Antibacterial activity produced by Enterococcus spp. isolated from an artisanal Mexican dairy product, Cotija cheese

作者：Garcia Cano Israel; Eduardo Serrano Maldonado Carlos; Olvera Garcia Myrna; Delgado Arciniega Estela; Pena Montes Carolina; Mendoza Hernandez Guillermo; Quirasco Maricarmen^*

来源：LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY, 2014, 59(1): 26-34.

DOI：10.1016/j.lwt.2014.04.059

• Farmhouse-made cheese microbiota
• Lactic acid bacteria
• Enterococci
• Peptidoglycan hydrolase
• N-acetylglucosaminidase

Several Enterococci were isolated from Cotija cheese, which is a Mexican farmhouse-made product prepared from whole raw milk. No thermal step, neither starter cultures, are used in its manufacturing process. From the isolated strains two were outstanding for their extracellular lytic activity against Staphylococcus aureus, and were identified by 165 rDNA sequencing as Enterococcus faecalis and Enterococcus faecium, respectively. They also showed bacteriolytic activity against other pathogenic bacteria, such as Yersinia enterocolitica, Salmonella enterica Typhimurium and Pseudomonas aeruginosa, as demonstrated by agar diffusion tests. By zymography it was shown that they produced proteins with bacteriolytic activity with molecular masses of 95 and 81 kDa, respectively. Protein identification by LC/ESI MS/MS showed that they correspond to different enzymes with peptidoglycan hydrolase (PGH) activity of N-acetylglucosaminidase. Two of them were considered as putative enzymes and had not been studied before. Concentrated protein preparations from both strains showed lytic activity on S. aureus growth in liquid culture, as well. Considering that the PGHs studied are produced by lactic bacteria isolated from a dairy product and their spectrum of bacterial inhibition, these enzymes have a potential use in food preservation.

• 出版日期2014-11