Study On The Selenium Enrichment Physiological Characteristics And Selection Of Se-polysaccharide Liquid Fermentation Conditions For Agrocybe Cylindracea

Selenium is one of the essential trace elements, which can form the center of many oxidases activity, enhance the body’s antioxidant activity and resist diseases. Selenium has physiological functions of anti-cancer, anti-aging, enhancing immunity, etc. As an organoselenium compounds, se-polysaccharide has both the activity of polysaccharide and selenium. Se-polysaccharide is one of the effective forms, which organisms turn inorganic selenium into organic selenium. Studies have shown that the biological activity of se-polysaccharide is generally higher than polysaccharide and selenium. Se-polysaccharide is also easier to absorbed and used by the body. Agrocybe cylindracea has the functions of anti-aging, lowering cholesterol, improving human immunity, enhancing human disease prevention and anti-cancer. This study wanted to make use of Agrocybe cylindracea as a carrier to study its enrichment of organic selenium physiological characteristics and se-polysaccharide fermentation conditions. Not only it could provide a theoretical basis of edible fungi absorbing and using trace elements, but also it could provide a new way for the future of human organic selenium supplement.This test was on the basis of determining the best concentration of Sodium Selenite, optimized the Agrocybe cylindracea enriching selenium liquid fermentation medium and liquid culture conditions, screened Agrocybe cylindracea producing se-polysaccharide liquid fermentation medium and liquid culture conditions, established Agrocybe cylindracea enriching se-polysaccharide and transforming organic selenium liquid culture system. This test also preliminarily studied Agrocybe cylindracea enriching selenium physical and chemical basis, the impact of selenium on mycelia extracellular enzyme activity. This study wanted to know and understand the mechanism of Agrocybe cylindracea conversion of organic selenium from the metabolism, which could provide a theoretical foundation for the mechanism of edible fungi conversion of organic selenium. The results were as follows:①Sodium Selenite concentrations was5mg/L, in this condition mycelia biomass, se-enriching rate and se-polysaccharide contents had reached the maximum.②Agrocybe cylindracea enriching selenium optimal liquid fermentation medium was:lactose20g, peptone2g, KH2PO43g, MgSO4·7H2O1.5g, VB10.01g, pH5, water1L.③Agrocybe cylindracea enriching selenium liquid culture conditions was: liquid volume100mL/250mL, inoculum volume12%, culture temperature27℃, shaking frequency100r/min.④Agrocybe cylindracea producing se-polysaccharide optimal liquid fermentation medium was:glucose20g, yeast extract2g, KH2PO43g, MgSO4·7H2O1.5g, VB10.005g, pH6, water1L.⑤Agrocybe cylindracea producing se-polysaccharide liquid culture conditions was:liquid volume100mL/250mL, inoculum volume12%, culture temperature25℃, shaking frequency120r/min.⑥Within a certain concentration range, selenium could promote mycelia growth, but high concentrations of selenium were toxic for mycelial growth. In high concentrations of selenium plates mycelium grew slowly, and the mycelium was sparse. Suitable concentrations of selenium could increase polysaccharides, soluble protein and soluble sugar, while high concentrations of selenium could inhibit its synthesis.⑦Selenium on the changes in enzymes activity had a certain impact. Suitable concentration of selenium would increase the activity of mycelium extracellular enzyme. But adding the selenium did not change the change trend of enzyme activity.