In Vitro Screening, Domestication and Identification of Lipid-lowering Functional Lactic Acid Bacteria

Objective: In order to screen Lactobacillus species with lipid-lowering function, 310 strains of the lactic acid bacteria were obtained from the source of traditional fermented foods. Methods: The o-phthalaldehyde method was applied to measure the strains’ rate of cholesterol removal. The culture strategy with a gradient rise in cholesterol concentration was utilized to domesticate the original screening strains. The single-reagent approach was used to determine the rate of triglyceride. The inhibitory potential of bacterial suspensions and intracellular extracts on the activities of cholesterol esterase and pancreatic lipase was tested. The 16S rDNA and the pheS gene sequences were utilized to determine the target bacteria. In addition, the self-aggregation force, hydrophobicity, and simulated gastrointestinal system tolerance were examined. Results: After high concentration cholesterol domestication, the cholesterol removal rate of strain BC17 in the initial screening increased to 35.70%. Additionally, the strain's triglyceride removal rate was 58.87%. Intracellular extracts inhibited the activities of pancreatic lipase and cholesterol esterase by 34.92% and 52.95%, respectively, while its suspensions inhibited the activities of the two enzymes by 7.01% and 42.99%, respectively. After being cultivated for 6 h in a simulated gastrointestinal system, BC17 had a 53.99% survival rate. BC17 had a high self-aggregation rate, which reached 69.04% in 24 h. The hydrophobic rates of ethyl acetate, xylene, and chloroform, respectively, were 33.71%, 38.36%, and 51.02%. BC17 was identified as Lactiplantibacillus plantarum based on morphology, 16S rDNA and pheS genes sequence analysis. Conclusion: Lactiplantibacillus plantarum BC17 has a good in vitro lipid-lowering activity and outstanding probiotic qualities, thus making it a prospective strain resource for the development of lipid-lowering functional fermentation products and probiotic agents with a wide range of applications.