Breeding Of Se-enriched Yeast Strain With High-biomass And The Study On Se-enriched Health-wine

Selenium(Se) is an essential micronutrient that is required in a variety of metabolic functions, and has numerous health effects. The Se content in artificial food is low, the Se content in artificial food can not satisfy people's require up to snuff, meal Se absorbed in low level has latency menace to human's health, in order to assure human's health, and prevent and cure relate disease, the abundant Se absorbed is essential, but inorganic Se can not be used in food because of its higher toxicity. Plants and bacteria have been shown to play a key role in the biological cycle of Se by transformation from inorganic Se to organic Se in the environment. Generally, Se is trace amounts in plants. So it weighs heavily for biosynthesis of large output an cheap Se-enriched organic production by microorganism.Saccharomyces cerevisiae was used for studying the ability of enriching Se in microorganism, the majority of work as follows:(1) A strain named UV-PT-2 with higher biomass, higher Se content is obtained after bearing Se adapted cultivation, chemical mutagenesis and ultraviolet mutagenesis. The biomass is up to 9.68g/L, the Se content is up to 967.25μg/g.(2)The optimum fermentation condition and culture medium is determined. The result shows that rotate speed, temperature and the initial pH have a high effect on the biomass of Se-enriched yeasts by Plackett-Burman experiment. The best conditions by response surface analysis method are that the optimum rotate speed is 203r/min, the optimum fermentation temperature is 30.3℃, the optimum initial pH is 4.52.The optimum fermentation conditions are as followed: temperature 30.3℃, initial pH 4.52, rotate speed 203r/min, inoculation volume 8%, volume-loading 40mL/250mL, culture time 40h. The inorganic Se is added gradually. The optimum source of carbon is glucose, the optimum source of nitrogen is yeast extract.(3)Under the optimum fermentation conditions and culture medium, the biomass of Se-enriched yeasts is from 6.59 g/L up to 10.92 g/L, the Se content is from 683.62μg/g up to 1206.96μg/g.(4)The best extraction process has been found by single factor and response surface analysis method. The best extraction processes are as followed: sugar content 10%, liquor degrees 59°, soaking temperature 40℃, soaking time 6days.(5)A new Se-enriched health wine is made by adding organic Se after cell breaking and the extract of organic Se. The Physical and chemical indicators of finished health wine after diluted are as followed: liquor degrees 30±5°(v/v); sugar content 7%～10%; total acid 1.8～2.0g/L; total ester 2.0～2.2g/L, ginsenosides 37.56 mg/100mL, organic Se 200～220μg/L , flavonoids 18.36 mg/100mL, alkaloids 260mg/100mL.At last, it designs the process flow of production on the base of the whole tests.