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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 (V max ) of 702.8 µg DOX h -1 L -1 and Michaelis-Menten constant (K M ) 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., (Copyright © 2020 Elsevier B.V. All rights reserved.)

• Doxorubicin can hinder biogas production rate. • The inhibition caused by doxorubicin was reversible. • Rapid drug sorption into the biomass was observed despite the low Kow value. • Methanosaeta and Methanobacterium were the most abundant archaeas in long-term exposure to doxorubicin. The inhibitory effect of the anticancer drug doxorubicin (DOX) on biogas production was evaluated in short-term and long-term exposure assays. The short-term assays reached the DOX IC 50 value on 648 ± 50 µg·L−1. In addition, it was found that inhibition caused by the exposure of 10×103 µg·L−1 was reversible after removing DOX from the feeding synthetic medium. Furthermore, DOX can be rapidly sorbed by the biomass (despite the low Kow), which might contribute to the inhibitory effect. The results of long-term exposure assays, when the DOX volumetric loading rate was increased from 100 µg DOX ·L−1·day−1 to 200 µg DOX ·L−1·day−1, showed that biogas production and COD removal decreased rapidly. However, the methanogenic Archaeas could recover from this exposure, corroborating the results on short-term exposure assays. In conclusion, DOX can play a key role in inhibiting biological wastewater treatment processes if its concentration in hospital wastewater treatment plants increases abruptly. [Display omitted] [ABSTRACT FROM AUTHOR]