(593c) Secondary Fermentation of Corn Ethanol Co-Products for Improved Amino Acid Qualities

Barnharst, T., University of Minnesota
Zhang, Y., University of Minnesota
Wang, J., University of Minnesota
Hu, B., University of Minnesota
Secondary Fermentation of Corn Ethanol Co-Products for improved Amino Acid Qualities

In 2016 5.28 billion bushels of corn were used to produce about 14.79 billion gallons of ethanol in the United States. As a result, about 36 million tons of Dried Distillers Grains with Solubles (DDGS) were manufactured and fed to livestock (U.S. Dept. of Energy, 2017). DDGS are a common feed supplement in cattle rations as it is inexpensive and has positive feeding characteristics. One of the drawbacks of DDGS is that it is lacking in in key amino acids such as tryptophan, arginine, and lysine. Historically these amino acids have been supplemented by external addition of feed grade amino acids to rations. The research carried out attempts to fortify DDGS with higher amounts of tryptophan through secondary fermentation of Whole Stillage (WS) by bacteria. When cultured on WS the bacteria secretes extracellular tryptophan, which serves to close the amino acid gap in corn ethanol co-products. The bacteria used is Generally Regarded as Safe (GRAS) and has been used to produce feed ingredients historically. Because of the research, profitability of corn ethanol operations will be increased due to the improved feeding value of the co-products produced.


United State Department of Energy, “Ethanol Fuel Basics,” Energy Efficiency & Renewable Energy http://www.afdc.energy.gov/fuels/ethanol_fuel_basics.html 03/16/2017