The Construction Of High Stability Cellulase Under Alkaline

Celllulose was the largest renewable resources and used cellulose resources had been attracted wildly attentions. Because highly crystalline structure of cellulose was a serious impediment to use cellulose, therefore, we found effective green solvents had become a keystep. Na OH / Urea was widely recognized as green solvents, and can effectively dissolve cellulose resources. However, cellulase would reduce the activity under alkaline system. In this article, new cellulose was constructed under alkaline system anddetermined its kinetics, which provided a favorable reference data for using cellulose.Cellulase was modified with MW of 5 K,10 K and 20 K monomerhoxyl-Polyethy-leneglycol maleimide(mPEG-MAL 5 K) and MW of 5 K monomethoxyl-polyethylene glycol succinimide(mPEG-SPA 5 K), then four kinds of modified cellulases were obtained. And we determined the average of thiol and amino of modified cellulases. The modified cellulases and native cellulase were characterized by infrared spectroscopy and atomic force microscopy. By modified cellulses and native cellulase to degrade carboxymethyl cellulase in the same kind of system to determine the activity.The reaction liquid of modified cellulase degraded carboxymethyl cellulose was placed in 0 ℃,-5 ℃,- 10 ℃ and-15 ℃ to precipitate cellulase. The result was showed that the modified cellulase would be precipitated in-10 ℃ and reacted 2 h. We used precipitated modified cellulases to degrade cellulose to measure the activity. One is directly added carboxymethylcellulose to the reaction solution, and the other is added to the reaction solution when carboxymethylcellulosewas poured.Using the three kinds of complex cellulases to degrade different substrates: exoglucanases degradated microcrystalline cellulose, endoglucanases degraded carboxymethyl cellulose and Cellobiose cellulases degraded cellobiose, we obtained the activity of Cellobiose cellulases was highest and had the strongest impact on complex cellulases. Added different amount of cellobiose cellulases to complex cellulases to study the amount of cellobiose cellulases affected the complex cellulases.In this article, we dissolved cellulose under NaOH / Urea and used polyethylene glycol derivatives to modify cellulases. We determined the kinetic constants and its recycle under alkaline systems and provided effective reference data for improving the activity of cellulase.