漆酶/香草醛体系生物降解毒死蜱影响因素的研究

Factors affecting the biodegradation of chlorpyrifos by laccase/vanillin system

研究了漆酶介体体系对有机磷农药毒死蜱生物降解的效果及影响因素。通过对6种介体的试验比较,筛选了合适的介体。在试验条件下,1-羟基苯并三唑(HBT)和2,2’-联氮-二(3-乙基-苯并噻唑-6-磺酸)(ABTS)对漆酶降解毒死蜱存在一定的抑制作用,紫脲酸(VA)和2,6-二甲氧基苯酚(2,6-DMP)对漆酶降解毒死蜱未起促进作用,而天然产物香草醛和愈创木酚可促进漆酶降解毒死蜱,香草醛的促进作用最为明显,选择香草醛作为漆酶介体体系中的介体。研究了漆酶/香草醛体系中,反应时间、漆酶初始酶活、pH、温度、介体投加量及投加方式、毒死蜱初始浓度等因素对毒死蜱生物降解效果的影响。结果表明,控制漆酶初始酶活为0.050U/mL、pH为5.0、温度30℃,分2次投加香草醛(香草醛与毒死蜱初始值摩尔比分别为40和80)情况下,漆酶/香草醛体系即可在24h内实现对25mg/L毒死蜱的有效降解,降解率达98%。

The biodegradation of organophosphorus pesticide chlorpyrifos by laccase-mediator system （LMS） was studied and main factors that influencing the degradation efficiency were investigated. The performance of six mediators in LMS were tested, results showed that vanillin and guaigcol promoted the degradation of chlorpyrifos by laccase, while 1-hydroxybenzotriazole （HBT） and 2,2 ＇-azino-bis （3-ethylbenzothiazoline-6-sulfonate） （ABTS） inhibited the degradation,violuric acid and 2,6-dimethoxyphenol had no obvious promotion. So vanillin was chosen as the media- tor in LMS. The effect of reaction time,initial laccase activity, p H, temperature,mediator dosage and the initial chlorpyrifos concentration on chlorpyrifos biodegradation was investigated. The results showed that chlorpyrifos could be well biodegraded by laccase/vanillin system. When laccase dosage was 0. 050 U/mL,initial pH was 5.0, temperature was 30 ℃ and adding vanillin for twice （molar rate of vanillin and chlorpyrifos was 40 and 80 respectively）,98% of chlorpyrifos could be degraded in laccase/vanillin system in 24 h.