Optimizing Liquid Cultural Conditions Of Stropharia Rugoso-annulata Accumulated Selenium And Studies On Its Antioxidative Activities

Selenium (Se) is an essential bio-trace element for human, animals and some microorganisms. In human and animal bodies it acts as a component of glutathione peroxidase (GSH-Px) to break chain reaction of lipid peroxidation by catalyzing peroxide decomposition and scavenging some organic hydroperoxides, such as nucleic hydroperoxide and thimine hydroperoxide, et al., so as to maintain the integrity of structure and function of biomembrane. Stropharia rugoso-annulata (King Stropharia or Winecap) is a gorgeous, nutritional and functional mushroom with a pleasant refreshing taste of delicate fragrance, crisp and slightly sweet, and is now being cultivated in several different countries. Its fruitbodies contain high protein levels, with all the essential amino acids and other elements, such as minerals, vitamins and polysaccharides. This mushroom can be used in the bioremediation of contaminated explosives. Therefore, cultivating this mushroom will benefit food provision and recycling of agricultural by-products.In this study, optimization of liquid culture medium components and fermentation conditions to produce exopolysaccharides (EPS) was carried out with hypha biomass and EPS content as target. The results showed that maltose and yeast extract were the optimum carbon and nitrogen sources respectively. Orthogonal experiment has conformed the optimum medium was potato 150 g/L, maltose 20 g/L, yeast extract 1 g/L, KH2PO4 1 g/L, MgSO4·7H2O 2.5 g/L. The optimum liquid cuture conditions were initial pH 6.5, 160 r/min, 6 days of the fermentation time, 10% of inoculation volume, fermentation temperature 28°C and 100 mL liquid medium per flask. Under these conditions the output of hapha biomass and EPS increased by 31.8%, and 51.6% respectively as compared with the control.Some edible mushrooms have the ability of transformation of inorganic selenium in the medium into organic selenium. Polysaccharides containing selenium extracted from edible mushrooms are compounds of organic selenium. And they have the biological activities of both inorganic selenium...