The soil isolates Pseudumonas strains pesticide biodegradation levels

In this study biodegredation of chlorpyrifos by soil isolates of Pseudomonas sp. strains and its degradation products were studied. The isolates strain named as P3, P4 and PI 5 were used for this study, which were isolated from pesticide pre-treated soil. This strains were biodegrated chlorpyrifos in minimal salt medium. P3 and PI 5 strain were better growth in the medium with chlorpyrifos than that of without chlorpyrifos. It was also observed that while the amount of chlorpyrifos decrases in the highest degree, the highest bacteria growth was determined. The decrease of chlorpyrifos in the medium was determined by gas chromatography (GC). P4 strain was degraded chlorpyrifos fester than that of other strains. In the hour of 12th of incubation, in the chlorpyrifos amount a decrease by 89.1% was determined; in the hour of 48th it was 4.3 % which remained from the first concentration of chlorpyrifos in the medium. P3 strain degraded 76.1% of chlorpyrifos in the first 12th hour, while P15 strain degraded 51.2 % of it. The abiotic degradation of chlorpyrifos was less than biotic one in the conrol medium. In the hour of 12* it was 3.4 % which reduced from the first concentration of chlorpyrifos in the control medium. Chlorpyrifos was not determined in the medium with bacteria in the 96th hour, while in the control medium the 42.3 % of chlorpyrifos was remained in the solution withouth degradation. The degradation products of chlorpyrifos in 96th hour was determined gas chromatoraphy-mass spectrometer (GC-MS). 3,5,6-trichloro-2-pyridinol (TCP) was determined as degradation product of chlorpyrifos. The clear pike of chlorpyrifos was observed in the control medium. Key Words: Pseudomonas sp., Chlorpyrifos, Biodegradation, TCP, GC-MS