Degradation of terbuthylazine, diflufenican and pendimethalin pesticides by Lentinula edodes cultures

Abstract

Much attention has been given to the use of pesticides in the field and the risk of pollution of ground and surface water. A major point source of contamination is spills during filling and cleaning of spraying equipment. One possible approach to reduce this contamination is to treat the pesticide contaminated water, using on-farm biopurification systems. In these systems organic wastes are biologically degraded by the stimulation of the activity of indigenous microorganisms (biostimulation) or by the inoculation of microorganisms with specific biotransforming abilities (bioaugmentation). The aim of the present work was to evaluate the abilities of white-rot Lentinula edodes fungus to degrade the herbicides terbuthylazine, diflufenican and pendimethalin. Among degradation microorganisms, white-rot fungi have demonstrated the ability to degrade a wide variety of aromatic xenobiotics, including polyaromatic hydrocarbons (PAHs), and various groups of pesticides. Liquid batch cultures of L. edodes were carried out in the presence of each pesticide (in triplicate) and the biological degradation was accessed during 20 days. Residual pesticide concentration was analyzed by HPLC-UV and LC–ESI-MS/MS. Pesticide metabolites in liquid cultures were also evaluated by LC–ESI-MS/MS. The results showed degradation rates higher than 70% for all pesticides, after 20 days of culture. In conclusion, it could be stated that the presence of this strain in the substrate of a biopurification system could enhance significantly the degradation of terbuthylazine, diflufenican and pendimethalin