Characterization of an anti‐listerial enterocin from wheat silage based Enterococcus faecium

Abstract

Two Enterococcus faecium and one E. faecalis strains isolated and identified from wheat silage were characterized based on plasmid content, hemolytic activity, antibiotic resistance patterns, bacteriocin production potential, and presence of enterocin structural genes (entA, entB, entP, entL50B). Among the isolates, only the E. faecium U7 strain exhibited bacteriocin activity against Listeria monocytogenes ATCC 7644, and vancomycin resistant Enterococcus spp. (VRE). A combination of three structural genes (entA, entB, and entP) was detected in E. faecium U7. A relationship between the presence of enterocin structural genes, and bacteriocin activity was detected in E. faecium U7; therefore partially purified enterocin (PPE) was further investigated from the isolate. Several bands of different molecular weights were expressed from PPE extracts following tricine SDS-PAGE analysis. However, the only band showing bacteriocin activity was in an approximate 4-kDa region. PPE treatment with proteinase K, lysozyme, and α -amylase caused complete loss of bacteriocin activity. PPE heat treatment at various temperatures resulted in a notable reduction in bacteriocin expression. Enterocin U7 was relatively heat stable, and presumably exhibits a glucoprotein nature with distinct inhibitory properties. Specific bacterial inhibitory activity of enterocin U7, and the producer strain absence of β -hemolysis and vancomycin susceptibility features deserves further investigation to evaluate its potential application in silage inoculation and food preservation.

Purification and Mode of Action of Antilisterial Bacteriocins Produced byLactobacillus pentosus SJ65 Isolated fromUttapamBatter

“…pentosus was studied against clinically relevant pathogenic organisms (Table 2) and showed Li. monocytogenes as the most sensitive, which was coinciding with the earlier reports (Liu et al 2008;Bal et al 2012). Li.…”

Dynamics and correlations of chlorophyll and phytol content with silage bacterial of different growth heights Pennisetum sinese

“…Enterococcus was aerobic fermentative Gram-positive coccus, which can utilize wide range of fermentable carbohydrates, mainly produced L(+) -lactic acid ( Murray, 1990 ). It is a common microorganism in silage, especially at the beginning of ensiling, so it belongs to silage beneficial microorganisms at some extent ( Bal et al., 2012 ; Wang et al., 2019 ). Sphingobacterium can consume carbohydrates and produce acid ( Yabuuchi et al., 1983 ; Palleroni and Bradbury, 1993 ; Li et al., 2021 ).…”

Enterocin HZ produced by a wildEnterococcus faeciumstrain isolated from a traditional, starter-free pickled cheese

“…Enterocin HZ was highly resistant to high temperatures, retaining its biological activity after heat treatment at 60-90°C for 30 min. This is a common property of the bacteriocins produced by Enterococcus and other LAB (Bal et al 2012;Isleroglu et al 2012). Nevertheless, only 50 % of its inhibitory activity remained after heat treatment at 110°C for 30 min.…”