1株高产蛋白酶嗜麦芽寡养单胞菌的分离鉴定及其酶学活性的研究

双齿围沙蚕消化道中分离1株高产蛋白酶菌株D2(CGMCC保藏号:1868),经形态学、生理学、16S rRNA基因序列测定及系统发育分析确定为嗜麦芽寡养单胞菌。Lowry法检测显示该菌株产酶能力为1104 U/mL,最佳产酶条件为pH 8.0、25℃培养48 h;酪蛋白酶图谱法和凝胶成像分析证实其蛋白酶分子量约为42 ku,在培养上清液中纯度大于97%;该酶对粗酶品比活性为301 U/mg,酶活性的最适pH值为9,是一种碱性蛋白酶;最适温度为60℃;在55℃以下及pH 6~10的环境中具有较好的稳定性。嗜麦芽寡养单胞菌D2株有望成为一种新的蛋白酶生产资源。

Isolation and Identification of a High-Protease-Producing Stenotrophomonas maltophilia Strain and Its Enzymatic Characteristics

A high-protease-producing bacteria,strain D2（CGMCC 1868）,was isolated from the alimentary tract of Perinereis aibuhitensis.Based on the study of its morphologic and physiological properties,and phylogenetic analyses of the 16S rRNA gene sequence,strain D2 was confirmed to be Stenotrophomonas maltophilia.Lowry method determined the enzymatic production capacity of the strain reached as high as 1 104 U/mL for 48 h-fermentation in an optimized production condition of pH 8.0 and 25 ℃.The enzyme was proved its molecular mass being 42 ku analyzed by casease atlas method and gel image,and its purity in fermentation broth was more than 97%,the specific activity of the enzyme to the crude enzyme was 301 U/mg.the most suitable pH of the enzyme was at 9,being an alkaline protease,the most suitable temperature was 60 ℃,and fairly good stability at pH 6~10 and 0~55 ℃.Therefore,D2 strain might be a novel promising resource of marine microbial protease.