The synergetic effect of ultrafine grinding and alkaline hydrogen peroxide pretreatment for the enzymatic saccharification of corn stover

Abstract

Cellulose in lignocellulosic biomass is difficult to hydrolyze during enzymatic hydrolysis. To further simplify the pretreatment process in high solid loading on the premise of reducing the consumption of chemical reagent and energy, an effective one step mechanochemical (combines wet ultrafine grinding (WUG) with alkaline hydrogen peroxide (AHP)) composite pretreatment (CP) method for corn stover was developed. This new method could be performed at room temperature with low H₂O₂ dosages (0.05–0.15 g/g corn stover) and short processing time (0.5–0.1 h). The CP pretreatment removed lignin and acetyl groups, disrupted the cell structure of corn stover, effectively superimpose the enhancement effects of AHP and WUG. Its optimized enzymatic glucose yield was 254.23 g/kg with a low H₂O₂ dosage (0.10 g/g corn stover) and grinding time (0.5 h). The single pretreatment of WUG and AHP at the same condition could only achieve a glucose yield of 163.85 g/kg and 132.76 g/kg, respectively. The quantitative linear regression equation between cellulose content and enzymatic glucose yield (GY) for the CP pretreatment was found to be: GY= 31.78 × cellulose content - 979.40. The slope was higher than that for AHP pretreatment (23.26). This suggests that CP pretreatment with low H₂O₂ doses can improve the efficiency of enzymatic saccharification.