Comparative Study On Ethanol Fermentation With Lignocellulose From Stress-Torlerant Sweet Sorghum And Vetiver Grass

In this study, the sweet sorghum cultivars YaJin1,6,13,14and69were analyzed and identified at the stages of seed germination and seedling by physiological characteristics measurement under drought and salt stresses, respectively. YaJin1with the highest tolerance against salt and/or drought was planted in the field and harvested to get the stalks which were dried and shredded in a shredder. Then the ingredient of the powder was measured through the method by Van Soest. The powder of sweet sorghum and vetiver grass were hydrolysated by optimized condition to get the primer fermentation culture of which the sugar composition was analyzed by HPLC. After the neutralization by Ca(OH)2, boiling and filtration, the sugar content reach to an appropriate concentrate for the following fermentation. The main results were showed as follows:Under the salt and drought stresses, the5sweet sorghum cultivar were identified through the physiological characteristics including relative seed germination, the relative water content, the relative electrolytic leakage, the contents of TBARS and the leaf chlorophyll, the net photosynthetic rate and the maximum quantum yield of photosystem II (Fv/Fm) which indicated that the YaJin1,14and69has a higher salt and/or drought stress tolerance. But compared with YaJin14and69, YaJin1showed a slight superiority and was thus used as the following experiment.The lignocellulose content of sweet sorghum YaJin1stalks were measured by Van Soest after it was dried and shredded in a shredder and the mass fraction of cellulose, hemicellulose and lignin content in sweet sorghum is48.71±0.34%,27.58±0.82%and10.23±0.22%, respectively. After the acid hydrolysis of sweet sorghum, the sugar content per100g sweet sorghum is xylose12.97±0.12g, glucose2.59±0.02g, arabinose2.50±0.02g and galactose0.43±0.05g, and the vetiver grass xylose17.29±0.27g, glucose1.97±0.06g, the arabinose4.38±0.23g and galactose1.59±0.01g. And the total reducing sugar content of sweet sorghum and vetiver grass reach to24.29g/l and36.43g/l after pretreatment. Then the acid hydrolysis of sweet sorghum and vetiver grass were fermentated by adapted P.stipitis, and in96h after the fermentation the maximum ethanol production by sweet sorghum and vetiver grass is2.63g/l and3.3g/l respectively.