Minnesota Researcher Extracts More Value From Distillers Grains

Contact: Mary Hoff, Institute on the Environment, (612) 626-2670
Reprinted with permission from the Minnesota Agri-Growth Council Newsletter, February 2012

MINNEAPOLIS / ST. PAUL (3/2/2012)—New technology developed by a researcher at the Natural Resources Research Institute (NRRI) at the University of Minnesota - Duluth promises to improve ethanol’s net energy balance and enhance the profitability and viability of ethanol plants.

NRRI chemist Pavel Krasutsky has extracted additional value from distillers dried grains and solubles (DDGS), the low-value co-product of corn ethanol production. With his patented extraction process, Krasutsky uses ethanol as a solvent to separate oil, free fatty acids, zein and solubles (primarily glycerol) from fiber and proteins. Biodiesel is produced from the oil and free fatty acids, while second-generation ethanol is produced from the glycerol using a biotransformation technique developed by GlycosBio Technolo­gies of Houston, Tex.

About one-third of the U.S. corn crop is used for ethanol production. Our state has 21 ethanol plants with the capacity to produce 1.1 billion gallons of ethanol. Minnesota produced 3 million metric tons of distillers grains last year. Ethanol production is the largest in-state use of corn, utilizing twice the amount of corn consumed by Minnesota livestock. However, Minnesota corn use for ethanol is exceeded by the amount of corn that is exported from the state.

Using the NRRI Integrated Technologies, mentioned above, the distillers grains will yield an additional 20 percent of biofuel (half ethanol and half biodiesel) from the same amount of corn. A 50 million gallon per year ethanol plant can pump out an additional 5 million gallons of ethanol and 5 million gal­lons of biodiesel. It also yields a high-protein feed (HPDG) and zein, a high value food preservative. All of this could provide about $16 million extra profit for a plant, according to University of Minnesota Extension economist Doug Tiffany.

NRRI, along with the Initiative for Renewable Energy and the Environment at the University of Minnesota, and the Minnesota Corn Growers Association (MCGA) have invested more than $450,000 in the research so far.

Pilot scale production got underway last year at Crown Iron Works in Minneapolis, a leading supplier of extraction technology and refining equipment. Preliminary results indi­cate additional capital costs for equipment and installation will run about $32 million in order to complement a 50 million gallon per year dry-grind ethanol plant. The equipment can be added to the plant without interfering with other plant processes.


Economic modeling shows that NRRI Integrated Technologies can improve the finan­cial rate of return from less than 1 percent to between 9 percent and 16 percent on ethanol plants operating with more than 50 percent debt. Debt-free plants would improve their rate of return from the current 11.4 per­cent to between 20 percent and 30 percent, depending upon the market demand for the HPDG.

“With the blender’s credit gone, this model of ethanol production becomes very important,” says Riley Maanum, MCGA research and project director. “Creating more products and income streams from the DDGS will make the ethanol industry more stable and profitable. We are excited to move the project forward.”

It’s projected that corn oil extracted from the backend of ethanol plants will be an important feedstock to help the biofuels industry meet higher demand arising from the Renewable Fuel Standard (RFS2), which by 2022 mandates that 21 billion gallons of the required 36 billion gallons of renewable fuel use be from non-corn starch feedstocks. It’s possible that the additional ethanol pro­duced from the glycerin-byproduct from the biodiesel process will qualify as an advanced biofuel.


NRRI Integrated Technologies makes ethanol production more sustainable and improves its net energy balance by producing 20 percent more biofuel without any additional corn.


Feed trials will be undertaken in 2013 to help determine the market price and demand for the result­ing high-protein, lower fat distillers grain. The feed would have from 35 percent to 40 percent crude protein content and about 2 percent fat content. The extraction process can be adjusted to customize the fat content, if desired. The extraction process also removes water, antibiotics and mycotoxins yielding a high quality, concentrated, flowable product with a long shelf life.

The process could be commercially available in two years. Brian Garhofer, an independent contractor working on the project says, “This could keep ethanol plants operating on a profitable level, even in hard times. We have some leading industry players very interested in this.”