抄録
Recently, enzymatic treatment has attracted much interest in the detoxication and/or transformation of suspected endocrine disrupting chemicals as an alternative strategy to conventional chemical, physical, and biological treatments that pose serious limitations. Therefore, this review summarizes our research efforts spent to remove BPA and its derivatives from an aqueous medium with oxidoreductases, such as horseradish and soybean peroxidases (HRP and SBP), mushroom tyrosinase, and Trametes versilolor laccase. HRP and SBP catalyzed the formation of phenoxy radicals from BPA and its derivatives in the presence of hydrogen peroxide (H2O2), and subsequently water-insoluble oligomers were generated. On the other hand, laccase catalyzed the formation of phenoxy radicals from BPA without H2O2. In these systems, when the enzymatic treatment was initiated in the presence of polyethylene glycol (PEG), the dose of enzymes was considerably less. In addition, when the pH value of the solutions was decreased to 3-4 after the enzymatic treatment, filtration of oligomers was facilitated by aggregation, probably due to hydrogen bonding between phenolic OH groups. BPA also underwent tyrosinase-catalyzed quinone oxidation and this enzymatic reaction was accelerated by the addition of H2O2. In addition, BPA was removed from the aqueous medium through nonenzymatic quinone adsorption on chitosan beads. This procedure was applied to the removal of other derivatives. The data and results reviewed here indicate that the enzymatic treatments we constructed are a promising procedure for removal of BPA and its derivatives.
