Solid Fermentation Of Ganoderma Lucidum Polysaccharides And Preliminary Studies On The Hypoglycemic Effect

Ganoderma lucidum polysaccharides is one of the main effective ingredients inGanoderma lucidum, which has been proved to have effect on anti-tumor, immuneregulation, antilipide, hypoglycemia, antioxygen and anti-senility. It has been widelyapplied in medicine, food, cosmetic and clinical therapy. At present, the production ofpolysaccharides was mainly based on log-cultivated fruitbodies method anddepths-layer-culture technology.This study was to produce Ganoderma lucidum polysaccharides effectively by solidstate fermentation. In comparison with conventional log-cultivated fruitbodies method, ithas the advantages of easy manipulation and high production with the same equipments.In comparison with liquid fermentation, it has the advantages of less investment on spaceand equipments, lower risk, comfortable taste, more accumulation of secondarymetabolites and broader culture medium source.Using phenol-sulphuric acid method to detect the contents of polysaccharides, theextraction of the water-soluble polysaccharides from Ganoderma Lucidum mycelium wasstudied. The optimum extraction conditions were determined by single-factor test andorthogonal test. The results showed that the optimum extracting temperature, time, ratioof mycelia to water （w:v） and extracting times were 85℃, 50 min, 1:70 and 1 timerespectively. And the optimum alcohol-extracting concentration was 90%.Aiming to high production of Ganoderma Lucidum polysaccharides, it wasconfirmed that the solid fermentation medium was A:B=1:4 with two-two compoundexperiments of A, B, bran, cassava residue and konjak powder. And there was no effect onpolysaccharide production by adding any one of nine saccharides （glucose, maltose,saccharose, lactose, starch, pectin, D-xylose, mannose, fructose） and three salts（KH₂PO₄、K₂HPO₄、MgSO₄） to solid fermentation medium.Response surface methodology （RSM） design was used to design and evaluate theexperiment. The solid medium A: B, best ratio of medium to water r （w: v）, inoculationvolume and fermentation time were confirmed to be 7.6: 23.1, 1:2, 10% and 12d. Underthe optimal conditions, the production of Ganoderma Lucidum polysaccharides andmycelium can reach 160 mg/g dry mycelium and 15.6%.GLPâ… ₅₀ which occupied 81.74% of total polysaccharides was isolated and purifiedfrom Ganoderma Lucidum mycelium polysaccharides by Sephadex G-25, alcoholfractional precipitation and Sephadex G-200. And the molecular weight andmonosaccharide composition of GLPâ… ₅₀ was determined by Sephadex G-100 gel filtration chromatography and thin-layer chromatography. The result showed that GLPâ… ₅₀ wascomposed of glucose and galactose, and its molecular weight was around 185 000 Dawhich was the average of a spectrum from 54 000 Da to 301 000 Da.Using alloxan-induced diabetes mice model, the effect of Ganoderma Lucidumpolysaccharides GLPâ… ₅₀, mycelium, and solid substrate on diabetes and normal micewas studied. Results showed that after alloxan inducing, the levels of blood glucose （BG）in normal mice were increased obviously （p＜0.05）. But the mice BG level would becontrolled significantly （p＜0.05） if treating the mice with GLPâ… ₅₀, mycelium, and solidsubstrate, even after stopping treating. And no obvious toxicity of GLPâ… ₅₀ was found tonormal mice.