English: Electrogenic activity was recorded from Lyngbya (left panel) or Nostoc (right panel) cultured under 24 h illumination cycles (12 h of light/12 h of dark) under red light (red lines), blue light (blue lines), or green light (green lines) of equal intensities. Electrogenic activity under standard white light source of the intensity equal to that of individual colors is provided as a reference (black lines). These experiments were performed using improved anodes that were constructed using nanostructured polypyrrole as previously described [15]. Because of improvements in anode properties, the amplitude of the light response was substantially higher that those reported for the same cultures in Fig. 1. Because nanostructured polypyrrole has properties of a capacitor, the shape of light response curves changed (more gradual increase in response to light). 12 h dark-phases are indicated by black bars along x-axis.