Laccase as an efficacious approach to remove anticancer drugs: A study of doxorubicin degradation, kinetic parameters, and toxicity assessment.

The degradation of an anticancer drug by laccase was investigated for the first time, bringing a new approach to treat these hazardous substances through the direct enzymatic application. Degradations of doxorubicin by laccase were performed in different enzymatic concentrations, pH values and temperatures through kinetic studies. The highest enzymatic degradation of doxorubicin was achieved at pH 7 and 30 ºC, which resembles effluent characteristics from wastewater treatment plants. Assays were carried out in different doxorubicin concentrations to comprehend the enzymatic kinetics of degradation. Michaelis-Menten kinetic parameters obtained were maximum velocity obtained (Vmax) of 702.8 µgDOX h-1 L-1 and Michaelis-Menten constant (KM) of 4.05 µM, which showed a good affinity for the substrate. The toxicity was evaluated against L-929 cell line, and the degraded doxorubicin solution did not show a reduction in cell viability in the concentration of 250 µg L-1. In contrast, the doxorubicin shows a reduction of 27% in cell viability. Furthermore, in the highest tested concentration (1000 µg L-1), enzymatic degradation reduced in up 41.4% the toxicity of doxorubicin, which indicates laccase degrades doxorubicin to non-toxic compounds. In conclusion, this study provides a new application to laccase since the results showed great potential to remove anticancer drugs from effluents.