Microbial community dynamics in continuous microbial fuel cells fed with synthetic wastewater and pig slurry

•Exoelectrogenic microbial communities were determined by the type of substrate used.•MFC performance was not affected by the addition of BES-Inh.•BES-Inh shifted the Eubacterial community, rather than the methanogenic community.•Six OTUs were considered as the bioanode core microbiome in both MFC systems.

Two-chambered microbial fuel cells (MFCs) operating with synthetic wastewater and pig slurry were assessed. Additionally, the use of 2-bromoethanesulfonate (BES-Inh) was studied. The synthetic wastewater-fed MFC (MFCSW) showed a maximum power density (PDmax) of 2138 mW m− 3, and the addition of BES-Inh (10 mM) did not show any improvement in its performance (PDmax = 2078 mW m− 3). When pig slurry was used as feed (MFCPS), PDmax increased up to 5623 mW m− 3. The microbial community composition was affected by the type of substrate used. While, Pseudomonadaceae and Clostridiaceae were the most representative families within the acetate-based medium, Flavobacteriaceae, Chitinophagaceae, Comamonadaceae and Nitrosomonadaceae were predominant when pig slurry was used as feed. Otherwise, only the Eubacterial microbial community composition was strongly modified when adding BES-Inh, thus leading to an enrichment of the Bacteroidetes phylum. Oppositely, the Archaeal community was less affected by the addition of BES-Inh, and Methanosarcina sp., arose as the predominant family in both situations. Despite all the differences in microbial communities, 6 operational taxonomic units (OTUs) belonging to Bacteroidetes (Porphyromonadaceae and Marinilabiaceae) and Firmicutes (Clostridiales) were found to be common to both MFCs, also for different contents of COD and N-NH4+, and therefore could be considered as the bioanode core microbiome.

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