一硫代磷酸酯类杀虫剂的微生物降解

Microbial Degradation of O-Phosphothioate Insecticides

在纯培养条件下测定了分离株 YF0 5对对硫磷等一硫代磷酸酯类杀虫剂的降解作用。在接种量 (OD4 15nm)为 0 .2、p H7.0、30℃条件下 ,测得 10、2 5、50、10 0、2 0 0、50 0 mg/ L对硫磷的降解符合一级动力学特征 ,其降解速率常数分别为 0 .0 77、0 .12 3、0 .12 8、0 .119、0 .0 84、0 .0 13,高浓度对硫磷对 YF0 5菌有抑制作用 ;分离株 YF0 5在不同温度及 p H下对对硫磷的降解作用为 4 0℃ >30℃ >2 0℃ ,p H8.0 >p H7.0 >p H6 .0。同样条件下 ,YF0 5对杀螟硫磷和甲基对硫磷也有较好的降解作用 ,对甲基对硫磷的降解速率常数与对硫磷相仿 ,对杀螟硫磷的降解速率常数略高于对硫磷。

Degradation characteristics of O phosphothioate insecticides by the isolated strain Pseudomonas sp. YF05 were measured. Degradation of parathion was determined to be first order kinetic under conditions of pH7.0, 30 ℃, and biomass of OD 415 nm 0.2. The rate constants for degradation of parathion at concentrations of 10, 25, 50, 100, 200, 500 mg/L, were measured to be 0.077, 0.123, 0.128, 0.119, 0.084, 0.013, respectively. The capability of YF05 was inhibited by parathion at high concentration. The degradation rate of parathion by YF05 was affected by pH and temperature as the orders of pH 8.0>pH 7.0>pH 6.0, 40 ℃> 30 ℃ >20 ℃, respectively. Parathion-methyl and fenitrothion could be degraded rapidly by the isolated strain YF05. The rate constant for degradation of parathion methyl was almost the same as that of parathion, and that of fenitrothion was greater than that of parathion.