Study On Green Tide Algal Ulva Prolifera Degradation For Ethanol Fermentation

At present,the status of the lack of fossil energy and the environment pollution problem constantly plagued by people around the world,speed up the search to explore renewable clean energy is the common wish of the people.When use of ethanol,only generate water and no pollution gases,in alleviating problems of shortage of energy and also can reduce pollution of the environment pressure at the same time.Since 2007 in China,as a result of seawater eutrophication,the favorable factors such as climate change,cause massive outbreak of Marine algae,form large biomass green ocean tide.This study combined with the current energy shortage problem,the biomass huge green tide algae resources,through certain transformation method,reasonable use of polysaccharide and its own materials such as cellulose,preparation of the third generation of ethanol fuel.Salvaged Ulva prolifera at the green tide algae outbreak period as experiment material.In order to further efficient degradation of Ulva prolifera composition lay a foundation for ethanol fermentation,Ulva prolifera of the main components of the algae body contains.Experiment measured,in the fresh Ulva prolifera,soluble polysaccharide content is higher,at 20.57%,followed by crude protein and crude fiber and protein content is 18.05%,crude fiber 15.33%,starch and ash content is less,1.96% and 9.53%,respectively,moisture content is 8.97%.Under the appropriate weak acid and weak base processing,the composition of Ulva prolifera has changed,the crude fiber,crude protein and the change of soluble polysaccharide,respectively: acid treatment Ulva prolifera algae,crude fiber 12.27%,crude protein 16.88%,25.82% soluble polysaccharide;alkali treatment Ulva prolifera algae,crude fiber 13.50%,crude protein 17.26%,soluble polysaccharide was 24.29%.In order to obtain high efficient degradation of crude fiber of Ulva prolifera,our laboratory screened 4 microbial strains can produce cellulolytic enzyme.Under the method of biological molecular,a fungus strains and 3 strains bacteria were identified.In which F strains in enzyme activity experiment and Ulva prolifera cellulose degradation experiments,both the cellulase from strong degradation ability,in the experiment of filter paper enzyme activity,F strain of enzyme activity of 41.69 U/mL,in the experiment of CMC enzyme activity,F strain of enzyme activity of 34.07 U/mL,in hemicellulase activity experiments,F strain of enzyme activity of 17.50 U/mL.In explore external factors on degradation of Ulva prolifera cellulose enzyme fluid from the strains of experimental inquiry,found that the optimum condition of the F strain degradation of cellulose was thick enzyme fluid adding amount was 6%,the reaction temperature is 38 ℃,the reaction time for 48 h,reaction pH pH= 6.8,at this point to the greatest reducing sugar yield.In fermentation experiments,in order to get the highest product ethanol yield,using orthogonal experiment design the Ulva prolifera fermentation conditions of the optimal combination.The influence of temperature is the largest in Ulva prolifera fermentation experiments,the second influence is the substrate type,the minimal impact factors for fermentation is time in Ulva prolifera fermentation experiments.The optimal combination of Ulva prolifera fermentation is: fermentation substrate type for a,fermentation strains inoculation quantity in 25%,fermentation temperature is 34 ℃,fermentation pH is 6.8,the fermentation time of 48 hours,under this kind of combination,the highest bio-ethanol yield of 28.6g/L.In exogenous additives to optimize the fermentation conditions of exploration,ammonium sulfate is the optimum adding amount of 7 g/L,and the optimum adding amount of magnesium sulfate for 2 g/L,sodium chloride,the optimum adding amount was 1.3 g/L.