A Study on Evaluation of Indigenous Microbial Consortium for Enhanced Decolorization of Textile AZO Dyes and Feasibility for Simultaneous Bioelectricity Generation in A Microbial Fuel Cell

Extensive use of synthetic azo dyes in various colored industries and the proven toxic and aesthetic effect of these dyes and their degradation metabolites on environment makes the proper treatment of these colored effluent essential before discharging them into the outside waterbodies. Biological treatment methods are taking attention now-a-days as it is proven to be the cheap, eco-friendly and highly efficient treatment method for dye effluent in industrial scale as compared to the other available treatment methods. Organisms isolated from contaminated regions are believed to be more efficient in treatment of any xenobiotic and recalcitrant compounds as they are acclimatized to the toxic effect of the pollutants. The present work emphasises on decolorization and degradation of different textile azo dyes (Reactive green-19 (RG-19), Remazol navy blue (RNB), Reactive Red-198 (RR-198) and a synthetic dye mixture (SDM) comprising of these three dyes using bacteria isolated from textile industry effluent. Three bacterial strains showing highest dye decolorization capacity were screened and identified as Bacillus pumilus HKG212 (GenBank Accession Number: KJ741252.1), Zobellella taiwanensis AT1-3 (GenBank Accession Number: FJ999669.1) and Enterococcus durans GM13 (GenBank Accession Number: KC213474.1) using 16s rRNA molecular analysis tool. Bacillus pumilus HKG212 was found to show highest decolorization capacity among the three isolates achieving 89% decolorization for RG-19, 95% decolorization for RNB and 94% decolorization for RR-198 dye within 24hr of incubation. However, all the three strains were found to be highly tolerant to higher dye concentrations achieving 80-95% decolorization for three model dyes in a wide range of dye concentration (i.e 50 mg/L to 1000 mg/L). Effect of different physico-chemical parameters on decolorization efficiency of the isolates revealed that, ambient temperature, neutral to slightly alkaline pH and static or anaerobic incubation condition favours the growth and decolorization potential of the organisms....