Enzyme-producing corn key to cellulosic ethanol?Enzyme-producing corn key to cellulosic ethanol?
Transgenic corn might be just what the cellulosic ethanol industry needs to get going – but not just any transgenic corn.A corn plant has been genetically engineered to produce its own special enzymes which break down cellulose into sugars for conversion into bioproducts, including ethanol. It’s cheap, it’s efficient, and it’s a technology that’s ready to go.If more of the corn plant can be used to create ethanol, then less of the annual U.S. corn crop is needed to produce the same amount of ethanol. This could help defuse the food for fuel debate.
October 20, 2010
Transgenic corn might be just what the cellulosic ethanol industry needs to get going — but not just any transgenic corn.
The corn that could transform the ethanol industry is genetically engineered to produce its own special enzymes which break down cellulose into sugars for conversion into bioproducts, including ethanol. It’s cheap, it’s efficient, and it’s a technology that’s ready to go, according to its developer.
Elizabeth Hood, a professor of agriculture at Arkansas State University, helped found a company for the enzyme-producing corn, Infinite Enzymes. She participated in a panel discussion on the bioeconomy at Biomass South 2010, held Oct. 14-15, in Memphis.
Hood, who is CEO of the new company, says a 50-million gallon cellulosic ethanol plant could work in the Mid-South. It would require about 225 square miles, or a square that is 15 miles wide on each side.
An ethanol plant would occupy the center of the square. Outside of this would be corn genetically altered to contain the enzymes for breaking down cellulose into sugars. Outside of that would be non-transgenic corn which also could be converted to ethanol.
Enzymes are needed to break down cellulose, which consist of long polymers of glucose sugars. But they are complicated polymers because they have a very rigid structure. It takes lots of enzymes to break them down.
The idea to put the enzymes in the corn plant is unique, if not ironic. But there is one big advantage, according to Hood. If more of the corn plant is used to create ethanol, then less of the annual U.S. corn crop is needed to produce the same amount of ethanol. This could help defuse the “food for fuel” argument that ethanol production from corn grain is driving up food prices.
Hood’s concept is for a Mid-South ethanol plant that could run on any cellulosic material.
To make the genetic transformation in the corn plant, genes from fungi that take apart cellulose are inserted into the germ of the corn kernel. The endosperm is 80 percent of the corn kernel’s dry weight, while the germ is about 12 percent.
The endosperm is often used for ethanol or feed, and the germ is the primary source of oil for the corn oil markets, Hood said. The stover of the corn plant, which is the cellulose part of the plant, can be harvested and the enzymes in the germ can be used on the corn stover. “So we have a process where we can use the entire corn plant,” Hood says.
“We dry mill the corn grain into the germ and the endosperm,” Hood said. “The endosperm can be put into ethanol, which is a bio-based product. The germ can then be fractionated into oil, which can go into industrial applications. The defatted corn germ contains our enzymes.”
The enzymes can be used to break down cellulose not only for ethanol but for other specialty products. “We produce the enzymes to produce the sugars, so we can partner with anybody who needs enzymes to produce biomass-based products. It’s a universal system.”
This transgenic solution also allows for enzymes to be produced cost effectively in the field. “We can provide massive quantities of enzymes without adding infrastructure,” Hood says. “There are no fermentation plants to be built for the production of the fungi that produce the enzymes. With our model, there are no transportation costs for the cellulose. Our crop does not compete with food and feed. There has been a lot of pushback on corn as a production system for ethanol because of the competition with the food and feed industry.”
Hood says the current market for breaking down cellulose is about a $1 billion market and includes laundry detergent and industrial cleaners used in the textiles and the pulp and paper industries. But entering the cellulosic ethanol market would open a multi-billion dollar door.
“We have product ready to sell. We have demonstrated its capability on a small-scale. Our model shows a great return on investment. Our technology is early in its development. We believe we can improve the cost of the enzymes by fourfold to tenfold.”
Other panelists at the conference, Debtosh Chakrabarti and John van Leeuwen, said fledgling biomass businesses can’t depend entirely on a “green premium” to make their ventures profitable. Green products must hold up under the rigors of the open market. But they’re up to the challenge.
“We believe that bio-based products represent a sound business opportunity, thanks in large part to the global trend toward sustainability,” said Chakrabarti, president of PMC Group, a global chemical and plastics company which derives over half its raw materials from renewable sources. “But bio-based products must succeed on their own merit. In other words, we don’t believe that it’s prudent to count on a ‘green’ premium.”
Van Leeuwen, CEO of EcoSynthetix, Inc., a biotechnology company based in Milton, Ontario, says sustainability is a chief concern for his company. “If we can still do what we’re doing today 30 years from now at a reasonable cost, then what we’re doing is sustainable. The idea is to use crops instead of fossil-based feed stocks, and do it in such a way that we don’t rob our future generation.”
Biomass South 2010 was presented by the Memphis Bioworks Foundation’s AgBioworks Regional Initiative and the Southern Growth Policies Board.
The conference explored the possibilities for entrepreneurship created by converting from a fossil-fuel global economy to a bio-based, renewable resource economy. The bioeconomy uses biomass products such as agriculture crops and forestry materials to replace petroleum-based products. Bioproducts include biofuels, green chemicals, novel polymers and other materials.
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