A sun-tracking light distributor system for use in one of an open-ended system and a closed photo-bioreactor for a photosynthetic culture having an aqueous liquid is described. The system comprises: two light distribution walls made of a transparent material allowing sunlight to pass therethrough, the two light distribution walls creating an elongated channel with an interior space adapted to receive the sunlight and an exterior surface adapted to be partly immersed in the aqueous liquid in use and a displacement system operatively connected to at least one of the two light distribution walls, the displacement system being adapted to change an orientation of the at least one of the two light distribution walls to track a solar position with respect to at least one axis.
