Yeast-Free Beer Using Recombinant DNA Techniques?

[res13]

I apologize in advance if this is a common question around here.

Purely theoretical, I was wondering if anyone knew why it HAS to be a yeast species that ferment sugars into drinking alcohol. Ethanol for biofuels is already made from many microorganisms for use in biofuels, so why couldn't someone genetically modify a bacteria or single-celled algae species for optimum beer-making? So far it seems to me that yeast is used because that is the convention and the public wouldn't want E. coli beer. Any thoughts?

 

[GilaMinumBeer]

You are in luck. Somebody just invented Peddiococcus bacteria. Enjoy your malt vinegar.

 

[snccoulter]

Because there is a tradition in beer making and part of the tradition is making beer with hops, malt, barley, water oh and yeast. You are pushing it whe you start to add extra stuff to beer but if you take it away you have crossed the line.

 

[david_42]

This is an example of trying to engineer something to replace something that works extremely well. Why bother? The effort that goes into fuel-ethanol is speeding the conversion of cellulose to sugars that yeast can handle.

 

[SteveM]

So make some e. coli beer and let us know how it tastes!

 

[Airborneguy]

This is an example of trying to engineer something to replace something that works extremely well. Why bother?

+1.

I'm thinking the OP makes crappy beer and wants to blame the poor yeast....

 

[devilishprune]

E. coli stinks once it gets going, I wouldn't want to drink beer made out of that.

 

[l1ranger]

can you imagine the time and money that would go into trying to develop something that may be impossible?

whereas, over the years, the time and money has been spent to develop yeast strains for particular brews that do work.

 

[riromero]

Pardon my ignorance but... Isn't recombinant DNA techniques exactly what we're getting right now thanks to nature? Isn't gene splicing what you're talking about? Maybe where you identify the DNA sequence from yeast that makes delicious beer and splice it into easy to grow bacteria?

I've done all kinds of crazy things in my long homebrew journey. So I agree with the previous poster... Try it and report back!

 

[res13]

I agree that spending time and money on creating something new besides yeast to make beer would be a waste, it was merely a theoretical question. I am trying to figure out exactly what it is about yeasts (and not other microorganisms) that make them good drinking-alcohol makers, and if it is possible (with unlimited resources) to make some sort of yeast-free drinkable alcoholic product using genetically-modified cyanobacteria or algae.

 

[BorisLobb]

Use yeast to ferment. Filter/pasteurize. Huzzah, yeast free beer...

Not rocket science. Why mess with what works?

 

[hal2814]

Because there is a tradition in beer making and part of the tradition is making beer with hops, malt, barley, water oh and yeast. You are pushing it whe you start to add extra stuff to beer but if you take it away you have crossed the line.

We didn't really understand what yeast was until Louis Pasteur proved that yeast is what caused fermentation. That happened some time in the mid-19th century. That's a good 350 years or so after the Reinheitsgebot was first adopted. Even only taking into consideration the modern definition of beer and leaving out things like gruit beers, yeast is only a "traditional" ingredient because we found out after-the-fact that it is what was doing the fermenting. If there were an acceptable alternative to yeast that didn't have a negative impact on the flavor profile, it would be just as "traditional" as a 16th or 17th Century German beer.

 

[christopher1260]

As a molecular microbiologist, I feel like I might be able to shed a little light on this question. The advantages of using bacteria instead of yeast include: faster doubling rate, the ability to grow the organism to a higher density, and the ability to overexpress the proteins involved in fermentation that would allow each bacterium to produce ethanol faster. Additionally, the handling and culture techniques utilized for yeast and bacteria are nearly identical: i.e. plates and slants for storage and propagation.
The biggest potential drawback that I forsee is that yeast are already adapted to tolerate the higher ethanol concentration in fermenting beer, while bacteria are not. In the face of this stress, it is possible for many stress response genes to be activated by the bacterium, leading to unwanted byproducts and off-flavors. Also, yeast conveniently drop out of solution when they are done fermenting a batch, leaving crystal clear beer. I'm not sure that bacteria would behave the same way without centrifugation or expensive filtration. The issue of smell could be circumvented by using a non-enteric organism (one that doesn't live in your intestine). Many bacteria have a pleasant smell (Pseudomonas aeruginosa is often described as smelling like grapes.)
In summary, after cloning the necessary fermentation genes and making stable integrations into the bacterial genome, the biggest advantage would be the ability to ferment a batch of beer in 2-3 days instead of about 1 week. With the risk of stress-response byproducts and the quick growth of yeast, I'm not sure if the risk of shifting the paradigm is worth it. I do like the forward-thinking ingenuity of the OP. Hats off to the views that leave the box far behind and advance the field. If anyone has any specific questions about how or why to do or not do this, please feel free to ask.
Cheers,
CJ

