Deciphering electron-shuttling characteristics of microalgal metabolites upon bioelectricity-generating community in microbial fuel cells

This first-attempt study used novel electrochemical alternatives to decipher stimulating effects of microalgal metabolites toward interspecific interactions in microbial fuel cells (MFCs). Extracellular metabolites of Chlorella sp. could stimulate electroactive activity of electron shuttling toward bioelectricity generation in MFCs. Whether such metabolites could express stimulating potency toward bioenergy generation still strongly depend upon interspecific interactions of species diversity and evenness in MFCs. As cyclic voltammetry indicated, the most electroactive metabolites of Chlorella sp. were produced at 10th-15th day cultures (ca. mid or late exponential growth phase). Microbial community in higher species diversity and evenness owned higher adaptation to stimulate stable bioelectricity-generating capabilities for bioenergy extraction in MFCs. That is, community ecology directly controlled stability of electroactive properties to be fully induced in MFCs. Thus, the maximal species diversity and evenness might be more electrochemically favorable toward symbiotic microalgal–bacterial cultures for species coexistence as win-win situation.