Degradation of UV filters in sewage sludge and 4-MBC in liquid medium by the ligninolytic fungus Trametes versicolor
Fecha
2012-08-15
Tipo
artículo original
Autores
Badia Fabregat, Marina
Rodríguez Rodríguez, Carlos E.
Gago Ferrero, Pablo
Olivares, Alba
Piña, Benjamí
Díaz Cruz, M. Silvia
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Resumen
Ultraviolet (UV) filters are xenobiotic compounds that can enter the environment through the liquid
effluent of wastewater treatment plants (WWTPs) and through adsorption in the sludge by-product
because of their high hydrophobicity, as the sludge is subsequently applied as a fertiliser. A solid-state
treatment of WWTP sludge with the white-rot fungus Trametes versicolor is reported in the present
work as a feasible method for UV filter degradation, with reductions ranging from 87% in the case of 3-
(40
-methylbenzylidene) camphor (4-MBC) to 100% for benzophenone-3 (BP3) and its metabolite 4,40
-
dihydroxybenzophenone (4DHB). This study represents a first step in the development of a future fungal
treatment for UV filters; thus, it is essential to prove that elimination is due only to the action of the
fungus and not that of other microorganisms. To this end, the sludge was sterilised prior to fungal
treatment. Biological assays indicate that T. versicolor readily eliminates oestrogenic activity, although it
may be inefficient at eliminating other compounds, including some with dioxin-like activity. Degradation
studies of 4-MBC in liquid media were also performed, and complete removal was achieved in less than
24 h. The main metabolites were identified, and the first steps of the transformation pathway were
elucidated: a mono- or di-hydroxylation by cytochrome P450 and a subsequent conjugation with
a pentose. None of 4-MBC transformation products was found to be responsible for increased dioxin-like
activity in the sludge.
Descripción
Palabras clave
Solid-state fermentation, 3-(4'-Methyylbenzylidene) camphor, Metabolites, Toxicological assays