Integrated transcriptomic and metabolomic analyses highlight the 2-phenylethanol impact on fermentation performance of Saccharomyces cerevisiae 31 from fermented sour fish.

2-Phenylethanol (2-PE), as a quorum-sensing signaling molecule, is widely present (produced by yeast) and can enhance yeast-driven fermentation flavors in foods such as wine. Previous studies have shown that 2-PE is also present/produced by the dominant strain S. cerevisiae 31 in fermented sour fish and affects its growth, metabolism and flavor. While extensive research has characterized the role of 2-phenylethanol (2-PE) as a quorum-sensing molecule in relatively simple fermentation systems like wine, its molecular mechanism in complex, high-protein matrices such as fermented sour fish remains largely unexplored. This study integrates untargeted metabolomics, transcriptomics, and various indicator to fill this critical gap, aiming to uncover the differential metabolite accumulation and molecular mechanisms that occur during the fermentation process of S. cerevisiae 31 upon the 2-PE supplement. KEGG pathway analysis showed that 2-PE mainly affected amino acid metabolizing pathway. Transcriptomic analysis further revealed that 2-PE supplementation significantly altered the expression of genes involved in cell wall biosynthesis, glycolysis, and the TCA cycle, providing a molecular basis for its effects on physiological metabolism and flavor synthesis. This study provides a novel molecular perspective for the targeted enhancement of flavor and quality in traditional fermented sour fish.