American bioengineers have created genetically modified yeast, capable of synthesizing aromatic components of hops - terpene alcohols geraniol and linalool, reports Nature Communications .
In the composition of the drink, where there are such yeast, hops can not be added. Thanks to this, the production process becomes cheaper and easier.
The taste of beer does not suffer. Volunteers noted that the taste and aroma even become more pronounced.
Hops are added to the wort during cooking, as well as at later stages of the preparation of the drink. The scientists found that the main contribution to beer hopping is made by the molecules geraniol and linalool, which are formed from one precursor with the participation of two different enzymes-synthases.
Identification of these enzymes in hops has not yet been possible, and the researchers tested several genes of the synthase of linalool and geraniol from other fragrant plants. The results showed that a sufficient level of activity in yeast cells for these two substances shows a truncated version of the mint enzyme and a full-length enzyme from basil. Bioengineers also overexpressed several of their own yeast enzymes to ensure the synthesis of the terpenic precursor.
The new technology was tested in practice by preparing several experimental batches of beer without hops. They were compared to a drink brewed according to standard technology.
It turned out that the modified yeast produced a more stable result in terms of flavor tones. Beer , cooked with genetically modified yeast, was distinguished by a distinctive intoxicating aroma.
