Synthetic Yeast

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According to the UK Telegraph, a worldwide effort is underway to create Synthetic Yeast, which scientists believe will allow brewers to “make beer cheaper and stronger.”

From the article:

Researchers, who have been awarded £1 million of government funding for the project, will first attempt to recreate a slimmed down version of Saccharomyces cerevisiae, the yeast used in the brewing industry to ferment beer.

It will be the first time a genome has been built from scratch for a eukaryotic organism, the branch of the evolutionary tree that includes plants and animals.

The scientists then aim to redesign parts of the yeast genome so that it can perform functions that are not possible naturally.

Professor Paul Freemont, from the centre for synthetic biology and innovation at Imperial College London who is helping to lead the British part of the project, said they could help make yeast more efficient so they required less energy and could tolerate more alcohol before dying, allowing beer to be made stronger.

He said: “The brewing industry is very interested in this project for any new opportunities it may present as they use yeast to manufacture beer.

“One of the aims of the project is to develop this yeast strain as a vehicle that you can put in new chemical pathways and directly manipulate it in a way that is not possible at the moment.

“Clearly there are strains of yeast that are highly resistant to alcohol, but they all die off as the alcohol gets higher, so making more alcohol resistant strains will be very useful for that industry in terms of cost value.

“Strains that are metabolically more optimal and don’t require as much energy will also be useful.”

The synthetic yeast project, also known as Sc2.0, will draw together expertise from around the world.

I can’t quite decide yet whether I think this is a good idea, offering brewers many more choices and opportunities to create unique beers or a Frankenstein moment of science going too far in manipulating an essentially natural process. I guess time will tell.

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Yeast Evolution Due To Reuse

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Today’s infographic is almost a humorous one, although it does illustrate a brewing principal, that of how genrations of yeast can be propagated for homebrewing. It was created by the Half Moon Brewer. Whatever you do, avoid the zombie yeast. I actually have one of those yeast stuffed animals in my office. I probably won’t be able to look at it the same way again.

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Click here to see the chart full size.

Beer From Beard Yeast, Yes; From Vaginas, No

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You most likely remember that Rogue harvested some yeast from the beard of their longtime brewmaster, John Maier, and White Labs analyzed it and propagated a brewing yeast that Rogue in turn used to brew a beer with. Not everyone responded favorably to the news, but in terms of attention and publicity, it’s been a huge hit, with almost every news agency, website and blog writing about it. I made it the subject of part of one of my newspaper columns back in July. A Google search of “rogue beard beer” turns up over 1.4 million hits.

But just when you think things can’t get any weirder, my wife — who’s been working in Shanghai this week — just sent me an article from a feminist blog she reads regularly, Jezebel. Inspired by John Maier’s beard beer exploits, they wrote an article about one more place known for its occasional yeast production that we can write off as a place to harvest for brewing. The article, entitled Just So You Know, You Can’t Make Beer With Your Vagina, answers the question I’m not sure anyone was asking. But now that I know there is an answer, I can’t look away. It’s like that car crash on the side of the road. I know I shouldn’t look, but I just can’t help myself.

Beginning with the premise that “[y]east is everywhere, even (as we ladies well know) buried deep inside our vaginas, waiting to go bad and ruin our week at any moment,” they wonder if anyone could “turn a yeast infection into a full-bodied IPA.” At this point, I’ll let author
Madeleine Davies share the results.

We did some research and, in a word, no. The yeast used in beer is a completely different strain of yeast than the one that causes yeast infections. And there goes your artisanal brewery idea!

The yeast used in beer is called Saccharomyces cerevisiae and works by converting carbohydrates to carbon dioxide and alcohols. This is also the yeast used in bread, which is why baking yeast can be used to brew beer, though it generally makes the end product doughy in flavor and texture. Yeast infections are caused by Candida albicans, a fungus that grows as both yeast and filamentous cells and can cause oral and genital infections in humans. Using this to brew would be entirely ineffective, not to mention, guh-ross.

So there you have it. No vagina beer. I, for one, am relieved. It was one thing to have Sam Calagione and his team spitting in his Peruvian-style chicha beer, and Maier’s beard never bothered me too much, because White Labs removed any lingering ick factor by growing the yeast in their San Diego lab. But in the on-going quest to push the envelope, generate publicity and maybe even make something worth drinking, this may be crossing a line. What do you think?

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Close, but no vagina.

Did Lager Yeast Come From Patagonia?

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You probably saw this little item, it’s been all over the interwebs over the last few days, about a group of eight scientists positing that a newly discovered yeast strain, dubbed Saccharomyces eubayanus, may have hitched a ride from Patagonia, in South America, to Europe where it got busy with local yeasts there — notably Saccharomyces cerevisiae — to form the yeast we know today as lager yeast, or Saccharomyces pastorianus (a.k.a. Saccharomyces carlsbergensis).

