Role of electricity production in the anaerobic decolorization of dye mixture by exoelectrogenic bacterium Shewanella oneidensis MR-1

This study investigated the anaerobic decolorization of the dye mixture containing methyl orange (MO) and naphthol green B (NGB) by Shewanella oneidensis MR-1. S. oneidensis MR-1 showed a strong ability to decolorize the dye mixture. MO was easier to get the electrons and inhibited the reduction of NGB, despite of its lower redox potential than NGB. The Mtr respiratory pathway played an important role in this process. Meantime, addition of extracellular electron shuttles accelerated the decolorization. Those results suggest that the decolorization capacity of S. oneidensis MR-1 is associated with the electricity production. The operating parameters, such as electron acceptors, temperature, and pH, were also investigated in this study. Thus, this work may facilitate a better understanding of the extensive nonspecific reduction capacity of exoelectrogens and is beneficial for promoting their application in bioremediation.