Green roads: engineers investigate biofuel co-product lignin for use in road construction
Scientists and engineers from the Iowa State University are looking at ways to strengthen difficult soils by adding lignin, a fibrous co-product of cellulosic biofuel production, so that better roads can be build on them. Soil around the Midwest is mostly soft clay and till deposited by glaciers, says Halil Ceylan, an Iowa State assistant professor of civil, construction and environmental engineering. It's hardly the bedrock engineers would like for a good, solid roadbed.
And so the soil under Iowa's roads often has to be mixed with chemicals that bind and stabilize soil particles. That improves soil strength and makes for better roads. While stabilizing soils for road construction is standard practice around the Midwest, there are limits to its effectiveness. Ceylan said costs can be high and current practices only work with certain soil types and site conditions. So civil engineers are always looking for better, cheaper and more efficient ways to get the job done.
That has Ceylan and Kasthurirangan Gopalakrishnan, a research scientist in civil, construction and environmental engineering, experimenting to see whether lignin, a co-product of producing ethanol from plant fibers, could be a good soil stabilizing agent.
Lignin is a complex chemical compound, the glue that holds plant fibers together. It is the most abundant organic polymer on Earth after cellulose. Lignin fills the spaces in the cell wall between cellulose, hemicellulose and pectin components (figure, click to enlarge). It is actually not one compound but many - all are complex, amorphous, three-dimensional polymers that have in common a phenylpropane structure, that is, a benzene ring with a tail of three carbons.
Cellulosic ethanol production breaks down these tough cell walls to free the sugars contained in cellulose which can be fermented into fuel; the co-product is the strong, fibrous lignin. Using lignin to stabilize soil make sense. There is not a lot of value in it when it's removed from corn stalks, switchgrass or other energy crops feeding the production of cellulosic ethanol:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: cellulose :: lignin :: fibers :: roadbed :: bioeconomy ::
As researcher Andy Aden of the National Renewable Energy Laboratory in Colorado recently told National Geographic magazine, "The old joke is you can make anything from lignin but money."
Ceylan said previous Iowa State studies of lignin from the paper-making industry found it to be a cementing agent that could be of value for soil stabilization. But nobody has determined if that's also the case for lignin from ethanol production. Ceylan thinks it will be.
"It is expected that the lignin derived from lignocellulosic biorefineries will see similar success, if not better," he wrote in his proposal for a Grow Iowa Values Fund grant.
To find out, Ceylan and his research team will head to the soils engineering lab in Iowa State's Town Engineering Building where they'll prepare soil samples containing various percentages of lignin. The mixtures will be tested and evaluated for strength, stability and other properties.
The researchers hope they come up with a new technology that's good for road builders, good for drivers, good for the environment and good for the cellulosic ethanol industry.
The research could also be a big help to the people who build and maintain Iowa's roads, especially as ethanol plants increase truck traffic through rural areas.
"When I talk to county engineers they're very concerned about increased traffic," Ceylan said. "Roads are designed according to traffic forecasts and suddenly there is a lot more truck traffic. This can be a cause of distress to the highway system. But, maybe we can also get the benefit of soil and road stabilization from these plants."
Their Iowa scientists' research is partially supported by a $93,775 grant from the Grow Iowa Values Fund, a state program that promotes economic development. The Iowa Highway Research Board, Grain Processing Corp. of Muscatine and Iowa State's Office of Biorenewables Programs are also supporting the project.
References:
Iowa State University: Iowa State engineers hope to build better roads by using ethanol co-products - October 15, 2007.
Article continues
And so the soil under Iowa's roads often has to be mixed with chemicals that bind and stabilize soil particles. That improves soil strength and makes for better roads. While stabilizing soils for road construction is standard practice around the Midwest, there are limits to its effectiveness. Ceylan said costs can be high and current practices only work with certain soil types and site conditions. So civil engineers are always looking for better, cheaper and more efficient ways to get the job done.
That has Ceylan and Kasthurirangan Gopalakrishnan, a research scientist in civil, construction and environmental engineering, experimenting to see whether lignin, a co-product of producing ethanol from plant fibers, could be a good soil stabilizing agent.
Lignin is a complex chemical compound, the glue that holds plant fibers together. It is the most abundant organic polymer on Earth after cellulose. Lignin fills the spaces in the cell wall between cellulose, hemicellulose and pectin components (figure, click to enlarge). It is actually not one compound but many - all are complex, amorphous, three-dimensional polymers that have in common a phenylpropane structure, that is, a benzene ring with a tail of three carbons.
Cellulosic ethanol production breaks down these tough cell walls to free the sugars contained in cellulose which can be fermented into fuel; the co-product is the strong, fibrous lignin. Using lignin to stabilize soil make sense. There is not a lot of value in it when it's removed from corn stalks, switchgrass or other energy crops feeding the production of cellulosic ethanol:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: cellulose :: lignin :: fibers :: roadbed :: bioeconomy ::
As researcher Andy Aden of the National Renewable Energy Laboratory in Colorado recently told National Geographic magazine, "The old joke is you can make anything from lignin but money."
