Metabolism of Schizosaccharomyces pombe under reduced osmotic stress conditions afforded by fed-batch alcoholic fermentation of white grape must

Abstract

Strains of Schizosaccharomyces pombe are being increasingly investigated with regards to their grape winemaking potential either in combination with the typical production yeast, Saccharomyces cerevisiae, or in monoseptic fermentations. Their ethanol tolerance and ability to degrade L-malic acid is oenologically convenient but contrasts with the comparatively high acetic acid and acetaldehyde formation potential which is considered undesirable, especially in white winemaking. The purpose of this work was to investigate the performance of a selected S. pombe strain in monoseptic femerntations of white grape must. Traditional batch fermentations were compared with an innovative and automated fed-batch fermentation technique were sugar concentrations are kept low during fermentations to decrease sugar induced osmotic stress. Because of its known effect on growth and ethanol tolerance, the effect of Mg was also tested. While Mg supplementation was not shown to significantly influence residual values of sugars, ethanol, glycerol, organic acids and acetaldehyde, the application of the fed-batch technique led to a fundamental change in yeast physiology. While glycerol values were only slightly reduced, the fed-batch approach allowed obtaining wines devoid of acetic acid whose levels were considerable in wines produced by the traditional batch technique (0.6 g/L). The work demonstrates that the acetic acid metabolism of S. pombe is associated to sugar induced osmotic stress such as for S. cerevisiae, too, and may be controlled by application of suitable fermentation techniques for winemaking.

The Impact of Chitosan on the Chemical Composition of Wines Fermented with Schizosaccharomyces pombe and Saccharomyces cerevisiae

“…Using fed-batch technology during the alcoholic fermentation for white wine production reduces the production of acetaldehyde by Sch. pombe by 50% [ 14 ].…”

“…Fed-batch fermentation technology with Sch. pombe allows for reducing acetic acid production during alcoholic fermentation by up to 100%, and leads to a 50% reduction in acetaldehyde production [ 14 , 15 ].…”

The Influence of Non-Saccharomyces Species on Wine Fermentation Quality Parameters

“…This acid usually produces a quality-detrimental vinegar character, which is not tolerated by consumers of quality wines. This undesirable effect has been solved with different strategies, such as the combined use with S. cerevisiae [94], L. thermotolerans [6,36], or T. delbrueckii [71]; the addition of magnesium [100]; or the use of alginate cells [101] and fed-batch fermentation [102]. These alternatives allow the production of wines with lower acetic acid contents than those produced with S. cerevisiae.…”

Mixed alcoholic fermentation of Schizosaccharomyces pombe and Lachancea thermotolerans and its influence on mannose-containing polysaccharides wine Composition

“…The deacidification ability of S. pombe allows the conversion of harsh-tasting l -malic acid to ethanol (Benito et al 2016c) which result in acidic grape juice from northern Atlantic European grape growing regions to become smoother. However, several collateral effects described for S. pombe , such as the production of high concentrations of acetic acid are common when this species is used in winemaking (Benito et al 2014; Roca-Domènech et al 2018) or other fermentation industries (Minnaar et al 2017; Satora et al 2018). Fleet (2008) proposed that through proper programs of yeast selection, specific strains could perform fermentation processes without the formation of excessive acetic acid, ethyl acetate, hydrogen sulphide and sulphur dioxide, or other off-flavors.…”