Study Of The Production Of Fuel Ethanol And Heavy Metal Adsorbent By Bad Corn

Fuel ethanol is a renewable alternative fuel, which is made from renewable raw materials, such as wheat, sugar beet, corn, straw etc. As an alternative transportation fuels, fuel ethanol is of great environmental significance, which can not only replace fossil fuels, but also can reduce the emissions of greenhouse gas. Rapid industrialization and urbanization have resulted in the deneration of large quantities of aqueous effluents, many of which contain high levels of toxic pollutants. Since being released into the water and soil, the persistence and non-degradable of toxic heavy metals will be a great threat to the environment. Yeast which is widely used in fermentation industry is not only inexpensive, but also has a strong tolerated to heavy metals, low pH etc. That makes yeast become the preferred material of biological adsorbent. In the study, the yeasts which were isolated from the environment, have been identificated and mutagenesised, while the process that fermentate fuel ethanol by bad corn has been optimized. The performance of fermentation abandoned yeast adsorpt heavy metal ions also has been studied.Eighteen strains of yeast were isolated from the environment. Polyphasic identification, which including 26S rDNA D1/D2 sequencing, single strand conformation polymorphism and physical and chemical identification, was applied to identify the yeasts. The result shows that 18 strains of yeast belong to Saccharomyces cerevisiae, Saccharomycopsis fibuligera and Pichia anomala respectively.Ammonia and formaldehyde method was carried out to detoxify the bad corn.During the preparation of corn mash, the optimal conditions of liquefaction determined by orthogonal test were:temperature of 90℃, pH 5.5, liquefaction time was 3.5h, liquefaction enzame addition level was 0.035g/100g corn flour. The optimal conditions of saccharification were:temperature of 58℃, pH 4.5, saccharification time was 2.5h, glucoamylase addition level was 0.3g/100g corn flour.Protoplast UV mutagenesis was carried out to mutagenesis the Saccharomyces cerevisiae; the best time of mutagenesis is lmin. High alcohol yeast was get after domestication, and its alcohol production is 18.3%.Concentrated the concentrationg of the corn mash, response surface methodology (RSM) was carried out to optimization the ethanol fermentation process based on the single-factor test. The optimum process parameters were: temperature 31℃, inoculation8.4%, strain age 17.5h, pH5.0, ethanol production achieve 18.61%.By orthogonal experiment, the optimal parameters of Saccharomyces cerevisiae Y16 adsorb Copper ion were:pH5.0, adsorption time 30min, concentration of copper ion 90mg/L, yeast added amount 0.5g/L.