The Screening Of High Xylanase And β-glucanase Producing Strain By Co～(60)γ Radial Mutation And Its Application

B-Glucan was extracted from hull-less barely by the improved sodium hydroxide methed and fermentation methed respectively ,The properties of physical and chemical characteritic study and the results showed that the purity of B-Glucan extracted by sodium hydroxide methed was higher than that by fermentation methed,the contents of reducing sugar was 0.0076% , the quantity protein was 1.3%,after dialysis,decolorization and purification by Sephadex G-100 , the quantity of B-Glucan in the purified extraction and standard was determined by the methed of Congo red, the results showed that the purity of B-Glucan was 98.2%,The purified B-Glucan extracted from hull-less barely by sodium hydroxide methed can be used as standard substrate for the determination the enzymatic activity.The spores of A.niger J506,the initial strain,was treated by Co60 Y radial at the dosage of 200Gy,A mutant with high Xylanase and P -glucanase activity was screened ,naming A.niger 25, Xylanase and P -glucanase activity of the mutant kept stable after 10 generations.After optimizing the culture medium ,the optimum fermentation conditions of A.niger 25 is :barley powder 4%,maize slurry 2.5 % , NaNO3 0.4%, Na2HPO40.1 %, MgSO4.7H2O 0.03%. FeSO4.7H2O 0.01%, CaCO3 0.5% polysorbate-800.25%,the initial PH 6.7, 50mL/300mL flask .After cultivating 84 hours, P -glucanase activity is 1203.9 U/mL, Xylanase activity is 395.2 U/mL After cultivating 96 hours.SDS-PAGE disquisite indicated that the initial strain and the mutant contained different protein bands obviously,the albumen expression is more than the initial strain,which proved that the mutant 25 occurred change in germ plasm compared with A.niger J506 from protein level .Xylanase and P -glucanase of the mutant A.niger 25 is very stable , after storing this enzyme liquid 90 days through adding preservative Na3N3 and Potassium sorbate in room temperature ,the remanent Xylanase and P -glucanase activity was over 50%,in the condition of 4℃, the remanent Xylanase and P -glucanase activity was over 60%. The antisepticise effect of Potassium sorbate is better than Na3N3.