Evidence for a radical mechanism in biocatalytic degradation of synthetic dyes by fungal laccases mediated by violuric acid.

Autor: Pogni, Rebecca, Brogioni, Barbara, Baratto, M. Camilla, Sinicropi, Adalgisa, Giardina, Paola, Pezzella, Cinzia, Sannia, Giovanni, Basosi, Riccardo
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Zdroj: Biocatalysis & Biotransformation; Mar2007, Vol. 25 Issue 2-4, p269-275, 7p, 2 Diagrams, 3 Graphs
Abstrakt: The bleaching activity of the Pleurotus ostreatus POXC laccase isoenzyme has been tested against selected single textile acid dyes (two anthraquinonic and two azo dyes), as well as towards a solution mimicking a real acid dye waste-water for wool. The catalytic reaction of POXC has been investigated both in the presence and in the absence of the synthetic mediator violuric acid (VIO) (-NOH type of mediator). In all the cases tested, the presence of the mediator enhanced the reaction rate and the percentage of decolorization, apart from one of the dyes (Acid Blue 62), which is itself a good substrate for the laccase-catalyzed oxidation. Electron paramagnetic resonance (EPR) experiments, after the addition of an excess of VIO to the solution of laccase, showed the presence of a strong and stable radical signal that was assigned to a neutral radical form of VIO. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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