Antimicrobial activity of protein-containing fractions isolated from Lactobacillus plantarum NRRL B-4496 culture

The interest in lactic acid bacteria, including Lactobacillus plantarum NRRL B-4496, has increased in recent years as bio-preservatives, due to the production of secondary metabolites capable of inhibiting pathogenic bacteria. The objectives of this study were to evaluate the antimicrobial activity, cytotoxicity and the anti-inflammatory response of L. plantarum NRRL B-4496 cell-free supernatant (CFS). Furthermore, the CFS was fractionated by size exclusion chromatography using Sephadex G-25, and a minimal inhibitory volume test was determined against a panel of pathogenic bacteria. The cytotoxicity and the inflammatory activities of the fractions were evaluated using the human-derived THP-1 cell line. Results of this study indicates that CFS of L. plantarum NRRL B-4496 possesses antimicrobial protein compounds against the pathogen Listeria monocytogenes and showed no toxicity nor a pro-inflammatory response to human macrophages. The obtained results contribute to the development of novel bio-preservatives, L. plantarum cell-free supernatant or its fractions, with a potential use in the food industry.