Laccase-catalyzed conversion of natural and synthetic hormones from a municipal wastewater

The Trametes versicolor- derived laccase-catalyzed oxidation of natural estrogens (estrone-E1; 17 ss-estradiol-E2; and estriol-E3) and a synthetic estrogen (17 alpha-ethinylestradiol-EE2) was studied in synthetic water and municipal wastewater to optimize the process for steroid estrogen removal in wastewater. The optimal pH for each studied steroid estrogen oxidation was approximately 6 in synthetic water. This research also focused on the wastewater matrix effect on developed enzymatic treatment. At pH 7.0 and 25 +/- 1 degrees C the experiments showed that the laccase-catalyzed system for the removal of steroid estrogens was not significantly affected by the municipal wastewater matrix. Laccase activity of 20 U/ml was sufficient to achieve complete removal of studied steroid estrogens in both synthetic water and municipal wastewater. Moreover, 1-hydroxy-benzotriazole, when used as a mediator, improved laccase-catalyzed system efficiency, thus decreasing the overall cost of the enzymatic system. (C) 2007 Elsevier Ltd. All rights reserved.