A new patented aseptic pilot-scale reactor (50 litre) was used and its performance validated in the case of the production of gibberellic acid (GA(3)) with Gibberella fujikoroi. Production was carried out by fed-batch solid state fermentation on a wheat bran supplemented medium at about 50% dry matter and 28 degrees C. After 11 days cultivation, a production of 3 g of GA(3) per kg of dry matter was obtained. The results show the evolution of the different physical and biochemical variables during this process, proving the efficiency of this reactor in the case of secondary metabolite production.