Peroxidase catalyzed phenolic compounds oxidation in presence of surfactant Dynol 604: A kinetic investigation

The kinetics of fungal peroxidase-catalyzed phenolic compounds (PCs) oxidation was investigated in presence of acetylenic-based surfactant Dynol 604 at pH 5.5 and 25 degrees C. It was shown that the presence of ppm concentrations of surfactant did not influence initial rate of PCs oxidation. The calculated apparent bimolecular rate constants were (1.8 +/- 0.2) x 10(5) M(-1) s(-1). (1.4 +/- 0.4) x 10(7) M(-1) s(-1), (1.30 +/- 0.006) x 10(7) M(-1) s(-1) and 1.1 x 10(8) M(-1) s(-1) for phenol, 1-naphthol, 2-naphthol and 1-hydroxypyrene, respectively. During an extensive Substrates conversion Dynol 604 showed diverse action for different PCs. The oxidation of phenol practically did not change, whereas the surfactant enhanced the conversion of 1- and 2-naphthol and 1-hydroxypyrene in dose response manner. The results accounted by a scheme, which contains a stadium of enzyme inhibition by oligomeric PC oxidation products. The action of the surfactant was explained by avoidance the enzyme active center clothing with the oligomers. The results acquired demonstrate a remarkable increase of substrates conversion in the presence of Dynol 604. (C) 2009 Elsevier Inc. All rights reserved.