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 β-estradiol—E2; and estriol—E3) and a synthetic estrogen (17 α-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 °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.