Growth parameters and bacteriocin expression analysis of E. mundtii CRL 35 in a meat model system

BONACINA, JULIETA; SUÁREZ, NADIA; SESMA, FERNANDO; RAYA, RAÚL; FADDA, SILVINA; SAAVEDRA, LUCILA

Rosario, Santa Fé, Argentina

Congreso; L Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Enterococcus mundtii CRL35 is a bacteriocinogenic non-starter strain with biotechnological potential in biopreservation and food safety. Food model systems constitute a useful and necessary instance to study the behavior of an organism before its application in a real matrix.The aim of this work was to study the growth, acidifying capacity, antimicrobial activity and the expression of bacteriocin genes in a food model based on meat extract at 25°C, in comparison with the laboratory culture media LAPTg. Thus, cell growth (OD600), pH, antimicrobial activity against the food-borne pathogen Listeria monocytogenes, as well as the expression of structural (munA) and ABC transporter (munB) genes of Enterocin CRL35 by qRT-PCR, were determined. E. mundtii CRL35 was able to grow in the food model system reaching an OD600 of 3.12 with a final pH of 4.52 after 25 h incubation. The same growth and acidification capability were observed in LAPTg (pH=4.6 and DO600 =3.06). Regarding the antimicrobial activity, an optimal enterocin CRL35 production was recorded after 10 h, being highly superior in LAPTg (3.6 x 103 UA/ml vs 2.2 x102 UA/ml ). Furthemore, expression analysis by qRT-PCR evidenced that munA and munB are expressed in both media and at the same level. These results suggest that E. mundtii CRL35 could be a suitable bioprotective non-starter culture for meat products.