Improving ergothioneine content in Pleurotus citrinopileatus through two-stage oxidative stimulus strategy

Mushroom is an important agricultural crop, rich in various nutrients and bioactive compounds. Ergothioneine (EGT), a naturally occurring antioxidant, is found in mushrooms that offers significant health benefits. This study developed a two-stage oxidative stimulus strategy to enhance the EGT content. After screening 11 species of macrofungi, P. citrinopileatus 303 was selected. With the cultivation conditions optimized, EGT titer reached 533.93 mg/L. To further boost EGT synthesis, oxidative stress was introduced by hydrogen peroxide (H₂O₂). An optimized strategy combining oxidative stress with clearance was then implemented. Finally, a two-stage oxidative stimulus approach was employed, where the cells were first exposed to H₂O₂, followed by oxidative clearance using vitamin C in the second stage. This strategy increased the EGT titer to 641.76 mg/L, 5.83 times that of the initial group, with the fermentation time reduced to 5 days. It offered valuable insights for the industrial-scale biosynthesis of this potent antioxidant.