The academic paper, to be published in the August edition of the journal Proceedings of the National Academy of Sciences of the United States of America (or PNAS), goes by the rather dry title, Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast. The Abstract summarizes the paper:

Domestication of plants and animals promoted humanity’s transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, despite the importance of microbes to the production of food, beverages, and biofuels. Lager-beer, first brewed in the 15th century, employs an allotetraploid hybrid yeast, Saccharomyces pastorianus (syn. Saccharomyces carlsbergensis), a domesticated species created by the fusion of a Saccharomyces cerevisiae ale-yeast with an unknown cryotolerant Saccharomyces species. We report the isolation of that species and designate it Saccharomyces eubayanus sp. nov. because of its resemblance to Saccharomyces bayanus (a complex hybrid of S. eubayanus, Saccharomyces uvarum, and S. cerevisiae found only in the brewing environment). Individuals from populations of S. eubayanus and its sister species, S. uvarum, exist in apparent sympatry in Nothofagus (Southern beech) forests in Patagonia, but are isolated genetically through intrinsic postzygotic barriers, and ecologically through host-preference. The draft genome sequence of S. eubayanus is 99.5% identical to the non-S. cerevisiae portion of the S. pastorianus genome sequence and suggests specific changes in sugar and sulfite metabolism that were crucial for domestication in the lager-brewing environment. This study shows that combining microbial ecology with comparative genomics facilitates the discovery and preservation of wild genetic stocks of domesticated microbes to trace their history, identify genetic changes, and suggest paths to further industrial improvement.

Mainstream media, picking up the story, has sensationalized it, looking for the human angle. For example the L.A. Times compared the discovery to finding the evolutionary missing link, titling their piece Scientists find lager beer’s missing link — in Patagonia. Essentially, they detail the scientists’ five-year quest to answer the question of where lager yeast originated, and how it came to be. The answer, according to the new paper, is a newly found strain of yeast discovered in the forests of Argentina’s Patagonia region. The wild yeast was named Saccharomyces eubayanus, and it was found living on beech trees.

According to the Times’ report:

Their best bet is that centuries ago, S. eubayanus somehow found its way to Europe and hybridized with the domestic yeast used to brew ale, creating an organism that can ferment at the lower temperatures used to make lager.

Geneticists have known since the 1980s that the yeast brewers use to make lager, S. pastorianus, was a hybrid of two yeast species: S. cerevisiae — used to make ales, wine and bread — and some other, unidentified organism.

Then one of the eight, Diego Libkind, a professor at the Institute for Biodiversity and Environment Research in Bariloche, Argentina, discovered sugar-rich galls on southern beech trees in Patagonia. Yeast were drawn to the galls like a moth to a flame, and had been used by native populations to make a fermented beverage. The yeast in the galls was sent to the University of Colorado, who analyzed the genome, finding that it was 99.5% identical to lager yeast. They named the new yeast Saccharomyces eubayanus, presumably because of its similarity to Saccharomyces bayanus, a yeast commonly used to make cider and wine. Said Stanford geneticist Gavin Sherlock, quoted in the L.A. Times: “The DNA evidence is strong.”

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Naturally, Sherlock, and many others have been wondering how Saccharomyces eubayanus hitched a ride to Bavaria at a time when there was no known contact between the two parts of the world, separated by an ocean and some 8,000 miles. The article also states that “Lager was invented in the 1400s,” though my memory is that European brewers were using lager yeast well before that, and it was the lagering process was developed in the 1400s, but perhaps I’m not remembering that correctly.

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In an interesting development surrounding this debate, U. Penn biomolecular archeologist, Patrick McGovern (author of Uncorking the Past), weighed in with his thoughts at the MSNBC article about this story, Beer mystery solved! Yeast ID’d. Here’s what McGovern had to say, as summarized by author John Roach:

Assuming the genetics work is correct, he said he is “troubled by how this newly discovered wild yeast strain made it into Bavaria in the 1500s.”

For one, he noted, Germans, and especially Bavarians, were not involved in the European exploration of Patagonia at the time. So, if the yeast somehow hitched a ride back to Europe via trade with the English, Spanish, and Portuguese, how did it get to Bavaria?

“Perhaps, some Patagonian beech was used to make a wine barrel that was then transported to Bavaria and subsequently inoculated a batch of beer there?” he asked. “Seems unlikely.”

He said a more likely scenario is that galls in the oak forests of southern Germany also harbored S. eubayanus, at least until it was out competed by the more ubiquitous S. cerevisiae.

“If true, then the use of European oak in making beer barrels and especially processing vats, which could harbor the yeast, might better explain the Bavarian ‘discovery’ of lager in the 1500s,” he said.

Nevertheless, he added, history and archaeology are full of surprises.

“Nowhere is this more true than of the seemingly miraculous process of fermentation and the key role of alcohol in human culture and life itself on this planet,” he said.

“This article has begun to unravel the complicated heritage and life history of the fermentation yeasts, and will hopefully stimulate more research to see whether the Patagonian hypothesis proves correct.”

Diplomatically put, because as everyone admits, the find in South America may not be the exclusive area where Saccharomyces eubayanus lives, just the first place it’s been found. The human history portion of this story doesn’t seem to quite fit at this point, but it’s certainly a compelling story and it will be interesting to see how it continues to develop.

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