Effect of Mitophagy-Related Gene Regulation on Antioxidant Activity of Lager Yeast

Lager yeast, which is mainly used for lager beer brewing, withstands significant oxidative stress during brewing process, leading to its rapid aging in serial beer brewing. Mitophagy plays a critical role in the antioxidant stress response of yeast. However, the relationship between mitophagy and the antioxidant capacity of yeast is still unclear. Previous studies indicated that ATG gene family in mitophagy significantly affects the antioxidant capacity of yeast cells in beer brewing. Herein, the expression of ATG8, ATG11, ATG32, DNM1, and MMM1 genes was regulated. The results showed that the overexpression of ATG8 and ATG11 significantly reduced the intracellular ROS contents to 52.05% and 22.57% of the initial state, respectively, and helped to maintain a high mitochondrial vitality during serial fermentation. Disruption of ATG8, ATG11 and ATG32 resulted in significant decrease in cell vitality when exposed to H2O2 stimulation. Meanwhile, the disruptions of these genes were detrimental to the balance of intracellular ROS. Excess DNM1 activity could affect the cellular energy balance and ATP depletion under prolonged stress conditions. The repression of MMM1 led to lower ATP levels during serial beer fermentation. The ATG8, ATG11, and ATG32 genes might be potential targets for regulating the antioxidant capacity of yeast. The current work provides new insights into improving the antioxidant capacity of yeast through mitophagy regulation.