Decolorization of textile dye by microorganis...

Decolorization of textile dye by microorganisms and estimation of azoreductase activity

Author Name : Dr. N. G. Ramesh Babu, B. Jayashree, S. Sandhya

ABSTRACT This study aims to observe the decolorization effect of three different microorganisms namely, Pseudomonas fluorescens, Aspergillus nigeand Arthrospira platensis on Congo Red, an azo dye. Congo red is a highly common textile dye and a highly toxic recalcitrant pollutant. Three sets of nutrition media were prepared for each microorganism with varied composition of the nutrient components to study the influence of nutrition over the decolorization process. One set of media was prepared with the complete amount of nutrients that is required, one with reduced nutrition, i.e., half the amount of the same components that was added in the first set and finally one with zero nutrition so that the microbes would utilize the dye as their sole carbon source. Also, each microbe with three different amounts of nutrition was provided with three different concentrations of the dye (50 mg/ml, 25 mg/ml, and 12.5mg/ml) and the decolorization process was carried out. After 5 days once the dye was considerably decolorized, Azoreductase assay was done to check enzyme activity. A mixture of 2.8 ml of 0.025M Tris HCl, 0.05ml of 1%Congo red, 0.1 ml of the enzyme produced and 0.05ml of NADH was taken and the absorbance at 532nm was observed using a UV-Vis spectrophotometer. The study presented that Pseudomonas fluorescensdisplays the best decolorization competence compared to the other two microbes selected hence it can be concluded that microorganisms that can degrade azo dye have the ability to establish degradation methods that are both cost-effective and secure.