The Biotechnology of Wine Yeast

The production of wine from grapes is one of the world's oldest biotechnological processes. The alcoholic fermentation, the conversion of grape sugars to ethanol, is conducted by yeast of the genus Saccharomyces. In addition to wide-ranging roles in beverage and food processing, Saccharomyces is also a premier research model system because of its genetic tractability. Its genome has been sequenced, and an extensive array of molecular technologies has been developed for the genetic manipulation of this organism. In spite of the availability of these molecular tools, genetically engineered yeast strains are not yet in use in the commercial wine industry. Anxiety over consumer acceptance is one reason genetically modified strains are not employed, but there are other concerns as well. Wine production is unique in many respects. The wine production process is not conducted under sterile conditions, and any modified organism has the potential to become an enduring resident of the winery flora. Further, wine production is both science and art. There is concern that many of the proposed genetic modifications of yeast are designed to correct processing errors or incompetence of the winemaker rather than being useful tools to enhance the artistry of wine making. In spite of these concerns, the efficacy of genetic modification of wine yeast has been demonstrated.