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A whole yeast cell (Saccharomyces cerevisiae) is viewed by X-ray microscopy. Inside, the nucleus and a large vacuole (shown in red) are visible.
Researchers say they've used genetic engineering to create a strain of yeast that can cut the time needed to make ethanol from cellulosic sources in half. It's the latest twist in efforts to fine-tune microbes for "frankenfuel" production.
Like Frankenstein's monster, these ethanol-producing organisms draw upon genetic combinations not found in nature. The scientists reporting their results today in the Proceedings of the National Academy of Sciences started out with common brewer's yeast, then adapted a few tricks used by a different strain of yeast as well as a cellulose-loving fungus.
The original yeast, Saccharomyces cerevisiae, is quite good at fermenting glucose, which is currently the primary sugar converted to ethanol in the industrial fermentation process. This is the process by which yeast makes bread rise, and by which yeast turns fruit and grain into wine, beer and other alcoholic beverages. But energy companies would rather make ethanol from cellulosic materials (such as wood waste and switchgrass) rather than from edible products (such as corn and sugar cane). So anything that raises the efficiency of cellulosic ethanol production makes biofuels look more attractive as a long-term energy solution.
One of the big problems is that glucose is only one of the sugars contained in cellulosic material. Brewer's yeast can't ferment the other major type of sugar, known as xylose. "Xylose is a wood sugar, a five-carbon sugar that is very abundant in lignocellulosic biomass but not in our food," Yong-Su Jin, a professor of food science and human nutrition at the University of Illinois, said in a news release. "Most yeast cannot ferment xylose."
Even if a yeast strain can handle xylose fermentation, it won't start in on the xylose until all the glucose is gone. "It's like giving meat and broccoli to my kids," Jin explained. "They usually eat the meat first and the broccoli later."
Jin and his colleagues — including researchers from the University of Illinois, Lawrence Berkeley National Laboratory, the University of California at Berkeley, Seoul National University and the energy company BP — inserted genes from a xylose-converting yeast to give S. cerevisiae the power to turn xylose into ethanol. They also added the capability of a fungus known as Neurospora crassa to work with a precursor of glucose known as cellobiose.
The combination of those two tricks, plus some extra tweaks, enabled the franken-yeast to ferment cellobiose and xylose at the same time. That avoided the glucose vs. xylose, meat vs. broccoli problem.
"If you do the fermentation by using only cellobiose or xylose, it takes 48 hours," Suk-Jin Ha, a postdoctoral researcher at the University of Illinois and the study's lead author, said in today's release. "But if you do the co-fermentation with the cellobiose and xylose, double the amount of sugar is consumed in the same amount of time and [the process] produces more than double the amount of ethanol."
The new yeast strain is at least 20 percent more efficient at converting xylose to ethanol than other strains, Jin said.
He said the potential cost benefits are significant: "We don't have to do two separate fermentations. We can do it all in one pot. And the yield is even higher than the industry standard. We are pretty sure that this research can be commercialized very soon."
This approach builds upon research published in September on the journal Science's website — and one of the researchers involved in that earlier study, Berkeley's Jamie Cate, played a role in the newly published study as well. As I noted back in September, other researchers are working on different ways to use yeast for producing biofuel. Bottom line? If cellulosic ethanol ever becomes a major part of America's energy equation, it's sounding as if genetically modified yeast will be the key that turns the ignition.
But what do you think? How will biofuel fit in alongside fossil fuels, solar and wind energy, nuclear power and other options? Feel free to discuss America's energy future in the comment space below.
In addition to Jin, Ha and Cate, the authors of the PNAS paper, titled "Engineered Saccharomyces Cerevisiae Capable of Simultaneous Cellobiose and Xylose Fermentation," include Jonathan Galazka, Soo Rin Kim, Jin-Ho Choi, Xiaomin Yang, Jin-Ho Seo and N. Louise Glass. The research was supported by the Energy Biosciences Institute, a BP-funded initiative.
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Qteros has been working with a consolidated bioprocessing organism for 4 years now. The microbe was discovered near the Quabbin resevoir in Massachusetts by Dr Susan Leschine. This microbe ferments C5 and C6 sugars naturally. BP is also an investor in Qteros. Full disclosure, I was a Founder at Qteros. It would be worth a comparison of all the CBP organisms currently under development.
When will a C2H6O/plug in hybrid car be on the road? Or at least an E85/hybrid?
Cellulose created bio-fuels are, IMHO, the most important change in the energy industry short of fusion. The US government pays farmers billions of dollar's a year not to grow food to stabilize the food prices.
Image, all of those acres of unused farmland, much of the grass clippings, and yard waste across the country and the world going into the production of bio-fuels. It would be in the order of 10's of millions of gallons a day in the US.
Global warming would be slowed because new carbon is not introduced into the environment with bio-fuels. it just used over and over again.
And best of all the consumer would not have to change many their habits.
I would like to see more work on Bio diesel. With it we can continue to use the current pipelines we have for
oil. With ethanol you have to very careful to avoid water entering it and diesel vehicles are generally more efficient.
