Transformation of N ',N '-dimethyl-N-(hydroxyphenyl)ureas by laccase from the white rot fungus Trametes versicolor

Transformation of N',N'-dimethyl-N-(hydroxyphenyl)ureas was assayed in the presence of purified laccase produced by the fungus Trametes versicolor. Th e para- and ortho-hydroxyphenyl derivatives were enzymatically transformed, whereas the meta derivative was not. The performance of laccase-mediated t ransformation depended on the pH, with an optimum for the para-derivative d egradation rate at pH 5. The pH also influenced the nature of the reaction products. The chemical was exclusively oxidised into p-benzoquinone at pH 3 and into mainly N',N'-dimethyl-N-[(2,5 -cyclohexadiene-1-one)-4-ylidene]ur ea at pH 6. The orthoderivative was transformed essentially into insoluble purple compounds, probably appearing as polymers resulting from coupling of the parent compound.