CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
MODIFICATION OF L-MALIC ACID UTILIZATION BY Saccharomyces cerevisiae IN CO-CULTURE WITH Kloeckera apiculata
MENDOZA L.; MANCA DE NADRA M.C.; FARÍAS M.E.
Lugar: Argentina; Año: 2006 vol. 30 p. 201 - 201
The ability of yeasts to degrade malic acid is dependent on the efficient transport of the dicarboxylic acid through the plasmatic membrane as well as the efficacy of the intracellular malic enzyme. In this work we evaluated the influence of Kloeckera apiculata mc1 on the utilization of malic acid by Saccharomyces cerevisiae mc2, both strains isolated from Argentinean wines. The yeasts were cultured in grape juice medium added with 2, 4 and 6 g/l malic acid. Pure cultures of S. cerevisiae consumed malic acid with specific rates of 0,007; 0,012 y 0,007 g g-1 d-1 in presence of 2, 4 y 6 g/l of the organic acid, respectively. 7, 24 y 5% increment of the ethanol production was detected in presence of the three malic acid concentrations. In co-culture with K. apiculata, the elliptic yeast showed a higher specific rate of dicarboxylic acid consumption (0,016; 0,028 y 0,020 g g-1 d-1). The ethanol production was higher than in pure culture by 21, 44 y 26%, for increasing concentrations of L-malic acid, respectively. The competence for the substrates in mixed culture could be responsible of the higher utilization of malic acid by S. cerevisiae. The physiological role of the malic enzyme in S. cerevisiae would be related to an auxiliary pathway for NADPH regeneration. The higher removal of malic acid by mixed cultures of K. apiculata mc1-S. cerevisiae mc2 has technological importance in the winemaking, contributing to the final product stability.