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Will the next leap forward in brewing come from genetically modified yeast?

Scientists want to tweak the genes of yeast, giving them the ability to tolerate heat, create new flavors and even glow in the dark.
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Josiah Zayner | Photo courtesy The ODIN

Josiah Zayner | Photo courtesy The ODIN

There are, according to the American Kennel Club, 189 registered and recognized dog breeds—meaning, one would hope, that there’s at least one breed out there that would make a perfect companion for any human person. Love to run? So do Australian shepherds. Fan of floppy ears? Get yourself a Basset hound.

But every dog also comes with its problems. Shepherds shed like crazy. Basset hounds howl all the damn time. What if you could design a dog from scratch—one perfect for your lifestyle that doesn’t shed, doesn’t howl, is free of health problems and always behaves exactly the way you want him to?

Scientists are beginning to ask the same questions—but about the yeast used in brewing.

In September 2016, a group of researchers from various biotech labs and university biology departments sequenced the genomes of 157 different types of Saccharomyces cerevisiae—aka, brewer’s yeast. They found that nearly all those strains are genetically separate from wild yeast and originate from just few ancestors based on local variances and their selection by brewers for characteristics like tolerance to heat, ability to convert malt sugar into alcohol, and the flavors they produce while they do it.

So, much in the way that dog breeds developed over centuries based on humans selectively breeding them for specific traits, most of today’s yeast strains became what they are based on selection by brewers. Strains that produced fewer off-flavors and got the job of fermentation done more quickly were used in subsequent batches; ones that didn’t perform so well got the boot.

But this is domestication, not design. And in a paper published earlier this year on beveragedaily.com, Zachari Turgeon and Matthew Dahabieh of Renaissance BioScience—a Canadian company that develops yeast strains for the food, beverage, biofuel and pharmaceutical industries—argued that 157 strains aren’t nearly enough, and that brewers and yeast labs should begin working toward further expanding the number of brewing yeasts as well as the flavors they produce.

“The brewing industry has gone too far and focused yeasts on a very small group of industrially useful traits,” the pair said in the paper. “What is needed is a return to the diversity and variety of the past.”

Fluorescent glowing genetically modified French saison yeast | Photo courtesy of The ODIN

Fluorescent glowing genetically modified French saison yeast | Photo courtesy of The ODIN

For a glimpse of the possible spectrum of flavors that could come from broadening yeast’s diversity, Turgeon and Dahabieh say, we need only look at the explosion of hop varieties that’s occurred in the past decade. As new varieties with a spectrum of flavor profiles have been developed, brewers have been able to create new and exciting beers. The same could occur with yeast.

For example, they say, a yeast researcher may be able to develop a yeast strain with increased production of hop-accentuating enzymes that can significantly change the hop aroma and flavor compounds in an IPA. Specific strains could even be designed to work with specific hop varieties, accentuating the hop’s particular balance of oils and acids. Yeast could also be adjusted to work within a broader temperature range without producing undesirable off-flavors, or tweaked to create flavors never before experienced in beer.

The building blocks for creating these unique and expressive strains are already here, Turgeon and Dahabieh say. What’s needed is the will and ingenuity to breed them.

Enter Josiah Zayner. A former synthetic biologist at NASA, Zayner founded his company, The ODIN, with the mission of democratizing genetic design. His idea is that genetic engineering should be like LINUX, the computer operating system on which Android phones and a sizeable percentage of technology worldwide run. It operates based on the notion that computer technology should be free and open to all; anyone with the ability can design a program to run on the system and install it himself.

“I think the same thing can be done with genetic engineering and synthetic biology, if we can just give people access to the tools,” Zayner says.

But you can’t just jump right into genetically engineered animals. If a layman is to be taught the basics of gene manipulation, it helps to start with the most basic of lifeforms: yeast. So in December, Zayner began selling a $199 DIY biohacking kit that contained tools and instructions for inserting a special fluorescence-producing protein from jellyfish into any kind of brewing yeast. Beer made with the yeast tastes the same as any other, but put it under a blacklight and BOOM: glowing, neon-green brew. Zayner says future kits will teach people to use the cutting-edge gene editing technology CRISPR to modify basically anything they want in the genome of any yeast strain.

“When you go to buy your yeast strain, they might tell you how flocculant the yeast is, or its attenuation based on some random percentage, and all these other vague characteristics,” he says. “But what brewers are actually looking for are very defined characteristics. ‘I want my beer to taste like X.’ … So with this, you can go in with precision and take away genes or add in or amplify genes to accentuate the exact characteristics you want in your yeast on the molecular level. Now that’s what I think brewing really should be.”

Even more exciting, Zayner says, is the possibility of creating new flavors never before seen in beer. Take glutamate, an amino acid that’s been found to give food a strong, savory flavor we’ve taken to calling umami. With the ability to engineer a yeast strain’s DNA, you could engineer the amount of glutamate and other amino acids it produces, combining them to forge new, never-before seen flavors.

“You can create compositions of amino acids that don’t exist anywhere in nature. Not only that, but you can create enzymes that can create these small molecules—phenols and other things—that don’t exist in nature,” Zayner says. “Imagine brewers each having their own unique yeast strains that allow them to make completely unique flavors that no one has ever tasted before. That would be crazy.”

Over the centuries, we’ve domesticated brewing yeast almost do exactly what we want. But even the most beloved strains can be temperamental, creating unpleasant off-flavors when mistreated. Genetic engineering may give us the ability to eradicate every undesirable aspect from a yeast cell, leaving behind only the flavors we want, as if we had created it from scratch.

“Up to now, we’ve been using yeasts that exist in nature; they didn’t evolve to make food for humans,” Zayner says. “Over the thousands of years we’ve been making beer, they’ve changed a little bit, but they didn’t evolve to be the perfect food source. But now, with the power of genetic engineering, we can make them uniquely designed as a food source for humans.”

Still might be while before you can design that perfect puppy, though.

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