一株酸性淀粉酶产生菌的分离鉴定及其酶学性质研究
Study on isolation and identification of acidic α-amylase producing strain and enzymatic properties
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摘要: 用含有淀粉的选择培养基,通过透明圈法筛选到一株产酸性淀粉酶的菌株,其发酵液酶活力达到123U/mL。通过形态观察。生理生化实验和16S rDNA序列分析等方法初步鉴定该菌株为地衣芽孢杆菌,命名为Bacillus lincheniformis BW-2。对其产生的淀粉酶的酶学性质进行分析发现,该菌株产生的淀粉酶最适反应温度为70℃;最适反应pH为4.5,同时具有较好的热稳定性和pH稳定性;Ca2+和Mg2+对该酶有激活作用,Mn2+和Cu2+对该酶有抑制作用,抑制剂PMSF(苯甲基磺酰氟)及DTT(二硫苏糖醇)对该酶活力影响较小。通过PAGE分析发现BW-2产生的淀粉酶与已知热稳定淀粉酶分子量或结构可能存在差异。Bacillus lincheniformis BW-2是一株具有研究开发潜力的产酸性淀粉酶的菌株。Abstract: An acidic α-amylase producing strain was screened through screening medium supplemented with starch by the method of hydrolysis halo, and the amylase activity of the fermentation broth was 123U/mL. The stain was identified as Bacillus lincheniformis by morphology observation, physiological and biochemical tests and 16S rDNA sequence analysis, and was named as Bacillus lincheniformis BW-2. The enzymatic properties of the amylase were also investigated. The optimum pH and temperature of the amylase was 4.5 and 70℃, respectively. It also showed excellent thermostability and pH stability. The amylase activity was activated by Ca2+and Mg2+, whereas, it was inhibited by Mn2+and Cu2+. Meanwhile, these inhibitors PMSF and DTT had little effect on the enzyme activity. The molecular weight and structure of the amylase from BW-2 maybe was different from the known thermostable amylase by PAGE analysis. BW-2 was an acidic amylase producing strain which showed research and development potential.