The Study On Synthetizing Biology Selenium By Compound Strains Fermentation Yellow Slurry Water

Selenium as one of the essential trace element,through research at home and abroad,selenium has proved many physiological functions,but the selenium deficiency problem is very serious in our country.Using the biological synthesis of synthetic biology selenium by transform inorganic selenium into organic selenium,reduce the selenium toxicity,more prone to the absorption of human body,is a very effective way of active filling selenium.This thesis mainly study selenium-rich ability of four bacterial species,Saccharomyces cerevisiae,Streptococcus thermophilus,Geotrichum candidum and Rhodotorula glutinis strains of a single bacterial species and different collocation in the same conditions,filter can effectively fermented yellow slurry water and synthesis of selenium compound strains,and the effect factors of composite synthetic biology selenium,through the orthogonal experiment with biological selenium and selenium conversion rate as index,to analyze various factors on the composite strains fermentation ability of yellow slurry water production of selenium synergy effect,optimization of fermentation process.The Saccharomyces cerevisiae,Streptococcus thermophilus,Geotrichum candidum,Rhodotorula glutinis as the starting strain,the table coating experiment is used to determine the initial level selenium concentration is 20mg/L,yellow slurry water as medium,use the DAB spectrophotometry to detect selenium concentration,determine that fermentation yellow slurry water composite strains are Saccharomyces cerevisiae?Geotrichum candidum?Rhodotorula glutinis.Composite strain capacity is higher than single Saccharomyces cerevisiae,instructions that composite strain have synergistic effect in selenium-rich.When inoculated quantity is 4%,inoculated ratio is 2:1:2,selenium content is 20mg/L,composite strain produce strain quantity by fermentation yellow slurry water is 0.45±0.04 g/100mL,selenium concentrations in strain water is 8.98±0.94mg/L,synthetic biological selenium quantity is 898?g/g,selenium conversion rate reached 20.21%.The Saccharomyces cerevisiae,Geotrichum candidum,Rhodotorula glutinis as the starting strain,biological selenium quantity and selenium conversion rate as testing index,using the single factor and orthogonal test method,to optimize the culture medium and culture conditions.The best biological selenium quantity fermentation condition is:3%glucose,0.5%(NH4)2SO4,0.04%MgSO4,0.2%KH2PO4 in yellow slurry water,selenium concentrations is 25mg/L,the temperature is 30?,incubation time is 42h,biological selenium in the bacteria content is the highest,can achieve 1275?g/g.But when selenium concentrations is 20mg/L,selenium conversion rate is highest,can reach 35.93%.The highest biological selenium content and selenium conversion rate need process conditions are not exactly same,because when selenium concentrations is 25mg/L,although biological selenium in the bacteria content is the highest,but high concentration of selenium inhibit the growth of bacteria breeding,strain quantity is less than when selenium concentrations is 20mg/L,lead to selenium conversion rate is less than when selenium concentrations is 20mg/L.