Enhancement of Mycelial Biomass Production and Bioactive Properties Related to Cosmeceuticals of Calocybe indica (Milky Mushroom) by Optimization of Submerged Culture Conditions

Calocybe indica or milky mushroom grown in submerged culture was investigated as a new source of antioxidants and anti-collagenase substances, and for its ability to inhibit three bacteria that trigger inflammatory acne, Cutibacterium acnes, Staphylococcus epidermidis, and S. aureus. To facilitate C. indica submerged cultivation and achieve high productivity, a three-level four-factor Box-Behnken design was utilized to find the optimal culture conditions for its mycelial biomass production. The model estimated the optimal conditions as 30 °C, a medium pH of 5.9, and incubation for 14 days under static culture, with results verifi ed by validation experiments. The optimal conditions gave mycelial biomass of 7.12 g/L, which is 5-fold higher than the original condition. This statistical method facilitated rapid identification and integration of key factors for C. indica high mycelial biomass production with significantly improved cosmeceutical properties in terms of antioxidant and antibacterial activities against acne-causing bacteria, especially C. acnes at 19-fold and 18-fold, respectively, compared to the original condition. An ethanolic extract derived from C. indica mycelia was nontoxic to human skin keratinocytes (HaCaT). These diverse functionalities indicate that the mycelial extract of C. indica may represent a promising source of bioactive substances for cosmeceutical applications.