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Joel Graham, University of Maryland
A 94°C geothermal pool, with a level-maintaining siphon, near Gerlach, Nevada. Sediment from the floor of this pool was enriched on pulverized miscanthus at 90°C and subsequently transferred to filter paper in order to isolate microbes able to subsist on cellulose alone.
A record-breaking microbe that thrives while munching plant material at near boiling temperatures has been discovered in a Nevada hot spring, researchers announced in a study published today.
Scientists are eyeing the microbe's enzyme responsible for breaking down cellulose — called a cellulase — as a potential workhouse in the production of biofuels and other industrial processes.
Cellulose is a chain of linked sugar molecules that makes up the woody fiber of plants. To produce biofuels, enzymes are required to breakdown cellulose into its constituent sugars so that yeasts can then ferment them into the type of alcohol that makes cars (not people) go vroom.
At the industrial scale, this process is done most efficiently at high temperatures that kill other microbes that could otherwise contaminate the reaction, Douglas Clark, a chemical and biomolecular engineer at the University of California at Berkeley, told me today.
"So finding cellulases that can operate at those temperatures are of interest," he said.
Hot spring
That's what led Clark, microbiologist Frank Robb from the University of Maryland, and colleagues to collect sediment and water samples from the Great Boiling Springs near Gerlach, Nevada. The spring is 203 degrees F, just short of boiling.
"It's on private land and has been surrounded by a low wall to keep cattle from going into it and that maintains the temperature," Robb explained to me today, noting that most hot springs have varying temperatures depending on the weather and water levels in the spring.
In addition, a siphon has been added to Gerlach hot spring to keep it from overflowing. The combination gives whatever microbes that are in there no choice but to grow at high temperatures, Robb noted. Bits of grass and woody material blown into the spring serve as a food source.
The team grew microbes found in the samples on pulverized miscanthus, a type of grass that is a common biofuel feedstock, to isolate the microbes that grow with plant fiber as their only source of carbon.
They then sequenced the community of surviving microbes, which indicated three species of Archaea, a type of single celled microorganism, were able to utilize cellulose as food. Genetic techniques identified the specific cellulase involved in the breakdown of cellulose.
This cellulase, dubbed EBI-244, was found in the most abundant of the three Archaea.
"We didn't really expect to find an organism that could grow at such a high temperature and degrade cellulose in this particular environment. But you never know," Clark told me. "It really underscores the diversity of life. And, obviously, if you don't look, you won't find it."
Too hot
The enzyme EBI-244 works optimally at 228 degrees F (109 degrees C), which is actually too hot for the efficient breakdown of cellulose into fermentable sugars due to side reactions that can occur, Clark noted.
"But it is interesting to know that such cellulases are out there," Clark said. "And then this cellulase might also serve as a good starting point to be engineered to work at a lower temperature but maintain the high stability that it has naturally evolved to work at such high temperatures."
Robb likened this engineering process to building a street car from parts used on cars found at the racetrack. "The enzyme itself could be the parts bin," he said.
So, the enzyme itself probably won't be hard at work anytime soon producing fuel to put in your gas tank, but it does lead researchers down the road to engineering the biofuels of the future. What's more, EBI-244 is a record holder for heat tolerance in cellulase.
"It is always nice to have a record breaker," Clark noted. "It adds to that wow factor a little bit."
A paper on the findings appears in the July 5 issue of the journal Nature Communications. Other authors are Dana C. Nadler, Sarah Huffer, Harshal A. Chokhawala and Harvey W. Blanch of UC Berkeley; and Sara E. Rowland of the University of Maryland Marine, Estuarine and Environmental Sciences graduate program.
More on heat-loving microbes:
- Yellowstone microbe converts light to energy
- Got milk? Convert it into biofuel
- How bacteria could help power the future
- How biology will help fill your fuel tank
- Hole-y Cow! Guts could lead to holy grail for cheap biofuels
- Not-so-stupid microbe tricks
John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).
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Again, underscoring the importance of science to this country. Its not just for fun, kids, it can help you in real life too(and it is also responsible for everything you have/wear/use outside of your own body).
Look what Gawd did!
He done gave me the by-oh-fuals!
This is great! Less corn ethanol = more food supply + cheaper fuel = happy me! "Good for u, good for us - Good for this family!"