I'm with you, Mike. I think bio-diesel has some great potential and can be integrated easily with existing feedstocks of fuels. However, anything is worth a try to get us off total dependence on the oil teat.
Which is better for the environment, leaving waste plant matter to decay and enrich the soil or turning it into fuel? If we turn all of the waste plant matter into fuel we will then have to use manufactured fertilizers to enrich the soil and guess where they come from. Petrochemicals.
Not necessarily so. You are only thinking of farm waste. What about the (most probably) millions of tons of yard waste and grass clippings from American suburbs that is simply discarded in landfills or incinerated?
Further, many fields of arable land are not used to grow crops so that the price of grains remains stable. Farmers don't want to flood the market with grain and lose their profits. These fields could be used to grow switch grass, which takes no fertilizer at all. Many of them already are. Now the farmers can turn a profit on those fields. Proper crop rotation can be used to help replenish the soil without as much fertilizer as you think. Also most fertilizers are nitrogen and phosphate based - not carbon. Plants get carbon from the air! Petrochemicals are not used. Since the plants are taking carbon from the air, which we are then turning into ethanol for fuel, we would actually be using less petrochemicals from the ground and using only what is above ground already. The exhaust from engines goes back into the air and then back into plants - a closed cycle.
Also think of wood chips from lumber operations. There are easily millions of tons of that waste generated every year. There are all sorts of ingenious products that people have thought to make from that and this is yet another.
Your name, "economykiller" is ironic since you come out against a process that seems to have the potential to create profits from waste, while spurring a new industry. I'll never cease to be amazed at the gymnastics it takes to make green tech sound bad!
This seems like such a great idea, I'm wondering why the government hasn't been plowing billions of dollars into it, way before this. We gnash our teeth about national security, then let ourselves get dependent upon the Middle East for oil. Isn't there a little disconnect there? Perhaps we should have spent the 100 billion's we spent in our recent wars on this or fusion. I predict once this idea is commercialized, we will wonder why we did not do it earlier. I'm still very puzzled. This is not rocket science.
As for an E85 hybird, the much anticipated (and hyped) Chevrolet VOLT was supposed to be E-85 ready out of the gate. However, General Motors has delayed making the VOLT E-85 ready for two reasons - gasoline is still cheaper (at today's pump prices) and the initial VOLT markets have very little in the way of E-85 infrastructure.
By the time the VOLT becomes available nationwide (the Midwest has more E-85 infrastructure) in 12-18 months, pump prices for gasoline, as many analysts now predict, will likely be at or near $4/gallon, about where E-85 starts to build a price advantage over gasoline. So perhaps the VOLT will be E-85 ready when it's rolled out nationally.
Delightful, all of it.here in Costa Rica there are miles of a palm that produces the nut that makes a margarine which turns out to be worse for your body than butter; but could become, thanks to its oil content, an easy road to a national bio fuel industry. Similarly, bio invasions like the Kudzu vine in the southern US could be harvested for the purpose of fuel.
On another barely tangential theme, I wonder if anyone can tell me if burning fossil fuel the way we do could release long-extinct micro organisms as pathogens in our air?
molly cruz
The answer to your question is no. Extinct means none are left alive. If you are asking about long dormant spores, any microorganism that existed before Man, and many exist that are that old, could not have become adapted to be a pathogen, as there were no humans for it to do this with.
(For all you who believe the world is 6,000 years old, then there could be no such thing as a long extinct organism)
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this is a very good article.it explained what is the possibilities of production of bio fuel used to yeast
I think it is a great idea to grow as much of our fuel as we possibly can- Alchohol based fuels can be a much better transportation fuel than gasoline is, because the emissions can be better ( methanol, ethanol, butanol are all very simple molecules compared to gasoline, and all burn much cleaner because of it), and the compression ratio can be much higher. Also, because of the clean burning characteristics of alchohol based fuels, the pistons and valves never get dirty, maintaining like new engine efficiency for the life of the engine. This is NOT true with gasoline fueled engines- they all need extra fuel addititves (techron...) to keep the pistons and valves clean.
This innovation to make more ethanol is a great thing, however, the big break through will come when Bio-based Butanol is less expensive than Gasoline, as the energy density of Butanol is nearly identical to gasoline,
and can replace gasoline gallon for gallon, with absolutely no problems.
Another writer here mentioned kudzu as a crop to convert to
ethanol and I agree it would fit right in. This Asian born weed has unmatchable
growth and would be a natural fit because there are no planting costs just
harvest, harvest, harvest.
I happened upon this article by mistake... led from reports on beer price spiking... This is the type of news that should be on the front page... not the latest gaff from a political candidate.
Before posting I thought "What are the unknowns?", like if we engineer an organism to do our bidding, are we short-circuiting evolution, and possibly creating an organism we can't "control"... but the others posting here made it more understandable to this simple country boy. THIS is what the internet is supposed to de... educate. Thanks to all who contributed.