%0 Journal Article
%T Optimization of C/N Ratio and Inducers for Wastewater Paper Industry Treatment Using Trametes versicolor Immobilized in Bubble Column Reactor
%A Aura M. Pedroza-Rodr¨ªguez
%A Refugio Rodr¨ªguez-V¨¢zquez
%J Journal of Mycology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/536721
%X 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 ( ) 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 ( ). T. versicolor bioremediation capacity was evaluated in bubble column reactor during 8 d. Effluent was adjusted according to optimized parameters and treated at 25¡ãC 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 ( ) 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). 1. Introduction The paper industries generate significant quantities of wastewaters requiring around 15¨C60£¿m3 per ton of pulp produced. Wood and the sugarcane bagasse are the main raw materials for the process. Kraft pulp is commonly bleached with chlorine and its oxides, with an initial oxygen bleaching step. Of the different waste streams, bleaching plant effluents are the most toxic, due to the chlorinated organic compounds, color, and COD generated [1]. The brown color of wastewater is due to various conjugated structures including quinones, benzoquinones, complexed catechols, chalcones, and stilbenes, which absorb visible light [2, 3]. 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]. Other mechanisms are related to physicochemical
%U http://www.hindawi.com/journals/jmy/2013/536721/