(710c) One Step Breaking Softwood Recalcitrance By Cellulose Solvent-Based Lignocellulose Fractionation Followed By Enzymatic Saccharification

In our efforts to shift away from conventional petroleum-based feedstock to supply transportation fuels, plant biomass has emerged as an attractive renewable alternative. Softwoods have great potentials as renewable feedstocks for biorefineries. However, softwoods are more recalcitrant compared to hardwood counterparts. Hence, the use of softwoods in biorefineries has been viewed as limited. In the present study, we applied a cellulose solvent-based pretreatment/fractionation process on southern yellow pine and douglas fir at a mild condition: 50 ºC and 1 atm for 90 min. Pretreated softwood samples were hydrolyzed fast by cellulase (15 FPUs) and > 85% glucose yield was achieved by 24 h. Cellulose accessibility to cellulase of pretreated samples was probed by the fusion protein and was found to increase by 39 folds. After fractionation, degree of crystallinity of pretreated samples decreased and fibrous structure appeared to be disrupted as observed by solid-state ¹³C Cross-Polarization Magic Angle Spinning (CP/MAS) nuclear magnetic resonance (NMR) and scanning electron microscopy. No changes in lignin functionalities after fractionation were observed by 2D Heteronuclear Single-Quantum Correlation (HSQC) NMR, giving rise to the potential use of lignin as a co-product in biorefineries.