Degradation of Reactive Black 5 dye by a newly isolated bacterium Pseudomonas entomophila BS1

The textile and dye industries are considered as one of the major sources of environmental pollution. The present study was conducted to investigate the degradation of an azo dye Reactive Black 5 (RB 5) using a bacterium isolated from soil samples collected around a textile industry. The bacterial strain BS1 capable of degrading azo dye RB 5 was isolated and identified as Pseudomonas entomophila based on 16S rDNA sequencing. Effects of different parameters on the degradation of RB 5 was studied to find out the optimal conditions required for maximum degradation which was 93% after 120 h of incubation. Static conditions with pH in the range of 5-9 and temperature of 37 oC were found to be optimum for degrading RB 5. Enzyme assays demonstrated that P. entomophila possessed azoreductase which played important role in degradation. The enzyme was dependent on FMN and NADH for its activity. Furthermore, possible degradation pathway of the dye was proposed through GC-MS analysis, which revealed that the metabolic products were naphthalene-1,2-diamine and 4-(methylsulfonyl) aniline. Thus the ability of this indigenous bacterial isolate for simultaneous decolorization and degradation of the azo dye signifies its potential application for treatment of industrial wastewaters containing azo dyes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author