Laccase-catalyzed degradation of anti-inflammatories and estrogens

Pharmaceuticals are regarded as emerging environmental pollutants since many of them are ubiquitous, recalcitrant and biologically active. In this paper, the degradation of several pharmaceuticals such as anti-inflammatory drugs (diclofenac and naproxen) and estrogen hormones (estrone, 17β-estradiol, 17α-ethinylestradiol) was assessed by means of the commercial laccase (Lac) from Myceliophthora thermophila. The influence of different mediators (synthetic and natural) and their concentration on the Lac-based oxidation system were evaluated. Estrogens were completely degraded after only 15 min while the other types of pharmaceuticals presented higher persistence since 1 h of incubation was required for total removal of diclofenac and 8 h to attain up to 60% of naproxen degradation. Among the different natural mediators, syringaldehyde greatly enhanced the action of the Lac, similarly to the synthetic mediator 1-hydroxibenzotriazole (HBT) in the case of estrogens and diclofenac. The other natural mediators presented significantly high efficiency, obtaining removal percentages ranging from 80% to 100% after 24 h of enzymatic reaction.