The Study On Cassava Alcohol Production Process Of Continuous Fermentation

The country are facing a huge problem that is the energy crisis,with the continuous exploitation of the non-renewable energy such as coal,oil,natural ect. Search for new alternative energy is become the key of energy strategy. Alcohol is not only a green energy which was transformed from renewable resources, but also it can be mixed with gasoline in any proportion, ease the oil pressure, reduce environmental pollution.So,more and more people pay attention on it.Used cassava as raw material,and studied alcohol fermentation with co-immobilized gels.They composed of yeast and glucoamylase and immobilized by aluminum alginate.This teconology could solve the energy problem with competition for food, and change the traditional batch operation to continuous operation.At the first, it studied the amount of immobilized gel which consisted of glucoamylase and yeast,and the properties of immobilized glucoamylase.The results showed that the best compositions of co-immobilized particles is 5 mL yeast activating solution and 2mL glucoamylase is added in 100 mL, 2% sodium alginate solution.The properties of immobilized glucoamylase is enzyme activity of 1265u/g,michaelis constant of 13.72 mg/mL,relative enzyme activity of 87.5%,activity recovery of 61.6%, the optimum temperature increase 5℃than the free enzyme, and half-life exended 10.7 days.Secondly,the simulation of the static test of alcoholic fermentation was studied. The best conditions in which the static fermentation of cassava starch liquefaction are liquefying temperature of 95℃,liquefying time of 90 min,and the amount ofα-amylase is 15 u/g. Under these conditions, DE values of glucose are 7.23%. The best conditions for fermentation are fermentation temperature is 36℃,the ratio of lique-solid is 1:3.5,the dosage of ammonium sulfate,potassium dihydrogen phosphate and magnesium sulfate is 0.5g/L,0.1g/L,0.1g/L,respectively.Finally,it studied the continuous fermentation with the parameters provided by static fermentation and obtained the best conditions are fermentation temperature of 36℃,flow rate of 10 ml/h, the filling amount of fixed grain of 40%,the ratio of lique-solid of 1:3.5and the addition of ammonium sulfate,potassium dihydrogen phosphate and magnesium sulfate is 0.5g/L,0.1g/L and 0.1g/L,respectively.The resulting output of alcohol reached 11.60% (by volume).