Optimization of C/N Ratio and Inducers for Wastewater Paper Industry Treatment Using Trametes versicolor Immobilized in Bubble Column Reactor

Abstract

C/N ratio and MnSO 4 and CuSO 4 concentrations were optimized for decolorization and chemical oxygen demand (COD) removal of bleached Kraft pulp mill effluent by Trametes versicolor immobilized in polyurethane foam. Statistical differences ( P < 0.0001 ) at high C/N ratios (169), 2 mM CuSO 4 , and 0.071 mM MnSO 4 were determined. Decolorization of 60.5%, COD removal of 55%, laccase (LAC) 60 U/L, and manganese peroxidase (MnP) 8.4 U/L were obtained. Maximum of decolorization (82%), COD removal (83%), LAC (443.5 U/L), and MnP (18 U/L) activities at C/N ratio of 405 (6.75 mM CuSO 4 and 0.22 mM MnSO 4 ) was achieved in step 7 at 4 d. Positive correlation between the decolorization, COD removal, and enzymatic activity was found ( P < 0.0001 ). T. versicolor bioremediation capacity was evaluated in bubble column reactor during 8 d. Effluent was adjusted according to optimized parameters and treated at 25°C and air flow of 800 mL/min. Heterotrophic bacteria growth was not inhibited by fungus. After 4 d, 82% of COD reduction and 80% decolorization were recorded. Additionally, enzymatic activity of LAC (345 U/L) and MnP (78 U/L) was observed. The COD reduction and decolorization correlated positively ( P < 0.0001 ) with enzymatic activity. Chlorophenol removal was 98% of pentachlorophenol (PCP), 92% of 2,4,5-trichlorophenol (2,4,5-TCP), 90% of 3,4-dichlorophenol (3,4-DCP), and 99% of 4-chlorophenols (4CP).