Abstract
Saccharomyces cerevisiae often undergoes strain degeneration during industrial serial subculturing, though this phenomenon remains understudied. This study first conducted strain screening and biological characterization through TTC (2,3,5-triphenyltetrazolium chloride) colorimetric assays, Durham tube fermentation gas production tests, and WL medium (Wallerstein Laboratory medium) cultivation. Subsequently, the changes in intergenerational biological traits after serial subculturing were investigated. Finally, transcriptomic analysis was employed to examine differential gene expression under high-glucose stress during continuous subculturing. The experimental results demonstrated that: (1) The S. cerevisiae QDSK310-Z-07 (GenBank: PP663884), isolated from farm soil, exhibited robust growth within a temperature range of 24-36 °C, with optimal growth observed at 28 °C. It thrived in a pH range of 4-5.5 and efficiently utilized various carbon and nitrogen sources; (2) After serial subculturing, the strain's ethanol production capacity and fermentation rate partially declined and then stabilized, while maintaining strong tolerance to high ethanol concentrations and hyperosmotic stress; (3) Transcriptomic analysis revealed significant differential expression of genes related to lipid metabolism, amino acid metabolism, and other pathways under high-glucose stress following continuous subculturing. These findings elucidate the biological trait variations in S. cerevisiae during serial subculturing and provide key metabolic regulation candidate targets for its long-term adaptive evolution under high-glucose stress.