Coordinated metabolic and structural adaptation drives improved baking performance of a robust Saccharomyces...

Commercial Saccharomyces cerevisiae strains often show reduced performance in high-sugar and fruit-derived substrates due to combined osmotic, oxidative, and matrix-associated stresses. In this study, strain robustness was operationally defined as the ability to maintain growth recovery and application-relevant fermentation performance under these restrictive conditions, with cellular stress-protection traits serving as mechanistic indicators. S4 exhibited faster growth initiation and higher cell density than commercial baker's yeasts under the defined high-sucrose condition and in concentrated apple-juice-derived media, and in fruit-extract-supplemented dough, it produced the highest specific loaf volume at 10% supplementation, reaching 4.75 cm³/g and exceeding both commercial strains. Genome sequencing revealed extensive variation enriched in pathways linked to metabolic regulation, membrane transport, and stress response. Transcriptomic analyses indicated enhanced glycolysis, amino-acid biosynthesis, oxidative-stress mitigation, and cell-wall/membrane biogenesis, accompanied by down-regulation of translation and other ATP-intensive processes. Metabolomics further indicated increased central‑carbon intermediates, elevated tricarboxylic acid cycle-related metabolites, accumulation of tryptophan-derived antioxidants, and membrane lipid remodeling consistent with improved stress adaptation. Together, these results suggest that S4 maintains high-sugar fermentation performance by coordinating osmoadaptation, redox homeostasis, and wall-membrane integrity, providing a mechanistic basis for its industrial robustness and guidance for strain optimization.