Biodegradation of the herbicide penoxsulam (triazolopyrimidine sulphonamide) by fungal strains of Aspergillus in soil

摘要

Penoxsulam is a new post-emergence triazolopyrimidine sulphonamide herbicide registered for weed control in rice crop. It is suspected to pose a potential risk for aquatic organisms and crop plants as well as for the soil microbial communities. Bacterial degradation of penoxsulam in soil have been reported widely, however, no information exist on fungal degradation. Therefore in the present study, biodegradation of penoxsulam in soil by two fungal strains, Aspergillus flavus and Aspergillus niger was investigated. Degradation kinetics showed that degradation of penoxsulam in the soil was followed by formation of several degradation products/metabolites by both the fungi. Cleavage of the sulfonamide was found to be a major degrading pathway, yielding the corresponding sulfonamide and heterocyclic amine. Penoxsulam degraded at a faster rate in the soil inoculated with A. flavus than A. niger. These results showed that Aspergillus flavus and Aspergillus niger can enhance microbial degradation of penoxsulam in the soil. (c) 2016 Elsevier B.V. All rights reserved.