Purpose: The goal of this study was to isolate and characterize a bacteriocinogenic LAB from donkey milk with potential beneficial properties.
Methods: LAB were isolated from donkey milk and identified based on physiological, biochemical and molecular methods. The promising isolate (Lact. plantarum LP08AD) was evaluated for production of bacteriocin, including stability in presence of various enzymes, surfactants, salts, pH and temperatures. Presence of bacteriocin genes in strain LP08AD was investigated. Growth of strain LP08AD in different pH values and presence of ox bile, adhesion to non- cancerogenic cell lines was explored.
Results: Based on the preliminary test, selected isolate LP08AD was identified as Lact. plantarum. Bactericidal effect of bacteriocin LP08AD on Listeria monocytogenes, Ent. 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 at 30°C or 37°C. Bacteriocin LP08AD adhere at low levels on the producer cells (200 AU/ml). Presence of plantaricin W gene on the genomic DNA was recorded based on PCR reaction. Good growth for strain LP08AD was recorded in MRS broth with pH from 5.0 to 9.0 and in the absence of ox bile or concentration below 0.8%. Lact. plantarum LP08AD was applied to the small intestinal epithelial polarised monolayers of H4, PSIc1 and CLAB and demonstrated low attachment ability on cell lines from human and pig origin.
Significance: 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 use of non-cancerogenic cell lines.