This is going to cause a shortage in cellulose, I imagine Kodak is going to raise their film prices. ^_^
Eric
So you think that Bio Fuels are the way to go, and that they will make the environment better?
Time is what nature has a lot of it takes long time for natural reactions, any fuels created by a bio fuel conversion is forcing the hand to make the conversion Fast, that mans more energy input then net energy gain. if any one has an example that proves the opposite, i would love to read it.
Eagle, you could not be more wrong. Enzymatic reactions of this type are extremely rapid and only require enough energy to heat and mix the vessel in which these microbes will be growing. Using microbes to produce biofuels is a scalable and cheap means of production. The only thing standing in the way is the identification of a species that can break down plant cellulose into fermentable sugars. The species that produces the enzyme EBI-244 is the best we have found so far. All of the technology for these microbial reactions exists today, right now.
The feedstock for these reactions is plentiful and currently is considered waste. Just think of how many tons of grass clippings are produced in every municipality in the country every week. Add to that the saw dust and wood chips left over from logging operations and other plant material waste from agriculture and you can begin to understand how easy it is to access the raw materials. There is no need to do exploratory drilling or maintain expensive rigs in hostile environments. The feedstocks can be sourced locally and converted to fuel locally for sale back to the community. I'm not proposing biofuels as a replacement for oil, but as a supplement they can absolutely make an impact in the availability of fuel and the cost of energy.
If you want to read up on microbial enzymatic reactions I would suggest any textbook on microbial biotechnology or enzymatics. This has been a well studied science for decades. These enzymes naturally catalyze these reactions in nanoseconds without any "forcing" of nature by man. We simply feed the microbes and they do what they do, naturally.
Eagle, you are correct that there is no net energy gain from making bio fuels. In fact, there is no net energy gain from any reaction, anywhere, at anytime, ever. Conservation of energy is a cornerstone of modern physics.
All they are doing in this situation is taking the chemical energy stored in the plant material (and originally provided from the Sun's light) and converting it into a form with a better energy to weight ratio so that they can use it in cars (and whatever other applications they come up with). The speed of this conversion has nothing to do with its efficiency.
On a side note, I do agree with you that biofuels are not the answer. I foresee (hopefully) a future where the majority of the worlds power needs are supplied by Solar/Fusion/Safe Fission (like Thorium MSRs) sources. The energy generation to area ratio for biofuels is too poor to be a long term solution.
@ Scubasteve58001
Agreed, I think that biofuels have a place however. Society generates A LOT of organic refuse, cellulose is one of the hardest to repurpose since its products take a significant amount of energy to produce by comparison to basic petrolium distillate counterparts (hint: that's why the X% organic plastic is heavily advertised...branding and eco-guilt-tripping are what they are trying to recoup the greater costs).
Having a few biofuel plants to literally digest the organic waste and repurposing much of it into usable fuel again could take a strain off of seeking more natural resources. And the nice thing about these enzymatic-methods is that the organisms do most of the work, which improves the margins for humans.
Easiest way to do that is to Train the Public to be less wasteful and use containers for Multi Use Rather then single use. here is an example of total waste of packaging, go and see if you can go and buy 2 rivets, you might find a package of 20 and the package will be about 30 times larger then the rivets mass, so why can they not have rivets in a Bulk bin and sell you as many as you want with NO packaging.. people still have Pockets they can put items in right ;-))
@ Eagle Averro
It's all about branding and packaging!
Rivets are ubiquitous and standardized. Companies try to compete with one another to get you to buy their rivets/nails/etc by trying to convince you of some added quality that the others don't possess. It's hard to do that when there's just a mess of 'em floating in a bin.
It sucks, but unless we require by law that this type of wasteful practice be stopped, companies will continue to do this type of marketing.
I wish that the government would crack down on the massive amounts of paper junkmail that's mailed out every week. I literally throw out pounds of the stuff a month...even though it goes to recycling, it's still wasting energy
Serious
Yes Agreed if a LAW is what is needed then a LAW they should get,
Re Cycling is about 70% waste, when one considers the energy needed for storage transportation and so on, so to use the term " it is recycled so it is OK" is anathema to any environmentalism, DO NOT create the " Junk" then there is NO need to recycle :-)
AGREED!
