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.