The instant invention refers to a novel process for potentiating the production of substances with antifungal activity obtained from Ganoderma lucidum, using a technological device for the differential, qualitative and quantitative expression of proteins and other bioactive molecules, selected from the group consisting of polysaccharides, triterpenoids, fatty acids and ganoderic acids. The compositions containing said substances showed antifungal activity and mycelium growth and fungi ascospore germination inhibiting activity, amongst them Mycosphaerella fijiensis, primary pathogenic agent causing black Sigatoka disease in banana and plantain crop fields.