Anaerobic fermentation of poplar processing residue to produce methane by alkaline hydrogen peroxide (AHP) pretreatment

The study evaluated the effects of alkaline hydrogen peroxide (AHP) pretreatment on poplar processing residue for methane production. The delignification of poplar processing residue was used as the basis for evaluation. The experiment considered the pretreatment time (0 h-24 h), the hydrogen peroxide (H2O2) concentration (0.5%-2.0%), and potassium hydroxide (KOH) concentration (1.0%-3.0%) at a temperature of 70°C. Subsequently, anaerobic fermentation experiments were conducted using the pretreated biomass with sludge as the inoculum under mesophilic temperature conditions (37 ± 1°C). The initial feedstock (poplar processing residue) contained 40.31 ± 0.06% cellulose, 31.17 ± 1.59% lignin, and 14.85 ± 0.38% hemicellulose. The AHP pretreatment caused changes in the lignocellulosic content of the feedstock, particularly affecting the lignin structure compared to cellulose and hemicellulose. At a pretreatment time of 18 hours, temperature of 70°C, and concentrations of 2.0% H2O2 and 1.0% KOH, the AHP pretreatment resulted in a higher methane production of 237.4 mL per gram. These findings demonstrate that AHP pretreatment is an effective strategy for enhancing methane production from poplar.