Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 2 4 2010 12 15 213 222 EN K Karthikeyan Gujarat Institute of Desert Ecology, Mundra Road, Bhuj-Kachchh -370001, Gujarat, India AND Department of Env. Sciences, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India. K Nanthakumar Department of Env. Sciences, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India. K Shanthi Department of Env. Sciences, P.S.G.C.A.S, Coimbatore-641 014, Tamil Nadu, India. P Lakshmanaperumalsamy Karpagam University, Eachanari Post, Coimbatore-641 021, Tamil Nadu, India. 2015 10 01 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. https://ijm.tums.ac.ir/index.php/ijm/article/view/74 https://ijm.tums.ac.ir/index.php/ijm/article/download/74/74