Isolation and characterization of probiotic lactic acid bacteria from human breast milk

Abstract

The lactic acid bacteria (LAB) isolated from human breast milk is known as probiotics and comprises numerous health benefits. This study aims to select and determine the species name of LAB based on the 16S rRNA gene, which has the potential to be the best indigenous probiotic. The method used included analysis of LAB resistance at acidic pH 2.0 and bile salts (0.5 %), antimicrobial activity against pathogenic microorganisms, and determining the autoaggregation properties. LAB isolates with the best ability in the analysis were then identified using a partial sequence of the 16S rRNA gene. The isolation and purification revealed eight LAB isolates with different parameters named as L19A, L19B, L19C, L19D, L19E, L19F, L19G, and L19H. Isolates L19A, L19E, and L19H have good tolerance ability against acid pH and bile salts, compared to others. Meanwhile, the L19H isolate had the strongest antimicrobial activity against pathogenic microorganisms E. coli ATCC 25922, S. aureus ATCC 25923, and C. albicans ATCC 11778, while the L19A had the highest hydrophobicity, autoaggregation, and coaggregation ability. Based on the partial sequence analysis of the 16S rRNA gene, the L19A, L19E, and L19H have similar values with L. casei, L. rhamnosus, and L. paracasei, respectively. These isolates belong to the L. casei group (LCG) from human breast milk, which can be used as an indigenic probiotic.