Evaluating probiotic properties of Lactobacillus species in terms of bacteriocin production

The main purpose of this study was to investigate the probiotic properties of lactobacilli including fermentability, acid and bile tolerance, bile salt hydrolysis, and hemolytic properties, antibiotics and antimicrobial activities and bacteriocin production from curdled milk samples.Methods:Among the total bacterial isolates, seven isolates were confirmed to be lactobacilli through examining morphological characteristics, biochemical tests and by means of 16S rDNA method. Its antimycotoxinogenic activity was investigated using some test bacteria, such as E. coli, Aspergillus parasiticus, Geotrichum candidum, Staphylococcus aureus.Results:LAB E showed the highest resistance to acidic environment. Also, in bile condition the number of LAB B and D colony significantly reduced from about 107 to 102 after 1 hour and to less than 100 after 2 and 4 hours. As well none of the strains showed any sensitivity towards fungal and microbes except for Escherichia coli which all strain was sensitive to. Bacteriocin production activity was confirmed after the incubation period by creating a clear zone around the wells in the Escherichia coli test.Conclusions:Based on this study results, LAB E and C isolated from cow curdled milk could be considered as probiotic microorganism considering the observed properties. They could be isolated in order to be used in the production of probiotic dairies.

Keywords:

Probiotic , Lactic acid bacteria , Crude milk