Contribution of the fermenting yeast strain to ethyl carbamate generation in stone fruit spirits
Contribution of the fermenting yeast strain to ethyl carbamate generation in stone fruit spirits
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DOI：
10.1007/s00253-006-0736-4
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发表时间：
2007-01
影响因子：
5
通讯作者：
B. Schehl;T. Senn;D. Lachenmeier;R. Rodicio;J. Heinisch
中科院分区：
文献类型：
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作者：
B. Schehl;T. Senn;D. Lachenmeier;R. Rodicio;J. Heinisch
发酵的水果和饮料通常含有氨基甲酸乙酯（EC），这是一种可能致癌的化合物，可以通过尿素与乙醇的反应形成。两者都是由酵母（酿酒酵母）产生的，乙醇是己糖发酵的主要最终产物，尿素是精氨酸分解代谢的副产物。在烈酒生产中，EC也可以从核果引入的氰化物中提取。为了确定酵母代谢对EC生产的相对贡献，我们对二倍体实验室菌株进行了基因工程改造，以降低精氨酸酶活性，从而阻断尿素生产途径。为此，构建了具有杂合子car1/car1缺失或纯合子缺陷（car1/car1）的菌株。这些菌株在樱桃醪发酵和烈酒生产中与亲本野生型和工业酵母菌株进行了比较。与非工程对照相比，纯合子scar1缺失的菌株在最终烈酒中显示出显著的EC降低。然而，使用这种菌株发酵无核樱桃泥并没有完全阻止EC的形成。这表明了这种化合物的另一种尚未确定的来源。
Fermented fruit and beverages frequently contain ethyl carbamate (EC), a potentially carcinogenic compound that can be formed by the reaction of urea with ethanol. Both are produced by the yeastSaccharomyces cerevisiaewith ethanol as the major end product of hexose fermentation and urea as a by-product in arginine catabolism. In spirit production, EC can also be derived from cyanide introduced by stone fruit. To determine the relative contribution of yeast metabolism to EC production, we genetically engineered a diploid laboratory strain to reduce the arginase activity, thus blocking the pathway to urea production. For this purpose, strains with either a heterozygousCAR1/car1deletion or a homozygous defect (car1/car1) were constructed. These strains were compared to the parental wild type and to an industrial yeast strain in cherry mash fermentations and spirit production. The strain with the homozygouscar1deletion showed a significant reduction of EC in the final spirits in comparison to the non-engineered controls. Nevertheless, using this strain for fermentation of stoneless cherry mashes did not completely impede EC formation. This indicates another, as yet unidentified, source for this compound.