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

Aura M Pedroza-Rodríguez,Refugio Rodríguez-Vázquez

doi:10.1155/2013/536721

Abstract

C/N ratio and MnSO4 and CuSO4 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 CuSO4, and 0.071 mM MnSO4 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 CuSO4 and 0.22 mM MnSO4) 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).

Highlights

The paper industries generate significant quantities of wastewaters requiring around 15–60 m3 per ton of pulp produced
calculate the different ascents was 0.5 (C/N) ratio and MnSO4 and CuSO4 concentrations were optimized for decolorization and chemical oxygen demand (COD) removal of bleached Kraft pulp mill effluent by Trametes versicolor immobilized in polyurethane foam
Other alternatives consist on the supplementation of simple carbon sources that are used as a cosubstrate and addition of the inducers such as MnSO4 and CuSO4 to increase the levels of enzymatic activity manganese peroxidase (MnP) and Laccase [10,11,12]

Summary

Introduction

The paper industries generate significant quantities of wastewaters requiring around 15–60 m3 per ton of pulp produced. Biological treatment using white rot fungi such as T. versicolor involves multiple biochemical and physical reactions that can be carried out simultaneously, like the breakdown of intermolecular bonds, demethylation, hydroxylation, dechlorination, and the opening of the aromatic ring [4]. All of these transformations are developed together through the combined action of several enzymes, for example, laccase, manganese peroxidase, lignin peroxidase, xylanases, veratryl alcohol oxidase, and so forth [5, 6]. Even though there are several reports related to the effect of these compounds, there are few reports about the effect of C/N ratio, Mn, and Cu on manganese peroxidase and laccase induction, during effluent decolorization under nonsterilized conditions

Methods

Results

Conclusion