Embracing the Carbohydrate Economy

Industry and academic research leaders share new research leads and emerging technologies for corn use at the 2008 Corn Utilization and Technology Conference.
By Susanne Retka Schill | July 08, 2008
The carbohydrate economy is taking shape as the cheap oil economy is showing signs of decline. "There is an agricultural and economic revolution underway in the United States and the world," USDA Undersecretary Thomas Dorr told the industry and academic researchers assembled at the Corn Utilization and Technology Conference in early June in Kansas City. In his keynote address, Dorr reiterated the USDA's defense of corn ethanol, saying a re-examination of the numbers by the department's economists conclude that ethanol is responsible for only 3 percent of the world's increase in food prices. He commended the National Corn Growers Association for its leadership in addressing the issues that arise regarding corn and for supporting the basic science, genetic research and progressive product development. "The carbohydrate economy is only limited by our imagination," he said.

The last couple of conferences sponsored by the NCGA have included more sessions on dry milling and ethanol technology and fewer on the wet milling technology that dominated the conferences in the past. Product development, new research leads and emerging new technologies comprised the core of the two-day conference, along with sessions covering research related to current issues.

Improving the Ethanol Process
Vijay Singh, associate professor in the Department of Agricultural and Biological Engineering at the University of Illinois, described recent research on technologies to improve the ethanol process. Since the start of ethanol production in the 1980s, dry-grind technologies have improved with the combination of saccharification and fermentation, Singh said, with the percentage of ethanol conversion improving as yeast nutrients are better balanced. New technologies are working toward simultaneous liquefaction, saccharification and fermentation in order to simplify the process and in turn, eliminate the management required to maintain two different temperatures and pHs when the processes are separated.

The new enzymes developed for the combined process are known by several namesno cook, cold hydrolysis, raw starch enzymes, low temperature hydrolysis enzymes or granular starch hydrolyzing enzymes.

Two companies are leading the development of the new enzymes, which are commercially available. Genecor International has trademarked its product as Stargen and Novozymes' technology has been licensed by Poet LLC under the BPX brand. Poet's chief science officer Steve Lewis said they have applied the BPX technology in 22 of the company's dry mills since the technology was introduced in 2002. The traditional jet cooking process kills much of the biology which can be capitalized upon in the BPX process, he said. "BPX ethanol conversions are approaching 3 gallons per bushel," he added. Energy costs at Poet plants are now concentrated on drying distillers grains, he said. The BPX process shows other benefits including improved flowability of distillers dried grains (DDG), minimization of feedstock variation and improved fermentation consistency. "Contamination is almost nonexistent," he said.

Novozymes scientist Randall Deinhammer said the company's large culture collection of enzymes has benefited its enzyme developments. Besides the raw starch hydrolyzing enzyme used by Poet, the company has developed a more robust glucoamylase enzyme it calls Spirizyme Ultra. The enzyme used for saccharification improves the efficiency of the starch conversion, results in higher ethanol yields and faster fermentation and improves the solid separation at the back end of the process. Novozymes has a cellulosic biomass kit available for lab testing on cellulosic ethanol conversions, which contains five enzyme complexes developed by the company, Deinhammer added.

David Johnston, lead scientist at the USDA Agricultural Research Service's Eastern Regional Research Center, described another promising new technology called E-Mill. The process uses protease enzymes in a short soak prior to fractionation and the addition of granular starch hydrolyzing enzymes. Johnston said the process yields a clean germ and bran, the product ferments more quickly resulting in a higher final ethanol yield, plus a greater number of coproducts and better nutrient content in the DDG comparable to soy meal and corn gluten meal. The process has been commercialized in a small modified wet mill in Malaysia, and he hopes to see it adopted in the United States soon. Genecor has licensed the technology.

Singh described other research designed to optimize the dry-grind saccharification and fermentation process through the dynamic control of process parameters. In the conventional dry-grind process, he explained, only three process parameters are monitored: pH, temperature and glucoamylase dose. The settings for these process parameters are based on compromises between the optimum conditions for enzymatic hydrolysis and yeast metabolism, he explained. Using dynamic controls that adjusted the pH, temperature and enzymes during the process resulted in a 50 percent reduction in glucoamylase with the final ethanol concentrations being similar to conventional treatments. A pilot test of the dynamic controller in a Midwestern commercial dry-grind ethanol plant resulted in a 35 percent reduction in enzymes used.

Johnston said other research is looking at new applications using enzymes during different stages to help in water removal to reduce energy costs in evaporation, enzymes to help with saccharification control to get higher ethanol yields and to push the yeast to complete fermentation. Also, using enzymes in dry fractionation can improve the process, he said.

Yet another promising technology described by Singh is still being developed on a bench scale using a vacuum combined with the new enzyme technologies that allow simultaneous liquefaction, saccharification, fermentation and distillation. In the process, fermentation is done under a vacuum where ethanol distills at 32 degrees Celsius (90 degrees Fahrenheit) and is continuously removed. In addition to permitting higher solid content (around 45 percent compared with 28 percent to 36 percent solids in traditional processes), the process eliminates the yeast inhibition caused by concentrated ethanol. The distillers grains come out of the process with the consistency of wet cake.

Beyond Ethanol
Several speakers covered new developments in coproducts and new products, both from the wet-milling perspective and for ethanol plants. The University of Illinois has been cooperating with Archer Daniels Midland Co. in developing a corn replacement pellet. In a different twist on utilizing cellulose, Kyle Beery, ADM's senior processing engineer, said they see a number of crop residues including corn fiber, corn stover, soy hulls and other fibrous materials being combined with distillers grains. "We see a logistical movement ahead to process cellulose components at feed mills or elevators," he said.

