Determination of some probiotic properties of bifidobacterium genus bacteria

In this study, fifty nine (59) strains of bifidobacteria isolated from breast milk and breastfed infants feces were isolated using BSM agar modified by the addition of mupirocin (200 u/L). The isolates were identified in the genus level by the detection of fructose-6-phosphate phosphoketolase enzyme activity. Thus thirty one (31) Bifidobacterium spp were determined. Identidication results showed that B. breve was the predominant species (15 strains). In this study, some important properties in terms of probiotic use such as resistance to acid, tolerance to bile, exopolysaccharide production, antimicrobial activities, and hemagglutination abilities of all strains has been examined. Resistance to acid, tolerance to bile and EPS production of all strains were determined by spectrophometrically. Positive correlations has been obtained between production of exopolysaccharide and tolerance to bile salts (p<0.05) or resistance to low pH (p<0.05). Also, it was also found that Bifidobacterium spp. had 0-9 mm zone radius inhibition effect on E. coli, which is known as an important intestinal pathogen. The hemagglutination abilities of the strains which are thought to have an important role on the adhesion to epithelial cells were investigated before adhesion studies to epithelial cells. The ten (10) strains showed moderate (+, ++) and high (+++) degree hemagglutination ability was detected. B. breve A28 strain which has the high acid resistance (pH 3.5), bile tolerance (0.40 %), EPS production capacity (97.64 ±0,01 mg/L), inhibition effect on E. coli ATCC 11229 (9±1 mm), and hemagglutination ability (+++) and B. bifidum A10 strain has the lowest properties were used in adhesion to epithelial surface studies. Caco-2 cells were used adhesion to epithelial studies. Epithelial adhesion index of B. breve A28 strain was found as 300< bacteria/cell, while epithelial adhesion index of B. bifidum A10 strain was found as 19 bacteria/cell. All these results confirmed by scanning electron microscopy observations. While the viability of A28 strain, which high EPS production, in the normal growth media was 7.1x108 CFU/ml, and its viability in media with inulin was found 7.4x1011 CFU/ml in prebiotic application. However, no significant change was observed in the viability of E. coli ATCC 11229 in inulin added media. Because of having all of these properties, A28 strain can survive in the gastrointestinal system for a long time. Hence, this study can suggested the use of B. breve A28 strain as a probiotic bacterium.