(374m) Ammoniation of Corn Stover for Cost-Effective Pretreatment and Bioconversion

Various pretreatment methods have been studied to enhance the enzymatic digestibility of lignocellulosic biomass. While many of them were effective, many drawbacks which prohibit scale-up exist including energy-consuming process due to high chemical input and excessive water use. In order to solve current problems in cellulosic ethanol process, cost-effective pretreatment method using anhydrous ammonia was developed. In this method, corn stover was treated with gaseous ammonia in a flow-through column reactor at different ammoniation levels. After pretreatment, biomass was directly saccharified and fermented without any additional washing or conditioning step. In this method, it is speculated that ammonia swells cellulose structure effectively and ammoniation prevents methoxyl group of lignins from absorbing cellulase enzyme, thus it enhances the enzyme hydrolysis rate and yield of lignocellulosic biomass. Ammoniation pretreatment can also supply assimilable nitrogen (up to 0.1 % of the weight of dry biomass) for yeast growth in the fermentor. In this study, various pretreatment conditions such as moisture levels, ammonia loadings, reaction time, and reaction temperature were explored to reduce the pretreatment cost and its pertinent costs. Enzyme digestibility and ethanol fermentation test results will also be presented.