[Objective] We cloned xylanase-encoding gene xynA and its promoter from Bacillus pumilus , expressed in Bacillus megaterium and characterized the recombinant xylanase. [Methods] We inserted the xylanase-encoding gene xynA and its promoter in Bacillus expression vector pWH1520 and pWG03 which was modified from pWH1520. We transformed the recombinant plasmid pWTEJX and pWGXYN into Bacillus megaterium , and obtained the recombinant stains BMJXH9 and BMGpp12. Enzymes produced by recombinant strains expressing xynA were produced in the medium. The xylanase activity produced by recombinant BMGpp12 was three times higher than that of BMJXH9. The recombinant xylanase had the original enzyme alkali-tolerant properties.[Conclusion] Alkali-tolerant xylanase gene was successfully expressed and this provided a basis for further study of xylanase applied.%[目的]从耐碱性木聚糖酶高产短小芽孢杆菌中克隆得到带有自身启动子的木聚糖酶基因,将其在巨大芽孢杆菌中进行表达,并对表达产物进行性质分析.[方法]将克隆得到的木聚糖酶基因xynA 以及带有自身启动子序列的结构基因,构建在芽孢杆菌表达载体pwH1520和改造后的载体pWGO3中,得到重组质粒pWTEJX和pWGXYN,分别转化到巨大芽孢杆菌BM70中,获得重组巨大芽孢杆菌BMJXH9和BMGpp12;经过诱导产酶培养,均得到分泌表达.[结论]重组巨大芽孢杆菌BMGpp12比BMJXH9产酶活力提高了3倍,重组表达的木聚糖酶的酶学性质研究表明其仍具有很好的耐碱性,这为木聚糖酶的进一步应用研究提供了重要的理论依据.
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