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

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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 269mWm(-2) for brewery waste alone (2000mgL(-1)) and after the azo dye (200mgL(-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. • Azo dye degradation and stable bioelectricity generation was achieved in the MFC. • Anodic biofilmwas analyzed by high-throughput pyrosequencing of the 16S rRNA gene. • Desulfovibrio (18.3%) was the dominant genus in the classified genera. • Of the genus, 62.3% were unclassified, thereby indicating highly diverse microbes. Graphical Abstract A schematic diagram of a dual chamber microbial fuel cell for azo dye degradation and current generation (with microbial communities at anode electrode).