Guaiacol-mediated oxidative degradation and polymerization of bisphenol A catalyzed by bitter gourd (Momordica charantia) peroxidase

Peroxidase from bitter gourd was found to be highly effective in the oxidative degradation and polymerization of endocrine disrupting compound, bisphenol A. Bisphenol A was recalcitrant to the action of bitter gourd peroxidase. However, the oxidation of bisphenol A by bitter gourd peroxidase was enhanced remarkably in the presence of a redox mediator, guaiacol. Maximum oxidation of bisphenol A was observed in the presence of 0.3 mM guaiacol, 0.75 mM H2O2 and 0.32 U mL−1 bitter gourd peroxidase in the buffer of pH 7.0 at 40 °C. In batch process, 90% bisphenol A was removed by this enzyme in 4 h. FT-IR spectral analysis showed the presence of OH group (3308 cm−1) and the benzene groups (1624 and 1224 cm−1) on the bitter gourd peroxidase-oxidized product. 4-Isopropenylphenol was identified as one of the peroxidase-catalyzed oxidation products of bisphenol A by GC–MS and 1H NMR spectral analysis.