The next speaker went into details of the work involved in creating a highly digestible feed from crop residues and distillers grains that approach the value of corn. University of Illinois-Urbana Champaign researcher Larry Berger said a pelleted feed containing 25 percent DDG and 75 percent crop residues performed favorably in feedlot trials for digestibility and rates of gain. Cattle ate the feed readily, and fecal samples showed the corn replacement pellets (CRP) were 60 percent digested compared with 66 percent on the corn diet. "Feed efficiency was best for corn, but not bad for the CRP," Berger said.

When corn was $2.50 a bushel, there was little incentive to collect residues for such a process, but Berger suggested that at $5 and higher, the ratio of corn price to residue price makes it more favorable. By taking some of the corn residue, combining it with distillers grains, "we can get ethanol and feed from the same acre," he said.

Berger predicted cattle will be the first to be weaned from heavy corn feeding since the 5:1 corn-to-gain ratio for cattle is much less efficient than the rate of gain that pork and poultry feeders experience.

DDG and corn stover show promise for the development of other new products, according to Rawle Hollingsworth, director of the Center for Renewable Resources at Michigan Sate University. "There are fibers in corn stover and DDGS that provide high-quality fibrils used in paper production," he said. The researchers are taking a second look at other chemicals such as glycolic acids formed from the sugars in cellulose. "We've been throwing them away because they have such low value," he said. Other chemicals derived from corn, such as the cholesterol lowering drug Crestor can result in extremely high-value chemicals netting $250,000 per ton, albeit using very small quantities.

Researchers reported on other compounds derived from corn that show promise in replacing petroleum-based chemicals in the $3 billion plastics market. Many of the chemicals used in the petroleum industry come from eight platform chemicals, said Carl Lira, assistant professor of chemical engineering at Michigan State University. In 2004, researchers looked at 300 molecules found in corn sugars and ethanol and identified the top 12 candidates for evaluation. Organic acids recovered from the fermentation broth have applications in solvents, polymers, polymer plasticizers and cosmetics. While it may require diverting a portion of the product stream away from ethanol to produce a compound like ethyl lactate, that alternative product may provide a new revenue stream for an ethanol plant.

Similarly, the New Jersey Institute of Technology has been partnering with the Iowa Corn Growers Association to study new uses for chemicals based on isosorbide molecules found in corn sugars. "Isosorbide is a ubiquitous building block used in polymers and personal care," said NJIT spokesman Mike Jaffe. "After three or four years we're beginning to understand these molecules and how to make compounds to do what we want them to do." One promising area is using the isosorbides as the building blocks for sunscreens that could go into cosmetics or be used in plastic manufacturing for ultraviolet stabilization. Other uses may be to make brittle plastics more flexible or to manufacture epoxy resins.

New Horizons
Not all presentations dug into the conversion process or the chemistry of corn compounds. Several speakers addressed issues surrounding the emerging cellulosic ethanol technology and issues that are becoming more important to the public. Two of the speakers provided an overview of work being done on global warming issues. The University of Illinois-Chicago and the Institute for Technology Development in Illinois have collaborated to conduct a study on land-use changes around the Illinois River Energy LLC ethanol plant, said John Fridgen, project manager at ITDI. The project correlated satellite imagery and farmer surveys in a study of land-use changes with the goal of determining carbon sequestration impacts.

Nobilis of Falls Church, Va., is developing a model for life-cycle analysis for biofuels. Darryl Banks, a fellow at the nonprofit center, said the initial work focused on the production of greenhouse gases and water used throughout the ethanol supply chain from raising the crop through distribution of the end product. Intended for policy makers, the model will allow the inputting of variable corn acreages, corn yields and ethanol plant capacity, to allow analysis of different scenarios.

As China is the second-largest producer of corn in the world, Scott Rozelle, senior fellow with the Institute of International Studies at Stanford University, described developments which are transforming that country from being an exporter of corn to very quickly becoming an importer. China's disappearance from the export market was caused when the country banned corn exports. It has also banned further expansion of corn ethanol, turning to other feedstocks as it continues to hold the position of third-largest ethanol producer in the world behind the United States and Brazil. As the population expands and agriculture develops to meet demand through improved productivity, mechanization and larger farm size, Rozelle predicted China will meet 90 percent of its corn needs in the future but will still need to import 1 billion bushels.

Future ideas and issues for cellulosic ethanol were also discussed at the conference. Bill Rooney, plant scientist at Texas A&M, described his work in developing a high yielding biomass sorghum which he believes will fit well into agriculture in the Southeast with its long growing season and adequate rains. Jacob Barney, weed scientist at the University of California-Davis, warned that the same characteristics that make a crop an ideal biomass producer may also indicate a potentially invasive weed. Strategies to prevent invasiveness and plan ahead with eradication methods need to be built into biomass development research, he said.

Maurice Hladik, director of marketing for Iogen Corp., described the challenge of developing a biomass-based biofuels industry in his presentation. "To meet 16 billion gallons [of advanced biofuels] by 2022 will require 266 biorefineries in 14 years, averaging 80 MMgy each year," he said. He estimates that will require 200,000 growers. "200,000 growers in the nation earning extra income could really benefit the ag economy," he said. The logistics of handling huge volumes of biomass to feed those biorefineries will require high yielding biomass feedstocks. Hladik thanked the corn ethanol industry for blazing the trail for cellulosic ethanol. "We would be dead in the water," he said, "without the work accomplished by the corn ethanol industry to educate consumers, automakers and the oil industry."

Susanne Retka Schill is an Ethanol Producer Magazine staff writer. Reach her at sretkaschill@bbibiofuels.com or (701) 738-4962.