Studies On Submerged Fermentation Of Selenium-riched Cordyceps Militaris

Selenium-riched Cordyceps Militaris, which has the functionality of both Cordyceps Militaris and selenium, is produced when fermented in liquid culture which had certain concentrate of selenium.In this thesis, characters of selenium-riched Cordyceps Militaris, including anti-selenium and selenium enrichment capability, fermentation conditions, functional factors, and prerequisite programs of fermentation industrialisation, including mutation and screening of Cordyceps militaris with high biomass and selenium-riched capability, and selenium-removal of castoff, were studied.JM, a strain of Cordyceps militaris with high biomass and selenium-riched capability, was screened through orthogonal experiment from four. After fermented in liquid culture for 72 hours, JM got the highest biomass and selenium-riched capability. The anti-selenium capability of JM was 10μg/mL Na2SeO3 in solid culture, and 12μg/mL in liquid culture. The optimum medium of Cordyceps militaris when cultured by liquid fermentation to rich selenium was determined. It contained 35g/L soy bean powder, 40g/L sugar, 1.5g/L KH2PO4, 50μg/L vitamin B1, 16 mg/L Na2SeO3, and pH 6.0. And the optimum culture condition was inoculating 3mL seeds cultrued for 24 hours in a flask of 250mL containing 100mL medium and cultured under 26℃. When fermented in such conditions, the biomass could get to 12.69 g/L, selenium enrichment could get to 5.61μg/mL.Four basic nutrients, including proteins, fats, carbohydrates, and cashes, of selenium-riched and ordinary mycelia of Cordyceps militaris were analyzed. Also, six functional components, including cordycepins, adenosines, polysaccharides, mannitols, amino acids, and inorganic elements, were analyzed. It was concluded that selenium-riched and ordinary mycelia of Cordyceps militaris were not nutritionally parallel, and there were significouldt differences between selenium-riched and ordinary mycelia on functional components.The ultraviolet radiation was used to treat protoplast of Cordyceps militaris JM, and then a mutant strain YM07, which had higher selenium enrichment capability, was obtained. Compared with JM, the biomass of YM07 increased 18%, and selenium enrichment capability increased 16%.After the mycelium of Cordyceps militaris was separated, the castoff had certain concentrate of selenium. So, selenium-removal technology was studied. Controlling pH valule to the level of 6.0-7.0, adding 5g/L FeCl3?6H2O, churnning up for 10 minutes, reposing for 30 minutes, and centrifuging under 2600r/min for 30 minutes, the concentrate of selenium in the castoff could accord with national standard.