牦牛瘤胃厌氧真菌木聚糖酶基因工程菌的构建及其酶学特性研究OA

To construct an engineered strain P.p(xyn-N.f)using the xylanase gene from the rumen anaerobic fungus Piromyces YakTz of Tianzhu yak.The β-1,4-endoxylanase gene was cloned from this fungus,codon-optimized,and used to generate a recombinant Pichia pastoris strain for inducible expression.Enzyme activity and enzymatic properties were determined by visible spectrophotometry.Results:(1)The xylanase produced by the genetically engineered strain P.p(xyn-N.f)exhibited an optimal temperature range of 40～60℃,an optimal pH value range of 5.0～9.0.(2)Mn2+,Fe2+,Hg2+,K+,Zn2+inhibited xylanase activity;Ba2+,Co2+had no significant effect;Cu2+,Mg2+enhanced its activity.(3)After 144 h of induction in aerobic shake flasks,xylanase activity reached 55.95 IU/mL.Upon scale-up cultivation in a 15 L fermenter,the activity increased to 500.70 IU/mL.Conclusion:This study successfully achieved high-level expression of the engineered strain P.p(xyn-N.f)under aerobic conditions.The enzyme produced shows high activity,favorable thermal stability,and broad pH adaptability,and holds promise for application in the feed industry.