Recombinant Trichoderma Reesei Synthesize A Xylanase And Its Application In Waste Paper Pulp

Paper industry is an important industry in the national economy in recent years, due to the shortage of virgin fiber materials and industrial pollution problems, the paper industry is facing serious challenges.Finding efficient and less polluting waste treatment technology has become the paper industry’s top priority. In this paper, a low agricultural waste as material, using the modified Trichoderma reesei(ATCC56765) fermentation for xylanase production,at the same time the enzyme was used foranalyzing the pharmacological properties of the enzyme produced xylanase and applying the xylanase to waste pulp hydrogen peroxide bleaching. The main findings are as follows: In reesei strains for the production, fermentation experiments in the fermenter. The study found cheap corn cob can be used as an excellent substrate for promoting the synthesis inducing xylanase, economic value is very important. After the fermentation process optimization are: corn cob 1.6%, 0.4% beef extract, glucose 0.15%, 0.4% Tween 80, 0.14% ammonium sulfate, potassium dihydrogen phosphate, 0.2%, 0.03% calcium chloride, magnesium sulfate 0.033%, 0.001% ferrous sulfate, cobalt chloride 0.00033%, 0.00026% manganese sulfate, zinc sulfate 0.00033%. Optimal culture conditions: inoculum 10%, 50 oC, p H value 8.0, fermenter speed 220 rpm, fermentation time 60 h. Xylanase activity synthesized according to the above conditions to reach 550 ± 20 U / m L, the leading domestic level. Fermentation enzyme solution pharmacology research performance enzymes, obtaining the xylanase catalytic optimum p H value is 8.0, while the range of p H 6.5 to 10.0 can also have a higher activity, while a p H of 4.0~12.0 are relatively stable; optimum xylanase catalytic temperature is 70 oC, to 55~75oC range, it is possible to maintain a high enzyme activity, under conditions of 60 oC, the thermal stability is better;Fe2+、K+、Na+ ion for xylanase activity promoted, especially Fe2+ ions, the largest increase enzyme activity.Ag+、Pb2+、Mn2+、Fe3+、Cu2+、Co2+on the xylanase activity has a role in inhibited.The high concentrations of Ag+、Fe3+ can make xylanase inactivation. Xylanase optimum reaction substrate is corn cob xylan, xylanase has no cellulase activity, it can be used in papermaking biological bleaching. Fermentative production of xylanase pretreatment of waste paper pulp optimum conditions: the amount of enzyme was 12 U / g, p H of 8.0, a temperature of 70oC;when the treatment time was 60 min, Xylanase pretreatment of waste paper pulp in favor of the subsequent hydrogen peroxide bleaching, so that after bleaching,the whiteness, tensile index, elongation, burst indexof the waste paper pulp lifting 14.9%, 41.4%, 31.13%, 12.4%respectively, at the same time it can make reversion value decreased 41.6 percent. Through high-tech analytical instruments for internal waste paper pulp before microscopic properties by xylanase pretreatment studies indicate that waste pulp xylanase pretreatment can improve the quality of the fiber, increase the relative crystallinity index increased, reducing the hemicellulose and lignin content has been reduced. Waste paper pulp after a xylanase treatment with conducive bleaching liquid penetration.