Metabolomics Analysis of Lactococcus lactis IMAU51121 Under Acid Stress

Abstract:

Objective The aim of the study is to investigate the metabolite changes of Lactococcus lactis (L. lactis) IMAU51121 under acid stress.Method L. lactis IMAU51121 was exposed to acid stress in the GM17 liquid medium at pH 4.0 for 0.5 h. The metabolites changes before and after acid stress were detected by liquid chromatography-mass spectrometry (LC-MS). The multivariate statistical analysis was performed for metabolomics data.Result In total, 1 178 metabolites were identified, from which 20 major differential metabolites were screened based on variable importance in projection (VIP)≥1, P<0.05, and fold change (FC)>1.2. After acid stress, 11 metabolites showed increased relative content, including L-histidine, aspartic acid, and isoleucine, while 9 metabolites demonstrated decreased relative content, including citrulline, β-tyrosine, and uridine diphosphate (UDP)-glucose. KEGG pathway enrichment and topological analysis revealed that acid stress affected five key differential metabolic pathways, including arginine biosynthesis and galactose metabolism.Conclusion Acid stress affects the growth and metabolism of L. lactis IMAU51121, which responds to acid stress by adjusting the levels of amino acids, sugars, lipids, and nucleotides and the metabolic pathways.