Chenlin Li1, Hongqiang Hu2, Hong Liu2, Kenneth P. Vogel3, Blake Simmons1, and Seema Singh1. (1) Deconstruction Division, Joint BioEnergy Institute, Emeryville, CA 94608, (2) Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR, (3) Grain, Forage and Bioenergy Research Unit, United States Department of Agriculture, Lincoln, NE
Pretreatment of lignocellulosic biomass is an essential step for bioenergy production. Ionic liquids have demonstrated great promise for plant cell wall disruption and lignin rejection. In this study, ionic liquid pretreatment is tested on switchgrass, a model bioenergy crop, to evaluate its effect on biomass conversion into biogas and electricity through anaerobic process. When subject to ionic liquid pretreatment (dissolution and precipitation of cellulose by antisolvent), switchgrass exhibited reduced cellulose crystallinity, increased surface area, and decreased lignin content compared to untreated one as characterized by powder X-ray diffraction, porosimetry, Fourier transform infrared and Raman spectroscopy. Microbial electrolysis cell (MEC) and microbial fuel cell (MFC) were used to directly convert switchgrass samples into biogas and electricity, respectively. In the MEC system, biogas yield and current density were significantly enhanced by ionic liquid pretreatment three-fold. In the MFC system, power density from pretreated biomass was 38% higher than the untreated. These results showed that ionic liquid pretreatment has great potential for improving the conversion of lignocellulosic substrates into biogas and electricity and its application in the biomass utilization through anaerobic technology holds considerable promise in the near future.
