中文摘要：

以木聚糖酶基因为研究对象，构建了枯草芽胞杆菌（Bacillus subtilis）稳定的高效表达系统。采用PCR方法从芽胞杆菌（Bacillus sp．）基因组DNA中分别扩增出完整和不带启动子的木聚糖酶（xynA）基因；利用芽胞杆菌的强启动子，即S-层蛋白的启动子，通过SOE（splicing by overlapping extension）法连接到xynA基因上得到重组基因S-xyaA，将xynA和S-xyaA分别装载到整合载体pDG1730上，转化α-淀粉酶高产菌株枯草芽胞杆菌B47，将重组基因整合到叶淀粉酶基因上，以期目标基因像淀粉酶基因一样高效表达。结果表明，2个重组菌的产酶活性均得到提高，其中S-层蛋白启动子表达的木聚糖酶活是自身启动子表达的酶活的1．69倍。重组表达的木聚糖酶在pH5—8和40-60℃范围内均具有较高活性。

英文摘要：

A stable and high-effective expression system was constructed in Bacillus subtilis with xylanase gene. The complete and promoterless xynA gene were amplified from Bacillus sp. by PCR, respectively. And the latter was ligated with the strong promoter of B.thuringiensis S-layer protein to construct recombinant S-xynA gene. The xynA gene and recombinant S-xynA gene were respectively inserted into integration vector pDG1730. Then the recombinant vector was stably inserted in between amyE-front and amyE-baek of B. subtilis 1347, which produces high quantity a-amylase, in order that the xylanase could be highly expressed as a-amylase. The result showed that the xylanase activity of two recombinant strains were both increased and the activity of xylanase expressed with S-layer promoter was 1.69 times than that with native promoter. The recombinant expressed xylanase activity was high at pH from 5 to 8 and temperature from 40℃ to 60℃.