Eliminating antibiotics by white-rot-fungi Trametes versicolor from manure solids and synthetic wastewater

Antibiotics have been abused in livestock as veterinary drug and feed additive. Their incomplete metabolization by animals resulted in heavy accumulation in livestock manure, and therefore they can pose a threat to the environment. In this study, the mechanism of three antibiotics (oxytetracycline (OTC), sulfadiazine (SDZ), enrofloxacin (ENR)) removal/biodegradation by Trametes versicolor pellets in air-pulse fluidized-bed reactor was explored, and the effects of wood immobilized T. versicolor on four antibiotics (OTC, SDZ, ENR and chloramphenicol (CAP)) removal in solid cow manures were evaluated. T. versicolor could remove OTC, SDZ, ENR through adsorption and biodegradation, with the removal efficiency at 92 % and 98 % in 21 h and 98 % after 68 h, respectively. The removal kinetics of those three antibiotics fitted well with the first-order kinetic model, with the removal constant k at -0.238 h^-1, -0.102 h^-1 and -0.023 h^-1, respectively. T. versicolor could biodegrade those three antibiotics using laccase and cytochrome P450 system with the order SDZ ≈ OTC > ENR. Furthermore, wood immobilized T. versicolor promoted SDZ, OTC, ENR and chloramphenicol (CAP) antibiotic biodegradation in cow manure, especially in high inoculation ratio (wood immobilized T. versicolor: solid cow manures = 1:2). This study revealed the mechanism of simultaneous SDZ, OTC, ENR and CAP antibiotic removal/biodegradation by white-rot fungi T. versicolor even by wood immobilized T. versicolor in solid cow manures, which provide a theoretical basis for future application of biological removal of antibiotics present in wastewater and solid manures.