Study On The Extraction And Purification Methods And Basic Properties Of Cyanobacteria Polysaccharides From Chaohu Lake

Use the fresh Cyanobacteria salvaged from Chaohu Lake to achieve high value-added utilization is a hot topic in the study of the utilization of blue algae in Chaohu Lake.The aquatic blue-green algae from Chaohu generally contain more than 20%of Polysaccharides.Polysaccharides are a kind of macromolecular substances with physiological and biochemical activity,and have biological activity such as anti-tumor,anti-inflammation,improving immunity and lowering blood sugar,in food、medicine and other industries are widely used.The study on the extraction methods and basic properties of the Cyanobacterial Polysaccharides from Chaohu Lake can lay a foundation for the deep research of Polysaccharides and also realize the harmlessness and recycling of aquatic blue-green algae,It has double meanings.In this paper,the extraction methods and optimization of crude Polysaccharides from Chaohu Lake were studied.The purification methods and optimization of crude Polysaccharides and the basic properties of Polysaccharides were also studied.Use the ultrasonic-assisted freeze-thaw extract the crude Polysaccharides of the Cyanobacteria and optimized the single factor experimental conditions by response surface analysis;Then,choose the best method of deproteinization:TCA combined enzymatic method.Optimized the single factor experimental conditions by response surface analysis;After that,the best method of decoloring was selected:hydrogen peroxide method.Optimized the single factor experimental conditions by response surface analysis too;Finally,the small molecule impurities were removed by dialysis,and use the freeze-dried obtain the samples of Cyanobacteria.The simple physical and chemical properties of the samples were analyzed and the solubility,stability and antioxidant activity in vitro were also studied.The main results are as follows:The method of ultrasonic assisted freezing and thawing was used to extract the crude Polysaccharides from Chaohu Lake.The best extraction conditions were as follows:ultrasonic power 480W,ultrasonic temperature 65℃,liquid ratio 25:1.Under this extraction condition,the extraction rate of crude Polysaccharide was 6.168%,which was close to the predicted value and the optimization effect was obvious.Compared with the ordinary freeze-thaw extraction,the extraction rate of Polysaccharide increased by 43.44%.The TCA combined enzymatic method was used to deproteinize the crude Polysaccharides.The optimal conditions of deproteinization were as follows:the concentration of enzyme was 1.5%,TCA dosage was 1-fold,the concentration of TCA was 7%,the number of deproteinization was twice,the overall ratings score was 87.96,the protein removal rate and the retention of Polysaccharides were all good.The hydrogen peroxide method was used to decolorize the crude Polysaccharides.The optimum conditions of decolorization were as follows:the dosage of hydrogen peroxide was 19.5%,the decoloring time was 2h,the decoloring temperature was 51℃,the overall ratings score was 84.21,the pigment removal rate and the retention of Polysaccharides were all better.The Cyanobacterial Polysaccharide samples is soluble in water and insoluble in organic solvents such as ethanol,ethyl ether,ethyl acetate,and acetone,and does not contain protein;The solubility is greatly affected by temperature,acidic conditions promote the dissolution of Cyanobacterial Polysaccharides,and alkaline conditions are notfavorableforCyanobacterialPolysaccharidesdissolved;Cyanobacterial Polysaccharides are stable under low temperature conditions,and may be partially decomposed or converted at higher temperatures.Illumination has a certain influence on the stability of Cyanobacterial Polysaccharides;Cyanobacterial Polysaccharides are stable at pH 6-8,while strong acid and strong alkali solutions it is Unstable;Al³⁺、Zn²⁺、Fe³⁺、Cu²⁺these four kinds of metal ions have a certain impact on Cyanobacteria Polysaccharides in Chaohu Lake.Cyanobacteria polysaccharides have a certain reducing power and have certain scavenging effects on the three free radicals·OH、DPPH·、O₂^-·.