Enhanced enzymatic hydrolysis of corn stover by γ-valerolactone pretreatment and the characteristics of enzymatic residues.

Efficient pretreatment methods are crucial for the generation of fermentable sugars from the renewable lignocellulose. In this study, γ-valerolactone (GVL), a biomass-derived green solvent, was used to fractionate corn stover (CS). The impact of different additives on the enzymatic hydrolysis and pretreatment of CS within the GVL/water system was carefully investigated. The results demonstrate that the use of H 2 SO 4 -assisted GVL/H 2 O (80:20, w/w) pretreatment at mild conditions successfully facilitates the depolymerization of CS, thereby improving the cellulase accessibility. Furthermore, by increasing the GVL pretreatment temperature to 160 °C with 100 mM H 2 SO 4 addition, the pretreated CS led to nearly 100 % of hydrolysis yield at 2 % (w/v) solid load. Finally, the thermogravimetric analysis (TGA) was performed to evaluate the thermal decomposition characteristics of untreated CS and enzymatic residues based on the H 2 SO 4 -assisted GVL/H 2 O pretreatment. The results indicate that the enzymatic residues had two depolymerization stages from 200 °C to 500 °C with a final residual mass of 22.73 %, which was higher than that of untreated CS (20.56 %). Overall, this study provides an efficient lignocellulose pretreatment for fermentable sugars production and valorization of enzymatic residues. [Display omitted] • Using H 2 SO 4 as γ-valerolactone (GVL) pretreatment additive enhanced xylan removal. • Glucose yield of GVL-pretreated corn stover (CS) was 3–5 folds higher than raw CS. • Sugars production reached 32.4 g/100 g CS by 50 mM H 2 SO 4 -assisted GVL pretreatment. • Enzymatic residues had two decomposition stages in 200–500 °C by thermal analysis. [ABSTRACT FROM AUTHOR]