Bioeconomy Institute

The overall cost of biofuel production is impacted tremendously by the value of the co-products derived from the process of making biofuels. In typical corn wet mills, the co-products return nearly one-half the cost of the corn feedstock. At times, however, there have been no cost-effective markets for the co-products of dry-grind ethanol plants, and the co-products have been given away. Key impediments to efficiently utilizing ethanol production co-products include excessive fat in DDGS for ruminant feeds, excessive fiber in DDGS for non-ruminant feeds, overly unsaturated oil in DDGS for swine feeds, poorly digestible protein and poor essential amino acid balance, and an absence of high value products. Potential solutions to this problem include the modification of the key traits of the corn plant, the improvement of processing and handling methods, and the identification of new uses and value-added products. For example, opportunities exist to fractionate grain prior to ethanol production to recover high value products, such as edible corn oil or biodiesel, while improving the efficiency of starch hydrolysis and the value of the co-products as ruminant feed. Another opportunity exists for developing post-fermentation processing methods to produce products with diverse uses. Thin stillage contains high levels of organic compounds that can be substrates for fermentation to derive further value-added products. Natural antimicrobials, probiotics, biosurfactants and antioxidants from co-products can be produced.