Antagonistic lactic acid bacteria isolated from goat milk and identification of a novel nisin variant Lactococcus lactis

Abstract

BackgroundThe raw goat milk microbiota is considered a good source of novel bacteriocinogenic lactic acid bacteria (LAB) strains that can be exploited as an alternative for use as biopreservatives in foods. The constant demand for such alternative tools justifies studies that investigate the antimicrobial potential of such strains.ResultsThe obtained data identified a predominance of Lactococcus and Enterococcus strains in raw goat milk microbiota with antimicrobial activity against Listeria monocytogenes ATCC 7644. Enzymatic assays confirmed the bacteriocinogenic nature of the antimicrobial substances produced by the isolated strains, and PCR reactions detected a variety of bacteriocin-related genes in their genomes. Rep-PCR identified broad genetic variability among the Enterococcus isolates, and close relations between the Lactococcus strains. The sequencing of PCR products from nis-positive Lactococcus allowed the identification of a predicted nisin variant not previously described and possessing a wide inhibitory spectrum.ConclusionsRaw goat milk was confirmed as a good source of novel bacteriocinogenic LAB strains, having identified Lactococcus isolates possessing variations in their genomes that suggest the production of a nisin variant not yet described and with potential for use as biopreservatives in food due to its broad spectrum of action.

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“…Coccoid isolated in this study were allocated to Lactococcus and Enterococcus representing 96.1% of all isolates recorded. The results were similar to study of researchers who isolated mainly genus of Lactococcus and Enterococcus from the goat milk [13][14][15][16].…”

“…Predominance of coccoid LAB were found in goat's milk, particularly Lactococcus and Enterococcus species and species of E. hirae was common in goat's milk [12,13,15,18]. Lactococcus and Enterococcus species were also found in the fresh milk of other mammals, for example in cows' milk [19] and camels' milk [20], but with no isolation of E. hirae reported in the research.…”

Genetic Diversity and Some Aspects of Antimicrobial Activity of Lactic Acid Bacteria Isolated from Goat Milk

“…The study was conducted with a collection of 57 LAB isolates (33 Enterococcus isolates, named GEn01 to GEn33, and 24 Lactococcus isolates, designated GLc01 to GLc24), all obtained from goat milk and characterized as bacteriocinogenic by Perin and Nero [50]. The isolates were identified by sequencing regions of the 16S rDNA and pheS gene (specific to enterococci) and characterized as bacteriocinogenic by the spot-on-the-lawn method [34,58] and enzymatic sensitivity [35].…”

Aislamiento, Caracterización y Selección de Bacterias Lácticas Autóctonas de Leche y Queso Fresco Artesanal de Cabra

“…Diferentes autores han aislado bacterias lácticas autóctonas a partir de leche de cabra (Alonso-Calleja et al, 2002;Nikolic et al, 2008;González y Zárate, 2012;Perin y Nero, 2014) y quesos artesanales (Cogan et al, 1997;Pérez-Erlotondo et al, 1998;Fraga-Cotelo et al, 2013;Terzic-Vidojevic et al, 2014), con el objetivo de identificarlas y caracterizar sus propiedades funcionales o tecnológicas en los procesos de elaboración y maduración de quesos; o bien con la intención de incluirlas como cultivos iniciadores, posibilitando la producción industrial de quesos con características similares a las artesanales. La selección de cepas autóctonas con propiedades deseables podría lograr una producción estandarizada, mejorar la calidad sensorial y al mismo tiempo preservar las características que definen la identidad de un queso artesanal (Pavunc et al, 2012;Speranza et al, 2015).…”