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United States Department of Agriculture

Agricultural Research Service

Research Project: FUNCTIONAL FOOD DEVELOPMENT BY MICROBIAL BIOTECHNOLOGY

Location: Dairy and Functional Foods

Title: Properties of durancin GL, a new antilisterial bacteriocin produced by Enterococcus durans 41D

Authors
item Du, Lihui -
item Somkuti, George
item Renye, John
item Huo, Guicheng -

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 5, 2011
Publication Date: February 1, 2012
Citation: Du, L., Somkuti, G.A., Renye Jr, J.A., Huo, G. 2012. Properties of durancin GL, a new antilisterial bacteriocin produced by Enterococcus durans 41D. Journal of Food Safety. 32:74-83.

Interpretive Summary: In addition to specific starter cultures used in the production of cheeses, the bacterial population may include Enterococcus species that contribute to the overall flavor of the final food product and also inhibit the growth of certain spoilage bacteria and foodborne pathogens. The inhibitory effect is due to the capacity of some enterococci to produce antimicrobial peptides or bacteriocins. The survey of enterococci found in Mexican cheese samples identified a culture that produces durancin GL, an apparently novel antimicrobial peptide with activity against pathogenic Listeria and undesirable enterococci that may contaminate food. Durancin GL was heat and acid stable and also retained activity after exposure to detergents. The bacteriocin killed pathogenic Listeria strains without causing cell lysis. The effectiveness of durancin GL against Listeria may be applied in preventing the contamination of foods by this pathogen and to reduce the frequency of outbreaks of foodborne listeriosis, which is a serious and occasionally fatal illness.

Technical Abstract: The properties of the antilisterial durancin GL were characterized. The bacteriocin was the product of Enterococcus durans 41D which was isolated from Hispanic-style cheese samples. The antibacterial activity of durancin GL was only evident against Gram-positive bacteria, including Listeria species. Bacteriocin activity was retained after treatment with surfactants (Triton X-100, Tween 40, Tween 80, Tween 85, SDS, Brij 35, Brij 36T, Brij 56, Brij 58, Brij 96), beta-mercaptoehanol and EDTA. Durancin GL was active over the pH range of 2 to 11 and heat resistant for at least 30 min at 100 deg C. However, exposure to 121 deg C for 17 min completely inactivated the bacteriocin. Durancin GL displayed primary metabolite kinetics with the bacteriocin production rate being parallel with the growth cycle of E. durans 41D. T he estimated molecular mass of durancin GL was 3 kDa to 6 kDa and it displayed a bactericidal effect on sensitive strains without concomitant cell lysis. The apparently new antilisterial bacteriocin from the putative probiotic strain Enterococcus durans 41D may be used to protect food products against various Gram positive bacteria including the foodborne pathogen Listeria monocytogenes.

Last Modified: 10/23/2014
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