Bioelectricity generation from the decolorization of reactive blue 19 by using microbial fuel cell

Microbial fuel cell (MFC) was compared to conventional biological techniques for decolorization of anthraquinone dye, reactive blue 19 (RB19) with simultaneous electricity generation. With 50 mg/L of RB19 in the anode chamber as a fuel, the MFC achieved 89% decolorization efficiency of RB19 within 48 h, compared with 51 and 55% decolorization efficiency achieved by aerobic and anaerobic techniques, respectively. The cyclic voltammetry results showed that RB19 could promote the electron transfer and redox reaction on the surface of anode. The RB19 decolorization process can be described by first-order kinetics, and the decolorization rate decreased with the increase of RB19 concentration. The high-throughput 16S rRNA sequencing analysis indicated significant microbial community shift in the MFC. At phylum level, the majority of sequences belong to Proteobacteria, accounting from 23 to 84% of the total reads in each bacterium community. At genus level, the MFC contained two types of microorganisms in general such as electrochemically active and decolorization bacteria. Overall, MFC is an effective method for anthraquinone dye treatment with simultaneous energy recovery. The 16S rRNA revealed that there were two major functioning microbial communities in the MFC such as electricity-producing and RB19-degrading bacteria which synergistically worked on RB19 degradation.