Biology and Medicine

Probiotic using and acid-bile resistance of Enterococcus faecium strains isolated from traditional naturally fermented white cheese in Iran and Turkey

2^nd World Congress on Beneficial Microbes: Food, Pharma, Aqua & Beverages Industry

September 22-24, 2016 Phoenix, USA

Derya Onal Darilmaz, Gulgun Discioglu and Yavuz Beyatli

Aksaray University, Turkey
University of Gazi, Turkey

Posters & Accepted Abstracts: Biol Med (Aligarh)

Abstract:

In this study, E. faecium RT 81, RI 41, RI 56 strains were isolated from white cheese produced in different regions of Iran and Turkey. All isolates and E. faecium DSMZ 20447 reference strains were examined for their abilities to survive at pH 2.0, 3.0, 4.0, 5.0, 5.5, 6.2 and in the presence of 0.06, 0.15 and 0.30% bile salts. Analysis of the low pH tolerance of all E. faecium strains was accomplished by incubating the strains in acidic MRS broth for 24 hours and then the cell growth was measured spectrophotometrically. Optical density significantly decreased the tolerance at the pH values of 4.0, 3.0 and 2.0. In these pH values, percent inhibition rates were determined as 96-97%. Strains maintained at pH 5.0 or higher showed no noticeable reduction in growth, while all the strains showed reduction in tolerance during incubation at pH 2.0 and 3.0. E. faecium RT 81 strain showed lower inhibition (12.98%) at pH 5.5 conditions than the other strains. pH values of 2.0, 3.0 and 4.0 could be considered as critical for the selection of potential probiotic Enterococcus spp. Tolerance to bile salt is essential for probiotic strains to colonize the small intestine. In the present study, we have determined the tolerance of three isolated strains and a reference strain of E. faecium to bile salts by including oxgallin the growth medium. For E. faecium DSMZ 20447 strain, there was an increase in percent inhibition after 24 hours of incubation at bile salt concentrations of 0.06, 0.15 and 0.30%. On the other hand, the growth of RT41 and RT 56 strains was stimulated with increasing concentration of bile salt. 0.30% bile salt concentration showed a slight inhibition on E. faecium RT 81 (26.05%). In conclusion, results showed that although the tolerance of E. faecium strains is affected by pH 2.0 3.0 and 4.0, most of the tested strains survived well at pH 5.0. Different bile salt conditions have little effect on the tolerance of E. faecium strains. The findings indicate that survival at pH 5.0 and pH 5.5, together with bile salt tolerance ability can be used for preliminary screening in order to identify potentially probiotic bacteria suitable for human or animal use.

Biography :

Email: derya_onal@yahoo.com