蜡状芽孢杆菌HY-1的生长及对毒死蜱的酶促降解特性  

The growth pattern of the Bacillus cereus HY-1 and the enzymatic degradation characteristics of insecticide chlorpyrifos

作　　者：段海明[1] 王开运[1] 朱玉坤[1] 

机构地区：[1]山东农业大学植物保护学院,山东泰安271018

出　　处：《微生物学通报》2011年第5期668-676,共9页Microbiology China

基　　金：国家863计划项目(No.2007AA10Z404)

摘　　要：为明确毒死蜱降解菌——蜡状芽孢杆菌Bacillus cereus HY-1的生长和粗酶液对毒死蜱的降解特性,采用种子液中定量添加毒死蜱和测定粗酶比活力的方法,研究含毒死蜱的种子液培养基中菌株的生长规律和环境因素对粗酶液降解毒死蜱的影响。结果表明:含毒死蜱的培养液和空白对照相比,菌株生长的适应期延长,对数期、稳定期顺序后延。随着培养液中菌体数量的增长,培养液的pH也随之升高。粗酶液中可溶性蛋白的含量为2.21 g/L,测得粗提酶中其米氏常数Km为1.235 6 mmol/L,最大降解速率Vmax为0.022 6μmol/(mg.min)。酶促反应时间为1 h时,粗酶液对50 mg/L毒死蜱的降解率最高可达74%,粗酶液加入体积为1 mL时的比活力最高。在20°C-44°C温度范围内,粗酶液能保持较好的降解活性,最适温度为28°C;在pH 5.0-9.0之间,粗酶比活力都能达最高比活力的66%以上,最适pH为6.0。进一步研究发现,该粗提酶具有较好的热稳定性和pH稳定性,在温度-20°C-40°C、pH 4.0-8.0的条件下,暴露1 h仍能保持较高的比活力。该粗酶液在10-70 g/L的NaCl浓度下保持1 h,仍能高效降解毒死蜱,其耐盐性与目前国内外已报道的毒死蜱降解粗提酶相比是最高的,其开发应用价值大。The growth pattern of the bacteria and degradation characteristics of the crude enzyme ex-tracted from an isolated strain Bacillus cereus HY-1 were approached in the paper.The results showed that the adaptation period of the bacteria was prolonged by addition of chlorpyrifos and the logarithmic phase and stationary phase were also extended against the control.Moreover,the pH of the culture me-dium increased with the growth of the strain.The results also indicated that the soluble protein of the crude enzyme was determined with Albumin（bovine serum） as standard protein and the soluble protein content of the crude enzyme was 2.21 g/L.The Km value and the maximal enzymatic degradation rate for chlorpyrifos were 1.235 6 mmol/L and 0.022 6 μmol/（mg·min）,respectively.The appropriate incu-bation time for the enzymatic degradation was 1 h.The highest specific activity of the crude enzyme was gained when the adding volume of the crude enzyme was 1 mL.The crude enzyme activity had op-timal temperature of 28 °C for the enzymatic degradation of chlorpyrifos,which was still over 78% of the maximal activity within temperature ranged from 20 °C to 44 °C.The crude enzyme showed com-paratively greatest enzymatic activity at pH 6,high activity pH ranged from 5 to 9.Furthermore,addi-tional experimental evidence revealed that the crude enzyme had some extent stability for temperature and pH.The crude enzyme also degraded chlorpyrifos efficiently while it was dealt with sodium chlo-ride from 10 g/L to 70 g/L for 1 h.

关 键 词：毒死蜱 蜡状芽孢杆菌 生长规律 酶促降解 KM值 

分 类 号：X172[环境科学与工程—环境科学]