Bi-directional regulation of electroactive microbial community using Au/ antimicrobial peptide nanocomposite

The power generation and pollutants removal efficiencies of mixed electroactive microbial community rely on the effective electron transfer between outer membrane proteins of electroactive electricigens. However, the poor conductivity of protein and various non-electrogenic bacteria greatly hinder the electron transfer and effective contact between electricigens. Herein, we report a novel "bi-directional" microbial community regulation method that can selectively inhibit Gram-positive non-electrogenic bacteria and enhances the conductivity and electron transfer between electrogenic bacteria and the electrode in MFC by taking the advantages of the excellent conductive and bacteriostatic properties of Au/Nisin nanocomposite. The Au/Nisin stimulation endows microbial fuel cell (MFC) a high-efficiency functional community, which increases the power density and decolorization rate by 103 % and 33 %, respectively. The high conductivity, and selectivity and antimicrobial activity of the nanocomposite improve the electrochemical activity of the bioanode, hereby promoting the microbial extracellular electron transfer and increasing the proportion of electrogenic bacteria such as Proteobacteria, Bacteroidetes and Desulfovibrio in the biofilm. Our work successfully demonstrates that the construction of multifunctional metallic peptide nanocomposite can effectively regulate microbial community to improve the electrochemical performance of MFC.