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Could Wood Feed the World?
ScienceNOW ^ | 15 April 2013 | Charles Q. Choi

Posted on 04/16/2013 6:08:16 PM PDT by neverdem

Enlarge Image
sn-plants.jpg
Future food? Cellulose from switchgrass and other nonfood plants might be converted into edible starch to feed the hungry.
Credit: Peggy Greb/ARS/USDA

The main ingredient of wood, cellulose, is one of the most abundant organic compounds on Earth and a dream source of renewable fuel. Now, bioengineers suggest that it could feed the hungry as well. In a new study, researchers have found a way to turn cellulose into starch, the most common carbohydrate in the human diet.

Ethanol is today's most common biofuel used to power vehicles. It's typically made using sugars from crop plants such as corn and sugar cane, a system critics decry is a waste of food. Enter cellulose. Plants generate as much as 180 billion tons of the substance globally per year. Companies around the globe are racing to produce biofuels from cellulose from inedible plants, such as switchgrass and poplar trees, grown on marginal land that requires little water, fertilizer, herbicide, and pesticides, or from the vast amount of scrap from crop and wood-based industries. For instance, every ton of harvested cereals is often accompanied by 2 to 3 tons of cellulose-rich scrap, most of which goes to waste.

Now, for the first time, it appears there may be a practical way that cellulose could also feed people, says bioprocess engineer Y.-H. Percival Zhang of the Virginia Polytechnic Institute and State University in Blacksburg. He credits his line of thought to his Chinese background. "Food security has always been the number one question for nearly 5000 years of Chinese history," Zhang says. "Without enough food, crises happened and dynasties shifted." For instance, famines spurred peasant rebellions that helped lead to the collapse of the Tang Dynasty in the 9th century and the Ming Dynasty in the 17th century.

Zhang and his colleagues focused on starch, which makes up as much as 40% of people's diets. The idea of turning cellulose into starch is one rooted in the similarities between the compounds: Cellulose is composed of hundreds to thousands of molecules of the sugar glucose, and starch compounds are made of glucose as well, although the sugar is bonded together in different ways.

To make the conversion, the researchers took genes from certain species of bacteria, soil fungi, and potatoes and then genetically modified Escherichia coli, a different bacterium and a common lab model, to produce the needed enzymes. One set of these enzymes break cellulose down into smaller molecules, while the other set builds these components into starch. Then they mixed this cocktail of enzymes with cellulose in a glass vessel.

Instead of breaking cellulose down entirely to its base components of glucose and reassembling them into starch, the first set of enzymes breaks cellulose down to cellobiose, a compound made from a pair of glucose molecules. The next set of enzymes then splits the cellobiose apart into an ordinary glucose molecule and a molecule known as G-1-P, which is a glucose with a phosphate molecule attached. This G-1-P serves as the building block of chains of the starch molecule amylose. "It's a simple but nice idea," says bioengineer Frances Arnold of the California Institute of Technology in Pasadena, who did not take part in the work.

So far, the process converts up to nearly a third of the cellulose into amylose, the team reports online today in the Proceedings of the National Academy of Sciences. That compound, which is a white powder when dried, can not only be added to food but can also be made into transparent, flexible, biodegradable plastics and store hydrogen for energy applications. Zhang and his colleagues even tried some of the final product: "No taste in the beginning," Zhang says. "After chewing for a while, it tasted slightly sweet."

The rest of the cellulose is turned into glucose, which can be fermented into biofuel. "No glucose released from the cellulose was wasted," Zhang says.

Though the process works, it's expensive. Zhang estimates that, given the current price tag of the enzymes that his team used, it would cost about $1 million to turn 200 kilograms of crude cellulose into 20 kilograms of starch, about enough to feed one person's carbohydrate needs for 80 days. Still, after 5 to 10 years of further research, Zhang says companies could do the same thing for just $0.50 per person per day. "We do not see big obstacles to the commercialization of this process."

Optimistically assuming 100 billion tons of cellulose is available per year, "we will have a potential of approximately 4.5 billion tons of starch, which is nearly twofold the annual production of cereal—that is, 2.3 billion tons per year now," Zhang says. That would provide up to 30% of the food that prior studies estimate is needed to feed the world in 2050.

Still, it remains uncertain whether the approach will be economically viable, says energy economist Wallace Tyner of Purdue University in West Lafayette, Indiana, who did not participate in the study. "I am not saying it will not be—just that it is so early there are and so many uncertainties that it appears to be a very long way from a commercial process," he says. "That is usually the case when new processes are introduced."

Arnold agrees that whether the process is economically feasible overall "is the big question, but that cannot be answered in a proof-of-concept study such as this one. I think the paper demonstrates an important conversion and overall idea—it's pretty cool."

*Update, 1:25 p.m., 16 April: This article originally reported that the researchers took genes from certain species of bacteria. In addition to taking genes from bacteria, the researchers also took genes from soil fungi and potatoes.


TOPICS: Business/Economy; Culture/Society; News/Current Events; Technical
KEYWORDS: amylose; bioengineering; biotechnology; cellulose; ecology; economics; starch

1 posted on 04/16/2013 6:08:16 PM PDT by neverdem
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To: neverdem
Let's burn our food for fuel, and eat our wood for food.

