Enzymatic degradation of tetracycline and oxytetracycline by crude manganese peroxidase prepared from Phanerochaete chrysosporium.

Pharmaceuticals have been attracting increasing attention in recent years as emerging contaminants, of which the most frequently detected kind in various environments are antibiotics. In this study, crude manganese peroxidase (MnP) prepared from the Phanerochaete chrysosporium, a white rot fungi, was taken as a highly efficient biocatalyst to degrade tetracycline (TC) and oxytetracycline (OTC) which are widely used antibiotics. The results show that 72.5% of 50mg/L of TC was degraded when added 40 U/L of MnP, while 84.3% of 50mg/L of OTC was degraded with the same amount of the catalyst added, both within 4h. The degradation rate was dependant on the pH and the temperature of the reaction system, and was likely sensitive to the concentration of H(2)O(2). With the pH at 2.96-4.80, the temperature at 37-40 degrees C, the Mn(2+) concentration higher than 0.1mM and up to 0.4mM, the H(2)O(2) concentration of 0.2mM, and the enzyme-substrate ratio above 2.0 U/mg, the degradation rate reached the highest. In addition, a separate series of experiments also show that the compensation of H(2)O(2) during the reaction process could improve the degradation of TC by MnP. Copyright (c) 2010 Elsevier B.V. All rights reserved.