 

[kanzimonson]

Also, we don't just make beer for alcohol - yeast have other flavor characteristics that we like.

I'm sure if you worked on it you could develop some sort of bacteria that performed just as well as yeast, but who's got the time and money to do this? Even Bud, Miller, Coors use yeast. If they believed there were a better alternative, they'd have already developed it.

 

[jbug440]

I'm a firm believer in the moto

" if it ain't broke, don't fix it"

 

[motobrewer]

I'm a firm believer in the moto

me too

 

[shroomzofdoom]

I apologize in advance if this is a common question around here.

Purely theoretical, I was wondering if anyone knew why it HAS to be a yeast species that ferment sugars into drinking alcohol. Ethanol for biofuels is already made from many microorganisms for use in biofuels, so why couldn't someone genetically modify a bacteria or single-celled algae species for optimum beer-making? So far it seems to me that yeast is used because that is the convention and the public wouldn't want E. coli beer. Any thoughts?

GMO beer? You mean like Godzilla beer? If it could have been invented, Budweiser would already be selling it.

 

[GilaMinumBeer]

GMO beer? You mean like Godzilla beer? If it could have been invented, Budweiser would already be selling it.

+1. Why argue with natural selection? It seems to me that yeast has been naturally selected to perform said function most efficiently.

Furthermore, there is nothing to say that yeast can't ferment out a beer in 2 days except for the brewers who interfere. Pitch enough yeast warm enough and they will ferment whatever volume you choose in a matter of hours until the alcohol tolerence is reached.

It's science that has caused yeast to become tempered and catagorized to cater to a specific desired set of chemical byproducts.

 

[prosper]

Also, we don't just make beer for alcohol - yeast have other flavor characteristics that we like./QUOTE]

This. Beer (even ultra-clean lagers) get much of their character from esters and other fermentation byproducts. Those byproducts make beer 'beer,' as much as the alcohol does.

 

[guinsu]

Wow the lack of intellectual curiosity in this thread is astounding. I think it is interesting to wonder "what if", especially if it leads to a higher understanding of what it is we are currently doing. Thanks Christopher for your insightful reply.

 

[brewzombie]

This sounds plausible to me. It would be a huge amount of work and is largely reinventing the wheel, but there are certain advantages to bacteria (as Christopher listed above). I was initially concerned with the bacteria being unsafe (many strains are opportunistic and can turn on you) but then I remembered that bacterial fermentation already produces cheese and yogurt etc. so it could be done safely.

Recent technological advances will make this easier to accomplish. It will soon (ish) be possible to make the entire organism from scratch, selecting only the genes needed for beer and reproduction and then synthesizing the entire genome from chemicals. This is what Craig Venter, one of the guys who sequenced the human genome, is presently working on. This tech is happening soon.

 

[Nokitchen]

As a molecular microbiologist, (snip)
CJ

Thank you, Christopher. That was fascinating and helpful.

I've got a couple follow-up questions. You talked about stress and off-flavors. With the current state of the science, do you suppose that could be turned on its head to create (or "evolve" by selection) a bacterium or alga which would create on-flavors in response to stress? Or at least esters which might be similar to those of current yeasts, whether "on" or "off" (banana ester is OK in the weisbeer, not so much in the IPA, for example)? Or is the chemical makeup of yeast sufficiently different from that of bacteria and algae such that the latter guys just wouldn't have the available acids to produce esters?

