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Production, mode of action and sequencing of the corresponding gene of a bacteriocin produced by Lactococcus lactis 19.3
Author(s) -
Zamfir Medana,
Stefan IuliaRoxana,
Stancu MihaelaMarilena,
GrosuTudor SilviaSimona
Publication year - 2016
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13196
Subject(s) - bacteriocin , lactococcus lactis , nisin , listeria monocytogenes , microbiology and biotechnology , listeria , lactobacillus , biology , food science , mode of action , strain (injury) , bacteria , probiotic , fermentation , chemistry , antimicrobial , biochemistry , lactic acid , genetics , anatomy
Summary Lactococcus lactis 19.3 produces a bacteriocin with a wide inhibitory spectrum, including the food pathogen Listeria monocytogenes . The producing strain was able to grow and produce similar amounts of bacteriocin in MRS medium, cow's milk and soya milk, respectively. The mode of action of this bacteriocin was further investigated using two indicator strains, Lactobacillus delbrueckii subsp. bulgaricus LMG 6901 T and Listeria monocytogenes ATCC 1911‐1. The bacteriocin displayed a bactericidal effect, causing a rapid decrease of the cell viability. Bacteriocin treatment of the sensitive strains resulted in major morphological changes, including pore formation, as shown by scanning electron microscopy. Finally, the bacteriocin‐encoding gene was identified by sequencing. The presence of nisin gene was confirmed. Based on all our data gathered so far, L. lactis 19.3 is a good candidate for a starter or protective culture in the manufacturing of both fermented dairy and vegetarian food products.