Unraveling novel acid tolerance mechanisms in Lactococcus lactis through physiological and multi-omics analyses

作者：Ran Gao, Xiaoyu Bo, Huiying Wang, Bao Yuan, Xin Zhao, Jianan Li, Lai‐Yu Kwok, Qiuhua Bao · 发表于：LWT · 年份：2025 · DOI：10.1016/j.lwt.2025.118387 · 被引用次数：4 · 研究领域：Probiotics and Fermented Foods、Microbial Metabolites in Food Biotechnology、Helicobacter pylori-related gastroenterology studies

Lactococcus lactis ( L. lactis ) is a key lactic acid bacterium widely used as a starter culture in food fermentation. However, acid stress during industrial processes poses a major challenge, impairing cell viability, metabolic activity, and fermentation performance, ultimately compromising the quality and consistency of fermented products. To uncover novel mechanisms underlying acid tolerance, we screened 60 L. lactis isolates from traditional fermented dairy products and identified XGL9-3 as highly acid-tolerant and XZ5304 as acid-sensitive. Comparative physiological analyses revealed that isolate XGL9-3 maintained superior cell membrane integrity, increased fatty acid unsaturation, synthesized the protective C19-cyclopropane fatty acid, and sustained intracellular pH homeostasis through elevated H + -ATPase activity and ATP production. Whole-genome sequencing showed that XGL9-3 possessed an expanded repertoire of genes involved in carbohydrate metabolism, energy production, and cell envelope biogenesis. Transcriptomic profiling of XGL9-3 under acid stress identified 317 differentially expressed genes (202 upregulated, 115 downregulated), including key players in ABC transporters, purine metabolism, and cationic antimicrobial peptide resistance. Integrated multi-omics analysis of XGL9-3 uncovered a coordinated acid tolerance strategy involving membrane remodeling, enhanced proton efflux, metabolic reprogramming, and modulation of quorum sensing pathways. Notably, the most ...