Lactic acid bacteria isolated from raw milk and soft cheese: detection of cultures able produced bacteriocins and bacteriocin-like substances and molecular identification

MARIA BEATRIZ ORTOLANI; PAULA MORAES; KATIA GIANNI; ABALBERTO SILVIA JUNIOR; LUIS AUGUSTO NERO

Porto de Galinhas, Brasil

Congreso; 25º Congresso Brasileiro de Microbiologia; 2009

The objectives of this study were identify naturally occurring bacteriocinogenic LAB in raw milk and soft cheese, verifying their sensitivity to proteolytic enzymes, and detect the presence of nisin genes in cultures identified as Lactococcus lactis. LAB cultures identified as antagonistic, 20 were randomly selected and submitted to enzymatic tests in order to confirm the proteinaceous nature of antimicrobial substances. Still, these cultures were submitted to 16S rDNA sequencing, and were identified as Lactobacillus plantarum (2) and Lc. lactis subsp. lactis (18). Nisin genes were identified by polymerase chain reaction in 7 of these cultures. The identified bacteriocinogenic cultures presented high variability in production and activity of the bacteriocins.