For microbial fuel cells (MFCs) to become a cost-effective wastewater treatment technology, they must produce a stable electro-active microbial community quickly and operate under realistic wastewater nutrient conditions. The composition of the anodic-biofilm and planktonic-cells communities was followed temporally for MFCs operated under typical laboratory phosphate concentrations (134 mg L (1) P) versus wastewater phosphate concentrations (16 mg L (1) P). A stable peak voltage was attained two-fold faster in MFCs operating under lower phosphate concentration. All anodic-biofilms were composed of well-known exoelectrogenic bacterial families; however, MFCs showing faster startup and a stable voltage had a Desulfuromonadaceae-dominated-biofilm, while biofilms co-dominated by Desulfuromonadaceae and Geobacteraceae characterized slower or less stable MFCs. Interestingly, planktonic-cell concentrations of these bacteria followed a similar trend as the anodic-biofilm and could therefore serve as a biomarker for its formation. These results demonstrate that wastewater-phosphate concentrations do not compromise MFCs efficiency, and considerably speed up startup times. (C) 2016 Elsevier Ltd. All rights reserved.