Isolation and Identification of Indigenous Lactic Acid Bacteria from Fermented Cabbage (Brassica oleracea L.) with Probiotic Potential

Abstract

Cabbage (Brassica oleracea L.) is a widely consumed leafy vegetable with high nutritional value. Cabbage is often processed into fermented foods. Lactic acid bacteria (LAB) grow naturally on fermented cabbage, and are generally recognized as safe (GRAS) microorganisms for consumption, and have probiotic potential. This study aimed to isolate and identify indigenous LAB from fermented cabbage which have probiotic potential. Cabbage was fermented in 3% sodium chloride solution at 37°C for 9 days. Selective isolation of LAB from the fermented cabbage was performed using de Man Rogosa Sharpe (MRS) Agar. The morphological identification of LAB isolates was done macroscopically, microscopically, and biochemically. Antibacterial activity evaluation against pathogenic bacteria was performed using the agar well diffusion method. The resistance of LAB isolates to acidic conditions and bile salt were also tested. Molecular identification was done using the Polymerase Chain Reaction (PCR) technique. A pair of primers 27F and 1492R were used to amplify the 16S rRNA gene and then sequenced. The sequencing results were aligned using the BLAST program. Five LAB isolates (KF 1 – KF5) were isolated and identified from fermented cabbage. The antibacterial activity test results showed that isolate KF4 had the highest antibacterial activity against Escherichia coli, Bacillus cereus, Salmonella typhimurium, and Staphylococcus aureus. KF4 was able to grow at pH 2, and was tolerant to bile salt. BLAST analysis results showed that isolate KF4 has 99.24% similarity to Lactiplantibacillus  plantarum. The findings from this study highlight the probiotic potential of the lactic acid bacteria Lactiplantibacillus  plantarum, that warrant further investigation.