Biodegradation mechanism of chlorpyrifos by halophilic bacterium Hortaea sp. B15.

For decades, most of the developing nations have relied on chlorpyrifos for insecticidal activity in the agriculture sector. It is a common chlorinated organophosphorus pesticide that has been widely used to control insects to protect plants. This study aimed to investigate the effects of environmental characteristics such as salinity, pH, temperature, and surfactant on Hortaea sp. B15 mediated degradation of chlorpyrifos as well as enzyme activity and metabolic pathway. The highest bacterial growth (4.6 × 1016 CFU/mL) was achieved after 20 h of incubation in a 100 mg/L chlorpyrifos amended culture. The fit model and feasible way to express the chlorpyrifos biodegradation kinetics in normal condition and optimized was a first-order rate equation, with an R 2 value of 0.95–0.98. The optimum pH for chlorpyrifos biodegradation was pH 9, which resulted in a high removal rate (91.1%) and a maximum total count of 3.8 × 1016 CFU/mL. Increasing the temperature over 40 °C may inhibit microbial development and biodegradation. There was no significant effect of culture salinity on degradation and bacterial growth. In the presence of non-ionic surfactant Tween 80, the maximum chlorpyrifos degradation (89.5%) and bacterial growth (3.8 × 1016 CFU/mL) was achieved. Metabolites such as 3,5,6-trichloropyridin-2-ol and 2-pyridinol were identified in the Hortaea sp. B15 mediated degradation of chlorpyrifos. According to the findings, Hortaea sp. B15 should be recommended for use in the investigation of in situ biodegradation of pesticides. [Display omitted] • Hortaea sp. Enzymatic transformation of insecticide chlorpyrifos is studied. • High bacterial growth is achieved after 20 h in the presence of 100 mg/L chlorpyrifos. • The effective pH for chlorpyrifos biodegradation (91.1%) Hortaea sp. Is pH 9. • Non-ionic surfactant Tween 80 exhibits the maximum chlorpyrifos degradation (89.5%). • 3,5,6-Trichloropyridin-2-ol and 2-pyridinol were identified as degradation products. [ABSTRACT FROM AUTHOR]