Application of hydrogen peroxide presoaking prior to ammonia fiber expansion pretreatment of energy crops

Abstract

This work presents the application of ammonia fiber expansion (AFEX) pretreatment both with (H-AFEX) and without hydrogen peroxide presoaking of energy crops moso bamboo, giant reed, and Miscanthus. The influences of AFEX and H-AFEX pretreatments on chemical composition and enzymatic hydrolysis were assessed. The results address the solid recovery, delignification, hydrolysis sugar yields, and micro-structural morphology of varying H-AFEX pretreatment conditions of energy crops. A strong negative correlation between solid recovery and H2O2 loading was found for all pretreated samples with H2O2 loading <2.0. In comparison with AFEX process, the addition of hydrogen peroxide in H-AFEX pretreatment could result in increases in glucose yields at the expense of xylose. The maximum sugar yields of moso bamboo, giant reed, and Miscanthus were 269.0, 424.6, and 485.0g per kg dry biomass respectively, which were obtained under their optimal pretreatment conditions following enzymatic hydrolysis. The micrograph of H-AFEX-treated giant reed demonstrated that the modified porous structure resulted in increased enzyme accessible surface area, and facilitated the subsequent enzymatic hydrolysis.