Exogenous vitamin D₂ relieves heat-induced growth suppression and remodels lipid metabolism in Saccharomyces cerevisiae

Heat stress is prevalent in industrial biomanufacturing processes including Baijiu brewing and bioethanol production. It disrupts the membrane structure and lipid homeostasis of Saccharomyces cerevisiae , interferes with genome-wide gene transcription and retards cell growth, thereby greatly lowering fermentation efficiency and product yields. There is an urgent demand for food-safe additives to alleviate heat-induced damage to industrial yeast. Although vitamin D₂ (VD₂) shares a similar sterol structure with endogenous yeast ergosterol, its regulatory effects on yeast under heat stress remain poorly understood. Here, we adopted an integrated strategy combining phenotypic characterization, lipidomics, transcriptomics and molecular docking to explore the protective effects and regulatory pathways of exogenous VD₂ against heat stress in S. cerevisiae . Phenotypic assays showed that VD₂ supplementation effectively alleviated heat-induced growth retardation, elevated intracellular glutathione peroxidase activity and reduced membrane injury. Lipidomic analysis revealed that VD₂ remodelled cellular lipid profiles by increasing triglyceride levels, decreasing phosphatidylcholine content and promoting sphingolipid synthesis. Transcriptomic results further demonstrated significant upregulation of key genes involved in the S-adenosylmethionine (SAM) metabolic axis. Integrated multi-omics data and molecular docking prediction support a tentative mechanistic hypothesis: VD₂ may interact with Opi3p and potentially interfere with its catalytic function, which could further drive downstream metabolic reprogramming. In conclusion, this study reveals that VD₂ alleviates heat-triggered growth suppression by remodelling the SAM-dependent lipid metabolic network. As a food-grade additive, VD₂ possesses promising potential to alleviate heat-induced growth retardation of yeast starters in industrial fermentation. Our findings provide a theoretical basis for developing natural additives to mitigate yeast heat damage and optimizing high-temperature fermentation bioprocesses.