| Bioethanol produced by fermentation of lignocellulosic biomass which from agricultural and forest by-product residues shows many potential advantages in comparison to traditional fossil fuel, from both energetic and environmental points of view. In this study, production process of bioethanol using bamboo cellulose as raw material with bamboo cellulose degrading fungus and yeast which were scereened by Applied Microbiology Laboratory of Jiang Xi Agricultural University was investigated.1. Due to the demand of appropriate microbes that are good at depolymerization of cellulose to fermentable sugars. With the methods of accumulation, lineation separation and purification by using bamboo-cellulose as the only carbonsource, we have isolated 5 fungal strains that can grew on bamboo-cellulose solid culture and degrade the bamboo-cellulose efficiently from the rotted bamboo root:Aspergillus sp.338-1, Aspergillus niger 356-2, Trichoderma sp.554-6, Aspergillus flavus 555, Aspergillus niger 567-2. After 5 days and 6 days of incubation in bamboo-cellulose liquid culture medium, the maximum reducing sugar concentration and CMCase activity in liquid culture medium was 0.268mg/ml and 74.03U/ml inoculated with Trichoderma sp.554-6 strain, respectively.2. In order to optimize the cellulase fermentation process of Trichoderma sp.554-6, effects of various factors such as powder size of bamboo cellulose, different kind of nitrogen resource, seed ages, temperature, initial pH, rotation speed, incubation time, were investigated by single factor experiment and orthogonal experiment during the incubation process. Bamboo powder diameter 0.15mm, ammonia sulfate as nitrogen resource, seed age 5d,40ml per Erlenmeyer flask(250ml), initial pH 5.5, incubating temperature 30℃, rotation speed 200rpm, fermentation for 6.5 days, are the optimum conditions for cellulase production of Trichoderma sp.554-6. The CMCase activity level is 109.72U/ml after fermentation under the optimum condition above.3. In order to find out the optimal conditions for enzymatic saccharification of bamboo cellulose, the effect of different treating conditions such as initial pH, enzymatic hydrolysis temperature, cellulase-xylase ratio, rotational speed and hydrolytic time were investigated with single factor experiment by taking the reducing sugar and total sugar yield as testing index, after dilute-acid hydrolysis pretreatment using 2.0% H2SO4 under the condition of solid-liquid ratio 1:15 and 80℃for 20h first. The yield rate of reducing sugar and total sugar in the sample liquid treated with dilute-acid under 80℃were 5.20 times and 6.43 times higher than the rate under room temperature, separately. Results of the pilot study on enzymatic saccharification conditions of bamboo cellulose with cellulase and xylase by treating with dilute-acid first are as below:initial pH is 5.5, cellulose-xylase ratio 1:1, rotational speed 100rpm, enzymatic hydrolysis temperature 50℃, hydrolysis for 24h. The output rate of reducing sugar and total sugar under the optimal conditions are both higher than 50.88%. which are 4.4 times and 3.0 times higher than the rate in the dilute-acid-treat only sample, separately.4. To obtain the optimum fermentation condition of bamboo to bio-fuel ethanol by SSF. various notable parameters were investigated with single factor experiment and orthogonal experiment. The optimal conditions shows by the experiment result are as below. The amount of cellulase and xylase is both 100U per gram bamboo powder, yeast adding amount 9×108 per gram bamboo powder, fermentation temperature 37℃, rotation speed 80rpm, incubation time 84h. The concentration of ethanol in culture medium liquid and fermentation rate under the optimal process were 12.92mg/ml and 21.53%, respectively.
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