| The fuel ethanol industry has grown to 14.8 billion gallons of ethanol produced in 2015. Finding alternative coproducts other than animal feed from the distillers dried grains with solubles (DDGS) is critical to future economic viability. One of the coproducts of interest are the phytochemicals present in the hexane extracted lipid content of the DDGS. The traditional dry-grind ethanol process has been optimized for the maximum amount of ethanol output given minimum inputs of energy, water, and feedstock. This optimization for feedstock conversion to ethanol can inhibit or decrease the amount of lipid extract available. The objectives of this dissertation were to study the influence of each unit operation in the traditional dry-grind ethanol process for grain sorghum and maize on lipid content of process streams, and investigate the influence of yeast stress during fermentation on the lipid content of distillers wet grains. Ground maize with a lipid content of 0.035 (g lipid/g dry matter) was 0.077 (g lipid/g dry matter) after enzymatic conversion, 0.169 (g lipid/g dry matter) after simultaneous saccharification and fermentation, 0.139 (g lipid/g dry matter) after distillation and 0.146 (g lipid/g dry matter) after drying. Ground sorghum with a lipid content of 0.026 (g lipid/g dry matter) was 0.059 (g lipid/g dry matter) after enzymatic conversion, 0.152 (g lipid/g dry matter) after simultaneous saccharification and fermentation, 0.096 (g lipid/g dry matter) after distillation and 0.092 (g lipid/g dry matter) after drying. |
