Metabolomics analysis of growth inhibition of Lactobacillus plantarum under ethanol stress

Abstract This experiment investigated the changes in morphology, cell membrane permeability and intracellular metabolites of Lactobacillus plantarum ( L. plantarum ) under different concentrations of ethanol stress. It was found that when treated with ethanol at the concentration of 8% (v/v), L. plantarum mortality was close to 60%, and the surface of cell was rough and collapsed, and the cell debris is obvious. The extracellular β‐galactosidase activity increased to 1.24 and 1.73 times higher as compared to the control group after 6% (v/v) and 8% (v/v) ethanol stress, respectively. The inhibition of bacterial growth was positively correlated with its concentration. Ethanol stress can cause changes in cell morphology and membrane permeability of L. plantarum , causing physiological damage to cells. Metabolomics analysis revealed that the ethanol stress led to the inhibition of primary metabolic pathways through the suppression of the tricarboxylic acid cycle and glycolysis. It is therefore proposed that the inhibition effect of ethanol on L. plantarum is achieved by inducing intracellular metabolic imbalance via disruption of cell membrane functions. Importance Lactobacillus plantarum is often subjected to ethanol stress during food processing, production and storage, thus inhibiting the growth of bacteria. However, the detailed inhibition mechanism of ethanol on L. plantarum has not been deeply studied on metabolomics analysis. By measuring the changes of intracellular metabolites under ethanol stress, we found that ethanol destroyed the function of the membrane by changing the membrane structure, which hindered the carbon metabolism in the cell centre and reduced the vitality of bacteria. The results made a contribution for improvement of the target strain physiological and the strain industrial utility under ethanol stress.