Elucidating the source and metabolic impact of 2-phenylethanol on Lactiplantibacillus pentosus 1 using a fish broth fermentation model.

BACKGROUND: The quality of traditional fermented sour fish is shaped by metabolic interactions between core microbiota dominated by lactic acid bacteria (LAB) and yeasts. 2-Phenylethanol (2-PE) is a characteristic metabolite and quorum-sensing molecule of Saccharomyces cerevisiae. This study aims to identify the primary source of 2-PE via pure culture of dominant strains, and preliminarily investigate its effects on LAB in a fish broth fermentation model under different fermentation modes. RESULTS: Single-strain fermentation experiments confirmed that Saccharomyces cerevisiae 31 is the main producer of 2-PE. Comparative analysis of different fermentation modes revealed that yeast metabolites exerted a stronger influence than cell-to-cell contact. Although not a dominant factor, 8 mg/L 2-PE significantly inhibited the growth, glucose metabolism, and lactic acid accumulation of Lactiplantibacillus pentosus 1. Correlation analysis showed that 2-PE had significant positive correlations with the formation of multiple alcohols, glucose consumption, pH, total acidity, lactic acid, and valine. It is speculated that 2-PE may regulate fermentation performance by interfering with the glycolytic pathway, fatty acid metabolism, and valine metabolism in LAB. CONCLUSION: This study clarifies the primary microbial source of 2-PE in sour fish fermentation and verifies its specific regulatory effect on LAB, though it is not the core effector molecule through which Saccharomyces cerevisiae modulates LAB metabolism. The findings provide new insights into metabolite-mediated microbial interactions in fermented food ecosystems, and the elucidated regulatory patterns offer reference for studies on other fermentation substrates including plant-based foods and beverages. © 2026 Society of Chemical Industry.