Gut reaction: Cow stomach holds key to turning corn into biofuel

EAST LANSING, Mich. — An enzyme from a microbe that lives inside a cow’s stomach is the key to turning corn plants into fuel, according to Michigan State University scientists.

The enzyme that allows a cow to digest grasses and other plant fibers can be used to turn other plant fibers into simple sugars. These simple sugars can be used to produce ethanol to power cars and trucks.

MSU scientists have discovered a way to grow corn plants that contain this enzyme. They have inserted a gene from a bacterium that lives in a cow’s stomach into a corn plant. Now, the sugars locked up in the plant’s leaves and stalk can be converted into usable sugar without expensive synthetic chemicals.

“The fact that we can take a gene that makes an enzyme in the stomach of a cow and put it into a plant cell means that we can convert what was junk before into biofuel,” said Mariam Sticklen, MSU professor of crop and soil science. She is presenting at the 235th national American Chemical Society meeting in New Orleans today. The work also is presented in the “Plant Genetic Engineering for Biofuel Production: Towards Affordable Cellulosic Ethanol” in the June edition of Nature Review Genetics.

Cows, with help from bacteria, convert plant fibers, called cellulose, into energy, but this is a big step for biofuel production. Traditionally in the commercial biofuel industry, only the kernels of corn plants could be used to make ethanol, but this new discovery will allow the entire corn plant to be used – so more fuel can be produced with less cost.

Turning plant fibers into sugar requires three enzymes. The new variety of corn created for biofuel production, called Spartan Corn III, builds on Sticklen’s earlier corn versions by containing all three necessary enzymes.

The first version, released in 2007, cuts the cellulose into large pieces with an enzyme that came from a microbe that lives in hot spring water.

Spartan Corn II, with a gene from a naturally occurring fungus, takes the large cellulose pieces created by the first enzyme and breaks them into sugar pairs.

Spartan Corn III, with the gene from a microbe in a cow, produces an enzyme that separates pairs of sugar molecules into simple sugars. These single sugars are readily fermentable into ethanol, meaning that when the cellulose is in simple sugars, it can be fermented to make ethanol.

“It will save money in ethanol production,” Sticklen said. “Without it they can’t convert the waste into ethanol without buying enzymes – which is expensive.”

The Spartan Corn line was created by inserting an animal stomach microbe gene into a plant cell. The DNA assembly of the animal stomach microbe required heavy modification in the lab to make it work well in the corn cells. Sticklen compared the process to adding a single Christmas tree light to a tree covered in lights.

“You have a lot of wiring, switches and even zoning,” Sticklen said. “There are a lot of changes. We have to increase production levels and even put it in the right place in the cell.”

If the cell produced the enzyme in the wrong place, then the plant cell would not be able to function, and, instead, it would digest itself. That is why Sticklen found a specific place to insert the enzyme.

One of the targets for the enzyme produced in Spartan Corn III is a special part of the plant cell, called the vacuole. The vacuole is a safe place to store the enzyme until the plant is harvested. The enzyme will collect in the vacuole with other cellular waste products.

Because it is only in the vacuole of the green tissues of plant cells, the enzyme is only produced in the leaves and stalks of the plant, not in the seeds, roots or the pollen. It is only active when it is being used for biofuels because of being stored in the vacuole.

“Spartan Corn III is one step ahead for science, technology, and it is even a step politically,” Sticklen said. “It is one step closer to producing fuel in our own country.”

To view a graphic illustrating how this new variety of corn has been genetically modified, go to: http://special.newsroom.msu.edu/newsroom_docs/spartancorn3v8.pdf.

Sticklen’s research was funded by the U.S. Department of Energy and Edenspace Systems Corp., the Consortium for Plant Biotechnology Research, and MSU Research Excellence Funds.

DTN News
Ethanol Gets Bum Rap
USDA: Price of Corn Just Small Part of Retail Food Price Jumps

Marcia Zarley Taylor DTN Executive Editor
Bio | Email
Tue Apr 8, 2008 05:46 AM CDT
WASHINGTON (DTN) — True, you’ll be paying higher prices for almost everything at restaurants and the supermarket checkout counter this year. But, while concerned about food price inflation, USDA policymakers and economists place most of the blame outside the farm gate.

“The big culprit in rising food prices is energy costs,” USDA Secretary Ed Schafer told the North American Agricultural Journalists gathered here Monday. “While consumers face huge impacts, agriculture is a factor, but not the driving factor” behind food price inflation.

Schafer assured the group, “I don’t believe we are in a position to take any dramatic steps today” to curb food inflation. He insisted he was not interested in restricting exports or allowing early-release of Conservation Reserve Program acres, although he did not rule out policy changes for 2009. He also dismissed the notion that cutting back on the 15-billion-gallon Renewable Fuel Standard for corn-based ethanol would have much impact.

USDA Chief Economist Joe Glauber agreed grain prices are getting a disproportionate share of the blame. “There are concerns over food prices, but commodities have such a small share of the retail prices” that it’s hard to criticize them for the food price run-up, he said. “Even if the price of wheat went up 80 percent, you’d have only a 7 percent or 8 percent impact on bakery prices.”

Corn prices have more than doubled since late 2007 and are poised to appreciate another 30 percent or 40 percent in 2008, said Ephraim Leibtag, USDA’s food markets economist. But so far, he added, higher corn prices and other raw ingredients have had “a rather minimal impact” on food inflation.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.