Journal of Pure and Applied MicrobiologyVol. 7 No. 4

A Complementary ??In Vitro?? Study of Bacteriocinogenic Activity and Probiotic Characteristics of Newly Isolated Enterococcus faecium SFD

Sahar F. Deraz1*, Mohammed G. Shehata1, Amer A. El-Banna2, Ashraf A. Khalil1 and Malak A. El-Sahn2

1Department of Protein Research, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research & Technological Applications, New Borg El-Arab City, P.O. Box: 21934 Alexandria, Egypt. 2Department of Food Science and Technology, Faculty of Agriculture, Alexandria University, 21545, Elshatby, Alexandria, Egypt.

Received on 29 September 2013 and accepted on 08 November 2013

 

ABSTRACT

In an attempt to search for candidate beneficial probiotic strain of Enterococcus faecium, isolate recovered from traditional Egyptian cheese (karish) was identified and evaluated regarding their antimicrobial activity and their standard biochemical profile. Bacteriocin SFD is highly inactivated by Papain, Trypsin, EDTA (0.5mM), DTT and Triton X-100, but not when treated with pH values between 2.0 and 8.0 for one hour, and after treatment at 40?C for 15 min. Activity was, however, lost after treatment at 100?C for 30 min. The highest level of activity (25600 AU/ml_1) was recorded when cells were grown in MRS broth, pH 6.5 after 20 h. Bacteriocin SFD differs from other broad-spectrum bacteriocins described for Enterococcus spp. by being extremely active against Gram-negative bacteria and by being smaller. The newly isolated culture was evaluated for a number of probiotic characteristics like viability under gut-like conditions, cell surface hydrophobicity, autoaggregation, coaggregation, phenol tolerance, adhesion to intestinal mucousand cholesterol assimilation. In vitro results obtained showed that the isolated Enterococcus faecium SFD, was able to meet the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 2.5, growth in 0.5% bile salts, growth in 0.3% phenol, hydrophobicity of 37%, adhesion to intestinal mucous and 35% cholesterol assimilation ability. In the light of this study, it is observed that, Enterococcus faecium SFD is regarded as a promising candidate probiotic and adjunct culture for new healthy food product.

Keywords : Probiotics, Lactic acid bacteria, Bile resistance, Acid tolerance, Adhesion, Bacteriocin.