Significantly enhanced biodegradation of profenofos by Cupriavidus nantongensis X1T mediated by walnut shell biochar

Abstract

The feasibility of using walnut shell biochar to mediate biodegradation of Cupriavidus nantongensis X1^T for profenofos was investigated. The results of scanning electron microscopy, classical DLVO theory and Fourier transform infrared spectroscopy indicated that strain X1^T was stably immobilized on biochar by pore filling, van der Waals attraction, and hydrogen bonding. Profenofos degradation experiments showed that strain X1^T immobilized on biochar significantly decomposed profenofos (shortened the half-life by 5.2 folds) by promoting the expression of the degradation gene opdB and the proliferation of strain X1^T. The immobilized X1^T showed stronger degradation ability than the free X1^T at higher initial concentration, lower temperature and pH. The immobilized X1^T could maintain 83% of removal efficiency for profenofos after 6 reuse cycles in paddy water. Thus, X1^T immobilized using walnut shell biochar as a carrier could be practically applied to biodegradation of organophosphorus pesticides present in agricultural water.

Keywords: Biochar; Biodegradation; Cupriavidus nantongensis X1(T); Mediated transformation; Organophosphorus pesticide.