A solution is described that enables a pressurised hydraulic circuit to be made inside the channels (5) of an alveolar panel (1); the panel (1) can be made of a transparent plastic material that enables the liquid to be irradiated by external light; the panel (1) in a transparent material can be used as a light exposure apparatus of a photobioreactor (14) destined to the cultivation of various types of organisms; the organisms produced can be used in the fields of energy generation, pharmaceutics, cosmetics and for human or animal nutrition.