Abstract:

To identify the degradation effect on pesticide of detoxifying enzyme produced by pseudomonas alcaligenes, the degradation of methyl parathion by detoxifying enzyme in aqueous solution and on vegetable was studied and the degradation products were also analyzed using gas chromatography-mass spectrometry (GC-MS) method. The results showed that the detoxifying enzyme could effectively degrade methyl parathion, and the higher the enzyme concentration was, the better the degradation of methyl parathion was. The degradation rate of methyl parathion could reach 81.7% after methyl parathion with the initial concentration of 0.3 mg/L in aqueous solution treated with 320 mg/L enzyme for 90 min. And the degradation rate of methyl parathion could reach 58.5% after the commensurate enzyme was applied to methyl parathion with the initial concentration of 0.5 mg/kg in vegetable samples 60 min later. Furthermore, the 4-nitrophenol was identified as the degradation product of methyl parathion by GC-MS. In addition, the degradation of methyl parathion fitted the first-order kinetic model well (R2>0.84), which provided theoretical basis for its application in practice.

Key words: detoxifying enzyme, methyl parathion, degradation, kinetics, degradation product

摘要：

为验证产碱假单胞菌代谢产生的解毒酶对农药的降解作用,研究了该酶对水体系和蔬菜中的甲基对硫磷的降解规律,同时采用气相色谱-质谱法(GC-MS)分析了酶作用后甲基对硫磷的降解产物。结果表明:此酶可以有效降解甲基对硫磷的残留,且酶浓度越高,其降解效果越好。当水体系中甲基对硫磷起始浓度为03 mg/L时,添加320 mg/L的酶作用90 min后,甲基对硫磷的降解效果可达81.7%;当蔬菜体系中甲基对硫磷浓度为0.5 mg/kg时,添加相同量的酶作用60 min后,甲基对硫磷的降解效果可达58.5%。通过GC-MS确定降解产物为4-硝基酚,水体系中甲基对硫磷的降解规律符合一级反应动力学模型(R2>0.84),这为促进其在实际生产中的应用提供理论依据。

关键词: 解毒酶;甲基对硫磷;降解;动力学;降解产物