Characterization and identification of bacteriocins produced by cheese isolated lab
| Autor: | Lamberti C., Genovese F., Lo Bianco G., Giunta C., Pessione E. |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | 36 th FEBS, pp. 166–166, Torino, 25-30 giugno 2011 info:cnr-pdr/source/autori:Lamberti C., Genovese F., Lo Bianco G., Giunta C., Pessione E./congresso_nome:36 th FEBS/congresso_luogo:Torino/congresso_data:25-30 giugno 2011/anno:2011/pagina_da:166/pagina_a:166/intervallo_pagine:166–166 |
| Popis: | Lactic acid bacteria are used for food improvement in a wide range of fermented foods and some strains can also produce antimicrobial peptides, named bacteriocins, active against food pathogens such as Listeria monocytogenes and Staphyloccus aureus.The aim of this study was to characterize antimicrobial peptides produced by two Enterococcus faecium strains, a Lactobacillus plantarum, a Lactococcus lactis ssp. cremoris and five Lactococcus lactis ssp. lactis. All bacteria were isolated from Italian cheeses. Lactococci and enterococci were grown in M17 broth at 37C while Lactobacillus plantarum was grown in MRS broth at 30C. All cultures were performed both in microaerophylia and in presence of O2 to test whether stress (presence of oxigen) stimulates bacteriocins production. The whole culture and the cell-free supernatant of both strains were tested against pathogens using well-diffusion assay and their antimicrobial activity was shown by the formation of an inhibition zone around the well on the plate. In order to evaluate the time of maximum production of bacteriocins, cultures at different growth phases were tested. Two different peptide purification protocols were tested in order to recover a larger amount of bateriocins. A biochemical characterization was performed: molecular size determination by Tricine-SDS-PAGE, thermostability at 70C, 80C and 90C and proteinase k sensitivity. Molecular targeting experiments of bacteriocins encoding genes by PCR were performed in order to confirm the bacteriocins identification. This study demonstrated that all lactococcal strains produced nisin A, the two enterecoccus strain produced enterocin A, while the L. plantarum was able to inhibit pathogen by means of large amounts of lactic acid. The most interesting strains (L. lactis L5 e L7) possess both extracellular and surface-bound bacteriocins and their maximum production occurs during the middle logarithmic phase. |
| Databáze: | OpenAIRE |
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