Technological and Probiotic Properties of Enterococcus faecium Strains Isolated from Tunisian Camel Milk Fguiri Imen1,*, Ziadi Manel2, Arroum Samira1, Khorchani Touhami1 1Laboratory of Livestock and Wild Life, Institute of Arid Lands (IRA), 4119, Médenine, University of Gabes, Tunisia 2Laboratory of Microbial Technology and Ecology (LETMi), National Institute of Applied Sciences and Technology (INSAT), BP 876, 1080, Tunis, University of Carthage, Tunisia *SEND REPRINT REQUEST TO IMEN FGUIRI email: imen.fguiri@yahoo.com
Online Published on 25 December, 2023. Abstract Sixty-two lactic acid bacteria (LAB) strains isolated from Tunisian raw camel milk were studied by focusing on their technological and probiotic potential. Strains were tested for their acidification activity, proteolytic and lipolytic activity, ability to use citrate, biomass yield, growth rate, and Exopolysaccharide (EPS) production. Probiotic tests used were pH and bile tolerance, antimicrobial activity, antimicrobial susceptibility, adhesion, cell surface hydrophobicity and aggregation abilities. Twenty-six strains showed survival at pH 2; only 10 strains tolerated 0.3 % of bile salt and will therefore further assessed for their probiotic properties. These strains were identified by partial 16S rRNA gene sequencing and were represented by Enterococcus faecium as the only group. Eight strains present ΔpH ≥0.3 U and then were considered as rapid acidifier strains. All strains have a significant proteolytic power. All strains produced EPS. Survival to the simulated in vitro digestion was strain-dependent. Strains were tested for cell surface acid-base properties and adhesion to gastric mucin and STC-1 cells. Isolates showed good adhesion rate to gastric mucin and only two strains (SCC1-33 and SLch6) were able to colonise STC-1 cells with an adhesion value of 7.8×103 and 4.2×103, respectively. Auto- and co-aggregation abilities were interesting and values were ranged from 33.10 to 63.10 %. Results from the cytotoxicity test showed a negative effect on STC-1cells of all the studied strains. Enterococcus faecium isolated from camel milk was characterised by their technological and probiotic properties. Top Keywords Camel milk, Enterococcus faecium, Probiotics, Technological properties, Lactic Acid Bacteria. Top |