Technological Characterization of Lactic Acid Bacteria Isolated from Different Sheep’s Milk

Abstract

Background: Technological characterization of lactic acid bacteria isolated from sheep’s milk collected in 3 regions in northwestern Algeria. Methods: During the period from 2018 to 2019, fifty strains of Lactic acid bacteria isolated from samples sheep’s milk were evaluated for several technologically-relevant properties: diacetyl and exopolysaccharides production, acidification, proteolytic and lipolytic activity and their antagonist activity against Escherichia coli and Pseudomonas aeruginosa. Result: The results indicate that among all the isolates only 20% were distinguished by their production of EPS mainly the genus Leuconostoc. Diacetyl production was observed in 71% of Lactobacillus, 60% of Enterococcus and 25% in Leuconostoc. 94% isolates showed moderate proteolytic activity. 56% and 60% of the strains degraded tween 80 and olive oil respectively for lipolytic activity. Inhibition activity by the cultures LAB was about 82% and 78% against E. coli and P. aeruginosa respectively. No culture supernatants inhibit P. aeruginosa, however 18% of the Enterococcus trains inhibit E. coli. BME1.A2 and BME2.D4 showed their highest acidification capacity developing a very large quantity of lactic acid after 24 h of incubation, i.e., 7.6 and 8.4 g lactic acid/L respectively.