Identification of the bacteriocin produced by cheese isolate Lactobacillus paraplantarum FT259 and its potential influence on Listeria monocytogenes biofilm formation

Lactic acid bacteria (LAB) are known by their technological properties, such as the inhibition of spoilage and pathogenic bacteria. The aims of this study were: (i) to evaluate the influence of Lactobacillus paraplantarum FT259 on biofilm formation by Listeria monocytogenes by using culture method and fluorescence in situ hybridization (FISH) and, (ii) to partially characterize the bacteriocin produced by this strain isolated from Brazilian semi-hard cheese by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE). We also performed polymerase chain reactions with primers for plantaricin NC8, plantaricin S and plantaricin W structural genes followed by DNA sequencing to possibly identify the bacteriocin produced. Results of microscopy assays demonstrated the complex and heterogenous structure of the biofilm formed by co-culture of both strains. SDS-PAGE analysis indicated that the partially purified bacteriocin presented a molecular mass around 3900 Da and, PCR-DNA sequencing detected the plantaricin NC8 gene. To our knowledge, this is the first report on the inhibitory effect of an L. paraplantarum strain on L monocytogenes biofilms, as well as the formation of biofilm by this LAB species. In addition, we have demonstrated L paraplantarum FT259 harbored the gene for plantaricin NC8 production, which may be responsible by the antimicrobial activity observed. (C) 2015 Elsevier Ltd. All rights reserved.