New cancer-combating yeast strains developed

By Lorraine Heller

- Last updated on GMT

Related tags Yeast

The manufacturer of a genetically modified yeast variety that is
designed to reduce levels of the carcinogen ethyl carbamate in wine
last week announced that it has transformed six new yeast strains.

First Venture Technologies on Friday said the functional improvement of these additional yeast strains to reduce the formation of ethyl carbamate was performed under a two-year service agreement with The University of British Columbia's (UBC) Wine Research Centre.

"We've improved the yeast transformation process over the last few years so that we can now enhance the yeasts much more quickly,"​ said Dr Hennie van Vuuren, director of the UBC Wine Research Centre. "We have a total of twenty-two transformants that we will screen and choose the most effective of each strain to commercialize."

Also known as urethane, ethyl carbamate, is formed during fermentation, distillation or storage, and can be present in widely consumed foods such as wine, distilled spirits, bread, yogurt and soy products.

For example, in wine production, yeast is used in a fermentation process to convert grape juice into wine, explained the company. Arginine, one of the most abundance amino acids in grape juice, is taken up by yeast as a nutrient and metabolized to produce urea. Urea then accumulates in the yeast cell until it reaches a critical concentration, at which point it is released into the wine. Urea spontaneously reacts with the alcohol in the wine to form ethyl carbamate. The chemical reaction between urea and ethanol is exponentially accelerated at elevated temperatures.

First Venture Technologies said its propriety yeast claims to be able to reduce ethyl carbamate levels in red wine by up to 89 percent, and in bread by up to 54 percent. The firm is currently commercializing its platform yeast technology, which it has exclusively licensed from the UBC.

"We are continuing to evaluate the use of our yeasts in bread making - preliminary lab trials having produced reductions of up to 54 percent in the formation of ethyl carbamate in this widely consumed food item. As well, we are investigating the use of our ethyl carbamate reducing yeasts in the production of stone-fruit and grain-based spirits, where ethyl carbamate formation is known to be high,"​ said Dr van Vuuren.

Subject to lab-based efficacy analysis, the company plans to have a number of its new yeast strains available for trial in the 2007 wine making season.

Wine making trials from the current 2006 fall harvest are already underway with several commercial clients and academic partners, said First Venture Technologies. The company expects these fermentation trials to complete sometime in December 2006. Production and sample analysis are being conducted during the trials, and full analysis is expected to be completed by spring 2007.

"The primary focus of this analysis is the development of detailed manufacturing protocols for winemakers,"​ said Andrew Starr, director of marketing and business development of First Venture Yeast Products.

"These protocols will allow winemakers to have detailed knowledge of how variations in wine making practices and methodology, as well as fluctuations in the grape harvest, affect the primary and enhanced functionality of First Venture yeast in this varied environment. This understanding will enable winemakers to make decisions on how to maximize the reduction of ethyl carbamate in their wines, taking into consideration the variations of their winemaking practices and the variations in seasonal grape harvest results."

In recent months, Environment Canada approved the import and manufacture of the firm's genetically modified yeast variety. The nation's endorsement of the environmental safety of the yeast follows the Generally Regarded As Safe (GRAS) status received from the US Food and Drug Administration (FDA) in January 2006. The company said it hopes the new approval will greatly assist its marketing efforts.

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