Isolation and identification of bacteriocinogenic strain ofLactobacillus plantarumwith potential beneficial properties from donkey milk

Abstract

Aims: The goal of this study was to isolate and characterize a lactic acid bacteria (LAB) from donkey milk with potential beneficial properties. Methods and Results: Lactic acid bacteria were isolated from donkey milk and identified based on physiological, biochemical and molecular methods. The isolate that presented highest bacteriocin potential (Lactobacillus plantarum LP08AD) was evaluated for the production of bacteriocin, including stability in the presence of various enzymes, surfactants, salts, pH and temperatures. Bactericidal effect of bacteriocin LP08AD on Listeria monocytogenes, Enterococcus faecium and Lactobacillus curvatus was shown for actively growing and stationary cells. Similar growth and bacteriocin production were observed when strain LP08AD was cultured in MRS broth at 30°C or 37°C. Bacteriocin LP08AD adhered at low levels on the producer cells (200 AU ml À1 ). The presence of plantaricin W gene on the genomic DNA was recorded based on PCR. Good growth for strain LP08AD was recorded in MRS broth with pH from 5Á0 to 9Á0 and LP08AD grew well in the absence of oxbile or concentration below 0Á8%. Lact. plantarum LP08AD was applied to the small intestinal epithelial polarized monolayers of H4, PSIc1 and CLAB and demonstrated low attachment ability on all cell lines studied, with values with a similar behaviour for cells from human and pig origin. Conclusions: Bacteriocin-producing Lact. plantarum LP08AD might be useful in the design of novel functional foods with potential probiotic or biopreservation properties. Significance and Impact of the Study: To the best of our knowledge, this is the first report on detection and characterization of bacteriocinogenic Lact. plantarum from donkey milk. The strain LP08AD shows to have potential beneficial properties, as demonstrated by the use of noncancerogenic cell lines.

Technology and safety assessment for lactic acid bacteria isolated from traditional Bulgarian fermented meat product “lukanka”

“…In fact, most of the bacteriocins described for Lactobacillus spp. were found to be active against a much broader range of microbial genera and species 19 . However, it is important to emphasize that the very strong activity against L. monocytogenes exhibited by BS7, BS30, BS36, BS37 and BS39 strains could have significant application in the biopreservation of fermented food products.…”

“…DNA was submitted to PCR reactions to detect genes responsible for codification of the following bacteriocins: nisin, pediocin PA-1, curvacin A, plantaricin S, plantaricin NC8, plantaricin W, sakacin G, sakacin Tα, sakacin Tβ and sakacin X (Table 3). 14, 15, 16, 17, 18, 19 The PCR reaction was prepared using primers at 10 pM/μL and conditions as described previously, adjusting the annealing temperature according to the specification of the primers used 14, 15, 16, 17, 18, 19. The amplified products were separated by electrophoresis on agarose gels in 0.5× TAE buffer.…”

Heterologous Expression of Pediocin PA-1 inEscherichia coli

“…Total antimicrobial activities of a protein/peptide expressed in arbitrary units per ml (AU/ml) were calculated using the following formula: AU/ml = (2 n × 1000)/V, where n is the folds of dilution with inhibition zone in the well ≥ 2 mm and V is the volume (μl) of sample filled in each well. [8]. With the concentration pediocin in the samples, arbitrary units per mg (AU/mg) were measured using the following formula: …”

Bioactive Compounds of Lactic Acid Bacteria. Case Study: Evaluation of Antimicrobial Activity of Bacteriocin-producing Lactobacilli Isolated from Native Ecological Niches of Ecuador

“…Antimicrobial heterogeneous compounds (i.e., bacteriocine) are ribosomally synthesized polypeptide or low-molecular-weight proteins (composed of 20-60 amino acid residues), which, in case of LAB, are generally recognized as safe compounds [9]. They bind to the receptor of the target cell, and their mode of action included pore formation, degradation of cellular DNA, disruption through specific cleavage of 16S rRNA, and inhibition of peptidoglycan synthesis [10,11]. Bacteriocins being proteinaceous agents differ from most antibiotics because they are rapidly digested by proteases in the digestive tract.…”

“…More than three hundred different bacteriocins have been described for the genera Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Enterococcus. These peptides are colorless, odorless, and tasteless, and according to their molecular mass, thermo stability, enzymatic, and sensitivity, the presence of posttranslational modified amino acids and their mode of action are classified into four major groups [10][11][12][13].…”