Metabolomics study on fermentation of Lactiplantibacillus plantarum ST-III with food grade proliferators in milk.

Milk is a naturally complex medium that is suitable for the growth of most lactic acid bacteria. Unfortunately, Lactiplantibacillus plantarum ST-III grow poorly in milk without supplementation. To solve this problem, we use fresh pineapple and mung beans juice to develop an edible proliferator for L. plantarum ST-III. Our comparative analysis of metabolomics changes before and after fermentation reveals that amino acids and dipeptides are the most consumed compounds, with other substances including nucleotides and vitamins, implying the mechanism of proliferation. Combining the KEGG metabolic pathway analysis, substances that may promote the growth of L. plantarum ST-III in milk were screened. To explore which component of the proliferator is required for L. plantarum ST-III cultivate, we supplemented with several combinations of molecules aforementioned in milk. The simulation addition experiment results of L. plantarum ST-III in milk show that if any additions are missing, the concentration of viable bacteria is lower. Only when it contains all additives can the highest concentration of viable bacteria be obtained. Compared with the control, the fold change of the viable bacteria is about 32. Thus, it proves that milk primarily lacked available amino acids, dipeptides, uracil, xanthine, nicotinamide, and manganese for the growth of L. plantarum ST-III.