ISOLATION, CLASSIFICATION AND IDENTIFICATION OF POTENTIAL PROBIOTIC LACTOBACILLUS STRAINS FROM INFANT FAECES

Abstract

Lactobacillus bacteria present in many probiotic products. This paper investigated probiotic Lactobacillus strains isolated from the human gastrointestinal tract. 15 Lactobacillus strains were isolated from breast-fed infant faeces and identified by both traditional methods and genus-specific PCR method. In vitro experiments were designed to investigate some probiotic properties such as resistance to low pH and bile, cell surface hydrophobicity, antimicrobial activity, bacteriocin and other antimicrobials production, antibiotic resistance and cholesterol reduction. As a result, 12 probiotic Lactobacillus strains were selected. Significantly, 11 strains of them reduced 10-33.34 % serum cholesterol level. By 16S rDNA analysis, the probiotic strains were classified at species level as Lactobacillus gasseri, L. fermentum, L. salivarius, L. rhamnosus and L. paracasei/ casei.