Influence of the culture conditions on the production of NGPs by Aspergillus tubingensis .

The filamentous fungus Aspergillus tubingensis that belongs to the black Aspergillus section has the capacity to produce high-value metabolites, for instance, naphtho-gamma-pyrones (NGPs). For these fungal secondary metabolites, numerous biological properties of industrial interest have been demonstrated, such as antimicrobial, antioxidant and anti-cancer capacities. It has been observed that production of these secondary metabolites is linked with fungal sporulation. The aim of this research was to apply osmotic and oxidative environmental stresses to trigger the production of NGPs in liquid cultures with CYB (Czapek Dox Broth). In addition, numerous parameters were tested during the experiments, such as pH value, incubation time, container geometry, and static and agitation conditions. Results demonstrate that the produced amount of NGPs can be enhanced by decreasing the water activity (a(w)) or by adding an oxidative stress factor. In conclusion, this study can contribute to our knowledge regarding A. tubingensis to present an effective method to increase NGP production, which may support the development of current industrial processes.