AMES, Iowa -- Iowa State University and University of Hawai'i researchers have won national recognition for their work to grow microscopic fungus in leftovers from ethanol production in an effort to improve the efficiency of the corn-to-ethanol conversion process.
The project has been named a winner of a 2008 R&D 100 Award presented by R&D Magazine. The Chicago Tribune has called the awards, presented annually since 1963, the "Oscars of Invention." This is the 30th R&D 100 Award presented to a project affiliated with Iowa State.
An award letter said editors and a judging panel consider the project "one of the top 100 most technologically significant products introduced into the marketplace over the past year."
The award goes to Hans van Leeuwen, an Iowa State professor of civil, construction and environmental engineering and the leader of the research project; Anthony L. Pometto III, a professor of food science and human nutrition; Mary Rasmussen, a graduate student in environmental engineering and biorenewable resources and technology; and Samir Khanal, a former Iowa State research assistant professor who's now an assistant professor of molecular biosciences and bioengineering at the University of Hawai'i at Manoa.
The award winners will be featured in the September issue of R&D Magazine. They'll also be honored at an Oct. 16 banquet at Chicago's Navy Pier.
Van Leeuwen said the researchers appreciate the recognition of their work and hope it will help them commercialize their processing technology.
The researchers are focused on using fungi to clean up and improve the dry-grind ethanol production process. That process grinds corn kernels and adds water and enzymes. The enzymes break the starches into sugars. The sugars are fermented with yeasts to produce ethanol.
The fuel is recovered by distillation, but there are about five gallons of leftovers for every gallon of fuel that's produced. Those leftovers, known as stillage, contain solids and other organic material. Most of the solids are removed by centrifugation and dried into distillers dried grains that are sold as livestock feed, primarily for cattle.
The remaining liquid, known as thin stillage, still contains some solids, a variety of organic compounds from corn and fermentation as well as enzymes. Because the compounds and solids can interfere with ethanol production, only about 50 percent of thin stillage can be recycled back into ethanol production. The rest is evaporated and blended with distillers dried grains to produce distillers dried grains with solubles.
The researchers added a fungus, Rhizopus microsporus, to the thin stillage and found it would feed and grow. The fungus removes about 80 percent of the organic material and all of the solids in the thin stillage, allowing the water and enzymes in the thin stillage to be recycled back into production.
The fungus can also be harvested. It's a food-grade organism that's rich in protein, certain essential amino acids and other nutrients. It can be dried and sold as a livestock feed supplement. Or it can be blended with distillers dried grains to boost its value as a livestock feed and make it more suitable for feeding hogs and chickens.
Van Leeuwen said the technology can save United States ethanol producers up to $800 million a year in energy costs. He also said the technology can produce ethanol co-products worth another $400 million per year.