Laccase production by Pycnoporus sp. W-9 using rose dregs and its application for phenol degradation

Abstract

Rose dregs were used for laccase production by the strain Pycnoporus sp. W-9 under liquid fermentation, and the obtained laccase was used for phenol degradation. The conditions for laccase production were optimized by Box-Behnken design, and the phenol degradation conditions using the crude laccase were optimized by central composite design. The optimal conditions for laccase production by the strain W-9 were as follows: rose dregs (40 g/L), KCl (0.144 g/L), KH2PO4 (1 g/L), K2HPO4 (0.699 g/L), NaCl (0.2 g/L), MgSO4·7H2O (0.3 g/L), CuSO4·5H2O (0.306 g/L), Tween 80 (0.2 g/L), and CaCO3 (1 g/L), at a pH of 6.0, incubated at 30 °C and 200 rpm for 7 d. The corresponding laccase yield reached 17.4 U/mL, which was approximately 1.8 times the original production. The optimal conditions for phenol removal by the crude laccase were as follows: laccase (12.2 U/mL), 0.1 mol/L citric acid-disodium hydrogen phosphate buffer (pH 3.5), phenol (100 μg/mL), and Triton X-100 (284 μg/mL), incubated at 45 °C for 2 h. The corresponding phenol degradation rate reached 86.6%. These results should be useful for utilization of rose dregs and bioremediation of soil and wastewater.