Chlorpyrifos degrading potential of a novel Kosakonia sp. FYF33 isolated from agricultural drainage water

The indiscriminate use of chlorpyrifos (CP) has led to significant environmental toxicity that adversely affects various water resources. The main metabolite of CP, 3,5,6-trichloro-2-pyridinol (TCP), is more toxic and persistent than CP. Most bacteria can degrade only CP but not TCP due to its antimicrobial activity. This study reports the efficiency of a new CP–degrading bacterium, Kosakonia sp. FYF33 (accession no. OK325589), which was isolated from CP-contaminated agricultural drainage water. Kosakonia sp. FYF33 was able to degrade 94.6 % of CP (700 mgl −1 ) within 9 days of incubation, which further reached 96.1 % within 5 days of incubation when Plackett–Burman (PBD) and central composite designs (CCD) were applied. This study also revealed that the oph gene (accession no. OM502408), encoding an organophosphorus hydrolase (OPH), was responsible for CP degradation in Kosakonia sp. FYF33. Quantitative real-time PCR (qRT–PCR) analysis revealed a 5.27-fold expression of this gene under CP treatment, indicating enhanced enzymatic activity for pesticide breakdown. On the basis of GC–MS analysis, a probable pathway for CP breakdown has been proposed that follows the pathway from CP to TCP to 2-ethyl-6-methyl-3-hydroxypyridine and then enters the TCA cycle. These findings could impact the development of bioremediation strategies. This study is considered the first publication to employ PB and CCD to optimize the degradation of CP and to elucidate the degradation pathway by the genus Kosakonia .