Abstract: A photobioreactor is disclosed for cultivating a photosynthetic organism. This photobioreactor provides innovative features that allow an easy cleaning of the light source. The photobioreactor has a container for containing a liquid culture medium for cultivating photosynthetic organisms, light-emitting tubes mounted within the container. The photobioreactor also has cleaning devices mounted within the container for cleaning the outer surface of the light-emitting tubes and actuators for actuating the cleaning devices.