Studies On Screening Of High Cx/FPA Cellulolytic Strains And Properties Of Cellulase From It

The components of washing cellulase are imbalance that has higher Cx activity,but lower FPA activity. The surface of dry goods can be hydrolyzed partly by thewashing cellulase .When it is controlled in certain range, the textile has elaborateappearance and good handle. Furthermore, washing cellulase has little pollution tosurroundings. But there are also problems such as low enzyme output, low enzymeactivity, and unclear fermentation condition on the application of washing cellulase,so it can not achieve to produce on a large scale and the replay of disposed effect isnot good. Therefore, to screen the high-activity strain, explore the fermentationcondition, and study on characteristic of cellulose which from high –yield strain, hasthe great significance.A high-yield M-18 was obtained from the original strain (M which cellulosehas the characters of high Cx/ FPA) by mutation and screening. Its Cx activity was2.56 higher than the original one, but the FPA activity grows no high. Itsfermentation conditions were optimized by the author. The optimized result isdescribed as below, 2% sweet sorghum dregs as the carbon source, 2% NaNO₃ asthe nitrogen source, 50 ml for medium volume, 30℃,180 r/min to ferment for 120hours. The cellulose activity is 90.55U/ml higher than before through optimization.Fed-batch fermentation was studied too; the result shows that, in the fermentationprocess of M-18, the Fed-batch of complex nitrogen source which composed of 1%peptone with fed-batching 1ml /bottle and 1% beef extract with fed-batching 0.6 ml/bottle will stimulate the Cx activity. And the fed-batch of 1% K₂HPO₄, and 1.5 ml1.0% CMC-Na promoted the activity of Cx enzyme too. Under the optimumfed-batch culture, the production of M-18 Cx was improved 78.95U/ml.Some basic specialities of the crude enzyme from M-18 were studied. Theoptimal conditions for enzymatic reaction were temperature 50℃, and pH value 4.6.And its heat-stability is good. Low-concentration of Zn²⁺,Cu²⁺,Fe²⁺ were theactivators. Cx that from M-18 was isolated and its molecular mass is 56.85KD.This cellulase preparation had a good application in the weave industry.