Ceylan said previous Iowa State studies of lignin from the paper-making industry found it to be a cementing agent that could be of value for soil stabilization. But nobody has determined if that's also the case for lignin from ethanol production. Ceylan thinks it will be.
"It is expected that the lignin derived from lignocellulosic biorefineries will see similar success, if not better," he wrote in his proposal for a Grow Iowa Values Fund grant.
To find out, Ceylan and his research team will head to the soils engineering lab in Iowa State's Town Engineering Building where they'll prepare soil samples containing various percentages of lignin. The mixtures will be tested and evaluated for strength, stability and other properties.
The researchers hope they come up with a new technology that's good for road builders, good for drivers, good for the environment and good for the cellulosic ethanol industry.
The research could also be a big help to the people who build and maintain Iowa's roads, especially as ethanol plants increase truck traffic through rural areas.
"When I talk to county engineers they're very concerned about increased traffic," Ceylan said. "Roads are designed according to traffic forecasts and suddenly there is a lot more truck traffic. This can be a cause of distress to the highway system. But, maybe we can also get the benefit of soil and road stabilization from these plants."
Their Iowa scientists' research is partially supported by a $93,775 grant from the Grow Iowa Values Fund, a state program that promotes economic development. The Iowa Highway Research Board, Grain Processing Corp. of Muscatine and Iowa State's Office of Biorenewables Programs are also supporting the project.
References:
Iowa State University: Iowa State engineers hope to build better roads by using ethanol co-products - October 15, 2007.
Article continues
Tuesday, October 16, 2007
Tropical maize could become biofuel 'super' crop in the US, similar to sugarcane
Early research led by Fred Below shows that the tropical maize, when grown in the Midwest, does not store energy in grain, but stores it more efficiently in its stalks instead. For this reason it requires few crop inputs such as nitrogen fertilizer, chiefly because it does not produce any ears. It also is easier for farmers to integrate into their current operations than some other dedicated energy crops because it can be easily rotated with corn or soybeans, and can be planted, cultivated and harvested with the same equipment US farmers already have. Finally, tropical maize stalks are believed to require less processing than corn grain, corn stover, switchgrass, Miscanthus giganteus and the scores of other plants now being studied for biofuel production.
What it does produce, straight from the field with no processing, is 25 percent or more sugar - mostly sucrose, fructose and glucose - in its stalks. Without ears, these plants concentrate sugars in their stalks instead of in grain as in ordinary corn. Those sugars could have a dramatic affect on Midwestern production of ethanol and other biofuels.
The maize differs from conventional corn and other crops being grown for biofuels in that the starch found in corn grain and the cellulose in switchgrass, corn stover and other energy crops must be treated with enzymes to convert them into sugars that can be then fermented into alcohols such as ethanol. The tropical maize stalks won't require such complex and costly bioconversion methods - the sugars contained in them can just be 'squeezed out' and fermented, in a way similar to how ethanol is made from sugarcane.
Storing simple sugars also is more cost-effective for the plant, because it takes a lot of energy to make the complex starches, proteins, and oils present in corn grain. By storing sugars in stalks, these energy savings per plant could result in more total energy per acre with topical maize, since it produces no grain.
Early trials also show that tropical maize requires much less nitrogen fertilizer than conventional corn, and that the stalks actually accumulate more sugar when less nitrogen is available. Nitrogen fertilizer is one of major costs of growing corn. Below explained that sugarcane used in Brazil to make ethanol is desirable for the same reason:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: genetics :: sugarcane :: maize :: sugar :: nitrogen :: efficiency ::
it produces lots of sugar without a high requirement for nitrogen fertilizer, and this sugar can be fermented to alcohol without the middle steps required by high-starch and cellulosic crops. But sugarcane can't be grown in the Midwest.
The tall stalks of tropical maize are so full of sugar that producers growing it for biofuel production will be able to supply a raw material at least one step closer to being turned into fuel than are ears of corn.
Below is studying topical maize along with doctoral candidate Mike Vincent and postdoctoral research associate Matias Ruffo, and in conjunction with University of Illinois Associate Professor Stephen Moose. This latest discovery of high sugar yields from tropical maize became apparent through cooperative work between Below and Moose to characterize genetic variation in response to nitrogen fertilizers.
Currently supported by the National Science Foundation, these studies are a key element to developing maize hybrids with improved nitrogen use efficiency. Both Below and Moose are members of the Illinois Maize Breeding and Genetics Laboratory (), which has a long history of conducting research that identifies new uses for the maize crop.
Moose now directs one of the longest-running plant genetics experiments in the world, in which more than a century of selective breeding has been applied to alter carbon and nitrogen accumulation in the maize plant. Continued collaboration between Below and Moose will investigate whether materials from these long term selection experiments will further enhance sugar yields from tropical maize.
References:
University of Illinois: Tropical Maize for Biofuels - October 16, 2007.
Eurekalert: If corn is biofuels king, tropical maize may be emperor - October 15, 2007.
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posted by Biopact team at 6:41 PM 0 comments links to this post