Enhanced production of questin by marine-derived Aspergillus flavipes HN4-13

Questin has favorable applications. Fractional factorial design, Box-Behnken design, and response surface methodology were adopted to optimize the fermentation conditions of the marine-derived fungus, Aspergillus flavipes HN4-13, thereby enhancing questin production. Optimal fermentation conditions in a 500-mL conical flask with 200 mL of medium were 4% soluble starch, 0.9% beef extract, 4% NaCl, 0.05% Na₂HPO₄, pH 6, 2% inoculum size, and shaking at 28 ℃ and 160 rpm/min for 7 days. The production of questin can achieve 64.93 ± 4.55 mg/L, with no significant difference from the predicted value (66.27 mg/L). Thus, this optimized process of questin production is feasible. Such production is 17-fold higher than that of the basal Sabouraud's dextrose medium. Results indicate the potential of A. flavipes HN4-13 in the large-scale production of questin through fermentation.