| In the cellulosic ethanol process, the cost of cellulase accounts for a high proportion, reducing the cost of cellulase can effectively reduce the cost of cellulosic etabanol. High-yielding cellulase strains, cheap and efficient inducers and optimizing cultivation technique can effectively reduce cellulase expenses.By researching feasibility inducers,the lactose, sucrose, galactose, xylose, malt extract powder, industrial cellulose, straw powder, large wheat-straw powder, soluble starch, maltose, screened appropriate inducer, optimized the media, found the optimal conditions for producting cellulase, constructed the non-structural dynamic model about batch cultivation, the last, did some researchs about cellulase characteristics.Through comparing to Trichoderma ressei mycelia dry weight, filter paper activity and beta-glucosidase activity and its variation tendency on the conditions of different concentrations of various inducers. Industrial cellulose was screened as inducer to induce Trichoderma reesei RUT C-30 produce cellulase.Based on the single factor experiments what found the scopes of the right concentrations on industrial cellulose, ammonium sulfate and biotin. The design-experit software designed the central components design and found the optimum concentrations on industrial cellulose, ammonium sulfate and biotin. The results show that, when the concentrations of industrial cellulose were 39.722g/L, the concentrations of ammonium sulfate for 5.970g/L, the concentrations of biotin for 239.072μg/L, the optimum filter paper activity, beta-glucosidase activity and soluble protein contents respectively attained 6.292U/ml,0.877U/ml and 1.174mg/ml. The validation experiences in flask culture, filter paper activity was 6.158U/ml with 2.13% bias to predictive value, beta-glucosidase activity was 0.864U/ml with 1.48% bias to predictive value, and soluble protein content was 1.159mg/ml with 1.28% bias to predictive value. Comparing to before the central components design, filter paper activity enhanced 18.66%, beta-glucosidase activity enhanced 5.75% and soluble protein content increased 12.52%. In 7.5 L bioreactor, filter paper activity was 4.817 U/ml, beta-glucosidase activity were 0.881U/ml and the soluble protein content reached 1.118 mg/ml, filter paper activity in 7.5L bioreactor was lower to filter paper activity in flask culture. In the meantime, protein electrophoresis showed cellulase which was induced by industrial cellulose almost did not contain other miscellaneous proteins.On the basis of response surface optimization results,keeping the constant of ammonium sulfate and biotin,adding a series concentrations of industrial cellulose in 7.5L bioreactor, cultivated Trichoderma reesei and structured the non-structural dynamic model about batch cultivation.It well fitted mycelia, industrial cellulose, soluble protein, filter paper activity and beta-glucosidase activity and its variation tendency.But the fitting effects of soluble protein, filter paper activity and beta-glucosidase activity were below in the fitting of mycelia, industrial cellulose. Every milligram exocellular protein was about to 4.4U filter paper activity.The modle of unit cost of filter paper activity is the function of cultivate time. Compared to unit cost changes of filter paper activity on cellulases which were induced by industrial cellulose and microcrystalline cellulose, found to industrial cellulose had certain economic advantage relative to microcrystalline cellulose.Comparative Km and Vmax of cellulase,which were induced by industrial cellulose and microcrystalline cellulose, enzymolysised the filter paper and 4-nitrophenyl-beta-D-glucopyranoside,and cellulase activity,found the cellulase induced by industrial cellulose what has higher zymolysing efficiency.The Co2+ inhibited filter paper activity and beta-glucosidase activity, other metal ion enhanced filter paper activity. |
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