Study On Liquid Fermentation Of Fermention Of Agaricus Blazei Murill And Bioactivity Of Its Polysaccharides

Agaricus blazei Murill is a kind of fungus that was used for food and medicine. Recently, it has been used an an important nature source of immunomodulators, antimutigens and anticarcinogens. It becoming to be a promising way to develop antitumor polysaccharides, beause fungus submerged fermentation posess characteristics of low-cost and short-period. Because of the lack of wild resources and the diffculties of artificial cultivation, the submerged fermentation technology to produce medicinal fungi have a widest potential application. Some kind of medicinal fungi have been achieven the industrialization of culture in submerged fermentation. Fungal polysaccharide is one of the main active component in medicinal fungi, and has obvious effect on anti-tumor, anti-oxidation, strengthening the body immunity and anti-virus. The fungal polysaccharides research has become one of the development of new drugs. his research systematically study the liquid fermentation conditions, polysaccharide extraction process and its bioactivity in vitro.Single factors tests were used to optimize the sort of nitrogen source, carbon source and metal ions, which were yeast extract, lactose, Na⁺ and Ca²⁺. The Plackett-Burman design was investigated the effect on the dry weight of medium. Three most important factors for dry weight of medium were selected from tatal 8 factors were lactose, yeast extract, magnesium sulfate. The concentration of lactose, yeast extractive, magmesium sulfate in the medium was investigated by the means of the path of steepest ascent tests and Response Surface Methodology. The optimized values were: yeast extractive 17.13 g/L , lactose 29.34 g/L, phosphate potassium 0.3 g/L, magnesium sulfate 0.64 g/L, calcium chloride 0.01 mmol/L, sodium chloride 0.01 mmol/L, vitamin B1 100 mg/L. The maximum dry weight of mycelium of 9.56 g/L was obtained. The flask culture conditions were investigated by single factor tests. It is initial pH 5.0, inoculum age 5 days, inoculum level 7%, liquid volume 60mL, fermentation time 5 days, the mycelium dry weight 14.32 g/L, mycelium polysaccharides production 1.87g/L. Single factor tests and Response Surface Methodology were applied to optimize the hot water extraction and ultrasound extraction conditions of Agaricus blazei Murill mycelium polysaccharides. Extracted temperature, extracted time and ratio of water to sample were chosen as the three factors of hot water extraction in RSM. The optimum hot water extraction conditions were: extracted temperature 94.7℃, extracted time 3.3 h, the ratio of water to sample 62:1. Under the optimum extraction conditions, the extraction rate of polysaccharides reach the value of 16.34%. Ultrasound extracted time, ultrasound power and the ratio of water ro sample were chosen sa the three factors of ultrasound extraction in RSM. The optimum ultrasound extraction conditions were: ultrasound extracted time 184 s, ultrasound power 410W, the ratio of water ro sample 48:1. Under the optimum extraction conditions, the extraction rate of polysaccharides reach the value of 17.44%.MTT assay was used to study the effect of Agaricus blazei Murill polysaccharides on human tumor cells in vitro. The polysaccharides significantly inhibited the proliferation of Hep G2 and Hela in vitro. Bur the polysaccharides couldn't inhibit the proliferation of CNE in vitro. The polysaccharides had certain reduction capacity and were able to remove a certain degree of O2-?. When clearing ? OH , the IC50 was 3.27 mg / mL,as when clearing the DPPH ? the IC50 was 5.66mg/mL.