Synergistic effects of peracetic acid and oxalic acid on structural transformation of eucalyptus and its conversion

Biomass pretreatment solvent plays an important role in the utilization of lignocellulosic feedstocks. In this study, the synergistic effects of peracetic acid and oxalic acid (PAO) were investigated as a pretreatment solvent for maximizing cellulose conversion as well as recovering biologically transformable lignin. The PAO pretreatment with 4.5% oxalic acid and 2.0% peracetic acid effectively fractionated lignin (85.4%) under a mild temperature (140 °C) and resulted in a high glucose release (758 mg/g biomass) from the pretreated eucalyptus. Also, the PAO pretreatment could fractionate and deconstruct lignin to low molecular weight (1231 g/mol) aromatics with 5.8% of β-O-4 linkages and a relatively uniform molecular weight distribution (PDI 1.3). The pretreatment using PAA and OA enhanced not only the hydrolysis of cellulose but also the recovery of biologically transformable lignin as a value-added coproduct for a successful biorefinery approach.