Study On Producing Fuel Alcohol From Sweet Sorghum By Liquid-state Fermentation

Use the six yeast strains bought from market as test strains,which was used to fermentate sorghum juice to produce fuel ethanol, the researches are as following:1. After single-factor experiments and orthogonal test, the test yeast for fermentation of the appropriate combination of conditions: Dan Baoli yeast: a temperature of 32℃; pH value of 5.03; inoculation of 1.0‰; juice Brix to 14 Brix. Anqi Yeast: a temperature of 32℃; pH value of 5.03; inoculation of 1.1‰; juice Brix to 14 Brix. LALVIN yeast: a temperature of 30℃; pH value of 5.03; inoculation of 1.2‰; juice Brix to 14 Brix. 1384 - Wier yeast: a temperature of 32℃; pH value of 5.03; inoculation of 2ml; juice Brix to 14 Brix. 1347 - Xuewa yeast: a temperature of 33℃; pH value of 5.03; inoculation of 3ml; juice Brix to 14 Brix. 1416– niangjiu yeast: a temperature of 32℃; pH value of 5.03; inoculation of 2ml; juice Brix to 14 Brix.2. After fermentation under every tested yeasts's best fermentation conditions we can see that not only judged from fermentation time but also from alcohol content after fermentation, Dan Baoli is superior.therefore, Dan Baoli is the best yeast strain of the tested six yeasts.3. Use Dan Baoli as test strain, test their nutrients through the single-factor experiments and orthogonal test to determine the application of nutrients than the amount of the portfolio are as follows: (NH4)2SO4 0.4%, MgSO4 0.1%, CaCl2 0.1%, K2HPO40.005%.4. When shaker works under 120rpm, the yeast added nutrients whose fermentation time is 16h, and other yeasts didn't add any nutrients whose fermentation time is 18h.therefore, add nutrients yeast's fermentation time is 2h than that do not add nutrients yeasts'. At the same time also increased the alcohol content of 0.2%.5. After single-factor experiments and orthogonal test, identified Dan Baoli immobilized yeast's more appropriate combination of: haizaosuanna of 2.5% , CaCl2 of 3%, PVA of 0.3%,SiO2 of 0.3% , Al2O3 of 0.3% , fixed time of 7h..6. Free yeast in the shaker which works under 120rpm condition, the fermentation time is 18h; immobilized yeast in the shaker whose speed is 120rpm, the fermentation time is 13h.therefore, compared to free yeast,immobilized yeast's fermentation time can be shortened 5h.,and alcohol yield rate up to 92%.7. Through three active dry yeast fermentation capacity direct comparison found that from the alcohol content, residual sugar, the fermentation cycle assessment of composite indicators, Dan Li Baoli dominant the whole fermentation.8. Direct fermentation and temperature -fermentation is no apparent from alcohol content after fermentation ; bactericidal more direct wine fermentation to improve the accuracy of 0.3%.9. From the energy point of view, direct fermentation is economically feasible.