Cholesterol-lowering effects of a putative probiotic strain Lactobacillus plantarum EM isolated from kimchi

•Lactobacillus plantarum EM showed high cholesterol removal by growing and even dead cells.•Cell wall fraction of L. plantarum EM removed cholesterol.•L. plantarum EM met the functional criteria required for beneficial probiotics.•L. plantarum EM could be a promising probiotic candidate regardless of its viability.

Lactobacillus plantarum EM, which was isolated from kimchi, showed high cholesterol removal by growing, resting, and even dead cells. Moreover, cell wall fraction of L. plantarum EM removed cholesterol in a cell wall concentration-dependent pattern. Lactobacillus acidophilus ATCC 43121 as a control showed high cholesterol removal by growing cells, whereas resting and dead cells showed less cholesterol removal. Scanning electron micrographs showed that large amounts of cholesterol adhered to surfaces of growing and dead cells of L. plantarum EM without changes in cell morphology. On the other hand, only a small amount of cholesterol adhered to the surface of L. acidophilus ATCC 43121 cells, and growing cells of L. acidophilus ATCC 43121 showed morphological changes with a thinner and longer shape. Based on these results, cholesterol removal mechanisms by L. plantarum EM could be attributed to enzymatic assimilation including bile salt hydrolase activity and cell surface-binding. Further, L. plantarum EM showed reasonable tolerance to acid and bile stresses and displayed antagonistic activity against pathogens. Moreover, L. plantarum EM did not represent a health risk due to antibiotic resistance. The results of this study indicate that L. plantarum EM may be a promising probiotic candidate and adjunct culture for reduction of serum cholesterol level regardless of its viability.