Enterobacter sp. SWLC2 for biodegradation of chlorpyrifos in the aqueous medium: Modeling of the process using artificial neural network approaches

Abstract

Chlorpyrifos is a widely used organochlorine pesticide. The unsystematic use of pesticides for the restrain of soil-borne pests and bacterium causes pollution of ecosystems and harming the health of animals and humans. Moreover, due to high persistence, mobility, and higher toxicity in soil environments, it causes severe destruction of species. Therefore the investigation of the degradation process of chlorpyrifos polluted locations to diminish its lethal effect is important. With this objective, the present study reports the efficiency of new isolated bacterial strain SWLC2 for chlorpyrifos degradation in an aqueous medium and the biotic/abiotic factors influencing the process and their optimization using statistical Taguchi design and artificial neural network (ANN) approaches. Results revealed a higher efficiency of bacterium SWLC2 for chlorpyrifos degradation at optimal environmental and general conditions (800 μL inoculum, glucose (97%), arginine (89%), and succinic acid (83%)). External supplements (carbon and nitrogen sources) had stimulating effects on chlorpyrifos biodegradation depending on the concentration of supplemented substrate. Chlorpyrifos biodegradation by SWLC2 also varied as the initial concentration of the tested compound changes, following first-order kinetics. The finding provides a basic understanding of the application of the bacteria strain SWLC2 in the bioremediation of soils contaminated with chlorpyrifos pesticide. ANN approaches have achieved an average R2 equal to 0.98–0.99 in the prediction of chlorpyrifos degradation considering the affecting biotic/abiotic factors.