Wine industry monitors GM yeast experiment
11/15/2005
The world's first genetically modified wine yeast has been released into the North American market. Developed in France, the yeast is expected to save costs through faster and more reliable fermentation. However, the Australian wine industry is standing by its commitment to remain GM-free and it is watching the experiment closely.Dr Paul Chambers from the Australian Wine Research Institute says labelling could become an issue for importers of US wines that use the modifed yeast.

"This yeast in the US system is regarded as essentially the same as any other yeast," he said.

"There is no requirement for the company to label the yeast when they sell it to winemakers and of course then the winemakers over there may or may not know they're working with a GM yeast."


Yeast biologists put winemaking world in a ferment 09:30 26 December 2002
Holiday feature from New Scientist Print Edition
Graham Lawton

Plastic corks were an innovation too far for some, but winemakers have their eye on another technology that will leave traditionalists spluttering into their claret: genetic modification.

All over the world, molecular biologists are tinkering with DNA to find ways to improve the quality of wine. Already they can do wonders, conjuring up rare but desirable flavours and aromas, and adding body and complexity to bog-standard plonk. Gene technology can also eliminate the spoilage compounds that can make wine taste like sweaty socks, and even get rid of those nasties that give you a bad head in the morning.

However, winemakers have focused only a little of their attention on modifying the vines themselves. Vines are difficult to engineer and the biological processes that control grape quality are poorly understood. Instead, it is the other organism involved in winemaking - the yeast - which has been taught new tricks. GM yeast has dazzling potential because many of the "organoleptic" qualities of a wine - its colour, aroma and flavour - are created by chemicals spat out by yeast as it munches its way through the mush of crushed grapes. And the metabolic pathways that produce these chemicals have proved obligingly easy to manipulate.

Right balance
The principal yeast used in winemaking is Saccharomyces cerevisiae, which also happens to be a standard experimental organism in genetics labs. Its long scientific pedigree has helped oenologists enormously.
Already, some research groups have carried out small-scale experimental fermentations. One major experimental success has been to use modified yeast to correct the balance between sugar and fruit in grapes, which can peak at different times.

But experimental yeasts are also helping to eliminate undesirable compounds. These are the off-flavours that make wines taste sweaty, eggy, gassy or vinegary, the nasties that give you a bad head in the morning, and the carcinogens that get you in the long run.

Most off-flavours are developed by unwanted bacteria, moulds and yeasts, so a good deal of effort is going to engineering compounds into wine yeast to kill off spoilage organisms. For example, Florian Bauer and colleagues, at the Institute for Wine Biotechnology at Stellenbosch University in South Africa, have expressed genes for three bactericides and two anti-fungals in yeast.

That is also good news on the morning after. "Most wine hangovers are not only due to alcohol," says Bauer. A big culprit is neurotoxic amines produced by spoilage bacteria. Another is sulphur dioxide, an essential and ubiquitous additive that kills bacteria but can make you feel rough as a badger's bum in the morning. So commercial yeasts that churn out comparatively harmless anti-microbials would be a boon.

Minimum quality
Yet despite the possibilities, you will not be drinking GM wine this Christmas, or next. "Winemakers don't want to be associated with gene technology," says Bauer, one of only a handful of people to have drunk wine made with GM yeast.

It is easy to see why, as wine trades heavily on its image as a traditional, artisanal product Also many consumers do not like the idea of GM products - and it would be a foolish winemaker who tried to force it down their throats.
But Bauer points out that no amount of tinkering with yeast can alter the fundamental ingredient of good wine - the grapes themselves. "And you still have to be a good winemaker to make good wine," Bauer says. "What GM yeast can do is make sure wines at least correspond to certain minimum quality criteria."

Monty Waldin, author of the Organic Wine Guide (HarperCollins, 1999), is unconvinced. He sees GM yeast as an extension of an insidious modern craze for "ultra-clean, technically perfect wine" with big fruit, clear fresh flavours - and no character. "It's phoney wine," he says.

GM yeast provides ultimate hangover cure for wine lovers
By Arifa Akbar
Published: 19 December 2002
Genetically modified yeast added to wine could stop hangovers, researchers said yesterday.
Genetically modified yeast added to wine could stop hangovers, researchers said yesterday. In what could become a wine drinker's dream, the addition of GM yeast might also improve flavour. Yet it is unlikely to become reality because of consumer resistance to gene technology.
Molecular biologists have been experimenting with ways to give a better and different flavour to wine, to remove nasty aftertastes and to enhance body to the most basic vintage.
However, wine makers do not want to be associated with GM because of the negative image it has among consumers, researchers say in the latest edition of the New Scientist.
Despite their opinions of GM, wine makers are said to be interested in the possibility of genetic engineering to improve vines. But the biggest potential could be in the yeast. Traditional wine-makers rely on natural yeasts that grow on skin of the grape, but GM yeasts would be more reliable by helping to improve the sugar-acid balance and body of the wine.
Florian Bauer, from the Institute of Wine Biotechnology at Stellenbosch University in South Africa, said GM wines could also reduce illness the morning after as most hangovers did not result from the alcohol itself. Neurotoxic amines and sulphur dioxide in wine also contribute to hangovers, so commercial yeasts that produce relatively harmless anti-microbials could help to prevent heavy heads. Despite consumer doubts about GM products, the dilemma could be resolved if wine made with the yeast did not contain any yeast DNA, meaning that, technically, it was not GM.
Products including cheese already use a technique similar to this. But European Union rules state that cheese does not have to be labelled because the GM element is a "processing aid" with no trace in the final product. The same regulations would not apply to wine because it might retain some yeast cells.
The likelihood of seeing GM wines on supermarket shelves remains low, with every researcher contacted by the New Scientist saying there were no plans to put GM products into commercial wine making.
But scientists could use GM yeasts as models that could be experimented with, to make the same changes without using GM technology.