Biodegradation of the Pesticide Diazinon by Bacteria Isolated From a Contaminated Soil

Abstract

Our research focused on the identification and isolation of diazinon (DZ)-degrading bacteria, as DZ is one of the most commonly used organophosphate pesticides in orchards and farms. We collected samples from a garden in Iran where DZ has been used for a long time. This allowed us to extract three types of bacteria capable of degrading DZ. Through biochemical and molecular tests, these bacteria were identified as Pseudomonas oryzihabitans, Enterobacter kobei, and Serratia species. The bacteria were cultured for 10 days in broth and soil media with DZ concentrations of 10 and 20 ppm. The degradation and utilization of the toxin by the bacteria were measured using gas chromatography. The results indicated that P. oryzihabitans degraded the toxin at concentrations of 10 and 20 ppm in liquid medium by 47.1% and 27.45%, respectively. In soil medium, the bacteria degraded 96.5% and 97.1% of the toxin at the same concentrations. Serratia sp. degraded DZ in broth medium with initial concentrations of 10 and 20 ppm by 64.3% and 78.4%, respectively. Additionally, these bacteria were able to degrade DZ by 90.2% and 98.25% in soil. E. kobei consumed DZ in the broth and soil media at rates of 23.1% and 17.95% and 31.19% and 88.05%, respectively. According to the results, P. oryzihabitans exhibited the highest degradation capacity compared to the other bacteria. Collectively, these three bacteria demonstrate a significant ability to biologically remediate environments contaminated with DZ.