Researchers have developed a new type of yeast that can make healthier, smoother, and hangover-free wine, beer, and other alcoholic beverages.
The yeast, which is a genetically engineered version of the polyploid strain Saccharomyces cerevisiae, was discovered after researchers at the University of Illinois developed a genome slicing technique that allows them to cut away multiple copies of a gene in the genome of yeast, allowing them to remove unwanted properties of wine, including its hangover-causing properties.
Yeast used for fermenting wine, beer, and other food was previously very difficult to engineer because of their polyploid nature.
Yong-su Jin, associate professor of microbial genetics at the university's Energy Biosciences Institute and principal investigator of the study, says polyploid strains contain multiple copies of genes, which means removing one copy will not remove certain properties in the wine.
"Until now, it's been very difficult to do genetic engineering in polyploid strains because if you altered a gene in one copy of the genome, an unaltered copy would correct the one that had been changed," said Jin.
The researchers used the enzyme RNA-guided Cas9 Nuclease as the genome knife to enhance the properties of wine. Jin says using the genome slicing technique, researchers can enhance the enzyme that is responsible for malolactic fermentation, a type of fermentation that, if it goes wrong, produces the toxic byproducts that cause hangovers.
Jin says the possibilities for enhancing the nutritional properties of wine and other fermented food are endless with the slicing technique. For instance, researchers can genetically engineer yeast to develop resveratrol by 10 times or more.
Resveratrol is a polyphenol found in the skin of grapes, blueberries, raspberries, and other red or purple fruits and is known to be the substance responsible for the health benefits of red wine. Studies have shown that resveratrol helps reduce bad cholesterol, prevent damage in the blood vessels, and even contribute to a longer life. Jin also speculates that the technique can help researchers add other healthy compounds into wine to enhance its health benefits.
Enhancing wine, however, is only the tip of the iceberg. The researchers say the slicing technique can also help genetic engineers develop better, healthier versions of other fermented foods.
"We could put resveratrol-producing pathways into yeast strains used for beer, kefir, cheese, kimchee, or pickles - any food that uses yeast fermentation in its production," said Jin.
Such a discovery will obviously not sit well with opponents of genetically modifying food for mass consumption, but Jin says using the slicing technique to genetically engineer organisms is far less objectionable because it does not use antibiotic markers to mark the spot of alteration. Critics say the use of antibiotics in genetic engineering could lead to the risk of developing resistance to antibiotics.
"With the genome knife, we can cut the genome very precisely and efficiently so we don't have to use antibiotic markers to confirm a genetic event," Jin said.
The research was published in the Applied and Environmental Microbiology journal.
Photo: Evan Wood | Flickr
