Isolement et caractérisation des lactobacilles à partir du lait de chèvre

Abstract

The present work aims at isolating and characterizing lactic strains of the genus lactobacillus and studying their competence according to the probiotic selection plan. An isolation of lactic strains from samples of raw goat's milk from four regions located in the wilaya of Ain Témouchent is carried out followed by a purification and a phenotypic, physiological description was carried out and a biochemical identification of one of these strains using the API50 CHL gallery. Then the probiotic properties of these isolates were studied in vitro, the attributes carried out concerned multitudes of tests. As results of isolation and purification we were able to recover 13 strains with Gram-positive and catalase-negative catalase among which (06) pure isolates related to the genus lactobacillus and the biochemically identified strain was defined as Lactobacillus plantarum. Most of the strains showed high hydrophobicity and capacity for self-aggregation, moderate co- aggregation and variable antibiotic antagonism and sensitivity, but showed low adhesion capacity. No evidence of hemolysis was observed for all strains. The results provided by the Lactobacillus plantarum strain are interesting, particularly the remarkable resistance to hostile conditions in the gastrointestinal tract, as well as the high adhesion capacity to chicken epithelial cells. This allowed us to define the probability of future use of this strain as a probiotic.