title: Inhibition of fungi and gram-negative bacteria by bacteriocin BacTN635 produced by Lactobacillus plantarum sp. TN635.
abstract: The aim of this study was to evaluate 54 lactic acid bacteria (LAB) strains isolated from meat, fermented vegetables and dairy products for their capacity to produce antimicrobial activities against several bacteria and fungi. The strain designed TN635 has been selected for advanced studies. The supernatant culture of this strain inhibits the growth of all tested pathogenic including the four Gram-negative bacteria (Salmonella enterica ATCC43972, Pseudomonas aeruginosa ATCC 49189, Hafnia sp. and Serratia sp.) and the pathogenic fungus Candida tropicalis R2 CIP203. Based on the nucleotide sequence of the 16S rRNA gene of the strain TN635 (1,540 pb accession no FN252881) and the phylogenetic analysis, we propose the assignment of our new isolate bacterium as Lactobacillus plantarum sp. TN635 strain. Its antimicrobial compound was determined as a proteinaceous substance, stable to heat and to treatment with surfactants and organic solvents. Highest antimicrobial activity was found between pH 3 and 11 with an optimum at pH = 7. The BacTN635 was purified to homogeneity by a four-step protocol involving ammonium sulfate precipitation, centrifugal microconcentrators with a 10-kDa membrane cutoff, gel filtration Sephadex G-25, and C18 reverse-phase HPLC. SDS-PAGE analysis of the purified BacTN635, revealed a single band with an estimated molecular mass of approximately 4 kDa. The maximum bacteriocin production (5,000 AU/ml) was recorded after a 16-h incubation in Man, Rogosa, and Sharpe (MRS) medium at 30 degrees C. The mode of action of the partial purified BacTN635 was identified as bactericidal against Listeria ivanovii BUG 496 and as fungistatic against C. tropicalis R2 CIP203.
authors.affiliation: Laboratoire d'Enzymes et de Métabolites des Procaryotes (LEMP), Centre de Biotechnologie de Sfax (CBS), Route de Sidi Mansour Km 6, B.P. "1177", 3018 Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Smaoui
authors.forename: Lobna
authors.initials: L
authors.lastname: Elleuch
authors.forename: Wacim
authors.initials: W
authors.lastname: Bejar
authors.forename: Ines
authors.initials: I
authors.lastname: Karray-Rebai
authors.forename: Imen
authors.initials: I
authors.lastname: Ayadi
authors.forename: Bassem
authors.initials: B
authors.lastname: Jaouadi
authors.forename: Florence
authors.initials: F
authors.lastname: Mathieu
authors.forename: Hichem
authors.initials: H
authors.lastname: Chouayekh
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.forename: Lotfi
authors.initials: L
authors.lastname: Mellouli
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D001430:Bacteriocins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D002417:Cattle; D003611:Dairy Products / Q000382:microbiology; D015536:Down-Regulation; D005658:Fungi / Q000187:drug effects* / Q000254:growth & development; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D048191:Lactiplantibacillus plantarum / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008460:Meat / Q000382:microbiology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D014675:Vegetables / Q000382:microbiology
chemical_list: D000890:Anti-Infective Agents; D001430:Bacteriocins