Metabolomics-based insights into the mechanism of quorum sensing-enhanced conjugated linoleic acid production in Limosilactobacillus fermentum L1

The mechanism underlying the QS-mediated regulation of metabolism to obtain a high yield of conjugated linoleic acid (CLA) from lactic acid bacteria remains unclear. In this study, the mechanism by which QS regulates high CLA production in Limosilactobacillus fermentum L1 ( L. fermentum L1) was revealed based on metabolomics and biochemical indices. Inhibition of the QS of L. fermentum L1 significantly decreased its CLA production. The content of CLA produced by L. fermentum L1 dropped from 795.12 μg/mL to 446.84 μg/mL with the addition of quorum sensing inhibitors ( P < 0.01). A total of 2389 metabolites were identified from L. fermentum L1. 306 differential metabolites were discovered in the high- and low-producing CLA groups based on multivariate statistical analysis, and QS clearly regulated the changes in the levels of these metabolites in the strain. Differential metabolites were mainly involved in energy metabolism, signal transduction, redox, and other metabolic pathways. The levels of glutathione and malondialdehyde in the redox pathway were significantly increased in the high-producing CLA group, indicating that QS regulates the redox imbalance of the strain to produce high CLA. This study provides a theoretical basis for development of CLA-rich functional foods. • New insights into the mechanism of quorum sensing regulating CLA based on metabolomics. • 306 differential metabolites regulate high CLA production in L. fermentum L1. • Signal transduction and membrane transport pathways promote CLA transformation. • Quorum sensing regulates CLA transformation by regulating the redox imbalance. • This study reveals the mechanism of high production of functional factors by lactic acid bacteria.