Temperature and pH conditions that prevail during fermentation of sausagesare optimal for production of the antilisterial bacteriocin sakacin K

Sakacin K is an antilisterial bacteriocin produced by Lactobacillus sake CT C 494, a strain isolated from Spanish dry fermented sausages. The biokineti cs of cell growth and bacteriocin production oft. sake CTC 494 in vitro dur ing laboratory fermentations were investigated by making use of MRS broth. The data obtained from the fermentations was used to see up a predictive mo del to describe the influence of the physical factors temperature and. pH o n microbial behavior. The model was validated successfully for all componen ts. However, the specific bacteriocin production rate seemed to have an upp er limit. Both cell growth and bacteriocin activity were very much influenc ed by changes in temperature and pH, The production of biomass was closely related to bacteriocin activity; indicating primary metabolite kinetics, bu t was not the only factor of importance. Acidity dramatically influenced bo th the production and the inactivation of sakacin K; the optimal pH for cel l growth did not correspond to the pH for maximal sakacin K activity. Furth ermore, cells grew well at 35 degrees C but no bacteriocin production could be detected at this temperature. L, sake CTC 494 shows special promise for implementation as a novel bacteriocin-producing sausage starter culture wi th antilisterial properties, considering the fact that the temperature and acidity conditions that prevail during the fermentation process of dry ferm ented sausages are optimal for the production of sakacin K.