Kinetics of production and consumption of organic acids during alcoholic fermentation by Saccharomyces cerevisae

This paper presents a study dealing with the production and consumption kin etics of the main organic acids during alcoholic fermentation carried out b y a Saccharomyces cerevisiae strain normally used for winemaking. The exper iments were carried out using a synthetic medium in which the initial malic acid concentration and the initial pH value were the parameters studied. T he kinetics of malic acid consumption and of some organic acids production was then quantified. The results show that a decrease in pH value favors ma lic acid consumption, while an increase of the initial malic acid concentra tion increases the consumed amount. The specific malic acid consumption rat e shows that its assimilation was microbial growth independent, while the o f her organic acids specific production rates show that their excretion was strongly associated with the microbial growth. The pH evolution during the fermentation was followed and partially explained by the evolution of the global organic acid production.