Fermentation,Extraction And Bioactivity Studies On The Polysaccharide From Tremella X-18

Tremella fuciformis is a medicinal and edible homologous fungus in China,and its polysaccharide can effectively fight tumor,anti-inflammatory and antioxidant effects.In this study,an excellent strain Tremella fuciformis X-18 was selected from the existing 5strains of Tremella fuciformis.After optimization of liquid fermentation conditions,extraction,separation and purification of Tremella fuciformis polysaccharide,composition and antioxidant exploration of Tremella fuciformis polysaccharide,data support and theoretical basis were provided for the realization of the fermentation production of Tremella fuciformis polysaccharide.Key results include:(1)Through plate culture method and shaking flask fermentation experiment,the best and simplest raw materials for Tremella fuciformis X-18 fermentation polysaccharide are glucose and soybean milk.The medium formula and culture conditions were as follows:glucose 4.0 %,soybean milk 4.0 %,p H 6.5,fermentation temperature 26 ℃,shaking speed150 rpm,fermentation time 6 days,the total polysaccharide content was up to 12.15 g/L under these conditions.(2)The optimal fermentation conditions of Tremella polysaccharide in a 20 L fermentation tank were determined by using a small test.Under the conditions of fermentation for 144 h,the total polysaccharide content was 12.04 g/L,and the extracellular polysaccharide content was 4.52 g/L.The results showed that the total polysaccharide content was 12.04 g/L and the extracellular polysaccharide content was4.52 g/L.The maximum content of total polysaccharide reached 16.10 g/L after 144 h fermentation in a 100 L fermenter.When tremella tremella X-18 was fermented in 1000 L tank for 144 h,the contents of total polysaccharide and extracellular polysaccharide were21.86 g/L and 6.43 g/L,respectively.(3)The single factor test was used to determine the extraction mode and technological parameters of tremella fuciformis polysaccharide.The results showed that the polysaccharide content and polysaccharide yield of Tremella fuciformis polysaccharide reached 50.62% and 9.85% under the conditions of ultrasonic cleaning power 80 W,ultrasonic extraction for 2 h and extraction temperature 80 ℃.(4)D101 macroporous resin was used to adsorb impurities in Tremella fuciformis.The optimal adsorption temperature was 28 ℃ and adsorption time was 2 h.Under these conditions,the decolorization rate of polysaccharide was 61.09 %,the protein removal rate was 81.09 %,and the polysaccharide retention rate was 72.40 %.(5)Ttremella polysaccharide by hydrochloric acid and enzyme hydrolysis and efficient hydrolysis derivative liquid chromatography(HPLC)analysis of the product and enzymolysis products of Tremella polysaccharide mainly for alpha 1,4 glycosidic bond is given priority to,followed by glycosidic bond beta 1,4-wood,followed by alpha 1,6-glucoside keys,beta 1,4-glucoside keys,beta 1,3-glucoside keys and beta 1,4-glucoside keys.The mass fractions of glucose,xylose,arabinose and glucuronic acid in tremella fuciformis polysaccharide were 33.85%,33.02%,29.62%,2.37% and 1.14%,respectively.(6)The total reducing power,DPPH radical scavenging ability,hydroxyl radical scavenging ability and Fe2+ chelating ability of Tremella fuciformis polysaccharide were measured.The antioxidant activity of tremella fuciformis polysaccharide increased with the increase of polysaccharide concentration.When the polysaccharide concentration was 5mg/L,the total reducing power of polysaccharide was 0.632,and the hydroxyl radical scavenging rate was 49.78%.DPPH free radical scavenging rate was 60.18% and Fe2+chelating rate was 42.85%.Its antioxidant activity is lower than that of vitamin C at the same concentration.