Determination of some starter and probiotic properties of lactobbacillus bacteria isolated from human milk

In this study, some starter and probiotic properties of Lactobacillus bacteria isolated from human milk were researched. The isolates which have bacillus morphology from human milk were selected. Then the isolates were identified with API 50 CHL kit and were selected three strains which had high definition rate. One was identified as Lactobacillus fermentum and the other two strains were identified as Lactobacillus acidophilus. It was determined that, all of the strains developed in 45 oC; whereas in 15 oC, the strains of M2-24 and M2-43 developed weakly and M2-6 didn't grow at all. All of the strains developed at growth medium containing 2%, 4%, 5% NaCl, however it was observed that the M2-24 strain developed weakly in growth medium containing 5% NaCl. During the pH measurements in 48 hours, it was observed that pH reduced in time and all three strains had acid production ability. The M2-6 strain had the highest rate of exopolysaccharide (EPS) producing with 4.34 g/L. At the same time other two strains had a high EPS production rate, too. It was determined that the M2-6 strain showed resistance against all tested nisin concentrations. At the same time, M2-43 strain showed more resistance against nisin than M2-24 strain. It was determined that all of the strains grew in low pH, but M2-24 strain grew weakly. All of the strains were resistant against kanamycin, on the other hand were sensitive to ampicillin, erythromycin and penicillin G antibiotics. In the determination of antimicrobial activity against the human patogen microorganisms, M2-6 strain showed no antimicrobial activity. It was observed that the strains of M2-24 and M2-43 showed antimicrobial activity against the test microorganisms. In the determination of antimicrobial activity on fish patogen microorganisms, it was observed that all three strains showed antimicrobial activity on A. hydrophila ATCC 19570, besides, M2-24 strain showed antimicrobial activity against L. garvieae, Y. ruckeri and V. anguillarum M1 and M2-43 strain showed antimicrobial activity against V. anguillarum M1. Key Words: Human milk, Lactobacillus, Starter, Probiotic