It sucks that we have to enact laws to do this stuff properly. I know of a few Legislators/Congress-people in my state that have pushed to create a "do not solicit" database that people could sign up on to stop junkmail from arriving in their physical mailbox. The annoying thing is how strongly the businesses-community fights to prevent such a database from appearing! First, I'm surprised at how much response they get from those weekly mailer ads for one, I'm disappointed that they pass the cost of 'recycling' their paper-waste onto the taxpayer, and lastly, why do they concern themselves with people that deliberately want to opt out, those people aren't customers! I guess their marketing-monkeys think that the right ad will persuade an otherwise "do not solicit"-person into a paying customer. I wonder how often that works with cold-calling telemarketers and spam.
Since I cannot conceivably find a way of pinning the cost back on the business for recycling the 1,000's of tons of junkmail waste they generate annually, I'll just make it illegal for them to approach people that do not want unsolicited ads in their mailbox.
Ethanol based fuels are not as efficient as fossil fuels. This is a good start to making biofuels but the goal shouldn't be to make inefficient alcohol based fuels. You need an additional catalytic process to convert the alcohol to aliphatic/aromatic hydrocarbon based fuels that are more efficient. This is an excellent discovery though because cellulose is abundant in biomass waste and biomass waste is typically free.
I Agree with ALL of the above, if that is possible, but i also digress, here is why grass clippings are not " waste" to nature ever seen the Huge colonies of organism that make any Grass clippings " home" so here the word " waste" is wasted ;-)
On energy conversion see Krebs scientists are still amazed that one step seems to be " Unnatural"...
Yes I Believe PV power is making better use of the excess NUCLEAR power we have given to us FREE daily home delivered by the Sun! Any other " Nuclear power is a fools paradise" see my album for that .
Brazil is largely self sufficient when it comes to energy in large part because they use alcohol based fuels fermented from their crop of sugar cane. With enough feedstock there is plenty of punch from alcohols. There is no need to convert an alcohol into an aromatic hydrocarbon in order to burn it within an internal combustion engine, the engine just needs to be designed for alcohol. Converting alcohol to hydrocarbon would actually waste more energy because those additional molecular bonds would have to be created and an exceptional amount of energy would need to be imparted to make this happen.
Brazil is right now running its cars on alcohol and has been doing so for decades. The process for fermenting and distilling the alcohol from simple sugars is known and well studied at industrial scale. In America we do not have an abundant crop of sugar cane to provide those simple sugars, but we do have an abundance of cellulosic feedstocks. Identifying the right enzymes for converting cellulose to simple sugars is the only thing that stands in the way of using those feedstocks to produce fuel ethanol at industrial scales without relying on corn.
Eagle, I have no idea what you are talking about. The Krebs cycle is one of the most well known metabolic processes in all of biology. There is no "unnatural" step. The point about the grass is that in many communities that grass is carted off to rot. If some of that could be reclaimed as energy - why not do it? The world has plenty of maggots and ants, I'm sure they won't be missed if they don't get a chance to live in a rotting heap of grass clippings!
ok I'll ask...what is the optimum temp to breakdown cellulose into fermentable sugars in this case...and...one point, how difficult to alter the plant to accept EBI-244 at 109 degrees C without the less than desirable side issues?
I'm not 100% sure, but it seems the side reactions may be occurring with either other enzymes in the microbe that break down the resulting sugars to non-usable molecules or the sugars themselves are degrading at those high temps. But just because theoptimum cellulase activity is at a high temp doesn't mean the enzyme won't work at lower temps.
I'm not sure what you mean by altering the plant. The plant materials are mostly cellulose, so they will need to be broken down enzymatically. I don't know any chemical treatments that would make the cellulose a better substrate for EBI-244 and any treatments would of course raise the cost. I think it would be far easier to evolve the microbes in the lab to thrive at specific conditions with cellulose as their only carbon source. Of course they could try mutating the enzyme directly as well and see which variant works best. Having identified a thermostable cellulase is a big first step!
thanks Radagst...the article was really llimited. Your approach at the microbe seems very sound.
Most planned commercial scale bio-refineries utilize separate hydrolysis and fermentation steps. Hydrolysis of glucan at those high of temperatures (for an acid hydrolysis) causes a number of fermentation inhibitors to be produced. Furfural is one particularly problematic inhibitor. Removal of these inhibitors is costly and technically difficult. So most cellulosic hydrolysis treatments are performed at about 150-220 F.
am listening