In my thesis I studied and examined the effect of zinc on itaconic acid production. It is produced by Aspergillus terreus under fermentation; the examination was held in a laboratory. In the literature review, I focused on talking about different fermentation parameters. I described itaconic acid, Aspergillus terreus, and the effect of zinc on itaconic acid production. In addition to that, I briefly described the methods used, where I concluded that zinc acts as a dose-dependent regulatory metal, with optimal production achieved under manganese limitation combined with mid-level zinc addition, where under limited manganese conditions, itaconic acid yields are maximized, and moderate zinc supplementation enhances specific product yield while maintaining favorable pellet morphology. While excess zinc induces stress and disrupts the hyphal structure and reduces biomass, although itaconic acid production remains relatively stable.