Technological features and ability to produce nisin by Lactococcus lactis subsp. lactis bv. diacetylactis obtained from dairy environment
type: CreativeWork
description: Lactococcus lactis subsp. lactis bv. diacetylactis strains are used in the dairy industry to produce acetoin and diacetyl, substances that are responsible for conferring organoleptical characteristics to some fermented foods. Bacteriocin production can be an additional beneficial feature presented by some strains. The identification and characterization of novel Lactococcus strains may reveal distinct attributes that have high technological potential for the dairy industry. This study aimed to characterize the technological and bacteriocinogenic potential of L. lactis subsp. lactis bv. diacetylactis strains obtained from dairy production systems. Twenty-three strains of L. lactis subsp. lactis isolated from cow, goat, and buffalo milks, cow's milk cream, artisanal cheeses from the Amazon region, artisanal cheeses from Marajó Island, forage peanut silages and grass silages were used in this study. The strains were identified at a biovar level (acetoin and dyacetil production, despite specific PCR assays), fingerprinted by rep-PCR and characterized for their technological potential: lactofermentation patterns, extracellular proteolytic activity, acidification capacity, and resistance to NaCl. Subsequently, the strains were subjected to PCR to detect bacteriocin-related genes (nisin, lacticins 481 and 3147, lactococcins A and 972) and further investigated by PCR and sequencing for the nisin operon. Cell free supernatants (CFS) of nisin-positive strains were tested by the spot-on-the lawn assay against a panel of 16 targets (Listeria monocytogenes - 4, L. innocua - 1, Staphylococcus aureus - 6, Lactobacillus sakei - 1, L. lactis - 4). Growth curves of 4 microbial targets (L. monocytogenes - 2, S. aureus - 2), with and without the CFS of nisin producers, were obtained by optical density (λ = 650 nm). Based on a culture collection of 23 L. lactis subsp. lactis strains, 15 presented molecular and phenotypical results that allowed them to be identified as L. lactis subsp. l…
abstract: Lactococcus lactis subsp. lactis bv. diacetylactis strains are used in the dairy industry to produce acetoin and diacetyl, substances that are responsible for conferring organoleptical characteristics to some fermented foods. Bacteriocin production can be an additional beneficial feature presented by some strains. The identification and characterization of novel Lactococcus strains may reveal distinct attributes that have high technological potential for the dairy industry. This study aimed to characterize the technological and bacteriocinogenic potential of L. lactis subsp. lactis bv. diacetylactis strains obtained from dairy production systems. Twenty-three strains of L. lactis subsp. lactis isolated from cow, goat, and buffalo milks, cow's milk cream, artisanal cheeses from the Amazon region, artisanal cheeses from Marajó Island, forage peanut silages and grass silages were used in this study. The strains were identified at a biovar level (acetoin and dyacetil production, despite specific PCR assays), fingerprinted by rep-PCR and characterized for their technological potential: lactofermentation patterns, extracellular proteolytic activity, acidification capacity, and resistance to NaCl. Subsequently, the strains were subjected to PCR to detect bacteriocin-related genes (nisin, lacticins 481 and 3147, lactococcins A and 972) and further investigated by PCR and sequencing for the nisin operon. Cell free supernatants (CFS) of nisin-positive strains were tested by the spot-on-the lawn assay against a panel of 16 targets (Listeria monocytogenes - 4, L. innocua - 1, Staphylococcus aureus - 6, Lactobacillus sakei - 1, L. lactis - 4). Growth curves of 4 microbial targets (L. monocytogenes - 2, S. aureus - 2), with and without the CFS of nisin producers, were obtained by optical density (λ = 650 nm). Based on a culture collection of 23 L. lactis subsp. lactis strains, 15 presented molecular and phenotypical results that allowed them to be identified as L. lactis subsp. l…
author: Fusieger, Andressa
language: por
keywords: Bactérias do ácido lático, Fermentação, Diacetil, Bacteriocinas
date published: 2019-02-19
date modified: 2026-07-24T01:21:47Z
provider: Brazil UFV
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universidade Federal de Viçosa