Study On Extraction And Purification Technology And The Physical-chemical Property Of Polysaccharide From Chaohu Cyanobacteria

Cyanobacteria in Chaohu, mainly composed of Microcystis aeruginosa,Whose percentage composition is more than98%.Lots of toxic or harmful substances are released in the decaying of microcystis aeruginosa.That will seriously damages the water and air of Chaohu.The direct salvage of cyanobacteria is positive and effective measures to control the eutrophication in Chaohu.How to make full use of the salvaged cyanobacteria is one of the problem that people must to face.However, the polysaccharides, proteins and other components contained in cyanobacteria are valuable bio-active components. The successful separation of polysaccharides from cyanobacteria is therefore significant for changing the waste to valuable materials.In this study, the separation of water-soluble acidic polysaccharides from cyanobacteria in Chaohu has been investigated, Orthogonal design method was set up to find optimization of the extracting conditions for polysaccharides from cyanobacteria,which could improve the rate of polysaccharide.Then polysaccharides extracted from the cyanobacteria were isolated and purified,the structural characteristics of the purified polysaccharides were detected and explained.Finally,these activities of polysaccharides on scavenging DPPH radicals, superoxide radicals and hydroxyl radicals were researched. The experimental results were given as follows:1.The extraction processes of crude polysaccharides from cyanobacteria were studied. Orthogonal design method was used to optimize the extracting conditions in order to improve the extraction efficiency and quality of polysaccharides.The final optimization extracting conditions were as follows:the ratio of material to water1:51,leaching time4.3h, leaching temperature53℃.2.Choose method of ammonium sulfate by comparing with two kinds of deproteinization method,ammonium sulfate and savage.The effectiveness of deproteinization of the former is much stronger than the latter,further more,the former is easy and simple to handle and do not produce harmful reagent.More than93%protein of crude polysaccharides can be removed by ammonium sulfate. 3.These crude polysaccharides were fractionated by DEAE-52anion-exchange chromatography.The acidic polysaccharide was obtained by lmol/L NaCl,Then acidic polysaccharides were further purified by gel permeation chromatography on sephadex G150.these homogeneous polysaccharides,CHAP,were obtained.4.Ultraviolet and visible spectrum suggests that the purity of CHAP was high.The mean molecular weight of CHAP was2.209×105.monosaccharide constituents of CHAP are L-arabinose(6.36%),glucose(35.47%),D(+)xylose(5.03%), D-mannose(27.36%),D-galactose(17.09%),and unknown monosaccharide.Infrared spectrum showed that CHAP was main pyranose polysaccharide and had β-glycosidic in its molecule structure,and there was a characteristic absorb peak of a-D-galactopyranosyl in it.Periodate oxidation analysis showed that CHAP mainly had1â†'6linked or contains1â†'2linked or1â†'441inked.5.Several in vivo studies revealed that CHAP were potential free-radical scavengers.The results of antioxidant activity showed that CHAP had a strong ability to scavenge both superoxide anion radicals and DPPH free radicals, with IC50values of186.05μg/mL and276μg/mL.However, almost no scavenging effect against hydroxyl was observed.All that can availably used as profitable data for resource utilization of CHAP.