Degradation and biotoxicity of azo dyes using indigenous bacteria-acclimated microbial fuel cells (MFCs)

[Display omitted] •Disclose factors that influence the predominance of dye-decolorizing species.•Unveil the limiting criteria to distinguish dye biodegradation and biosorption.•Exhibit power-stimulating characteristics of the consortia in microbial fuel cells. This study explored a bioenergy platform of biodegradability and toxicity evaluation through microbial fuel cells (MFCs) modules for simultaneous decolorization and bioelectricity generation. The most appropriate decolorizer consortia NIU pond exhibited the extent of decolorization: Sunset Yellow FCF (93 %), Allura Red (96.6 %), and Tartrazine (91.41 %) in 3, 8, 12 h respectively. The ranking for bioelectricity generation in MFCs (unit: mW m−2) (Sunset Yellow FCF Degradation) was hot spring water (46.42) > hot spring soil (22.17) > NIU pond (17.75) > NIU soil (7.89). In the presence of the dye, power density was increased by 88 %, 84 % and 27 % for NP, HS, and HW, respectively. Acclimation process was inspected in terms of bioenergy-extracting capability to evaluate toxicity potency of model dyes. According to metagenomics analysis upon microbial populations before and after acclimation, indigenous microbial community was only predominated by Pseudomonas monteilii and of Bacillus pumilus. Significant increased biodiversity was evolved under selection of dye stress. After acclimation, community ecology in the consortia contained Klebsiella, Citrobacter, Enterococcus faecalis, Lactobacillus lactis, and Escherichia shigella. Tandem mass spectrometric analysis pointed out sunset yellow ECF was gradually degraded and decolorized intermediates steadily accumulated. MFC modules were promising platforms to select candidate biodecolorizers from microbial populations.