Microbial community structure in a dual chamber microbial fuel cell fed with brewery waste for azo dye degradation and electricity generation

The expansion in knowledge of the microbial community structure can play a vital role in the electrochemical features and operation of microbial fuel cells (MFCs). In this study, bacterial community composition in a dual chamber MFC fed with brewery waste was investigated for simultaneous electricity generation and azo dye degradation. A stable voltage was generated with a maximum power density of 305 and 269 mW m(-2) for brewery waste alone (2000 mg L-1) and after the azo dye (200 mg L-1) addition, respectively. Azo dye degradation was confirmed by Fourier transform infrared spectroscopy (FT-IR) as peak corresponding to -N=N- (azo) bond disappeared in the dye metabolites. Microbial communities attached to the anode were analyzed by high-throughput 454 pyrosequencing of the 16S rRNA gene. Microbial community composition analysis revealed that Proteobacteria (67.3 %), Betaproteobacteria (30.8 %), and Desulfovibrio (18.3 %) were the most dominant communities at phylum, class, and genus level, respectively. Among the classified genera, Desulfovibrio most likely plays a major role in electron transfer to the anode since its outer membrane contains c-type cytochromes. At the genus level, 62.3 % of all sequences belonged to the unclassified category indicating a high level of diversity of microbial groups in MFCs fed with brewery waste and azo dye. aEuro cent Azo dye degradation and stable bioelectricity generation was achieved in the MFC. aEuro cent Anodic biofilm was analyzed by high-throughput pyrosequencing of the 16S rRNA gene. aEuro cent Desulfovibrio (18.3 %) was the dominant genus in the classified genera. aEuro cent Of the genus, 62.3 % were unclassified, thereby indicating highly diverse microbes.