LAUSR

Corn stover is residual biomass that can be used for the production of fermentable sugars through enzymatic hydrolysis. However, a pretreatment step is required to enhance the enzymatic digestibility of biomass. Even though the alkaline hydrogen peroxide (AHP) method shows promise as an effective pretreatment for corn stover, a typical reaction time of 24 h is too long, and the amount of hydrogen peroxide required (~5% w/v) is too high. To address this problem, we developed a novel catalytic alkaline hydrogen peroxide (cAHP) method to shorten the pretreatment time and reduce hydrogen peroxide usage. This is the first time a metal catalyst, iron tetraamidomacrocyclic ligand (Fe-TAML) is combined with AHP to accelerate the oxidation of lignin using hydrogen peroxide under an alkaline condition. The reaction time can be shortened to 4.4 h from a typical reaction time of 24 h. With 5 ppm of Fe-TAML, the reducing sugar concentration is increased by 15% to 27.9 g/L, compared to the one without Fe-TAML. Next, the cAHP method is optimized by using response surface methodology (RSM). After the pretreatment of 10% corn stover in an alkaline solution (pH 10) with 8850 ppm H2O2 and 0.91 ppm catalyst for 4.4 h, the residual biomass can be recovered and hydrolyzed by using 10 U/mL at 12% solid loadings. After 24 h of hydrolysis, 36.2 g/L of reducing sugar is obtained, representing a 39.6% increase compared to traditional AHP using the same optimized condition.