 

[christopher1260]

Nokitchen,
You can clone just about any gene into bacteria to produce proteins. We can even clone these genes to only produce proteins in the presence of a particular sugar or compound, which is called inducible expression. The only limitations that I can think of are proteins that are toxic to the bacterium. The astounding diversity in the bacterial community should be able to overcome this. For example, some bacteria produce antibiotics such as streptomycin which kill or inhibit the growth of their competitors. I have no data, but I'm pretty sure that bacteria could be engineered that will ferment with similar to various yeast strains. As Brewzombie alluded to, there are artificial bacteria whose entire genome was synthesized in a lab (link: http://www.dailymail.co.uk/sciencet...life-created-Craig-Venter--wipe-humanity.html) Using this process, a bacterium could be designed step by step to express only the proteins necessary for life and fermentation. I can't imagine the amount of time, funding, and effort this would take to re-create yeast which do a darn fine job of this. As an intellectual exercise, I am intrigued. I like the thought process, even if the feasibility is a stretch.

Just for your personal information, bacteria (as a mixed population) produce and have available far more compounds (acids/ esters) than human can. In fact, animals who are raised to have sterile digestive tracts have 40% less body fat than animals raised with normal intestinal flora, though the sterile animals consumed more food. (Backhed et al. Science, 2005)
The take home message from this study is that bacteria aid animals in digestion and utilization of nutrients by breaking down undigestible compounds into things that we can utilize.

Also, certain species of bacteria can consume and thrive on some crazy carbon sources, such as oil. Google "bioremediation" to learn about how engineered bacteria are used to clean up toxic spills. That's the type of stuff that makes me love learning about these "bugs." I'm just using these as a couple of the many examples that the bacterial community can utilize and produce just about any compound on earth. Loving the dialogue.
Cheers,
CJ

 

[motobrewer]

don't microbreweries already ferment in a few days?

 

[ForRealBeer]

^ The larger guys use a "continuous fermentation" process and it does speed up their process greatly. I remember that from going through the A-B plant at Williamsburg some 20 years ago, and it was interesting and obviously very different from anything I was doing as a homebrewer.

If you are interested, this paper describes it
http://nzic.org.nz/ChemProcesses/food/6A.pdf

 

[smizak]

One big problem is the fact that yeast don't just make alcohol, and beer flavor is not produced by alcohol alone. If you could magically transform just the fermentable sugars in wort to alcohol, and leave all else the same, it would taste nothing like beer.

 

[GilaMinumBeer]

One big problem is the fact that yeast don't just make alcohol, and beer flavor is not produced by alcohol alone. If you could magically transform just the fermentable sugars in wort to alcohol, and leave all else the same, it would taste nothing like beer.

Chris has already explained that bacteria can be genetically selected to produce a specified range of esters or phenols.

Please keep up.

 

[smizak]

Chris has already explained that bacteria can be genetically selected to produce a specified range of esters or phenols.

Please keep up.

Yeah, but his posts are just too long and wordy.

Hey, did you know that if you put beans in chili, it's no longer chili anymore?

 

[rexbanner]

As a molecular microbiologist, I feel like I might be able to shed a little light on this question.

I love scientists. If there's one thing I hate, it's speculation, and you guys make it so we don't have to.

The world be such a better place if the majority of the population valued real knowledge. We prefer to concentrate on what we believe in, not on reality. We have collected so much knowledge and empirical evidence about our amazing world. Anyone can become pretty knowledgeable about any subject just by reading a few good books. I could spend forever reading non-fiction.

 

[Bensiff]

Sounds like you are thinking in terms of how to make alcohol in different ways which is great for science. However, the vast collection of byproducts produced in the reactions from glucose to ethanol makes up many of the plethora of flavor compounds that make beer, well, beer. If you coaxed bacteria to produce all of the enzymes necessary to make all these compounds you would have spent a fortune to yield the same thing only slightly faster. In the mean time I will limit bacteria to pediococcus and lactobacillus...and hope that they only get introduced intentionally.

And don't worry, that is not a common question around here