CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PARTIAL CHARACTERIZATION OF THE INHIBITORY COMPOUNDS PRODUCED BY Saccharomyces cerevisiae.
Autor/es:
LUCÍA M. MENDOZA; MARTA E. FARÍAS
Lugar:
La Habana, Cuba
Reunión:
Congreso; Congreso Biotecnología Habana 2008; 2008
Resumen:
Malolactic fermentation is carried out mainly by Oenococcus oeni and plays an important role in winemaking. The antagonism of O. oeni by Saccharomyces cerevisiae could be due to inhibitory compounds produced by the wine yeast such as ethanol, SO2, medium chain fatty acids and antibacterial proteins/peptides. In previous studies we determined by the double-layer plate method that S. cerevisiae mc2 wine strain showed a strong inhibitory activity on the growth of Oenococcus oeni X2L and Lactobacillus hilgardii 5w. Also, neither ethanol nor SO2 seem to be the only factors responsible for the inhibitory yeast activity. The aim of this work was to characterize the nature of the other metabolites produced by S. cerevisiae with inhibitory activity on wine bacteria.  S. cerevisiae was cultured in grape juice medium for 6 days at 25ºC and the supernatant was used as fermented medium. Unfermented grape juice medium was used as control. When O. oeni and L. hilgardii were sequentially inoculated in the media fermented by wine yeast, showed lower growth rate and final cell population in regards to control medium. The inhibitory compounds produced by S. cerevisiae were sensitive to the heat and protease treatments, suggesting that the inhibition on lactic acid bacteria could due to proteinaceous compounds. The inhibitory fraction containing compounds larger than 3 kDa exhibited a typical saturation kinetics of bacterial inhibition. The inhibitory effect exerted by S. cerevisiae mc2 on bacterial growth could be due to a synergistic effect between fermentation metabolites and proteic factors produced by the yeast.