Removal of various aromatic compounds from synthetic and refinery wastewater using soybean peroxidase

Crude soybean peroxidase (SBP), isolated from soybean seed hulls, catalyzed the oxidative polymerization of hazardous aqueous pollutant aryldiamines, aryldiols, 2-mercaptobenzothiazole and phenol in the presence of hydrogen peroxide. Experiments were conducted to investigate the optimum operating conditions including pH, hydrogen peroxide-to-substrate concentration ratio and the minimum SBP concentration required to achieve at least 95 conversion of these pollutants in synthetic and refinery wastewaters. In addition, the effect of PEG3350 on enhancing the conversion efficiency was studied. The substrate conversion and hydrogen peroxide consumption were monitored over the period of the reactions. The enzymatically-generated polymeric products from aryldiamines could be removed with surfactant, sodium dodecyl sulphate (SDS), whereas polyvalent metal cation salt, aluminium sulphate (Alum), was able to remove the products from aryldiols. Enzyme-catalyzed polymerization using SBP and the methods for removal of the generated polymeric products can provide an alternative means to the conventional treatment methods for treating aromatic wastewater pollutants