抄録
The use of pentachlorophenol (PCP) as a wood-preserving agent at many wood treating sites has resulted in widespread contamination of the environment. Biodegradation catalyzed by oxidative enzymes such as horseradish peroxidase (HRP) has been proposed as a treatment method for aqueous PCP. One major issue associated with the use of enzymes is enzyme inactivation which increases treatment costs due to the high cost of the enzymes. To enhance the cost-effectiveness of the enzymatic approach, various additives have been tested for their ability to minimize enzyme inactivation. This study was initiated to investigate the potential influence of two nonionic surfactants (Tween 20 and Tween 80) on the catalytic behavior of HRP in PCP transformation. The surfactants were tested at concentrations below and above their critical micelle concentrations (CMC). Enhancement of PCP removal was observed at sub-CMC concentrations. The presence of surfactant in the reaction mixture reduced enzyme inactivation which occurred predominantly through binding with pentachlorophenoxyl radicals. At supra-CMC concentrations, the surfactants caused a noticeable reduction in PCP removal from the reaction mixture, presumably through micelle partitioning of the hydrophobic PCP molecules, precluding them from interacting with the enzyme.
