Molecular Screening of Functional Lactic Acid Bacteria with Potential Production of Antimicrobial Peptides from Milk Proteins for Application as Preservative Dairy Starter

This study aimed to assess the molecular screening and safety of 14 lactic acid bacteria isolates for their capacity to produce antimicrobial peptides from milk proteins. The isolates were molecularly identified as Enterococcus faecium, Enterococcus durans, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. hordniae, Lactiplantibacillus plantarum, and Weissella confusa. The tested lactococci isolates produced bioactive peptides with a wild-type antimicrobial spectrum against Salmonella typhimurium, Pseudomonas aeruginosa, Bacillus cereus, and Listeria monocytogenes. The majority of isolates were susceptible to chloramphenicol, tetracycline, and ampicillin but resistant to nalidixic acid. Lactococcus lactis FFNL-2034 and Weissella confusa FFNL-1850 presented antibiotic multiresistance. Antibiotic resistance genes bla, ermB, tetK, cat, vanA, and vanC were absent in most of the tested isolates. The ermC, strA, strB, and tetM genes were positive in some isolates. These results provide safe LAB, which could act as a potent biopreservative agent for functional dairy products.