English: Scanning electron microscopy (A) and intrinsic fluorescence microscopy (B) images of mixed phototrophic biofilm consortium. Microalgae included individual cells with spherical morphology (blue arrows) and sets of four cells (red arrows). Filamentous and non-filamentous (green arrows) cyanobacteria were apparent in biofilm. (C) Electrogenic activity of duplicate MFCs containing pond biofilm consortia cultivated under photoautotrophic conditions and 24 h illumination cycles (black and gray lines). The negative control represents cell voltage in MFC loaded only with BG11 media in the absence of biofilm (dotted line). 12 h dark-phases are indicated by black bars along x-axis.