Pseudomonas Putida XP12’s enzymatic degradation in pyrethroid pesticides and its application study

The experiment adopts Beta-cypermethrin,Deltamethrin and Cyhalothrin,which are widely used,highly toxic and hard to be degraded,as trial pesticides and further studies a strain of Pseudomonas Putida XP12,which can effectively degrade Pyrethroid Pesticides,to get to know enzymatic distribution of this strain in biodegradation system of Pyrethroid Pesticides and dynamic characteristics of enzymatic degradation.The result proves that the enzyme,which has catalysis in Pyrethroid Pesticides,is a kind of constitutive intracellular enzyme.When reaction ph varies between 6.5 and 8.0,degradation rate of degrading enzyme in Beta-cypermethrin,Deltamethrin and Cyhalothrin reaches about 70% and optimum reaction ph is 7.5;when temperature varies between 25℃ and 40℃ and degradation rate is above 70%,temperature of optimum reaction is 30℃.With optimum reaction ph and temperature,crude enzyme liquid’s Km of degrading enzyme in Beta-cypermethrin,Deltamethrin and Cyhalothrin is respectively 42.78 nmol/mL,50.64 nmol/mL and 77.90 nmol/mL,and Vmax is respectively 12.05nmol/min,10.31nmol/min and 16.39 nmol/min.Crude enzyme liquid also has obvious degradation effect on Pyrethroid Pesticides of leaf vegetable and its degradation rate in Beta-cypermethrin,Deltamethrin and Cyhalothrin is respectively 93.3%,85.2% and 83.5%.