Metabolites of the phenylurea herbicides chlorotoluron, diuron, isoproturon and linuron produced by the soil fungus Mortierella sp.
Phenylurea herbicides are used worldwide, and often pollute surface- and groundwater in concentrations exceeding the limit value for drinking water (0.1 microg l(-1)). Bacteria degrade phenylurea herbicides by successive N-dealkylation to substituted aniline products. Little is known about the corresponding fungal pathways, however. We here report degradation of chlorotoluron, diuron, isoproturon and linuron by the soil fungus Mortierella sp. Gr4. Degradation was fastest with linuron and resulted in successively dealkylated metabolites and 3,4-dichloroaniline. A major new metabolite was detected that has not yet been fully identified. Thin layer chromatography and nuclear magnetic resonance spectroscopy indicate that it is a non-aromatic diol. Degradation of isoproturon, chlorotoluron and diuron involved successive N-demethylation and, in the case of isoproturon and chlorotoluron, additional hydroxylation. A new hydroxylated isoproturon metabolite was detected. The study thus shows that the fungal pathways differ from the bacterial pathways and yield new metabolites of possible environmental concern.
Badawi
Nora
N
Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Østervoldgade 10, DK-1350 Copenhagen K, Denmark.
Rønhede
Stig
S
Olsson
Stefan
S
Kragelund
Birthe B
BB
Johnsen
Anders H
AH
Jacobsen
Ole Stig
OS
Aamand
Jens
J
D001673:Biodegradation, Environmental; D004237:Diuron / Q000378:metabolism*; D006540:Herbicides / Q000378:metabolism*; D008044:Linuron / Q000378:metabolism*; D020094:Mortierella / Q000378:metabolism*; D010671:Phenylurea Compounds / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
D006540:Herbicides; D010671:Phenylurea Compounds; D012989:Soil Pollutants; D008044:Linuron; C028904:isoproturon; D004237:Diuron; C007033:chlortoluron