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Functional Technologies' proprietary yeasts are designed to virtually eliminate ethyl carbamate formation by amplifying the yeast's ability to break down urea, a precursor to ethyl carbamate, during fermentation.
In nature, S. cerevisiae naturally contains a gene that encodes for an enzyme called urea amidolyase. This enzyme degrades urea into ammonia (NH2) and carbon dioxide (CO2) where NH2 can be used as a secondary nitrogen source. However, it has been shown conclusively that wine yeast strains of S. cerevisiae do not fully metabolize urea during fermentation. The result is the accumulation of urea in the yeast cell until it is released into the wine where it reacts with alcohol to form Ethyl Carbamate. The lack of urea metabolism is probably a result of the urea amidolyase gene being repressed in the presence of a good nitrogen source found in the grape juice. As a result, urea amidolyase is not produced sufficiently to break down urea.
Functional Technologies'proprietary yeast strains have amplified urea degradation capabilities that will limit the formation of Ethyl Carbamate. These advanced urea-degrading yeasts make use of a constitutive and regulated expression of the urea amidolyase gene in widely used red and white wine, brandy and sake (rice wine) yeast strains of S. cerevisiae. This allows the yeasts to continually break down urea, even in the presence of a good nitrogen source.
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