中文摘要：

以枯草芽孢杆菌 BJ3-2 的 glsA1 基因为同源序列，通过构建单交换整合载体，将高活性谷氨酰胺酶基因glsA2 定点整合入 BJ3-2 菌株染色体中，获得能够稳定遗传的重组菌株 BJ3-2A2。经检测重组菌株谷氨酰胺酶活力为BJ3-2 菌株的 3.36 倍。利用重组菌株 BJ3-2A2 发酵豆豉，全氨基酸检测显示，重组菌株发酵的豆豉谷氨酸含量比出发菌株高 12.8%。说明枯草芽孢杆菌 BJ3-2 可以转化且为 RecE＋菌株，glsA2 基因在 BJ3-2 菌株染色体上可实现较高活性表达，并提高发酵豆豉的鲜味。

英文摘要：

With glsA1in BJ3-2 as the homologous sequence, glutaminase gene glsA2 with high activity was targeted andintegrated into the Bacillus subtilis BJ3-2 chromosome by constructing a single-exchange integrative vector. A recombinantstrain BJ3-2A2 was obtained with good genetic stability. The results of detection showed that glutaminase activity in therecombinant strain was 3.36 times higher than that in the original strain BJ3-2. The amino acid contents in douchi fermentedwith BJ3-2A2and the original BJ3-2 were measured, and the results showed that glutamate content in fermentation productsfrom the recombinant strain was increased by 12.8% as compared to that observed with the original strain. All the analysesshow that B. subtilis BJ3-2 is transformable as a RecE＋strain and that glutaminase gene glsA2can be highly expressed in theBJ3-2 chromosome, thus improving the flavour of douchi.