Abstract

In this study, we selected and characterized different pesticide-tolerant bacteria isolated from a biomixture of a biopurification system that had received continuous applications of a pesticides mixture. The amplicon analysis of biomixture reported that the phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were predominant. Six strains grew in the presence of chlorpyrifos and iprodione. Biochemical characterization showed that all isolates were positive for esterase, acid phosphatase, among others, and they were identified asPseudomonas,RhodococcusandAchromobacterbased on molecular and proteomic analysis. Bacterial growth decreased as both pesticide concentrations increased from 10 to 100 mg L(-1)in liquid culture. TheAchromobactersp. strain C1 showed the best chlorpyrifos removal rate of 0.072-0.147 d(-1)a half-life of 4.7-9.7 d and a maximum metabolite concentration of 2.10 mg L(-1)at 120 h. On the other hand,Pseudomonassp. strain C9 showed the highest iprodione removal rate of 0.100-0.193 d(-1)a half-life of 4-7 d and maximum metabolite concentration of 0.95 mg L(-1)at 48 h. TheAchromobacterandPseudomonasstrains showed a good potential as chlorpyrifos and iprodione-degrading bacteria.