锰过氧化物酶(MnP)对农药毒死蜱降解的初步研究

以广泛使用的有机磷杀虫剂毒死蜱为研究对象,利用白腐菌P.sordida YK-624菌株所产锰过氧化物酶(MnP)对其进行生物降解的初步研究。首先比较确定了MnP降解毒死蜱所需要的降解体系,即对于毒死蜱的降解,需要在有机酸(丙二酸)存在的缓冲体系中进行,此体系不需要表面活性剂Tween 80,但必须含有Mn2+和葡萄糖氧化酶氧化葡萄糖产生的H2O2。随后对主要影响因素的试验结果表明,MnP降解毒死蜱较好的条件是在pH 4.5的丙二酸缓冲体系中含7.5 mmol/L MnSO4、2.5 mmol/L葡萄糖以及40 U葡萄糖氧化酶,温度30℃。此时,400 U/L的MnP可将30 mg/L的毒死蜱经3 d时间降解77.51%。同时,利用GC-MS对毒死蜱酶降解后的产物进行了初步分析,得到1种可能的酶解产物O,O,O’,O’-四乙基二硫代焦磷酸酯,不同于水解和细菌降解途径,值得进行进一步研究。

Biodegradation of Chlorpyrifos by Manganese Peroxidase

Biodegradation of chlorpyrifos by manganese peroxidase(MnP) which was prepared using whit rot fungi P.sordida YK-624 was studied.The systems of chlorpytifos biodegradation were tested.Results showed that the chlorpyrifos biodegradation by MnP should be done in organic acid buffer solution(malonic acid)containing Mn2+ and H2O2 which was produced by glucose oxidase oxidizing glucose.But surfactant Tween 80 was not necessary because of poor solubility of chlorpyrifos.Main influencing factors were determined.It proved that chlorpyrifos could be biodegraded by MnP at 30 ℃ in pH 4.5 malonic acid buffer system,which contained 7.5 mmmol/L MnSO4,2.5 mmol/L glucose and 40 U glucose oxidase.Under the conditions,400 U/L MnP could degrade 77.51% 30 mg/L chlorpyrifos.GC-MS was used to analyze the product of chlorpyrifos biodegradation by MnP.It was found the possible enzymolysis product was O,O,O',O'-tetraethyl-dithiopyrophosphate,different from hydrolysis or bacterium degradation production of chlorpyrifos.