毒死蜱降解菌株的分离鉴定及降解条件优化

目的:分离筛选出毒死蜱降解菌株，研究其生长特性及降解特性，菌株降解酶的定位及降解广谱性研究。方法:取自长白山区周边农田土，利用以毒死蜱为碳源的无机盐培养基对土壤中的微生物进行富集培养，通过形态学观察、生理生化鉴定以及16S rRNA分子测序确定菌属。菌株毒死蜱降解酶的定位，菌株对敌敌畏、氧化乐果、甲基对硫磷、水胺硫磷、乙草胺和莠去津广谱降解的测定，通过单因素实验和正交试验对菌株降解毒死蜱条件进行优化。结果:筛选到一株毒死蜱降解菌Pseudomonas aeruginosa AY-1，经初步鉴定为铜绿假单胞菌，其毒死蜱降解酶为胞内酶，对敌敌畏、氧化乐果、甲基对硫磷、水胺硫磷、乙草胺和莠去津具有良好的广谱降解能力，经正交试验优化后，最适降解条件为35 ℃，pH=8，底物浓度为100 mg/L，降解效率为75.09%。结论:菌株Pseudomonas aeruginosa AY-1对毒死蜱具有较高的降解能力，对有机磷农药有一定的广谱降解效果，在有机磷农药污染环境修复及去除食用农作物表面有机磷农药残留方面极具应用潜力。

Isolation and Identification of Chlorpyrifos Degrading Strains and Optimization of Degradation Conditions

Objective: Isolating and screening the chlorpyrifos-degrading strains, and studying their growth characteristics and degradation characteristics, the location of the strain’s degrading enzymes and the broad-spectrum degradation studies. Methods: Taken from the farmland soil around Changbai Mountain, the inorganic salt medium with chlorpyrifos as carbon source was used to enrich the microorganisms in the soil, and the genus was determined by morphological observation, physiological and biochemical identification and 16SrRNA molecular sequencing. The location of the chlorpyrifos-degrading enzyme of the strain, the determination of the broad-spectrum degradation of the strain against dichlorvos, omethoate, methyl parathion, hydrocarbamate, acetochlor, and atrazine, and the degradation of the strain by single factor experiment and orthogonal test. The chlorpyrifos conditions are optimized. Results: A chlorpyrifos-degrading bacterium Pseudomonas aeruginosa AY-1 was screened and initially identified as Pseudomonas aeruginosa. Its chlorpyrifos-degrading enzyme was an intracellular enzyme. Phosphorus, acetochlor, and atrazine had good broad-spectrum degradation ability. After orthogonal test optimization, the optimal degradation conditions were 35 ℃, pH=8, and the substrate concentration was 100 mg/L, the degradation efficiency was 75.09%. Conclusion: The strain Pseudomonas aeruginosa AY-1 had a high ability to degrade chlorpyrifos, and had a certain broad-spectrum degradation effect on organophosphorus pesticides. It would have a great application potential in the remediation of organic phosphorus pesticides polluted environment and the removal of organophosphorus pesticide residues on the surface of food crops.