CHARACTERIZATION OF PROBIOTIC LACTIC ACID BACTERIA ISOLATED FROM ALGERIAN CAMEL MILK INVITRO

A total of 78 lactic acid bacteria (LAB) were isolated from spontaneously fermented camel milk samples and investigated in vitro for their characteristics as potential new probiotic strains. Only nine LAB were active against pathogenic bacteria and imply adhesive properties. The presumed probiotic strains were evaluated for their tolerance to low pH and to 0.3% and 0.5% of bile salts. None of them was able to develop at pH 2 but all showed high resistance to pH 3 compared to the optimal (pH 6.2). Furthermore, all strains showed good bile tolerance. Based on their morphological, physiological and some biochemical characteristics, probiotic strains were assigned to the genus Leuconostoc. Nucleotide sequences of their 16S rRNA showed 94 to 99% similarity to Leuconstoc mesenteroides. The safety results of all nine strains showed the absence of ?. haemolytic activity, gelatinase, DNase, and coagulase. From 14 antibiotics tested, all strains resisted to five only: nalidixic acid, colistin, cefixime, oxacillin and fusidic acid. Overall results indicated that Leuconostoc mesenteroides strains isolated from camel milk could serve as promising probiotic candidates.