Trends in Biotechnology
Volume 20, Issue 10, 1 October 2002, Pages 426-432
Journal home page for Trends in Biotechnology

Review
Meeting the consumer challenge through genetically customized wine-yeast strains

https://doi.org/10.1016/S0167-7799(02)02049-8Get rights and content

Abstract

Wine producers are facing intensifying competition brought about by a widening gap between wine production and wine consumption, a shift of consumer preferences away from basic commodity wine to top quality wine, and economic globalization. Consequently, they are calling for a total revolution in the ‘magical’ world of wine. The process of transforming the wine industry from a production- to a market-orientated industry results in an increasing dependence on, amongst others, biotechnological innovation. Market-orientated wine-yeast strains are currently being developed for the cost-competitive production of wine with minimized resource inputs, improved quality and low environmental impact. The emphasis is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and capacities for an increase in the wholesomeness and sensory quality of wine.

Section snippets

The genetic improvement of wine-yeast strains

Yeasts are predominant during wine fermentation. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts originating from the surfaces of grape berries and the winery equipment 2., 3.. Yeasts of the genera Kloeckera, Hanseniaspora and Candida predominate in the early stages, followed by several species of Metschnikowia and Pichia in the middle stages, when the ethanol rises to 3–4% 2., 3., 4.. The latter stages of spontaneous wine fermentations are invariably

The genetic features and techniques for the analysis and development of starter yeast strains

The majority of laboratory-bred strains of S. cerevisiae are either haploid or diploid, whereas industrial wine-yeast strains are predominantly diploid or aneuploid, and occasionally polyploid 11., 12.. The nucleotide sequence of the entire genome of S. cerevisiae is known. It has a relatively small, compact genome (∼13 000 kb), a large number of chromosomes (16 linear chromosomes, varying in length from 200 to 2200 kb), a small number of genes (∼6000 protein-encoding genes), little repetitive

Targets for the genetic improvement of wine yeasts

Generally, the targets of strain development all relate to the improved economics of production and wine quality. Table 2 highlights some of the improvements that can be achieved using genetically engineered wine yeasts. These targets include increasing the efficiency of the fermentation process, the processing of wine and control of microbial spoilage, in addition to enhancement of wholesomeness and sensory quality 2., 6., 7., 8., 9., 10., 11., 12., 14., 15..

Improvement of fermentation performance

Wine fermentations generally proceed at a rate greater than desired and are usually controlled by lowering the fermentation temperature. ‘Runaway’ fermentations have a commercial implication because fermentor space is reduced owing to foaming and volatile aroma compounds being lost by entrainment with the evolving carbon dioxide [2]. However, wine fermentation sometimes ceases prematurely or proceeds too slowly. The financial losses caused by ‘stuck’, ‘sluggish’ or incomplete wine fermentations

Improvement of processing efficiency

The main objectives of fining (addition of adsorptive compounds, followed by settling or precipitation) and clarification (sedimentation, racking, centrifugation and filtration) during wine processing include the removal of excess amounts of certain components and microbial cells to achieve clarity and to ensure the physicochemical stability of the end product. The fining and clarification of wine often include expensive and laborious practices that generate large volumes of lees for disposal,

Improving biological control of wine-spoilage microorganisms

Uncontrolled microbial growth before, during or after wine fermentation can alter the chemical composition of the end product, detracting from its sensory properties of appearance, aroma and flavour. Healthy grapes, cellar hygiene and sound oenological practices are the cornerstones of the winemaker's strategy against the uncontrolled proliferation of spoilage microbes. Added safety is provided by the addition of chemical preservatives, such as sulfur dioxide, dimethyl dicarbonate, benzoic

Improvement of wholesomeness

It is generally accepted that moderate wine drinking is socially beneficial and can be effective in the management of stress and the reduction of coronary heart disease. The principal protective compounds found in wine include the phenolic compounds, resveratrol, salicylic acid and alcohol. However, some unwanted compounds, including suspected carcinogens (e.g. ethyl carbamate), neurotoxins (e.g. biogenic amines) and asthmatic chemical preservatives (e.g. sulfites) can sometimes also be found

