Effect of low severity hydrothermal pretreatment on anaerobic digestion performance of corn stover

Biomethane Yield, Physicochemical Structures, and Microbial Community Characteristics of Corn Stover Pretreated by Urea Combined with Mild Temperature Hydrotherm

“…Daily biomethane production observations were better for all pretreated groups than in untreated groups during the first 48 h. This result revealed that more hydrolysed products were generated from the solid phase of CS and dissolved in the liquid phase after pretreatment, indicating its bioavailability and ability to conduct more biomethane production in the initial AD stage. This observation was consistent with previous studies that highlighted more biodegradable volatile fatty acids (VFAs) and reducing sugars were released into the liquid after hydrothermal pretreatment processes [ 31 ].…”

“…In this study, the acetic acid (3002.0–6388.2 mg/L) was the major compound in TVFAs—accounting for 65–78% of the TVFAs in different pretreatment groups—followed by ethanol (810.4–1865.7 mg/L)—which made up 10–27% of total TVFA amounts. Similar results have been demonstrated in other studies [ 31 ].…”

“…For the T96 group—in which CrI decreased from 46.5% to 44.7%—the possible reason was that the long pretreatment period destroyed the amorphous region and affected the crystalline region of cellulose. Similar trends were reported by Yuan et al [ 31 ] using hydrothermal pretreatment on CS.…”

“…Although the 96-h pretreatment group (T96) also led to the most significant changes in the CS microstructure ( Figure 5 e), the biomethane yield was relatively low, indicating that the microstructural change of CS was not the only factor affecting AD performance. Perhaps the inhibitor produced during the pretreatment process had a greater influence on the biomethane production of CS [ 31 ]. Meanwhile, some degraded parts of the outer layer flocked together, recovering the surface and decreasing the total surface area, which could be another reason for the low biomethane yield of the T96 group.…”

Comparison of Operating Methods in Cartridge Anaerobic Digestion of Corn Stover

“…Pretreating corn stover is to reduce the recalcitrance of lignin and increase enzymatic contact surface area, so that increases the biogas yield [9,11]. Various pretreatment methods have been tested such as physical pretreatment (steam-explosion [12], hydrothermolysis [13], and irradiation [14]), chemical pretreatment (acid [15] and alkali [16]), and biological pretreatment (fungi [17] and enzymes [18]). Co-digestion refers to digesting two or more feedstocks simultaneously.…”