Functional in vitro screening of Lactobacillus strains isolated from Tunisian camel raw milk toward their selection as probiotic
Résumé
Tweenty probiotic lactic acid bacteria (LAB) strains from Tunisian camel raw milk were identified among a collection of 177 isolates. The selected strains were able to tolerate pH 2, pepsin, pancreatin and bile salts, as restrictive criteria for probiotic potential. LAB strains were identified using 16S rRNA gene sequencing. Fourteen isolates belonged to the species Lactobacillus fermentum and six to Lactobacillus plantarum. None of this LAB showed mucin degradation or hemolytic activity, while proving resistant to a series of clinically antibiotics. All strains have antibacterial activity against Listeria monocytogenes, Staphylococcus aureus and Escherchia coli. However, only 18 strains inhibited Salmonella thyphimirium. The L. fermentum strains showed an important level of adhesion to human Caco-2 and HT29-MTX epithelial cells. Our work suggests that camel raw milk is valuable source of probiotic bacteria with functional characters of intestinal lactobacilli. These bacteria may be further used in probiotic applications.