Optimization of omethoate degradation conditions and a kinetics model

Omethoate is an organophosphorus pesticide that presents a high pollution potential and health risk. The objective of this study was to use response surface methodology (RSM) to determine the optimal conditions for degradation of omethoate by Aspergillus niger, and to establish a model of the degradation kinetics. The Box–Behnken center-united experimental design was used to determine the effects of glucose concentration, initial pH and culture temperature on omethoate degradation. On the basis of the response surface and contour plots, the optimum conditions for omethoate degradation were; 1.9% (w/v) glucose, initial pH 6.21, and culture temperature 32.64 °C. According to the hypothetical kinetic model for omethoate degradation, the kinetics for omethoate degradation could be described by a first-order rate equation. The results of this study are very useful as a first step in studying the biodegradation of omethoate.