Bacteria

Biology

Ethanol fermentation

Microbial metabolism

Oenococcus oeni

Biochemistry

Food science

Fermentation in winemaking

Genetics

Malolactic fermentation

Winemaking

Yeast in winemaking

Saccharomyces cerevisiae

Lactic acid

Chemistry

Wine

Microorganism

Citric acid

Malic acid

Fermentation

Yeast

Wine fault

Foods

The main role of acidity and pH is to confer microbial stability to wines. No less relevant, they also preserve the color and sensory properties of wines. Tartaric and malic acids are generally the most prominent acids in wines, while others such as succinic, citric, lactic, and pyruvic can exist in minor concentrations. Multiple reactions occur during winemaking and processing, resulting in changes in the concentration of these acids in wines. Two major groups of microorganisms are involved in such modifications: the wine yeasts, particularly strains of Saccharomyces cerevisiae, which carry out alcoholic fermentation; and lactic acid bacteria, which commonly conduct malolactic fermentation. This review examines various such modifications that occur in the pre-existing acids of grape berries and in others that result from this microbial activity as a means to elucidate the link between microbial diversity and wine composition.

The Role of Yeasts and Lactic Acid Bacteria on the Metabolism of Organic Acids during Winemaking