Vajihe Yousefi - Department of Chemical Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran
Hamid-Reza Kariminia - Department of Chemical Engineering, University of Waterloo, ۲۰۰ University Avenue West, Waterloo, ON, N۲L ۳G۱, Canada

Coprinus cinereus (NBRC ۳۰۶۲۸) peroxidase was implemented to eliminate the diazo dye of reactive black ۵ (RB۵). The optimization was conducted in batch mode using three approaches, i.e., the one-factor-at-a-time (OFAT), factorial design, and response surface methodology (RSM). Based on the results of the OFAT method, the optimum conditions for decolorization of RB۵ dye were at a temperature of ۳۰oC, a pH of ۹-۱۰, an H۲O۲ concentration of ۳.۹ mM, and an RB۵ concentration of ۴۰ mg/L. In the first stage of statistical optimization, these factors plus enzyme activity were screened by the ۲-factorial design, wherein enzyme activity, temperature, and hydrogen peroxide concentration were distinguished as the most significant parameters in the enzymatic decolorization of RB۵. In the second stage, RSM was applied over three adopted factors through the central composite design (CCD), and a reduced cubic polynomial model was generated, which indicated an accurate regression (R۲ = ۰.۹۹۷, Adj.R۲ = ۰.۹۹۴) and no significant lack of fit (p-value> ۰.۰۵). The contour and surface plots suggested that the removal efficiency was enhanced by increased enzyme activity and decreased H۲O۲ concentration and temperature. The optimum condition was obtained at ۱.۰ mM H۲O۲, ۶ U/mL enzyme activity, and ۳۵oC for a maximum decolorization efficiency of ۹۶.۰۴۶%.

Response surface methodology, white-rot fungus, peroxidase, azo dye, Decolorization