Abstract

Microorganisms isolated from soil samples using enrichment culture technique have been grown in the minimal growth media where diazinon served as a sole carbon source. The in vitro biodegradation of diazinon by four bacterial strains entitled S₁, S₂, S₃ and S₄ that isolated from soil was studied in liquid medium. The High-Performance Liquid (HPLC) used for measurement of diazinon residues at successive intervals until 15 days after incubation. The results indicated that during 15 days of incubation all bacteria isolates were able to totally degrade 50 mgkg^-1 diazinon in mineral salt medium (MSM) as a phosphorus and carbon sources.Diazinon Recovery rate was performed at 0.1 and 1 mg kg^-1, achieved values were 80.30 and 91.80%, respectively, limit of detection (LOD) was 0.4mgkg^-1 while limit of quantification (LOQ) was 0.2mgkg^-1. Diazinon half-life values (DT50) were 4.66, 3.76, 3.84 and 3.87 days for S₁, S₂, S₃ and S₄, respectively and control value was 6.44 days. No significant effect on diazinon occurred with S₁ (Stenotrophomonasmaltophilia), S₂ (Pseudomonas Stutzeri), S₃ (AlealigenSp) and S4 (Pantoaanatis) treatments showed significant effect that increased diazinon degradation rate compared to control treatment. These results highlight the potential of these bacteria to be used in the clean-up of contaminated pesticides-waste in the environment.