Bacterias ácido lácticas con potencial bacteriocinogénico obtenidas de quesos artesanales del austro del Ecuador

Lactic acid bacteria with bacteriocinogenic potential obtained from artisanal cheeses from south of Ecuador

Resumen

El objetivo del trabajo fue identificar bioquímicamente varias cepas de bacterias lácticas aisladas de quesos artesanales del Austro del Ecuador y determinar su capacidad bacteriocinogénica. De las cepas identificadas se escogió Lactococcus lactis, el cual se cultivó en condiciones adecuadas y se obtuvo un extracto concentrado que se neutralizó con HCl 0,1N. Se evaluó su actividad inhibitoria frente a cepas de patógenos, que incluyeron estabilidad térmica, condiciones de pH y acción de enzimas. La actividad inhibitoria se evaluó por el método de difusión en pozo frente a Staphylococcus aureus y Listeria monocytogenes, no evidenciándose actividad frente a Gram negativas. El análisis de varianza (p ≤ 0,05) determinó que existe una ligera pérdida de actividad luego de los tratamientos en relación con la del extracto crudo neutralizado. No se descarta que el compuesto activo se trate de una bacteriocina con potencial uso en el control de microorganismos patógenos de interés en alimentos.
Palabras clave: bacteriocina, patógenos, extracto, Lactococcus, actividad, alimentos.

ABSTRACT

Lactic acid bacteria with bacteriocinogenic potential obtained from artisanal cheeses from south of Ecuador

The aim of the present work was to identify biochemically several strains of lactic acid bacteria isolated from artisanal cheeses from the Austro of Ecuador and determine their bacteriocinogenic capacity. From the strains identified, Lactococcus lactis was chosen, which was cultivated under appropriate conditions. A concentrated extract was obtained, which was neutralized with 0,1N HCl. Their inhibitory activity was evaluated against strains of pathogens, which included thermal stability, pH conditions and the action of enzymes. The inhibitory activity was evaluated by the well diffusion method against Staphylococcus aureus and Listeria monocytogenes, with no evidence of activity against Gram negative bacteria. The analysis of variance (p ≤ 0.05) determined that there is a slight loss of activity after the
treatments in relation to the neutralized crude extract. It is not excluded that the active compound, it is a bacteriocin with potential use in the control of pathogenic microorganisms of interest in foods.
Keywords: bacteriocin, pathogens, extract, Lactococcus, activity, foods.