It's so simple -- why has no one thought of this before?

2 posted on 04/16/2013 6:12:46 PM PDT by ClearCase_guy (The ballot box is a sham. Nothing will change until after the war.)
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To: neverdem

I think that wood feeds quite a lot of North Koreans.


3 posted on 04/16/2013 6:13:38 PM PDT by Steely Tom (If the Constitution can be a living document, I guess a corporation can be a person.)
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To: neverdem

They’re getting close!!!! It’s called “Soylant Green”!!!!


4 posted on 04/16/2013 6:15:51 PM PDT by Forrestfire (("To educate a man in mind and not in morals is to educate a menace to society." Theodore Roosevelt))
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To: neverdem

I totally mis-read that as “Could (Tiger) Woods Feed the World?” (Yes!)


5 posted on 04/16/2013 6:16:52 PM PDT by SparkyBass
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To: ClearCase_guy

Asparagus in your tank, and oak on your plate.


6 posted on 04/16/2013 6:17:58 PM PDT by smoothsailing
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To: SparkyBass

I was going to post that Tiger is still good, but not THAT good.


7 posted on 04/16/2013 6:20:18 PM PDT by gov_bean_ counter (Romans 1:22 Professing themselves to be wise, they became fools,)
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To: neverdem

Nothing new, Asimov foresaw yeast farms using organics such as this to feed the teeming masses of Earths future.


8 posted on 04/16/2013 6:23:18 PM PDT by Mastador1 (I'll take a bad dog over a good politician any day!)
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To: neverdem

“I’ve got wood.” Treebeard the Ent


9 posted on 04/16/2013 6:26:00 PM PDT by tumblindice (America's founding fathers: All armed conservatives.)
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To: neverdem

Nothing new. During WWII there was talk of making a substitute sugar from wood.
I remember seeing a cartoon strip in which a waitress offers a soldier sugar for his coffee. He says..”No thanks! I’ll just cut a chunk out of the table leg.”


10 posted on 04/16/2013 6:31:13 PM PDT by Ruy Dias de Bivar (Do we now register our pressure cookers?)
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To: neverdem

The norks have already implemented this.

They eat twigs.


11 posted on 04/16/2013 6:35:14 PM PDT by Hardraade (http://junipersec.wordpress.com (Vendetta))
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To: neverdem

12 posted on 04/16/2013 6:43:04 PM PDT by Paradox (Unexpected things coming for the next few years.)
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"Ever eat a pine tree?

13 posted on 04/16/2013 6:50:48 PM PDT by A.A. Cunningham (Barry Soetoro can't pass E-verify)
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To: Paradox

I’ll have mine medium rare please!


14 posted on 04/16/2013 6:50:59 PM PDT by Conserev1 ("Still Clinging to my Bible and my Weapon")
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To: neverdem

I know the geniuses of the academic world would never think of it, but they could make great strides forward by not making ethanol from corn but using the corn for food and oil for fuel. But, it is a really complex thought that may be beyond their mental capabilities.... they are only tenured professors!


15 posted on 04/16/2013 6:57:10 PM PDT by RetiredTexasVet (Progressives, Margret Sanger, Josef Mengele and the Butcher of Philadelphia)
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To: neverdem

How much wood would chuck upchuck if chuck ate wood?


16 posted on 04/16/2013 7:00:44 PM PDT by Vendome (Don't take life so seriously, you won't live through it anyway)
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To: neverdem

Might make a very good animal feed.


17 posted on 04/16/2013 7:02:25 PM PDT by Sherman Logan
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To: neverdem

According to rumor, it works for North Koreans.


18 posted on 04/16/2013 7:15:11 PM PDT by familyop (We Baby Boomers are croaking in an avalanche of rotten politics smelled around the planet.)
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To: neverdem

There is one ton of edible vegetation for every man. woman, and child on Earth.


19 posted on 04/16/2013 7:41:31 PM PDT by TBP (Obama lies, Granny dies.)
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To: neverdem

[[Could Wood Feed the World? ]]

Yay- deforrestation- no more emerald ash borer problems- no more pesky spotted owl ifnestations, no more woodland turtles crappign all over the place- no more forrest’s fopr bigfoot to hide in- no more pesky trees obscurign our views- brign it on


20 posted on 04/16/2013 8:25:44 PM PDT by CottShop (Scientific belief does not constitute scientific evidence, nor does it convey scientific knowledge)
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To: neverdem

Eating charcoal briquettes would be just like having a cookout.


21 posted on 04/16/2013 8:36:26 PM PDT by FlingWingFlyer (Dude! Where's my Bill of Rights?)
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Comment #22 Removed by Moderator

To: neverdem

I’ll eat mine after the cow converts it to meat!


23 posted on 04/16/2013 8:59:23 PM PDT by dalereed
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To: NotYourAverageDhimmi

Ewwww.


24 posted on 04/16/2013 9:06:50 PM PDT by married21
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To: neverdem

25 posted on 04/17/2013 12:55:59 AM PDT by clearcarbon
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To: neverdem

Feed them grass, ever seen a skinny cow?


26 posted on 04/17/2013 5:23:03 AM PDT by TASMANIANRED (Viva Christo Rey)
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