Metabolite analysis on reductive biodegradation of reactive green 19 in Enterobacter cancerogenus bearing microbial fuel cell (MFC) and non-MFC cultures

•First comparative study deciphered dye decolorization in SCML-MFC and non-MFC conditions.•Menaquinone was used as a redox stimulator to decolorization of Enterobacter cancerogenus.•Reduced organic sulfides formed in MFC significantly enhanced reductive decolorization.•E. cancerogenus was capable to anaerobically degrade tertiary alcohols and phenols.

The first-attempt study uncovered metabolic pathways of reactive green 19 (RG19) decolorization by Enterobacter cancerogenus BYm30 in single chamber membrane-less microbial fuel cell (SCML-MFC) and non-MFC cultures. The finding indicated that menaquinone from BYm30 might play as a redox mediator (or an electron-shuttling carrier) to stimulate dye decolorization and bioelectricity generation in MFC. Due to the formation of reduced organic sulfides from RG19 in MFC, color removal in MFC was significantly faster than non-MFC cultures. In addition, tertiary alcohols and phenols originally present in LB broth might be degraded by BYm30 under anaerobic condition regardless of MFC or non-MFC condition. Apparently, these novel findings could clarify the mechanism(s) behind reductive decolorization of RG19 taking place in MFC and non-MFC conditions for wastewater decolorization.