Screening Of High Yield Cellulase-Producting Strains、 Optimization Of Culture Medium And The Study On Its Purification Technology

Research was about enzymic characteristics of6kinds of cellulose production strains inthe laboratory. Through observing the size of enzymatic hydrolysis clarity circle on celluloseflat, compared cellulase activity of seed fermentation liquid from6strains. According to thedifferent kinds of cellulase react with substrate special chemical bonds, measured filter paperactivity（FPA）, endoglucanase（CMCase）, cellobiohydrolase and β-glucosidase of fermentationstrains. Obtained that cellulase production indicators of Aspergillus niger strain were higherthan other strains, and FPA can achieve40.66U·mL^-1, CMCase activity reached60.88U·mL^-1, CBH activity reached14.94U·mL^-1, CB activity reached65.08U·mL^-1, all ofdifferent synergy enzymic component can achieve maximizing between120¹44h. Thecellulase producted by each fermentation liquid respectively effect on cellulose powder andcrop straw, it was found that the cellulase from diffrent strains all had existed ability ofdegrading natural cellulose after enzymolysis. And the highest content of sugar yield wasproducted by Aspergillus niger, reaching at0.56mg·mL^-1and0.26mg·mL^-1respectively.The Aspergillus niger fermentation optimized process was designed on the basis ofsingle factor expertment and Box-Behnken principle, The optimum straw powder was9.47g·L^-1for carbon source concentration,49.33g·L^-1for bran concentration,2.0g·L^-1（NH4）2SO4for nitrogen source, the filter paper activity of Aspergillus niger strain reached76.72U·mL^-1after fermentation, amount of filter paper activities optimization increased by88.69%thanwhat it was before. Using enzymatic hydrolysis from optimized fermentation liquid processedcellulose powder and crop straw, through scanning electron microscope and infrared spectrumanalysis found that what happened about its surface structure and the characteristic peak ofdifferent compositions.Three kind of synergy enzymic components from fermentation liquid of Aspergillusniger were identified and isolated, results of the study showed that70%ammonium sulfateprecipitation can achieve the best effect, the specific activity of endoglucanase by Sephadex G^-100increased obviously, its recovery reached18.09%, purification multiple was3.48, therecovery of cellobiohydrolase reached12.97%, purification multiple was4.12, the recovery ofβ-glucosidase can reach22.38%, purification multiple was3.59. Through SDS-PAGEanalysis, cellobiohydrolase extended homogeneity, its molecular mass was50.51KD.