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Fructophilic yeasts to cure stuck fermentations in alcoholic beverages
Thesis (PhDAgric (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2010.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : University of Stellenbosch
2010
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| _version_ | 1867614030766538752 |
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| access_status_str | Open Access |
| author | Sutterlin, Klaus A. (Klaus Alfred) |
| author2 | Bauer, Florian |
| author_browse | Bauer, Florian Sutterlin, Klaus A. (Klaus Alfred) |
| author_facet | Bauer, Florian Sutterlin, Klaus A. (Klaus Alfred) |
| author_sort | Sutterlin, Klaus A. (Klaus Alfred) |
| collection | Thesis |
| dc_rights_str_mv | University of Stellenbosch |
| description | Thesis (PhDAgric (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2010. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/4013 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:45:33.890Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2010 |
| publishDateRange | 2010 |
| publishDateSort | 2010 |
| publisher | Stellenbosch : University of Stellenbosch |
| publisherStr | Stellenbosch : University of Stellenbosch |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/4013 Fructophilic yeasts to cure stuck fermentations in alcoholic beverages Sutterlin, Klaus A. (Klaus Alfred) Bauer, Florian Gafner, Jurg University of Stellenbosch. Faculty of Agrisciences. Dept. of Viticulture and Oenology. Institute for Wine Biotechnology. Stuck fermentation Fructophilic yeasts Zygosaccharomyces bailii Fructose utilisation Dissertations -- Wine biotechnology Theses -- Wine biotechnology Fermentation Alcoholic beverages -- Microbiology Wine yeasts Thesis (PhDAgric (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2010. ENGLISH ABSTRACT: Stuck alcoholic fermentations are a major enological problem for the international winemaking industry. Incomplete wine fermentations are frequently characterized by high residual fructose concentrations and the near-absence of residual glucose, a fact that is due to the glucophilic character of the wine yeast Saccharomyces cerevisiae. Wines with high contents of post fermentation sugar are very susceptible for microbial spoilage since residual fructose and/or glucose can be metabolized by bacteria and yeast to undesired by-products such as volatile acid and off-flavours, resulting in wine spoilage and considerable economic losses. It has been reported that stuck fermentations are usually caused by several synergistically acting inhibition factors, and the glucose to fructose ratio (GFR) is thought to play an important role in this context. This study is aimed at contributing towards a better understanding of this industrial problem, and at finding industrially applicable solutions. In a first part, this study describes the isolation of two appropriate strains of the fructophilic yeast Zygosaccharomyces bailii from the natural microflora of grapevine, followed by trials in small scale test fermentations using stuck industrial fermentations as model media. These experiments were expanded to also investigate large scale industrial fermentations. As a result, a strategy for the treatment of stuck fermentations was developed and successfully applied in several wineries with fermentation problems. This methodology represents an entirely novel and industrially applicable solution to high residual fructose levels. In a second part, the data contributes to elucidating the molecular nature of the fructophilic phenotype of Z. bailii by characterizing some of the genes and proteins that may be responsible for the fructophilic character. In particular, the investigation focused on the first two steps of hexose metabolism, the transport of sugar into the cell by permeases and sugar phosphorylation by hexokinases, which combined are thought to be primarily responsible for sugar preference. One result of this study was Fructoferm W3©, a dry yeast product which is commercially available. Fructoferm W3 was awarded with the innovation medal for enological products at Intervitis/Interfructa, Stuttgart, Germany in 2007. AFRIKAANSE OPSOMMING: Die voorkoms van steek alkoholiese fermentasies is ‘n ernstige problem in die internasionale wyn industrie. Onvolledige fermentasies word dikwels gekenmerk deur hoë residuele fruktose konsentrasies en die veitlike afwesigheid van residuele glukose. Die kenmerke kan meestal toegeskryf word aan die glukofilliese kakakter van die wyngis Saccharomyces cerevisiae. Wyne met ‘n hoë suiker inhoud na die afloop van fermentasie is vatbaar vir mikrobiese bederf aangesien residuele fruktose en/of glukose gemetaboliseer kan word deur bakterië en gis om ongewenste byprodukte soos vlugtige sure en bygeure te vorm wat kan lei tot wyn bederf en aansienlike ekonomies verlies. Dit is vasgestel dat steek fermentasies gewoonlik veroorsaak word deur verskeie sinergisties werkende inhibisie faktore, waartoe die glukose/fruktose verhouding ‘n noemenswaardiege bydrae lewer. Die mikpunt van hierdie studie was om ‘n bydrae te lewer tot die begrip van steek fermentasies en die daarstelling van moontlike industriële oplossings. Die eerste deel van die werk beskryf die isolasie van twee rasse van die gis Zygosaccharomyces baillie uit die natuurlike wingerd mikroflora, gevolg deur steekproewe in die vorm van kelinskaalse fermentasies met steek industriële fermentasies gebruik as model media. Hierdie ekserimente is vervolgens uitgebrei om grootskaalse industriële steek fermentasies te bestudeer. Die uitkoms van hierdie werk het gelei tot die ontwikkeling van ‘n strategie vir die behandeling van steek fermentasies wat susksesvol toegepas is in verskeie wynmakerye. Die metodiek bring ‘n nuwe en industrieel toepasbare oplossing vir hoë residuele fruktose vlakke. Die data aangebied in die tweede afdeling dra by tot die verheldering van die molekulêre natuur van die fruktofilliese fenotipe van Z. baillie deur die tipering van gene en protiëne wat moontlik verantwoordelik is vir die fruktofilliese karakter van die gis. Die ondersoek het spesifiek op die eerste twee stappe van heksose metabolisme, naamlik die invoer van suiker in die sel deur permeases en suiker fosforilering deur heksokinases, gekonsentreer. Die kombinasie van die twee prosesse is vermoedelik verantwoordelik vir die regulering van suiker voorkeur. ‘n Gevolg van die studie was die ontwikkeling van ‘n droë gisproduk, Fructferm W3©, wat kommersieel beskikbaar gestel is. Fructoferm W3 is in 2007 toegeken met die innovasie medalje vir wynkundige produkte by Intervittis/Interfructa in Stuttgart, Duitsland. Doctoral 2010-02-24T05:28:11Z 2010-08-13T13:11:16Z 2010-02-24T05:28:11Z 2010-08-13T13:11:16Z 2010-03 Thesis http://hdl.handle.net/10019.1/4013 en University of Stellenbosch 186 p. : ill. application/pdf Stellenbosch : University of Stellenbosch |
| spellingShingle | Stuck fermentation Fructophilic yeasts Zygosaccharomyces bailii Fructose utilisation Dissertations -- Wine biotechnology Theses -- Wine biotechnology Fermentation Alcoholic beverages -- Microbiology Wine yeasts Sutterlin, Klaus A. (Klaus Alfred) Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title | Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title_full | Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title_fullStr | Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title_full_unstemmed | Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title_short | Fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| title_sort | fructophilic yeasts to cure stuck fermentations in alcoholic beverages |
| topic | Stuck fermentation Fructophilic yeasts Zygosaccharomyces bailii Fructose utilisation Dissertations -- Wine biotechnology Theses -- Wine biotechnology Fermentation Alcoholic beverages -- Microbiology Wine yeasts |
| url | http://hdl.handle.net/10019.1/4013 |
| work_keys_str_mv | AT sutterlinklausaklausalfred fructophilicyeaststocurestuckfermentationsinalcoholicbeverages |