Biodegradation of anthraquinone dyes: Interactive assessment upon biodecolorization, biosorption and biotoxicity using dual-chamber microbial fuel cells (MFCs)

Abstract

In this work, indigenous microbial consortium was employed to degrade four (4) anthraquinone dyes. Apart from biodecolorization, the interactive effects of biosorption and biotoxicity via microbial fuel cells (MFCs) were investigated thereby suggesting feasible strategies to assess toxicities of anthraquinone dyes. Serial microbial acclimatization upon indigenous mixed consortia was first implemented to obtain optimal consortia for decolorization. The well-acclimated consortium was capable to degrade 50 mg L−1 Acid blue 62 (AB62) at 47.07 ± 1.411 mg L−1 h−1. The ranking of decolorization performance at 50 mg L−1 was AB62 > Acid Blue 25 (AB25) > Acid Blue 40 (AB40) > Reactive Blue 19 (RB19). The appreciably decreased rates of decolorization at higher concentrations (300 mg L−1) was mainly biosorption due to dye inhibition. However, as power densities in MFCs at < 300 mg L−1 were still not significantly attenuated, indicating that dyes at such levels were still under threshold of toxicity for bioenergy extraction. After decolorization, considerable increases in power generation were exhibited due to accumulated degraded intermediates as electron shuttles. Microbial community analysis suggested that an increase in species diversity and abundance of both dye-decolorizing and electroactive bacteria was revealed after the consortium underwent successful serial acclimation.