| With the development of the energy crisis and increasing attention for the environmental problem, energy structure was changed from the fossil energy to the renewable energy. Cellulose, the biggest renewable resource, that is available in large quantities. There was a litter bit of cellulose were utilized, however, the rest of it were wasted and also led to environment pollution. Thus, cellulose ethanol has the prospect and ecological value. The main results of this paper as follows:(1) In order to obtain the optimal conditions of liquid fermentation, raw herb powder was added to the substrate of liquid fermentation from Penicillium oxalicun in this study. The results showed that adding minute quantity Gastrodia elata to the substrate of liquid fermentation could enhance the activity of cellulase. Taking the activity of CMCase as an index, the monofactorial experiment and the Box -Behnken experiment were applied to optimize the conditions of Cellulase medium. According to results, the optimal medium formula were listed as follows:Peptone 0.4%,Yeast extract 0.05%, Ammonium sulfate 0.60%, Dipotassium phosphate 0.40%, Magnesium sulfate heptahydrate 0.03%, maltos 3.00%, Gastrodia elata 3.00% and calcium chloride 0.03%; The optimal enzyme production conditions:speed of rocking 180 r/min, temperature 28 ℃, inoculum volume 10.00%, pH 6.5, fermentation time 5d and loading volume 50mL/250mL. Under on the optimal conditions,146.95 U/mL of cellulose activity which was higher 3.7 times than the original medium had been obtained.(2) Natural cellulose is hard to degrada directly, therefore, pretreatment is the key technology of the conversion of lignocellulose biomass into fuel ethanol. Pretreatment parameters were investigated. Including smash size, pretreatment solution type, pretr-eatment solution concentration, retention time and solid to liquid ratio (S/L)on the Ca-mphor tree leaves. The optimal pretreatment parameters were as follows:smashing the Camphor tree leaves through 100 mesh, immersing leaves in the 5.00% KOH solution (1:20 solid to liquid ratio), setting pretreatment temperature at 121 ℃ for 60 mins. U-nder the optimal pretreatment, the cellulase activity of 43.36 U/mL was higher3.9 times than before.(3) Compared with bagasse and straw, the Camphor tree leaves are free from lignin, so they can be fermented and pretreated easily. Based on the fermention condi-tions, single factor experiment and response surface methodology were applied to optimize fermention medium. The results for fermentation medium optimization were listed as follows:Camphor tree leaves 5.00%, bran 1.60%, Gastrodia elata 3.00%, Sodium chloride1.50%, monopotassium phosphate 0.125%, Dipotassium phosphate 0.50%, Ammonium sulfate 0.50%, Magnesium sulfate heptahydrate 0.03%, Magnes-ium sulfate heptahydrate 0.03%, Calcium chloride 0.03%. Under these optimal condi-tions, the concentration of reducing sugar was 2.54 mg/mL.(4) After a series of single factor experiments and response surface experiments to the optimize fermentation conditions of ethanol production using Camphor tree lea-ves by fractional step saccharification and fermentation method, the optimum fermen-tation conditions were as follow:degradation times of Camphor tree leaves 68 h, add-ing 10 mL 4.00% ammonium sulfate, inoculum volume15.00%, fermentation time 36 h. The optimal model was constructed by SAS8.1 soft ware with R2=99.60%, which meant that the model could explain the 99.60% variation of the factor experiment re-sult. |
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