Source: Donghai Wang, 785-532-2919, dwang@k-state.edu
Pronouncer: Wang rhymes with "long"
Photo available. Contact media@k-state.edu or 785-532-6415.
News release prepared by: Mary Rankin, 785-532-6715, mrankin@k-state.edu
Thursday, June 12, 2008
K-STATE ENGINEER RESEARCHING HOW SORGHUM CAN MEET THE NEED FOR ETHANOL IN AGRICULTURAL REGIONS WHERE CORN'S POTENTIAL IS NEARLY EXHAUSTED
MANHATTAN -- Corn is the key grain crop used in the production of fuel ethanol in the United States. As demand for ethanol has increased, so has construction of new ethanol facilities.
But in some areas of the Corn Belt, concentration of these facilities is reaching near saturation relative to the volume of corn grain available. Statistics show that if the entire 2007 corn crop had gone for ethanol production, it still would have only met less than 17 percent of U.S. energy needs.
 |
(Composite photo courtesy of the College of Engineering) |
That's why Donghai Wang, associate professor of biological and agricultural engineering at Kansas State University, is researching how sorghum might solve this problem. Funded by the U.S. Department of Agriculture, a U.S. Department of Transportation SunGrant, the Kansas Sorghum Commission and the K-State Agricultural Experiment Station, Wang's current research is threefold.
He is investigating sorghum as a viable renewable resource for biofuels, as well as developing a comprehensive understanding and utilization of sorghum stover and forage sorghum for ethanol production. He's also researching the use of sweet sorghum for ethanol production.
"Currently, feedstock for commercial ethanol production is about 95 percent from corn grain and about 4 percent from sorghum grain," Wang said. "Grain sorghum is a reasonable feedstock for ethanol and could make a larger contribution to the nation's fuel ethanol requirements.
"Due to climate variability and continuing decline of water resources, utilization of dry land to grow sorghum and forage sorghum is critically important to ensure available energy resources and sustainable economic development. Sorghum requires 40 percent less water than corn to grow and can be produced in the semiarid regions of the nation and the world," he said.
Major sorghum-producing states include Kansas, Oklahoma and Texas. Sorghum outperforms corn on dry land. However, Wang said that sorghum has been underused for industrial applications, especially for bioenergy. He said there has been little research conducted on performance of grain sorghum for ethanol, especially on sorghum biomass -- stalks and leaves -- for biofuel production.
"In general, the major barrier limiting industrial use of sorghum has been its relatively difficult enzymatic degradation in typical dry-grid ethanol production," Wang said. "The factors impacting ethanol yield for sorghum are not well understood compared to corn. Particularly, little information is available on performance of sorghum varieties for ethanol production."
Wang's research focuses on understanding such key factors as composition, chemical structure and physical properties that impact the bioprocessing of sorghum for biofuels.
"I believe that fully understanding the relationship among 'genetic structure- function conversion' may lead to significant breakthroughs for utilization of sorghum via improved bioprocessing," he said.
Grain sorghum, Wang said, has a similar chemical composition to corn, with more than 70 percent starch content. Currently, the dry-grid ethanol fermentation method converts starch into glucose, then uses yeast to ferment glucose into ethanol. For sweet sorghum, the major chemical compositions are sucrose, fructose and glucose, which can be directly fermented into ethanol by yeast. But technical challenges of using sweet sorghum for biofuels are its short period of harvesting for highest sugar content and fast sugar degradation during storage.
For stovers -- the stalks and leaves -- the major chemical compositions are cellulose, hemicellulose and lignin. Cellulose and hemicellulose can be converted into sugars and fermented into ethanol and other chemicals. Conversion of cellulosic biomass, such as sorghum biomass, into biofuels offers major economic, environmental and strategic benefits.
However, production of biofuels from cellulosic biomass faces significant low-conversion technical challenges. Wang said that success will depend largely upon the physical and chemical properties of the sorghum biomass, processing methods, effective enzyme systems or catalysts, efficient fermentation microorganisms, and optimization of the processing conditions.
Wang's research is part of the work of the K-State Center for Sustainable Energy, which focuses on providing sustainable, renewable energy while maintaining the environment and providing an adequate food supply.
"Kansas is the leading producer of sorghum with more than 40 percent annual production of total U.S. sorghum production," Wang said. "Utilization of sorghum for biofuels offers a unique opportunity for Kansas. Research and development of biofuels from sorghum grains and sorghum biomass, as well as improvement of sorghum biomass quality through biotechnology, will continue to be important. My basic approach is that biofuels can reduce U.S. dependence on foreign energy supplies, reduce environmental pollution and support our sustainable economic development."