Isolation and characterization of organophosphate pesticides degrading bacteria from contaminated agricultural soil

Abstract

The soil sample was collected from Agriculture University Gwalior, Madhya Pradesh, India which is having a history of repeated pesticide application. Bacterium capable of degrading Malathion and Dichlorvos were isolated and identify as Staphylococcus sp. Micrococcus sp. Entrobacte sp. Bordetella sp. Pseudomonas sp. and Klebsella sp. The growth of all six pesticide degrading isolates was assessed in Mineral Salt Medium (MSM) canting 100 mg/lit of each pesticide. The maximum growth rate by the isolates Pseudomonas sp. AUG12 were 1.564 and 1.435 for Malathion and Dichlorvos respectively after 140 h Plate assay revealed that Pseudomonas sp. AUG12 could grow with high concentration of Malathion (1900 mg/lit) and Dichlorvos (1500 mg/lit). The total protein concentration was higher in the supernatant of Pseudomonas sp. AUG12 extracellular fraction which is 97 μg/mL for Malathion and 99 μg/mL for Dichlorvos. The beast Pseudomonas sp. AUG12 was therefore used in further experiment. The maximum growth ret of Pseudomonas was recorded at 30°C and pH 7.0 the growth of Pseudomonas was maximum in the presence of sucrose fallowed by starch maltose the least growth was recorded in lactose the growth of Pseudomonas sp. AUG12 was maximum in the presence of peptone fallowed by yeast extract and beef extract. The least growth was recorded in urea as nitrogen source. The result of this study suggested a relation among microbial growth pH and temperature in MSM medium with different carbon and nitrogen source. The Organophasphorus Phosphatase (OPP) production and that OPP concentration were higher in the supernatant of Pseudomonas sp. AUG12 extracellular fraction.