Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Civil, Construction, and Environmental Engineering


Civil Engineering (Environmental Engineering); Biorenewable Resources and Technology

First Advisor

Hans Van Leeuwen

Second Advisor

Anthony Pometto Iii


Public opinion of the U.S. fuel ethanol industry has suffered in recent years despite record ethanol production. Debates sparked over the environmental impacts of corn ethanol and competition with food and feed. The industry continues to actively address the concerns and to seek innovations that will enhance process efficiency, sustainability, and feed coproducts. Our research on fungal cultivation of thin stillage, a byproduct stream of dry-grind corn ethanol production, achieves those goals. Fungal treatment offers the potential to recover water and enzymes for in-plant reuse, to save energy by eliminating water evaporation from thin stillage, and to produce value-added animal feed (high-protein fungal biomass). The fungal coproduct could command an increased market value as a feed ingredient in nonruminant diets, such as swine and poultry, while improving profits and minimizing environmental impacts of fuel ethanol production. Our research on the no-cook corn ethanol process investigates an alternative method to antibiotics addition for controlling contamination by lactic acid bacteria during fermentation. The use of antibiotics is problematic because of rising concerns about the emergence of antibiotic-resistant bacteria. This research seeks to replace antibiotics with a disinfection method, ozonation of corn mash, and to enable ethanol fermentation at a more conducive, higher pH. Operating at a higher pH reduces sulfuric acid requirements for pH adjustment and the resulting sulfur content in the distillers grains, an improvement for cattle feed. In addition to saving money on antibiotic and chemical costs, the enhanced feed coproduct could be marketed as antibiotic-free and reduced-sulfur distillers grains.


Copyright Owner

Mary Rasmussen



Date Available


File Format


File Size

197 pages