| Polysaccharide is an important class of biologically active substances which has very broad application prospects in the field of human, animal and plant health care, animal breeding, pest control, crop cultivation. Modern medical researchs have found that mushroom polysaccharide, the physiologically active substances in edible fungi and easily separated from mushroom, can significantly enhance the patients’ resistance to cancer and whose toxicity is very small. Compared with plant polysaccharides, the polysaccharides in edible and medicinal fungi has the features, such as short production cycle, the stable yield and quality, higher performance to price ratio and some special effects-immunomodulatory, antiviral, antitumor, antioxidant, reduce blood lipids, anti-thrombosis while other polysaccharides don’t have.Lepista sordida is not large-scale artificially cultivated yet, whose fruiting body is rich in nutrients such as amino acids and carbohydrates, and the species of mineral composition.According to reports, the contents of trehalose in Lepista sordida fruiting body is 8.34%, more than other common edible mushrooms apparently. This test studied the law of accumulation of Lepista sordida’s intracellular polysaccharide and trehalose and the change of enzyme activity, and made a preliminary exploration for the future comprehensive development and utilization of edible fungus polysaccharides and trehalose resources. In addition, this test studied the physicochemical properties and the monosaccharide composition of intracellular polysaccharide.These reseach provided a theoretical basis and help for industrial production Lepista sordida’s intracellular polysaccharide and development of products of Lepista sordida’s polysaccharide.The test result are as follows:①The intracellular polysaccharide’s deep fermentation liquid optimal level combination was Sucrose 20g, yeast extract 4g, pH=7, the concentration of CuSO4 1.5 ×10-4g/100mL, water 1000 mL, strain age 12d. The dry biomass can be achieved 1.13g/100ml and the content of intracellular polysaccharide in wet mycelium is 24.72%, wich is higher than the fruiting bodies.②When the N content is high, It is conducive to the growth of the mycelium. With the rise of the C content, It is beneficial to the accumulation of intracellular polysaccharide. Monosaccharide is not conducive to the growth of mycelium, and Mycelium can be a good use of corn flour. When the mass concentration of corn flour increased to 25g/L, The intracellular polysaccharide production began to decline. It is because of Corn flour’s low solubility and high viscosity resulting in a decline in dissolved oxygen in medium, mycelial growth has been hampered. The carbon source is the decisive factor of the intracellular polysaccharide production in Lepista sordida mycelium.③As with other edible fungi, such as Ganoderma lucidum, Grifola frondosa, Agaricus blazei Murill, its mycelium can make better use of organic nitrogen than inorganic nitrogen. Trace element and pH value on mycelial growth and the Intracellular polysaccharide Accumulations have a smaller impact. It was better that the strain age was 8d to 12d.④The pure Intracellular polysaccharide of Lepista sordida is White powdered, Odorless, Soluble in water but not in organic solvent, such as ether and acetone,95% ethanol etc. It’s a kind of non-reducing polysaccharide and does not contain a protein component. The monosaccharides group is divided into glucose, xylose and mannose. And the main Composition is glucose.⑤The Lepista sordida mycelium trehalose liquid fermentation excellent level combination was sucrose 20g, yeast extract 4g, pH=7, the final concentration of CUSO4 1.5×10-4g/100mL, water 1000mL, strain age 12d.Trehalose content in the wet mycelium was 19.02%, significantly higher than the content of trehalose in the body.⑥Monosaccharide is not conducive to the Lepista sordida mycelium trehalose liquid fermentation. Using glucose as the carbon source for liquid fermentation resulted in that trehalose content was the lowest. The trehalose content of the mycelial body was higher when The Mycelium using organic nitrogen sources-yeast extract, peptone-to liquid fermentation than using inorganic nitrogen as a nitrogen source. trace elements had Less impact on liquid fermentation of trehalose. The strain age is the decisive factor of the trehalose production in Lepista sordida mycelium.⑦The Maximum yield of intracellular trehalose and polysaccharide in Lepista sordida mycelia appeared in the 12d, that is to say in stationary phase, the yield be maximized. Accordingly, we can extract both trehalose and polysaccharide in stationary phase, so as to achieve the comprehensive utilization of Lepista sordida mycelia.⑧Different carbon sources, nitrogen source, fungus age have certain effect on extracellular enzyme activity, but do not change the change rule of enzyme activity. Hyphae of Lepista sordida would be easier to absorb and utilize organic carbon sources, organic nitrogen source, the corresponding enzyme activity also can increase. It can be explained by that mycelia biomass and sugar yield have a certain correlation. But pH value, trace elements have little influence on enzyme activity. |
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