Improvement of sensory quality

The single most important factor in winemaking is the organoleptic quality (appearance, aroma and flavour) of the final product. The endless variety of flavours stems from a complex, completely non-linear system of interactions among many hundreds of compounds. The bouquet of a wine is determined by the presence of a well-balanced ratio of flavour compounds and metabolites [30]. With the exception of terpenes in the aromatic grape varieties and alkoxypyrazines in the herbaceous cultivars,

Conclusion

The tailoring of wine yeast strains will undoubtedly help the wine industry meet the technical and consumer challenges of the 21st century. Over the past few years, considerable progress has been made in improving wine yeasts. However, owing to a multitude of complex scientific, technical, economic, marketing, safety, legal and ethical issues, no recombinant wine yeast has been used on a commercial scale to date. Given the current deeply rooted concerns of consumers and traditionalists, the

Acknowledgements

Marisa Honey for critical reading and editing of this article. The research conducted in the Institute for Wine Biotechnology is supported by grants from the National Research Foundation (NRF) and the South African Wine Industry (Winetech).

References (39)

  • A. Querol et al.

    The application of molecular techniques in wine microbiology

    Trends Food Sci. Technol.

    (1996)
  • A. Tanghe

    Identification of genes responsible for improved cryoresistance in fermenting yeast cells

    Int. J. Food Microbiol.

    (2000)
  • M. Bony

    Metabolic analysis of S. cerevisiae strains engineered for malolactic fermentation

    FEBS Lett.

    (1997)
  • Spies, P.H. (2001). Vision 2020: A Strategic Outline for the South African Wine Industry — A road Map for Future C...
  • P.A. Henschke

    Wine Yeast

  • M.K. Grossmann et al.

    Verfahren zur Identifizierung von Weinhefen und Verbesserung der Eigenschaften von Saccharomyces cerevisiae: eine Übersicht. (Methods for the identification and the improvement of specific properties of Saccharomyces cerevisiae: a review.)

    Die Weinwissenschaft

    (1999)
  • I.S. Pretorius

    Yeast biodiversity in vineyards and wineries and its importance to the South African wine industry

    S. Afr. J. Enol. Vitic.

    (1999)
  • I.S. Pretorius et al.

    The impact of yeast genetics and recombinant DNA technology on the wine industry

    S. Afr. J. Enol. Vitic.

    (1991)
  • I.S. Pretorius

    Engineering designer genes for wine yeasts

    Aust. N.Z. Wine Indust. J.

    (1999)
  • I.S. Pretorius

    Tailoring wine yeast for the new millennium: novel approaches to the ancient art of winemaking

    Yeast

    (2000)
  • I.S. Pretorius

    Gene technology in winemaking: new approaches to an ancient art

    Agric.Consp. Sci.

    (2001)
  • Pretorius, I.S. (2002) The genetic analysis and improvement of wine yeasts. In Fungal Biotechnology (Arora, D., ed.)...
  • R. Snow

    Genetic improvement of wine yeast

  • P. Barre

    Genetic improvement of wine yeast

  • C. Ivorra

    An inverse correlation between stress resistance and stuck fermentations in wine yeasts. A molecular study

    Biotechnol. Bioeng.

    (1999)
  • S. Dequin

    The potential of genetic engineering for improving brewing, wine-making and baking yeasts

    Appl. Microbiol. Biotechnol.

    (2001)
  • S. Ostergaard

    Metabolic engineering of Saccharomyces cerevisiae

    Microbiol. Mol. Biol. Rev.

    (2000)
  • J. Kim

    Disruption of the yeast ATH1 gene confers better survival after dehydration, freezing, and ethanol shock: potential commercial applications

    Appl. Environ. Microbiol.

    (1996)
  • F.F. Bauer et al.

    Yeast stress response and fermentation efficiency: how to survive the making of wine

    S. Afr. J. Enol. Vitic.

    (2000)
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