ABSTRACT
As part of a study conducted on the fate of xenobiotics in the environment, a selection of 100 strains of micromycetes (Ascomycetes, Basidiomycetes and Yeasts) have been cultivated in liquid synthetic medium with 3 phenylurea herbicides: chlortoluron and isoproturon (100mg L-1) and diuron (20mg L-1). While 17 strains depleted isoproturon over 50% only 4 depleted diuron and 2 chlortoluron at the same level. The best results were obtained with Bjerkandera adusta and Oxysporus sp which were the most efficient towards the 3 substrates. After 2 weeks Bjerkandera adusta depleted chlortoluron 98%, diuron 92% and isoproturon 88%.
Subject(s)
Ascomycota/metabolism , Basidiomycota/metabolism , Diuron/metabolism , Herbicides/metabolism , Methylurea Compounds/metabolism , Phenylurea Compounds/metabolism , Soil Microbiology , Yeasts/metabolism , Biodegradation, Environmental , Chromatography, High Pressure Liquid , Soil/analysisABSTRACT
As a part of a study conducted on the fate of xenobiotics in the environment, a selection of 90 strains of micromycetes, mostly isolated from soil and belonging to various taxonomic groups, have been cultivated in liquid synthetic medium with chlortoluron (100 mg.L-1), diuron (20 mg.L-1), and isoproturon (100 mg.L-1) for 5 days. Evaluation of the chemicals in the culture media was made by HPLC. Our results show a wide variation not only with taxonomic groups but also with the species, and with the tested chemicals. On the whole, 4, 7, and 11% of the strains depleted respectively chlortoluron, diuron, and isoproturon, at 50% or over. Rhizoctonia solani was the only strain that depleted each of the 3 substituted phenylureas over 70%, nevertheless, the growth of this fungus was slightly inhibited by diuron. The very fast disappearance of the chemicals from the culture media was only due to biotic phenomena, as no adsorption occurred on the fungal biomass. So, depletion translated a real biodegradation of the tested substrates.
