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Tailoring wine yeast for the third millennium: novel approaches to the ancient art of winemaking
Professor Isak S. Pretorius
Institute for Wine Biotechnology, University of
Stellenbosch, Stellenbosch, ZA-7600, South Africa
The history of winemaking parallels that of civilisation: historians believe that wine was being made in the Caucasus and Mesopotamia as early as 6000 BC. References to wine have been found in Egypt and Phoenicia dating as far back as 5000 BC, and by 2000 BC wine was being produced in Greece and Crete.
Eight thousand years later we are still enjoying our wine and the wine industry
is keeping pace with the times. Find out here how top African scientists are
leading the wine industry into the new millenium. Then take the leap, and
follow the link for a sparkling overview of novel approaches to wine
making.
 Yeasts play a dominant role in the ancient and complex process of winemaking. In spontaneous fermentations there is a sequential growth pattern of indigenous yeasts with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces
cerevisiae.
This species is universally known as the wine yeast and is widely preferred for initiating wine fermentations. The primary role of wine yeast is to catalyze the rapid, complete and efficient conversion of grape sugars to ethanol, carbon dioxide and other minor, but important, metabolites without the development of off-flavors. However, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing need for specialized wine yeast strains possessing a wide range of optimized, improved or novel oenological properties. Over the last few years considerable progress has been made in developing new wine yeast strains. However, the wine industry, two decades after the first successful yeast transformation, is entering the third millennium without a transgenic wine yeast used on a commercial scale to produce wine.
Successful commercialization of transgenic wine yeasts will depend on a multitude of scientific, technical, economic, marketing, safety, regulatory, legal and ethical issues. Therefore, it would be foolish to entertain unrealistic expectations about rapid commercialization and short-term benefits. The information and technology that currently exist for laboratory strains of S. cerevisiae must be expanded to the much more complex genomes of industrial wine yeast strains before dramatic breakthroughs can be expected. Simultaneously, innovative technical strategies are required to comply with the strict statutory regulations that pertain to the use of genetically modified organisms
(GMOs). Credible means must be found to effectively address the concerns of traditionalists within the wine industry and the negative overreaction of some consumer groups.
These are daunting challenges that will have to be overcome during the next few years. But given the availability of the complete genome and proteome of S.
cerevisiae, the current energetic effort to decipher the functions of the roughly 6000 yeast genes and the eventual understanding of the interaction of gene networks within the yeast cell, there is no question of new and innovative developments that will be of great benefit to both the winemaker and the wine consumer.
With their broad experience in yeast-based fermentations, winemakers are well placed to explore new opportunities offered by the exciting age of molecular yeast genetics and modern biotechnology. I am confident that leading edge gene technology will be sensibly applied to wine yeast strains and that it will help the wine industry meet the technical challenges of the 21st century. Wine yeast toasts the new millennium!
Enter here for the full and in-depth article by Professor Isak Pretorius
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