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China is an energy consuming countries, the energy shortage would seriously endanger China's economic development and national security. Therefore, the development of new energy sources to replace the gradual depletion of traditional energy sources will be the direction of the future development of the energy industry. Bio-fuels with renewable, non-polluting characteristics, so much national attention. The lignocellulose Is the earth's most abundant and cheapest renewable resources, is considered to be the most important bio-fuel alcohol production follow-up resource material. Relative to the first generation of biofuels food as raw materials such as corn and soybeans, straw and other plant fiber as raw material for cellulosic ethanol is called second-generation biofuels, its biggest advantage is to avoid \, food fight \Therefore, the use of biotechnology in the lignocellulose into ethanol, has important social and economic significance. Which one of the ways is to use biotechnology plant fiber raw materials are converted into simple sugars, mainly divided into two steps: 1, raw material pretreatment; 2, the enzymatic hydrolysis of cellulose. Pretreatment technology is unsatisfactory, the presence of sugar was low, and complex technical process, the enzymatic hydrolysis of cellulose to slow hydrolysis, enzyme dosage. These two aspects at the same time restricting the development of fiber raw materials biotransformation. The thesis of agricultural waste corn stalks as raw material, pretreatment of fiber raw materials and the optimum processing conditions screening, the optimization of enzymatic saccharification conditions, ultrasonic and metal ions on the enzymatic impact, the main results are as follows using the ammonia soaked pretreatment, pressurized ammonia pretreatment solution, ultrasonic assisted ammonia pretreatment are three ways to deal with the corn stalks. The optimal solution of ammonia soaking pretreatment: ammonia concentration of 15%, 39h, temperature 40 ° C, the substrate concentration 162.5g / L, the particle size of 0.5mm. In this condition, the pretreatment reducing sugar yield of 3.23%, 61.20% lignin. Corresponding enzymatic reducing sugar was 45.28%, 32.77% 12.51% than the untreated. Pressurized ammonia solution pretreatment optimal solution: 15% of the ammonia concentration, time 6min, pressure 0.075MPa substrate concentration 150g / L, the particle size of 1mm. Under this condition, the pretreatment of reducing sugar was 1.74%, and the lignin removal rate of 43.30%. The corresponding enzymatic reducing sugar was 21.36%, a 8.85% increase. The optimal solution for ultrasonic assisted ammonia pretreatment: 12.5% ??of the ammonia concentration, time 24min, power 240W, substrate concentration 187.5g / L, temperature 70 ° C, the particle size of 0.5mm. Under this condition, the pretreatment of reducing sugar yield was 1.51%, 32.20% lignin. The corresponding enzymatic reducing sugar was 40.33%, 27.82%. Optimal treatment results were compared, and the overall economic efficiency of factors, the ultrasonic assisted ammonia pretreatment shorter time, low energy consumption, better is the ideal way pretreatment. Using ultrasonic assisted ammonia pretreated corn stalks as raw material, in an ambient temperature of 50 ℃ under the conditions of enzymatic hydrolysis. Substrate concentration factors reducing sugar yield was significantly (p lt; 0.01), enzymatic hydrolysis time on reducing sugar yield was significantly (p lt; 0.05). The optimal solution for the enzymatic hydrolysis: pH value of 5, the substrate concentration 60g / L, the enzyme dosage of 47 mg / g (dry straw), hydrolysis time 30h. The enzymatic reducing sugar in this condition was 49.00%, than those without pretreatment of corn stover enzymatic reducing sugar yield 36.49%. Promote a certain degree of ultrasonic radiation on the enzymatic hydrolysis. When the enzymatic substrate concentration of 60g / L, the enzyme dosage of 47mg / g (dry straw), the optimal ultrasonic power 39W, ultrasonic time of 9min. The enzymatic reducing sugar yield was 56.55%, 7.55% higher than without ultrasonic involved in enzymatic. K, Na, Ca2, Mg2, Zn2 cellulase from activating effect, contribute to the enzymatic hydrolysis of the pretreated product, improve the yield of the enzymatic reducing sugar. Zn2 activating effect on the cellulase is the most obvious, the concentration of 1.5mg/ml (enzyme solution) is activated when the largest role. Fe3, Al3 cellulase disincentive.
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