Characterisation of Lactobacillus plantarum isolated from pickled cucumber, and its antagonist effect on pathogenic bacteria

Lactic acid bacteria (LAB) have the potentials to produce antimicrobial peptides against pathogens, and grow on traditional fermented foods such as pickled cucumber, which is widely consumed in Indonesia. LAB convert carbohydrates into organic acids, while hydro-gen peroxide and antimicrobial peptides inhibit the growth of spoilage bacteria. The present work aimed to identify the antibacterial activity of LAB strains isolated from pickled cucumber. The strains were morphologically and physiologically identified, and selected based on their ability to inhibit the indicator bacteria using the well-diffusion agar method. Furthermore, the identification based on biochemical and molecular tests were carried out on strains with antibacterial activity. The present work isolated four LAB strains, namely S1K2T1, S5K7T1, S5K8T1, and S10.2K6, with antibacterial activities which varied from medium to strong. Strains S1K2T1, S5K7T1, S5K8T1, and S10.2K6 had inhibitory activity against pathogenic bacteria. Strain S1K2T1 had strong inhibition against Sta. aureus ATCC 2592.3. Strain S5K7T1 had strong inhibition against Sal. Typhi BPE 122.4 CCA. Strain S10.2K6 had strong inhibition against P. putida FNCC 0071. Strain S5K8T1 had medium inhibition against both B. subtilis ATCC 6633 and P. putida FNCC 0071. The four LAB strains were identified as Lactobacillus plantarum based on API 50CHL test and phylogenetic analysis of 16S rRNA genes. The plnA gene was detected in the four strains, and identified as a bacteriocin protein from L. plantarum. (c) All Rights Reserved