Farhana Hussain¹, Md. Reazul Karim^*1, Fahmida Hossain², Faisal Hasan³

¹Department of Microbiology, University of Chittagong, Chittagong-4331, Bangladesh

²Department of Chemistry, Jahangirnagar University, Savar, Dhaka, Bangladesh

³University of Science and Technology, Chittagong, Chittagong-4202, Bangladesh

Abstract

Water pollution due to the desertion of enormous volume of effluent like synthetic dyes mostly azo dyes from the textile dyeing industries has become an alarming trend in the present world.  Biological degradation of synthetic dye is gaining popularity because of its cost effectiveness and ecofriendly procedure. Hence, the present study was aimed to isolate and identify the indigenous azo dye decolorizing bacteria from dyeing industry effluent and to assay their dye decolorization potential in order to use them as an efficient bio-agent for decolorizing and mineralizing toxic azo dyes. Thirty indigenous bacterial colonies were isolated initially from which eight bacterial isolates were selected by further screening method, exhibiting 10% Novacron Red SB decolorization in semi-solidified screening medium. The decolorizer isolates were identified upto species as Bacillus alvei, Bacillus polymyxa, Corynebacterium rathayi, Staphylococcus aureus, Zymomonas anaerobia, Bacillus megaterium, Aerobacter aerogenes and Micrococcus conglomeratus on the basis of their morphological, cultural, physiological and biochemical characteristics. The maximum decolorization by the isolates was achieved with 5% dye concentration at 37°C temperature and pH 9 and peptone as co-substrate. So, this study demonstrates that the selected eight indigenous isolates can be used as efficient biological agent for the removal of toxic industrial novacron dyes by maintaining the above mentioned optimum value of the process parameter.

Keywords: Water pollution, Dyeing industry effluents, Azo dyes, Decolorization, Biodegradation