MAR 20, 2018 03:09 PM PDT

Better Beer Through Genetic Engineering

WRITTEN BY: Carmen Leitch

Hops are an essential part of brewing beer, but they need a lot of water to grow; one pint of beer requires around 50 pints of water just for raising the hops. Now, researchers have come up with an alternative - a genetically engineered yeast that can both ferment the beer and impart flavors customarily provided by hops. Employees of the Lagunitas Brewing Company in Petaluma, California participated in double-blind taste tests and described the modified yeast beer as hoppier than a brew made from regular yeast and hops.

This work, reported in Nature Communications, may help improve beer’s environmental footprint, and be cheaper to make as well. ”My hope is that if we can use the technology to make great beer that is produced with a more sustainable process, people will embrace that," said the co-first author of the study, Charles Denby, a UC Berkeley biologist.

The engineered yeast could standardize flavors too, since the flavorful part of hops, essential oils, are highly variable from year to year. New kinds of tastes could also be introduced. Bryan Donaldson, the innovations manager at Lagunitas, detected notes of "fruit-loops" and "orange blossom" with no off flavors, during the Lagunitas taste test.

Co-first author Rachel Li launched a startup with Denby called Berkeley Brewing Science. They are planning to market hoppy yeasts as well as new types that use flavor notes that aren’t usually in beer. 

The gene editing tool CRISPR-Cas9 was applied to industrial brewer’s yeast for this work. The researchers used it to add four new genes and the corresponding promoters that regulate them. Two genes code for the enzymes linalool synthase and geraniol synthase, which make flavor notes found in many plants. The other two genes were meant to boost the production of two molecules, Linalool, and geraniol, to add the hops flavor.

They used a computer to get the proportions just right, and asked UC Davis brewing authority Charles Bamforth to brew beer using three of their best strains. Hops were used only in the first stage of brewing to impart bitterness without hoppy flavor. Then the yeast strains supplied all of the hop flavors. Another standard beer was also made, and former student, Donaldson from Lagunitas, conducted a blind taste test with 27 brewery employees.

"This was one of our very first sensory tests, so being rated as hoppier than the two beers that were actually dry-hopped at conventional hopping rates was very encouraging," said Li.

Hops, the dried flowers of a climbing plant, give beer flavor, but they require a lot of energy to grow. / Image credit: Pxhere

Denby started out at UC Berkeley to research sustainable transportation fuels with synthetic biology pioneer Jay Keasling. Keasling uses bacteria and yeast to produce terpenes, and adds genes that make terpenes into important products like the antimalarial drug, artemisinin, flavors used in industry, and the fuel butanol.

But the brewing "found me," Denby said. "I started home brewing out of curiosity with a group of friends while I was starting out in Jay's lab, in part because I enjoy beer and in part because I was interested in fermentation processes. I found out that the molecules that give hops their hoppy flavor are terpene molecules, and it wouldn't be too big of a stretch to think we could develop strains that make terpenes at the same concentrations that you get when you make beer and add hops to them."

Because hops require a lot of resources, Denby was inspired to make brewing more sustainable. He was in the right place, the Keasling lab, to pursue that idea.

"We started our work on engineering microbes to produce isoprenoids - like flavors, fragrances, and artemisinin - about 20 years ago," said Keasling. "At the same time, we were building tools to accurately control metabolism. With this project, we are able to use some of the tools others and we developed to accurately control metabolism to produce just the right amount of hops flavors for beer."

"Charles and Rachel have shown that using the appropriate tools to control production of these flavors can result in a beer with a more consistent hoppy flavor, even better than what nature can do itself," Keasling said.


Sources: AAAS/Eurekalert! Via University of California - Berkeley, Nature Communications

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
NOV 19, 2019
Genetics & Genomics
NOV 19, 2019
Left-handedness Linked to Genetic Regions, Brain Architecture
Scientists found genomic regions linked to left-handedness, which are associated with the connections between language-related regions....
NOV 19, 2019
Genetics & Genomics
NOV 19, 2019
Can Autism be Diagnosed from Blood Tests?
Diagnosing Autism Spectrum Disorder (ASD) early on in life through behavioral signs alone has been difficult. This comes as typical markers for the conditi...
NOV 19, 2019
NOV 19, 2019
Using CRISPR to Alter or Kill Bacteria
In recent years, the gene editing tool CRISPR/Cas9 has been applied to a wide variety of different organisms, and now, bacteria....
NOV 19, 2019
Genetics & Genomics
NOV 19, 2019
Rare Gene Mutation Prevents Memory Problems Brought on by Sleep Deprivation
A few rare people can get by with less sleep than the rest of us; after only four to six hours they are well-rested....
NOV 19, 2019
NOV 19, 2019
Machine-Learning and Epigenetics Drug Discovery
Machine learning is known for detecting patterns seen in complex data—such uniqueness has proven it roles in health and medicine. Now, researchers at...
NOV 19, 2019
NOV 19, 2019
Alcohol Consumption Linked to Epigenetic Changes in Brain Memory System
For a recovering alcoholic, walking past a familiar bar or attending social events are often challenging situations. In the past, stimuli such as the smell, sight, and sounds of a bar become...
Loading Comments...