Study On Extraction,optimization,structural Characterization And Antioxidant Activities Of Polysaccharides From Ganoderma Lucidum With Chinese Medicinal Residue

Ganoderma Lucidum,an ancient and precious Chinese medicine,has been included in a pilot list of edible and medicinal products.Modern research shows that polysaccharide is the main active component of G.lucidum,which has various physiological functions.The annual production of Chinese medicinal residues is about 35 million tons,mostly as waste,incineration or landfill.The results showed that 30%of the effective ingredients in the residue were not utilized.The annual output of G.lucidum in Guanxian county accounts for about 40%of the country,but the quantity is large and the price is low,and the added value of the product is not high.Therefore,this thesis developed a G.lucidum fungus package with pharmaceutical residue as the main material.The G.lucidum strain LDM006 was screened and acclimated,and high quality G.lucidum was cultivated.Then the extraction optimization,separation,structure characterization and antioxidant activity of G.lucidum were studied.Firstly,the strain and culture medium suitable for G.lucidum were acclimated and screened.In this study,3 strains isolated by our laboratory and 6 strains purchased from outside were used as the research objects.After acclimation test of first,second and third grade strains,growth and sensory characteristics of G.lucidum were selected as the main screening criteria.The results showed that LDM006（Hanzhi 1,LD-202023.2）was the best strain.It was a new species based on ITS gene sequence.After screening and optimization,the optimal formula of residue medium was as follows:Buxue Yangshen granule residue60%,wheat bran 38%,gypsum 1%,glucose 1%,potassium dihydrogen phosphate 0.4%,and the ratio of water to material was about 1:1.1～1.2.High quality G.lucidum was cultivated on the basis of the best culture medium and strain.Secondly,the extraction method and process of polysaccharide from G.lucidum residues（GLP）were optimized.Four extraction methods（cold water extraction,hot water extraction,acid extraction and alkali extraction）,hot water extraction was the best.Response surface test results showed that the optimal extraction conditions were as follows:liquid-solid ratio 30:1 m L/g,extraction time 2 h,alcohol precipitation time 12 h,and the extraction yield was 1.91%.Thirdly,the polysaccharide of G.lucidum was isolated,purified and characterized.Three kinds of polysaccharides,GLP30,GLP60 and GLP80,were obtained by ethanol concentration classification method.The structure of polysaccharides from G.lucidum and Guanxian G.lucidum were characterized by HPLC,FT-IR and XRD.The results showed that the monosaccharide compositions of polysaccharides obtained by different extraction methods were Fuc,Gal,Glc and Glc A,but their mole ratios were different.Ft-ir showed that the four polysaccharides were all type I pyranose,and XRD showed that they all coexisted in two forms of crystallized and amorphous states,but the proportions of the two states were different.Finally,the antioxidant activities of polysaccharides from G.lucidum were evaluated.The total reducing power,scavenging power of DPPH radical（1,1-phenyl-2-picrhydrazyl）and hydroxyl radical（·OH）were analyzed.The results showed that G.lucidum polysaccharides from four kinds of residues had certain antioxidant activities,but there were significant differences,among which GLP-H had the strongest reducing power,RP_0.5AUwas 1.02 mg/m L.Gl P-A had the strongest scavenging ability of DPPH free radical,EC₅₀was 1.30 mg/m L.Gl P-C had the strongest scavenging ability of hydroxyl radical,EC₅₀was 0.57 mg/m L.Moreover,the antioxidant activity of G.lucidum polysaccharide from medicinal residue was significantly higher than that from xylitol residue.GLP,GLP30,GLP60 and GLP80 all had antioxidant activity,and GLP60 was the highest,which was significantly higher than its precursor GLP-H.This study successfully transferred the remaining active substances of traditional Chinese medicine residues to G.lucidum to produce highly active G.lucidum and provided a theoretical basis for the intensive processing and follow-up research of G.lucidum residues.