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

ABSTRACT Background Saccharomyces cerevisiae is susceptible to high sugar stress in 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 effects of Ca 2+ signal on the antioxidant mechanism of yeast during high sugar fermentation. Results Compare to yeast without avaibale Ca 2+ , yeast in high glucose with Ca 2+ group had higher dry weight, higher ethanol output at 12 h and 24 h, higher glycerol output at 24 and 36 h. During the whole growth process, the trehalose synthesis capacity of yeast in high glucose with Ca 2+ group was lower and intracellular ROS content was higher compared to yeast without avaibale Ca 2+ . Intracellular malondialdehyde content of yeast under high glucose with Ca 2+ was significantly lower than yeast in high glucose without available Ca 2+ except for 6 h. The superoxide dismutase, catalase activities of yeast and glutathione content were higer in high glucose group with Ca 2+ compared to yeast in high glucose without avaibale Ca 2+ . The expression level of SOD1, GSH1, GPX2 genes were higher in high glucose without available Ca 2+ at 6 h, while yeast in high glucose with Ca 2+ group had a higher expression of antioxidant‐related genes except SOD1 and CTT1 at 12 h, whole antioxidant‐related genes of yeast in high glucose with Ca 2+ were higher at 24 h, and the genes except SOD1 of yeast in high glucose with Ca 2+ were higher at 36 h. Conclusion High glucose stress limited the growth of yeast, while the moderate extracellular Ca 2+ signal could improve the antioxidant capacity of yeast in a high glucose environment by regulating protectants metabolism, enhancing the antioxidant enzyme activity and expression of antioxidant genes in high sugar environment. This article is protected by copyright. All rights reserved.