Isolation and Characterisation of Bacteriocin and Aggregation-Promoting Factor
Production in Lactococcus lactis ssp. lactis BGBM50 Strain  


Nemanja Mirkovic^1,2, Zorica Radulovic¹, Gordana Uzelac², Jelena Lozo^2,3, Dragojlo Obradovic¹,
Ljubisa Topisirovic² and Milan Kojic²*


¹Faculty of Agriculture, University of Belgrade, RS-11080 Belgrade, Serbia
²Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, RS-11010 Belgrade, Serbia
³Faculty of Biology, University of Belgrade, RS-11000 Belgrade, Serbia



Article history:
Received August 4, 2014
Accepted March 3, 2015



Key words: 
bacteriocin lactococcin G, aggregation-promoting factor, plasmid curing



Summary:
Lactococcus lactis ssp. lactis BGBM50, a producer of lactococcin G and aggregation-promoting factor, was isolated from selected lactic acid bacteria taken from semi-hard cheese traditionally produced in the village Žanjic, Montenegro. Strain BGBM50 harbours a number of plasmids of different sizes. Plasmid curing experiments showed that genes for bacteriocin production are located on pBM140, a plasmid 140 kb in length. PCR analysis with primers specific for lactococcin Q and G genes gave fragment of the expected size. In addition, after plasmid curing of strain BGBM50, different derivatives with altered phenotypes were obtained, among them BGBM50-34 strain, which retained bacteriocin synthesis but had enhanced aggregation ability.

*Corresponding author:      mkojic@imgge.bg.ac.rs,  mkojics@eunet.rs  
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