Probiotic potential of nutritionally improved Lactobacillus plantarum DGK-17 isolated from Kimchi – A traditional Korean fermented food

Abstract

The aim of the study was to evaluate the functional properties of the Lactic acid bacterium Lactobacillus plantarum DGK-17 isolated from Kimchi-a traditional fermented Korean food, and to assess its antimicrobial and cell-invasion protection activity. Nutritionally improved DGK-17 showed antimicrobial activity, checked via agar well diffusion assay against several pathogenic microorganisms and showed enhanced antimicrobial activity against target microbes Pseudomonas aeruginosa 03K711 and Klebsiella pneumoniae 05K279. Bactericidal activity of DGK-17 Cell-free Culture Supernatant (CFCS) was evident from the decreased growth of P. aeruginosa 03K711 and K. pneumoniae 05K279. Altered membrane integrity was observed in scanning electron microscopy which indicated that CFCS acts on cell membrane of bacteria leading to a cell burst. CFCS also acts on DNA as shown by the DNA damage study. Our auto-aggregation, co-aggregation and adhesion studies indicated that DGK-17 prevents colonization of pathogenic bacteria thereby limiting their infection. Also, DGK-17 is able to survive under low pH and high bile salt conditions – a simulated gastric juice environment. Efficacy of DGK-17 to protect HCT 116 colon cells against P. aeruginosa (03K711) and K. pneumoniae (05K279) invasion suggests its role in protection of host cells from such infections. Finally we conclude that L. plantarum DGK-17 has a strong probiotic potential, antimicrobial activity and a potential for invasion protection.