Characterisation of a cell-free supernatant obtained from cultures of Enterococcus faecalis DBFIQ E24 with antagonistic activity against bacteria, yeasts and moulds

Enterococcus faecalis DBFIQ E24 strain produces antimicrobial substances that inhibit the growth offood-borne pathogenic bacteria, yeasts and moulds. This broad antimicrobial spectrum was determined by obtaining the cell-free supernatant (CFS) and employing the agar-well-diffusion method. Its antibacterial activity was completely inactivated by the action of proteinase K and not affected by catalase action. Besides, it was stable to thermal treatments, showing maximum antibacterial activity at pH 7.0. Moreover, CFS showed a bactericidal effect against Escherichia coli DBFIQ Ec9 strain. All these interesting physicochemical properties allow that either CFS or E. faecalis DBFIQ E24 strain to be considered as potential food biopreservatives. Fil: Cardoso, Maria de Las Mercedes. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina Fil: Manzo, Ricardo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Tonarelli, Georgina Guadalupe. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina Fil: Simonetta, Arturo Carlos. Universidad Nacional del Litoral. Facultad de Ingeniería Química; Argentina