Simultaneous Removal of the Antimicrobial Activity and Toxicity of Sulfamethoxazole and Trimethoprim by White Rot Fungi

The excessive use and ineffective treatments have turned antimicrobial drugs into common biologically active micropollutants which are contributing for the rising number of resistant bacteria. Considering the demand for alternative and efficient treatments for the removal of antibiotics from water matrices and also for treatment of expired drugs, the aim of this study was to evaluate the potential of Pleurotus ostreatus, Pleurotus pulmonarius, and Trametes sp. for degrading simultaneously trimethoprim (TMP) and sulfamethoxazole (SMX). Each strain was inoculated in a liquid medium composed of wheat bran extract, Vogel's salts, and 50 mg l(-1) of each antibiotic. The production of laccase was stimulated by the presence of the drugs in cultures of all fungi evaluated. However, extracellular laccase activities were not statistically correlated (p < 0.05) to the reduction of TMP and SMX concentrations in liquid media. Biomass levels were also higher in the presence of the antibiotics. A significant (p < 0.05) correlation was observed between biomass production and SMX removal. Pleurotus spp. were more efficient than Trametes sp. in the removal of the drugs. Approximately 74% of SMX and 40% of TMP were removed from culture medium by P. ostreatus after 15 days of cultivation. The antibacterial and acute toxicity bioassays validated the effectiveness of the assessed fungi in degrading the drugs and hence inactivating its pharmacological activity.