Liquid Fermentation And Antioxidant Research Of Lycium Barbarum Polysaccharides

[Objective]To study the technology of polysaccharide production through Liquid-state fermentation of Poria cocos,and to optmize the best culture conditions for Liquid-state fermentation,Extract intracellular and extracellular polysaccharide from fermentation production,and conduct antioxidant activity in vitro.[Methods]1.Single factor optimization study:Extracting polysaccharide through water extracting and alcohol precipitating method,the dry weight of mycelium as well as intracellular and extracellular polysaccharide are treated as investigative indicators,the best carbon source,nitrogen source,the optimum PH value for the fermentation broth,the optimum metal ion and accessory factors and appending conditions are all worked out by optimization.2.The amplification study on fermentation cylinder:Cultivation in fermentation cylinder under the conditions that was acquired from single factor optimization,and study the dry weight of mycelium,intercellular polysaccharide,extracellular polysaccharide,PH value of the fermentation broth and the time-dependent changes of dissolved oxygen.3.Antioxidation research in vitro:by separation and extraction from fermentation cylinder,intracellular and extracellular polysaccharide were obtained,VC and Tuckahoe as contrast,we studied the pachymaran in term of its hydroxyl radical in vitro,DPPH free radicals,free radical scavenging activity of superoxide anion free radicals.[Results]1.Glucose as carbon source,yeast extract powder as nitrogen source,in the liquid-state fermentation system with initial fermentation broth at pH 5,0.01 g/L of sulpho-barbituric acid was added as cofactor,which can definitely promote cell growth of Poria cocos as well as the synthesis of intracellular and extracellular polysaccharide.Meanwhile,the addition of MnSO₄,CuSO₄ can obviously promotethe synthesis of extracellular polysaccharide,while the addition of MgSO₄,CuSO₄,FeSO₄,ZnSO₄ can promote the synthesis of intracellular polysaccharide markedly.2.For liquid-state fermentation and culture in 6 L fermentation cylinder,biomass of Poria cocos,the contents of intracellular and extracellular polysaccharide reached maximizing at 11th day,the results were 3.44 g/L,17.25 mg/g,1.58 g/L respectively.During course of fermentation,the initial PH of Poria cocos fermentation broth,the dissolved oxygen value presented a time-declining trend with the cell growth and accumulation of products,and tended to be stable at the 11^th day.3.Anti-oxidation experiment in vitro showed that pachymaran acquired from liquid-state fermentation system have obvious anti-oxidation activity in vitro.At concentration of 1 g/L,intercellular polysaccharide showed the clearance rate for hydroxyl radical,DPPH free radicals as well as superoxide anion were 32.07%,90.12%,39.74%,and as for extracellular polysaccharide the clearance rate were16.40%,87.35%,26.02%respectively.The FTIR spectral analysis shows that the structure differences from three kinds of polysaccharides is not obvious,but the intracellular polysaccharide may contains mannan glycosidic bond.It may be the main structural features of intracellular polysaccharide lead to higher antioxidant activity.[Conclusions]The production of pachymaran through liquid-state fermentation from Poria cocos is reasonable and practicable.Through the amplification of fermentation cylinder,we can obtain a large amount of polysaccharide products with preferable antioxidant activity in vitro.