Lignocellulosic material is a renewable and sustainable feedstock for the conversion to energy products. The anaerobic treatment breaks down the lignocellulosic material by a community of various microorganisms to produce energy. This treatment, often referred to as anaerobic digestion, has long been adopted by countries, such as Germany and Denmark, because of desirable waste management and energy recovery practices. A novel approach with anaerobic digestion is to use it as a pretreatment method to generate a feedstock that is beneficial for a biofuel production. In this report, raw corn stover was digested with swine manure taken from Michigan State University in 0.5 L reactors. Digestion performance and solid fiber quality were measured and assessed on five different ratios of corn stover to swine manure. Biogas and solid fiber were collected over a period of 60 days. The remaining fiber after digestion was further pretreated using optimized dilute alkali conditions (2% sodium hydroxide, 130°C, and 2 hours), enzymatically hydrolyzed on a 5% dry basis. Ethanol concentration was calculated based upon the glucose production from the fiber of each ratio. Mass and energy balances were evaluated to determine which ratio would be most beneficial for adoption into a biorefinery. The stover-to-manure ratio of 40:60 generated the most energy at 3.4 MJ kg-1dry raw feed, which was at most a 30% increase in total net energy compared to the other reactor ratios. The ratio effectively produced ethanol and methane at 41 and 101g kg-1dry raw feed, respectively. Using anaerobic digestion as an energy producer and as a feedstock generator for biorefinery processing can contribute to solving energy problems that are prevalent in this country.
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