Screening of lactic acid bacteria with cholesterol-lowering function and evaluation of its biological characteristics
Objective To screen lactic acid bacteria with favorable biological characteristics and cholesterol-degrading function.Methods The basic salt medium containing cholesterol as the sole carbon source was employed for the screen-ing of lactic acid bacteria with cholesterol-degrading capability from healthy human feces.The identification of strain spe-cies was performed through 16S rRNA gene sequencing;their physiological characteristics including acid resistance,bile salt resistance,hydrogen peroxide resistance,bacteriostatic activity of fermentation supernatant,adhesion to intestinal epi-thelial cells,and cholesterol scavenging ability were systematically assessed.Lactiplantibacillus plantarum with good per-formance was selected for animal experiments to explore its cholesterol-lowering function in vivo.Results Five strains of Lactiplantibacillus plantarum with cholesterol-lowering properties were obtained.The five strains had good acid resist-ance,bile salt resistance and hydrogen peroxide resistance,and the counts of viable bacteria maintained the same order of magnitude as the initial bacteria amount under the acid condition of pH 3.0 for 6 hours.After being treated with 3.0 g/L bile salt for 6 hours,the viable bacteria counts remained at 106 CFU/mL.After treated with 1.0 mmol/L hydrogen peroxide for 6 hours,the counts of viable bacteria increased significantly.Their MRS fermentation supernatants had different degree of antagonism against five common foodborne pathogens,and the diameters of inhibitory zone were greater than 8.5 mm.The adhesions of Caco-2 cells to intestinal epithelium were more than 25％.The cholesterol clearance rates of Lactiplantibacil-lus plantarum GLPL03 and GLPL04 were higher,reaching 59％and 53％respectively.Lactiplantibacillus plantarum GLPL03 and GLPL04 were selected for a 12-week animal experiment,and it was found that the two strains significantly reduced the concentration of serum total cholesterol and total triglycerides,and alleviated the progression of hypercholes-terolemia in mice.Conclusion The five strains of Lactiplantibacillus plantarum derived from healthy human body have good biological characteristics and can be used as probiotics for further study.
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