The impact of acetate metabolism on yeast fermentative performance and wine quality: reduction of volatile acidity of grape musts and wines

Abstract

Acetic acid is the main component of the volatile acidity of grape musts and wines. It can be formed as a by-product of alcoholic fermentation or as a product of the metabolism of acetic and lactic acid bacteria, which can metabolize residual sugars to increase volatile acidity. Acetic acid has a negative impact on yeast fermentative performance and affects the quality of certain types of wine when present above a given concentration. In this mini-review, we present an overview of fermentation conditions and grape-must composition favoring acetic acid formation, as well the metabolic pathways leading to its formation and degradation by yeast. The negative effect of acetic acid on the fermentative performance of Saccharomyces cerevisiae will also be covered, including its role as a physiological inducer of apoptosis. Finally, currently available wine deacidification processes and new proposed solutions based on zymological deacidification by select S. cerevisiae strains will be discussed.

Improved Acetic Acid Resistance in Saccharomyces cerevisiae by Overexpression of the WHI2 Gene Identified through Inverse Metabolic Engineering

“…Acetic acid severely inhibits cell growth and fermentation activity in Saccharomyces cerevisiae (5, 6, 11-13), the predominant microorganism used in industrial fermentation (14, 15). Therefore, improvement in S. cerevisiae resistance to acetic acid is highly desired and critical for achieving efficient and economically viable bioconversion of cellulosic sugars to biofuels.The toxic effects of acetic acid in S. cerevisiae have been intensively characterized, and toxicity mechanisms have been proposed (10,11,(16)(17)(18)(19)(20). When the external pH is lower than the pK a of acetic acid (4.7), the undissociated form of acetic acid prevails and can enter the cells simply by diffusion through plasma membranes.…”

Targeting Demalication and Deacetification Methods: The Role of Carboxylic Acids Transporters

“…Several works have being done about this subject [1,7,8,28,29] and they all agree that excessive volatile acidity can be removed by refermentation with an appropriate S. cerevisiae wine yeast. The transport of acetate into the yeast cell is an imperative step for its metabolism [1]. In glucose-repressed yeast cells, at low pH, acetic acid enters mainly by simple diffusion [30].…”

“…cerevisiae is able to metabolize acetic acid during a refermentation process [6,28]. Several works have being done about this subject [1,7,8,28,29] and they all agree that excessive volatile acidity can be removed by refermentation with an appropriate S. cerevisiae wine yeast. The transport of acetate into the yeast cell is an imperative step for its metabolism [1].…”

“…Though some acids are formed during wine fermentation, is during this biological process that the winemakers must act, to produce a wine with the appropriated acidic balance. For instances, acetic acid, formed during yeast metabolism (fermentation) and also, among others, during the metabolism of acetic and lactic acids, has a negative impact on yeast fermentation performance and affects wines quality when present above his detection threshold [1].…”

Microbial Succession in Spontaneously Fermented Grape Must Before, During and After Stuck Fermentation

“…Acetic acid normally occurs in wine at a concentration ranging from 0.2 to 0.6 g/L (Vilela- Moura et al, 2011). High acetate concentrations could cause stuck fermentation by inhibiting yeast growth (Alexandre & Charpentier, 1998).…”