Response surface methodology for optimization of culture conditions for dye decolorization by a fungus, Aspergillus niger HM11 isolated from dye affected soil

BACKGROUND AND OBJECTIVES Discharge of wastewater from textile dyeing industries has been a problem in terms of pollution and treatment of these waters is a great task. Keeping this in mind, the aim of our current research is to study the effect of various bioprocess variables on decolorization of an azo dye, Congo red, by a fungal isolate, Aspergillus niger HM11. MATERIALS AND METHODS CENTRAL COMPOSITE DESIGN (CCD) AND RESPONSE SURFACE METHODOLOGY (RSM) HAVE BEEN APPLIED TO DESIGN EXPERIMENTS TO EVALUATE THE INTERACTIVE EFFECTS OF THE OPERATING VARIABLES: on the decolorization of Congo red. A total of 30 experiments were conducted in the present study and a regression coefficient between the variables was generated. RESULTS The RSM indicated that pH 6.0, 150 rpm agitation, incubation time of 36 hrs and a glucose concentration of 1.0% were optimal for maximum decolorization of Congo red and the response indicated excellent evaluation of experimental data. CONCLUSION From this study, it is very obvious that the fungal isolate, Aspergillus niger HM11 can be used as a promising microbial strain for decolorization of textile dyeing effluent containing similar dyes.