Physico-chemical Characterization of Exopolysaccharides of Potential Probiotic Enterococcus faecium Isolates from Infants’gut

Microbial exopolysaccharides (EPS) may have technological applications in food and pharmaceutical industries, and in environmental health. EPS may be used in foods as natural thickening, stabilizing, bodying or gelling agent, and/or as emulsifiers or as fat replacer. In addition, EPS has been reported to have health augmenting features such as prebiotic, immunostimulatory, anti-tumor and hypocholesterolemic properties. EPS producing probiotics bacteria may help enhancing organoleptic properties of fermented foods. In present study, Enterococcus faecium strains viz. Enterococcus faecium 1.1, E. faecium 2.0 and E. faecium 4.0, which had several probiotically important attributes, were investigated for their EPS producing potential. E. faecium 4.0 produced highest yield of EPS (470 mg/L) and was followed by E. faecium 1.1 (220 mg/L) and E. faecium 2.0 (180 mg/L). FTIR analysis showed that EPS from all the three E. faecium strains was homopolymer of glucose. Degradation temperatures of EPS from three E. faecium strains varied in the range of 270.4°C-279.3°C as studied by thermal gravimetric analysis. Differential scanning calorimetry of EPS from E. faecium 1.1, E. faecium 2.0 and E. faecium 4.0 showed the melting point of 55.9°C, 88.6°C and 83.5°C; and enthalpy of 102.5, 56.03, and 213.9 J/g, respectively. EPS from all the three E. faecium strains expressed growth inhibition of E. coli. Purified EPS from all three E. faecium strains exhibited excellent emulsification properties i.e. 96.70 % (E. faecium 1.1), 96.78 % (E. faecium 2.0) and 97.77 % (E. faecium 4.0).