Combinations of alkaline hydrogen peroxide and lithium chloride/N,N-dimethylacetamide pretreatments of corn stalk for improved biomethanation

The purpose of this study was to improve methane generation from corn stalk (CS) through alkaline hydrogen peroxide and lithium chloride/N,N-dimethylacetamide (AHP–LiCl/DMAc) pretreatment. Changes in the structures of treated and untreated CSs were investigated, and biomass components, including cellulose, hemicellulose and lignin, were analysed. Our findings revealed that AHP-LiCl/DMAc pretreatment improved accumulative methane yield by forceful delignification and effectively destroyed the structure of cellulose. The AHP–LiCl/DMAc-treated group had a maximum methane yield of 318.6 ± 17.85 mL/g volatile solid, which was 40.08% and 10.10% higher than the maximum methane yields of the untreated and AHP-treated group, respectively. This result showed enhanced cellulose dissolution by the ionic solvent of LiCl/DMAc and improved enzymatic saccharification in fermentative bacteria without structural modifications. The AHP–LiCl/DMAc treated group had higher glucose level, acetate followed by biomethanation process. Furthermore, the decrease in crystallinity indexes for AHP-LiCl/DMAc treated group was reported. Overall, this investigation proved a promising pretreatment approach for enhancing the degradation of CS into reducing sugars and improving methane generation. •To improve methane from corn stalk using (AHP-LiCl/DMAc) pretreatment system.•The AHP-LiCl/DMAc pretreatment improved methane yield by forceful delignification.•Methane yield of 318.6±17.85 mL/g-VS was found 40.08% higher than untreated group.•The AHP-LiCl/DMAc treated group were found with higher glucose and acetate.•An encouraging pretreatment approach for the enhanced degradation of corn stalk.