Start at the Beginning

Corn and switchgrass have been modified to become more efficient feedstocks.
By Kris Bevill | April 15, 2011

Corn is corn, right? Not necessarily. The first corn seed bred specifically for ethanol production finally received full deregulation from the USDA in February and is ready for the market. Its creator, Syngenta Seeds Inc., expects it to revolutionize corn-based ethanol production.

David Morgan, president of Syngenta Seeds, refers to the seed, named Enogen, as a breakthrough product. “The adoption of Enogen grain by U.S. ethanol producers can unleash a cascade of efficiency and environmental benefits industry wide,” he says. “[It] provides ethanol producers a proven means to create more value per gallon while offering targeted corn growers an opportunity to cultivate a premium specialty crop in a contracted, closed production system.”

Enogen is the first genetically modified corn of its type to enter the market, but it’s not exactly a new product. In 2006, EPM reported that Syngenta hoped to release the product to growers in 2007. In fact, the U.S. Food and Drug Administration approved the product as being safe for food and feed in 2007 but the company needed the USDA to deregulate it before it could become a true option for growers. That didn’t happen as quickly as expected. David Witherspoon, head of renewable fuels at Syngenta, says lawsuits filed in 2007 and 2008 against the USDA regarding its deregulation of genetically modified alfalfa and sugar beets dramatically slowed the deregulation process for Enogen. “The whole process of approving products moving through the USDA system basically came to a standstill,” he says. Witherspoon credits the federal government’s “science-based approval system” and USDA cooperation for finally granting Syngenta’s deregulation request.

Enogen’s Energy

So how does Enogen affect the efficiency of an ethanol plant? It begins with enzymes. Enogen corn has been engineered to include the alpha amylase enzyme—one of two enzymes required for ethanol production—directly into the grain. Ethanol plants typically use liquid alpha amylase and gluco amylase in their production process. Enogen entirely eliminates the need for liquid alpha amylase. Syngenta says this makes starch conversion far more efficient due to its specific effect on viscosity. “The more efficient the starch conversion, the more efficient the conversion is to ethanol,” the company states. The use of Enogen impacts a plant’s water and fossil fuel requirements, reducing the plant’s carbon footprint by a full 10 percent, according to Syngenta. Testing completed at four ethanol plants showed that by using Enogen, a 100 MMgy plant could reduce water usage by 450,000 gallons, electricity by 1.3 million kilowatt hours and natural gas by 244 billion Btu. Witherspoon says it’s this combination of savings that will make it possible for ethanol producers to pay growers a premium price for the specialized corn.

“If this was just a replacement for an alpha amylase, there wouldn’t be enough money for the ethanol plant to pay the grower and improve the bottom line,” he says. “But because this particular enzyme helps get more ethanol production, reduces the amount of water, electricity, natural gas, and because it works on broad pH and temperature changes (reducing the need to purchase sulfuric acid and ammonia to modify pH levels), the savings they’ll get is more than what they’ll need to pay the grower.”

Syngenta initially hoped to see 15,000 acres of cropland in Kansas and Nebraska planted with Enogen this growing season. But due to the lateness of the USDA’s deregulation approval, those numbers are likely to be much lower. “If we’d gotten approval prior to Feb. 1, I think we could have been in the 15,000 range,” Witherspoon said in late March. “Right now, I think we’ll be closer to the 5,000-acre range. There’ll still be a few acres that will move a little bit, but it’s just too close to planting time. Farmers already have their farm planned, so we just can’t get the acres. We’re very happy we got [Enogen] deregulated, but we wish we could have gotten it deregulated four to six weeks earlier.”

Between 10 and 20 percent of the corn used at an ethanol plant will need to be Enogen corn in order for the plant to realize its efficiency benefits. Witherspoon says the acres planted this year will be used to introduce potential customers to the feedstock, with the intent of acquiring three to five new customers by fall for next season. Kansas and Nebraska are the first target areas, but Syngenta plans to quickly expand the growing area to the heart of ethanol production, including Iowa, South Dakota and southwest Minnesota. “The reason we started where we did is we initially had to grow the crop regulated and we grew as many as 11,000 acres one year,” Witherspoon says. “You need to have isolation to meet the government requirements, so we had to go out West.” While the seed has been deemed as safe for food and feed, its benefits would be lost on any industry other than ethanol and Syngenta’s risk mitigation efforts include a closely monitored closed-loop grower-to-ethanol plant system for the corn. Ethanol plants will contract growers to supply Enogen and Witherspoon expects the majority of Enogen corn to be grown within a 20-mile radius of the contracted plant for several reasons. “It’s hard to grow any specialty-type grain and haul it 60 or 70 or 80 miles,” he says. “And it doesn’t make sense. That ethanol plant already has very loyal customers that support that plant. Many of them are partial owners of the plant. We designed our program to work with those local growers. It makes a really nice situation in that they’re growing a specialty product, getting paid by the ethanol plant to grow it, and then it benefits the ethanol plant for which many of them are members.”

