Study of the effect of calcium signal participating in the antioxidant mechanism of yeast under high-sugar environment.

BACKGROUND

Saccharomyces cerevisiae is susceptible to high-sugar stress in the production of bioethanol, wine and bread. Calcium signal is widely involved in various physiological and metabolic activities of cells. The present study aimed to explore the effects of Ca signal on the antioxidant mechanism of yeast during high-sugar fermentation.

RESULTS

Compared to yeast without available Ca, yeast in the high glucose with Ca group had higher dry weight, higher ethanol output at 12 and 24 h and higher glycerol output at 24 and 36 h. During the whole growth process, the trehalose synthesis capacity of yeast in the high glucose with Ca group was lower and intracellular reactive oxygen species content was higher compared to yeast without available Ca. Intracellular malondialdehyde content of yeast under high glucose with Ca was significantly lower than yeast under high glucose without available Ca except for 6 h. The superoxide dismutase and catalase activities of yeast and glutathione content were higher in the high glucose with Ca group compared to yeast in high glucose without available Ca. The expression levels of SOD1, GSH1, GPX2 genes were higher for high glucose without available Ca at 6 h, while yeast in the high glucose with Ca group had a higher expression of antioxidant-related genes except SOD1 and CTT1 at 12 h. The expression levels of antioxidant-related genes of yeast for high glucose with Ca were higher at 24 h, and those of genes except SOD1 of yeast in the high glucose with Ca group were higher at 36 h.

CONCLUSION

High-glucose stress limited the growth of yeast, while a moderate extracellular Ca signal could improve the antioxidant capacity of yeast in a high-glucose environment by regulating protectant metabolism and enhancing the antioxidant enzyme activity and expression of antioxidant genes in a high-sugar environment. © 2024 Society of Chemical Industry.