Essai de caractérisation des bactériocines Issues des bactéries lactiques et l’étude De l’effet antagoniste vis-à-vis de quelques Germes pathogènes.

Abstract

Lactic bacteria are naturally part of our environment. It has long been recognized that lactic acid bacteria have the property of producing antimicrobial substances. Indeed, lactic acid bacteria have the particularity to synthesize inhibiting substances, among others bacteriocins. Those ones are also used as pharmaceutical and parapharmaceutical products. Our study reachcs in the first place: A confirmation of the identity of our lactic strains namely Lactobacillus plantarum KP178099, Enterococcus faecium CP013994, Enterococcus faecium KT124593, Enterococcus faecium KF303433, Enterococcus faecium JQ806726, through physiological, biochemical tests, and macroscopic and microscopic observation . Secondly, we conducted the search for bacteriocin and antibacterial substances was carried out using the double layer method and well method , that allows us to quantify the inhibitions and identify inhibitors developed by lactic strains, our study also focused on the inhibitions between lactic and pathogenic strain. The results showed that our lactic strains have inhibitory ettects against pathogenic bacteria namely Staphylococcus aureus ATCC 25922 , E.coli ATCC 25922 et Pseudomonas aeroginosa ATCC 27853. Finally, in our study, we tested the effect of some parameters on the action of bacteriocins ; The antimicrobial activity of bacteriocins has been found to occur at pH between 2.4 and 9; the bacteriocin activity remains constant after heating at 100 ° C. for 30 minutes. and these bacteriocins lose their activities after treatment with pepsin, trypsin