WINETECH Technical Yearbook 2020

REFERENCES Vaughan-Martini, A. & Martini, A. 2011. Schizosaccharomyces Lindner (1893). Kurtzman, C., Fell, J.W. & Boekhout, T. (eds). The Yeasts (5th Edition), p 779- 784. Elsevier Science. Benito, A., Calderón, F. & Benito, S. 2016. New trends in Schizosaccharomyces use for winemaking. Morata, A. & Loira, I. (eds). Grape and Wine Biotechnology, Chapter 14. IntechOpen. Loira, I., Morata, A., Palomero, F., González C. & Suárez-Lepe, A. 2018. Schizosaccha- romyces pombe : A promising biotech- nology for modulating wine composition. Fermentation 4, 70. Beni to, S. , Palomero, F. , Morata, A., Calderón F. & Suárez-Lepe, J.A. 2012. New applications for Schizosaccharomyces pombe in the alcoholic fermentation of red wines. International Journal of Food Sci- ence and Technology 47, 2101-2108. Yang, H.Y., 1975. Effect of sulfur dioxide on the activity of Schizosaccharomyces pombe . American Journal of Enology and Viticulture 26(1), 1-4.

Benito, S. , Palomero, F. , Calderón, F., Plamero, D. & Suárez-Lepe, J.A. 2014. Selection of appropriate Schizosaccharo- myces strains for winemaking. Food Mi- crobiology 42, 218-224. Benito, A., Calderón, F. & Benito, S. 2019. The influence of non- Saccharomyces species on wine fermentation quality parameters. Fermentation 5, 54. Vejarano, R., 2020. Non- Saccharomyces in winemaking: Source of mannoproteins, nitrogen, enzymes and antimicrobial compounds. Fermentation 6, 76. Morata, A., Escott, C., Bañuelos, A., Loira, I., De Fresno, J.M., González, C. & Suárez- Lepe, J.A. 2020. Contribution of non- Saccharomyces yeasts to wine freshness – a review. Biomolecules 10, 34.

has been used to reduce acidity in wines presenting high levels of malic acid. TRAITS OF OENOLOGICAL INTEREST Generally, S. pombe is reported to produce significantly lower concentrations of higher alcohols and esters than S. cerevisiae and other yeast species (Benito et al ., 2019). However, it is considered as a desirable yeast for modulating other wine organ- oleptic characteristics and wine quality. Amongst its positive attributes are the con- trol of biogenic amines as no bacterial ma- lolactic fermentation is required, and the reduction of gluconic acid in wines derived from rotten grapes (Benito et al ., 2016). • Extracellular enzymes Schizosaccharomyces pombe produces high levels of urease. This enzyme hydrolyses urea which is a precursor of ethyl carbamate, a carcinogen (Vejarano, 2020). • Mannoprotein content – effects on wine stability Schizosaccharomyces pombe has high au- tolytic release of cell wall polysaccharides which makes it desirable for aging over

lees. Its most prominent polysaccharides are α-galactomannose and β-glucans (Beni - to et al ., 2016 & 2019). • Pyruvic acid content – effects on wine colour Schizosaccharomyces pombe displays elevat- ed production of pyruvic acid producing up to five times more pyruvic acid than S. cere- visiae depending on the strain (Benito et al ., 2019). The high pyruvic acid facilitates the formation of stable vitisin A-type derivatives (and some strains, also vinyl phenolic pyro- anthocyanins, which are less sensitive to SO 2 bleaching) by chemical condensation with grape anthocyanins (Morata et al ., 2020). CONCLUSION Schizosaccharomyces pombe is the most recommended non- Saccharomyces species to de-acidify excessively acidic wines from cool areas, such as those from the north of Europe (Benito et al ., 2019). However, this has not spurred the development of commercial strains. Currently, only S. pombe Promalic (www.aeb-group.com/ en/promalic-oenology-4903) is available on the market.

For more information, contact Evodia Setati at setati@sun.ac.za.

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