Mechanisms for enhancing ethanol tolerance of Saccharomyces cerevisiae through nano-selenium supplementation during Chinese rice wine brewing.

Background: The toxic environment created by elevated ethanol levels presents significant challenges to Saccharomyces cerevisiae, leading to incomplete fermentation of the raw materials, poor flavor of the product, and even increased difficulty in post-processing of the product. Therefore, enhancing the ethanol tolerance and metabolic capacity of strains is critical for the brewing of Chinese rice wine.

Results: Results revealed that 1-3 mg L^-1 nano-selenium significantly increased viable bacteria counts, reproduction rates and antioxidant enzyme activities, while reducing malondialdehyde levels and lipid peroxidation of S. cerevisiae. Notably, a concentration of 2 mg L^-1 nano-selenium improved the cell membrane integrity and morphology under ethanol stress. Transcriptome analysis revealed that nano-selenium influenced gene expression related to cell wall repair, ribosome synthesis, carbon cycle and energy metabolism, and stress response. These changes represent a coordinated response to ethanol stress, enhancing the ability of yeast to cope with ethanol stress.

Conclusion: Our results indicated that an optimal concentration of nano-selenium can effectively boost the metabolic capacity of S. cerevisiae, improving fermentation efficiency and product quality. © 2025 Society of Chemical Industry.