In March, Syngenta was in the process of establishing an advisory council to educate both growers and ethanol producers about Enogen. Syngenta will also council ethanol plants on how to properly use the corn in order to receive the efficiency benefits and advise them as to what equipment may be required for long-term use of the product. Witherspoon says a grain bin may need to be added at some plants to use for blending the Enogen with non-amylase corn, but some plants already have storage on-site that can be used for that purpose. No additional equipment is necessary inside the plant.

Growing Better Grass

At The Samuel Roberts Noble Foundation, researchers are focused on commercializing and improving the switchgrass varieties designed for cellulosic ethanol. In February, researchers announced they had successfully modified a strain of switchgrass to produce more sugars than other strains, resulting in fewer enzyme requirements as well as higher yields of ethanol. This long-term project addresses and reduces the amount of lignin produced by the plant, thus making conversion to ethanol much easier.

Richard Dixon, plant biology division director at the Noble Foundation, says the research that led to this discovery was originally focused on modifying forage crops, such as alfalfa, to make them more easily digestible for ruminant animals. About three years ago, the team realized that reducing levels of lignin in the cell walls of these plants would also improve the ability to extract sugars from the cell walls for biofuel production. “We basically have been translating the technology that has been developed for forage crops into bioenergy crops,” he says. “The trick is that switchgrass is not that easy to genetically transform, so this has been a long project. It takes about a year and a half to get the plants back after you start to do the genetic transformation.”

The transgenic version of switchgrass developed at The Noble Foundation was developed by a team led by Zeng Yu Wang, who chose to decrease the cellular component gene in Alamo switchgrass. This change resulted in a one-eighth decrease in the amount of lignin within the plant. That small change had a big impact on the ethanol conversion process.

“The transgenic lines require lower temperature preprocessing and only one-quarter to one-third the level of enzymes for equivalent ethanol fermentation compared to the unmodified switchgrass,” Wang says. “This significantly lowers the cost of biofuels and biochemicals from this switchgrass.” The higher yielding crop will also require one-third fewer acres of land than other varieties of switchgrass, consequently reducing herbicide, land management, transportation and storage requirements, he says.

Because lignin serves to strengthen plant cell walls and act as a barrier to protect against such things as disease and insects, it would be expected that reduced amounts of lignin would cause issues related to plant strength and disease. The research conducted at the Noble Foundation has proved otherwise, however. Field trial data has been generated for six years on alfalfa that has been engineered in exactly the same way as the new switchgrass variety. None of the alfalfa plants have displayed negative agronomic impacts and the lignin-modified version of alfalfa is currently being commercialized, Dixon says. “We’ve generated lignin-modified plants now using seven or eight different genes to target the lignin pathway and never have we seen plants that are more susceptible [to diseases or insects,]” he says.

So far, the modified switchgrass has been grown only in greenhouses. Testing has also currently been at the lab-scale, with the U.S. DOE’s Oak Ridge National Laboratory serving as the ethanol producer. That could change in 2012, at least on the growing side of things. California-based Ceres Inc. is the Noble Foundation’s commercial partner and Dixon says, “We have a fast track for getting these plants in the field now.” Commercial-size plots are expected to be planted next year.

While the findings so far have been significant, Dixon foresees even greater discoveries as the project continues. Wang’s team continues to further reduce the lignin content of the plant while maintaining its agronomic performance. Researchers recently discovered a gene that could be modified to increase the amount of biomass in the stem of a plant, Dixon says. If they are successful at adding that gene into a switchgrass strain that also has reduced lignin concentrations, they just might develop the ideal feedstock. Dixon says the research being conducted on switchgrass could also be applied to other cellulosic feedstocks, including poplar and other energy grasses.

Author: Kris Bevill
Associate Editor, Ethanol Producer Magazine
(701) 540-6846