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Antimicrobial Activity of a Bacteriocin Produced by Enterococcus faecalis KT11 against Some Pathogens and Antibiotic-Resistant Bacteria
Korean J. Food Sci. An. 2018;38:1064-1079
Published online October 31, 2018;
© 2018 Korean Society for Food Science of Animal Resources

Hilal Seval Abanoz1 and Buket Kunduhoglu2,*

1Institute of Science, University of Eskişehir Osmangazi, 26480 Eskişehir, Turkey
2Department of Biology, Faculty of Science and Arts, University of Eskişehir Osmangazi, 26480 Eskişehir, Turkey
Correspondence to: Buket Kunduhoglu
Department of Biology, Faculty of Science and Arts, University of Eskişehir Osmangazi, 26480 Eskişehir, Turkey
Tel: +90 222 2393750
Fax: +90 222 2393578
Received May 16, 2018; Revised September 24, 2018; Accepted September 26, 2018.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
In this study, the antimicrobial activity of a bacteriocin produced by Enterococcus faecalis KT11, isolated from traditional Kargı Tulum cheese, was determined, and bacteriocin KT11 was partially characterized. The results showed that bacteriocin KT11 was antagonistically effective against various Gram-positive and Gramnegativetest bacteria, including vancomycin- and/or methicillin-resistant bacteria. The activity of bacteriocin KT11 was completely abolished after treatment with proteolytic enzymes (proteinase K, α-chymotrypsin, protease and trypsin), which demonstrates the proteinaceous nature of this bacteriocin. Additionally, bacteriocin KT11 remained stable at pH values ranging from 2 to 11 and after autoclaving at 121℃ for 30 min. In addition, the activity of bacteriocin KT11 was stable after treatment with several surfactants (EDTA, SDS, Triton X-100, Tween 80 and urea) and organic solvents (chloroform, propanol, methanol, ethyl alcohol, acetone, hexane and ethyl ether). Cell-free supernatant of E. faecalis KT11 was subjected to ammonium sulfate precipitation and then desalted by using a 3.5-kDa cut-off dialysis membrane. The bacteriocin activity was determined to be 711 AU/mL in the dialysate. After tricine-SDS-PAGE analysis, one peptide band, which had a molecular weight of ~3.5 kDa, exhibited antimicrobial activity. Because the bacteriocin KT11, isolated from E. faecalis KT11, exhibits a broad antimicrobial spectrum, heat stability and stability over a wide pH range, this bacteriocin can be used as a potential bio-preservative in foods. Additionally, bacteriocin KT11 alone or in combination with conventional antibiotics may provide a therapeutic option for the treatment of multidrug-resistant clinical pathogens after further in vivo studies.
Keywords : antimicrobial peptides, bacteriocin, Enterococcus faecalis, Kargı Tulum cheese

October 2018, 38 (5)