraction was combined to improve the low extraction rate of acid extraction and neutral boiling water extraction, and the yield could attain 14.88%. The best experiment factors are received Cellulase (16000U/g ) 8%, pectinase (20000U/g) 4%, pH3.0, weight of material : weight of water=1:40. The time of enzymolysis 3hr> the time of extraction 3hr the temperature of extraction 120℃. Compared with other extraction methods,enzymatic treatment made yield of polysaccharide increasing 117.23% and up to 75.06%, which was higher than the method of four time extractions mentioned in literaturesSeveral methods includeing, Sevag method, enzyme decomposition with Sevag method, trichloroacetic acid(TCA) sedimentation, ultrafiltration , anion and cation exchange resin chromatography were studied to remove the protein in the SFP. Based on experimental results and general consideration, it was suitable to adopt using anion and cation exchange resin in series chromatography once. After that, 91.76% protein of crude polysaccharides could be removed, the recovery rate of polysaccharide was 92.56%, and the ratio value of polysaccharides content to protein content was up to 42.27.Then after dialysis and freeze dryness, light yellow powder was produced. In this powder, polysaccharide and protein content was 90.27% and 3.15%.Higher molecular and lower molecular weight sections were gained by using Sephadex G-200 gel chromatograph. Then a polysaccharide fraction containing 1.5% protein was gained by Sephacryl S-400 chromatographing to the higher molecular. The purity of this fraction was proved by HPGPC and its molecular was more than 2×106 dalton and was named F1. The portion of F1 was 28.45% of fine polysaccharides. And the low molecular weight was chromatographed by Sephadex G-100 gel filtration, and three fraction f1, f2, f3 were gained , the molecular weight of them was 8.2×104(37.4%), 5.6×104 (15.1%), 1.4× 104(47.5%), the weight ratio was 38.2%, 16.1%, 45.7% separately.In this paper, purified powder of SFP was obtained by isolated protein in rude SFP effectively. The research offers some scientific basis for producing healthy foods and medicines. It provides theoretical foundation for industrialization of extraction and isolation polysaccharides from Sagasssum fusiforme.