Genome Sequence of Saccharomyces Carlsbergensis

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Here’s an interesting journal article for the yeast wrangler in you to geek out on. Genome Sequence of Saccharomyces carlsbergensis, the World’s First Pure Culture Lager Yeast details the efforts of Andrea Walther, Ana Hesselbart and Jürgen Wendland from the Carlsberg Laboratory to get a handle on the origins of modern lager yeast using more modern gene sequencing tools. Here’s the wonderfully obtuse explanation from the Abstract:

Lager yeast beer production was revolutionized by the introduction of pure culture strains. The first established lager yeast strain is known as the bottom fermenting Saccharomyces carlsbergensis, which was originally termed Unterhefe No.1 by Emil Chr. Hansen and used in production in since 1883. S. carlsbergensis belongs to group I/Saaz-type lager yeast strains and is better adapted to cold growth conditions than group II/Frohberg-type lager yeasts, e.g. the Weihenstephan strain WS34/70. Here, we sequenced S. carlsbergensis using next generation sequencing technologies. Lager yeasts are descendants from hybrids formed between a Saccharomyces cerevisiae parent and a parent similar to Saccharomyces eubayanus. Accordingly, the S. carlsbergensis 19.5 Mb genome is substantially larger than the 12 Mb S. cerevisiae genome. Based on the sequence scaffolds, synteny to the S. cerevisae genome, and by using directed PCRs for gap closure we generated a chromosomal map of S. carlsbergensis consisting of 29 unique chromosomes. We present evidence for genome and chromosome evolution within S. carlsbergensis via chromosome loss and loss of heterozygosity specifically of parts derived from the S. cerevisiae parent. Based on our sequence data and via FACS analysis we determined the ploidy of S. carlsbergensis. This inferred that this strain is basically triploid with a diploid S. eubayanus and haploid S. cerevisiae genome content. In contrast the Weihenstephan strain, which we re-sequenced, is essentially tetraploid composed of two diploid S. cerevisiae and S. eubayanus genomes. Based on conserved translocations between the parental genomes in S. carlsbergensis and the Weihenstephan strain we propose a joint evolutionary ancestry for lager yeast strains.

If that made your head spin, try the full article, which was released in full online at the end of February. It will be published in the journal G3: Genes, Genomes, Genetics in a future issue. It’s fascinating reading.

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Emil Christian Hansen, taken in 1908. Hansen was the scientist at the Carlsberg Brewery responsible for isolating the lager yeast in 1883.

Beer In Film #40: Analyzing American & Belgian Beers

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Today’s beer video, in honor of it being Sour Sunday, is a film of a talk given by Jeff Clawson, who’s the Pilot Brewery Manager at Oregon State University’s Food Science & Technology Department. In the 23-minute video, Clawson “discusses a recent study on sour beers at a Science Pub event at the Calapooia Brewery in Albany, Oregon. OSU is one of the world’s leaders in research on hops and the brewing sciences, and many graduates of the fermentation sciences programs go on to have a huge impact in the industry.”

The Difference Between A Lager And An Ale

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BeerSci
Here’s another interesting post on brewing science from Popular Science‘s BeerSci series. If you’re reading the Bulletin, chances are you’re already pretty familiar with the question What Is The Difference Between A Lager And An Ale? But author Martha Harbison gives a good overview of the technical differences in layman’s terms and goes into yeast’s history. It’s a great tale, which she refers to hilariously as a “unicellular soap opera.”

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“From Eubayanus to Pastorianus Ale yeast and yeast from the forests of Patagonia met in a brewery…and lager was born! Libkind et al., PNAS; August 2011″
Click here to see the chart full size.

Selecting And Generating Superior Yeasts For The Brewing Industry

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After my post a couple of days ago about Genetically Engineered Yeast, Chaz from Alaskan Brewing sent me a link to an interesting blog post by Dmitri, an amateur yeast wrangler who writes about his yeasty adventures at BKYeast. The post is a review of science literature from Cerevisia, the Belgian Journal of Brewing and Biotechnology. The article in question is titled Selecting and Generating Superior Yeasts for the Brewing Industry, which was published in 2012. It’s deliciously geeky and technical, but should be scrutable to anyone who brews either professionally or at home, thanks to Dmitri’s writing, as his goal is to take the jargon and science and make it accessible to a broader audience. As brewers struggle to have their beers stand out in an ever-increasingly crowded marketplace, it should be obvious that we’ll be seeing more and more experimentation with flavors and ingredients and ultimately more unique beers, and even new types of beers as others copy the successful ones, in the coming years. As the author notes, new varieties of hops are already facilitating that effort, and it seems likely that new strains of yeast are a logical next step in that evolution. And that’s what this research by a group from Leuven, Belgium is trying to make easier, finding the right yeast to create the right range of flavors for your beer. Give it a read.

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“Graphical representation (heat map) of different characteristics of industrial yeast strains. Every row consists of data from a different yeast strain, every column is a different characteristic. ‘Yellow’ is a low score, and ‘red’ is a high score for this certain characteristic. The dendrogram on the left represents the genetic relatedness of the yeasts, based on an AFLP fingerprint exploiting transposon TY1 insertion site polymorphisms. The colour code on the top right indicates the origin of the yeast strains. This kind of analysis allows us to select yeasts with specific beneficial traits, for example to use in industry, or for breeding.”

Genetically Engineered Yeast

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Mashable had an interesting piece about Genetically Engineered Yeast being done by at least two companines, Amyris and Evolva, and based in part on a New York Times article, What’s That Smell? Exotic Scents Made From Re-engineered Yeast. In the Times article Amyris co-founder Jay Keasling explained “that the process is ‘just like brewing beer, but rather than spit out alcohol, the yeast spits out these products.’” The relatively new discipline, dubbed synthetic biology, is only about a decade old. There are apparently issues about whether it would be considered natural. SOme say no, because the synthetic version “contains scores of components besides” what it’s being used as, while John B. Hallagan, from the Flavor and Extract Manufacturers Association believes “it conceivably could be called a natural ingredient since it is made in a living organism.”

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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Beer Birthday: Chris White

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Today is the 45th birthday of Chris White. Chris founded the yeast company White Labs in 1995 and he’s also on the faculty of the Siebel Institute. He’s also a fixture at virtually every brewing industry and homebrewing conference. Join me in wishing Chris a very happy birthday.

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Chris and his brother Mike bookending Chuck, from Green Fash Brewing, Natalie Cilurzo, from Russian River Brewing, John Harris, from Full Sail Brewing, and Vinnie Cilurzo, also from Russian River, at CBC in Austin, Texas in 2007.

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Chris at the new White Labs taproom during the Craft Brewers Conference a couple of years ago in San Diego.

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Surly brewer Todd Haug with Chris.

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Chris with Technical Sales and Marketing Coordinator Ashley Paulsworth at the NHC.

[Note: last two photos purloined from Facebook.]