As if the human population needed an excuse to drink more booze: Scientists have demonstrated that it is possible to genetically engineer yeast in such a way that it could improve the content of the health-boosting substances of wine and beer. And the icing on the cake? It could potentially reduce the amount of toxic byproducts that can contribute to that dreaded hangover. Praise science!
Yeast is critical in the production of fermented foods, like beer and wine, but in the past, scientists have struggled to fiddle with their genomes because the strains used possess several copies of their genes, which is known as polyploidy. As explained by study author Yong-Su Jin, this is problematic because it means that if you successfully manage to alter a gene, unchanged copies automatically correct the modification, undoing the whole process.
To get around this, scientists from the University of Illinois adopted a recently developed enzyme that acts as a “genome knife,” selectively slicing through multiple copies of a target gene in a highly precise manner. In their study, which has been published in Applied and Environmental Microbiology, the researchers demonstrated that it is possible to use this system to successfully modify the genome of a popular industrial strain of the yeast Saccharomyces cerevisiae, which is commonly used in the generation of beer, wine and other fermented produce. Furthermore, they demonstrated that beneficial traits could be inherited from parental strains, such as tolerance of fermentation inhibitors and high temperatures.
Now that scientists have proved that it is indeed possible to successfully modify these industrially valuable organisms, Jin says the opportunities for improving nutritive values in fermented foods are “staggering.” For example, red wine contains the compound resveratrol, which is known to have powerful antioxidant and anti-inflammatory properties that have been associated with a variety of health benefits.
“With engineered yeast, we could increase the amount of resveratrol in a variety of wine by 10 times or more,” Jin said in a news release. “But we could also add metabolic pathways to introduce bioactive compounds from other foods, such as ginseng, into the wine yeast.” Jin also says it might be possible to add in genes for resveratrol into other foods that use yeast fermentation during the production process, such as beer, cheese or pickles.
Interestingly, the researchers think it might be possible to use this technique to improve a secondary fermentation process known as malolactic fermentation, which is used in the production of the vast majority of red wines and a few white wines. The process involves converting the harsher, more tart-tasting malic acid into lactic acid, which is softer, resulting in a smoother wine. According to Jin, if something goes wrong in this process, toxic byproducts can be generated that contribute to hangover symptoms.
Alongside potentially improving some fermented products, the researchers believe this technique could also help us understand more about which genes are responsible for certain flavors. For example, they could knock out genes until a particular flavor disappears, which would tell the scientists which bits of DNA were responsible for that taste.
