Combined Effects of Alkaline Hydrogen Peroxide and MnO2 on Anaerobic Digestion of Corn Stover: Methanogenic Performance and Microbial Community Response
Corn stover (CS), as a major agricultural residue in Northeast China, suffers from inefficient anaerobic digestion (AD) due to its rigid lignocellulosic structure and the generation of inhibitory phenolic compounds during pretreatment. Alkaline hydrogen peroxide (AHP) disrupts lignocellulosic structures while generating methanogenesis-inhibiting phenolic compounds. Current pretreatments only resolve either lignocellulosic rigidity or phenolic toxicity, with no integrated method to mitigate both simultaneously. This work investigated a combined strategy of AHP pretreatment coupled with MnO2 amendment to improve methane production from CS using laboratory-scale batch AD. Results demonstrated that 3% AHP pretreatment induced structural modifications and altered lignin-related functional groups, while the subsequent addition of 1.0 g MnO2 significantly (p < 0.05) removed up to 28.4% of the generated total phenolic equivalents and alleviated volatile fatty acid (VFA) accumulation. The Mn-AHP group achieved the highest cumulative methane production of 449.28 ± 13.25 mL/g VS, representing a 14.6% increase compared to the control and a 3.24% improvement over the AHP-only group. Microbial analysis revealed increased relative abundance of acidogenic bacteria (e.g., Synergistota) and a compositional shift in the archaeal community toward a structure dominated by Methanobacterium and Methanothrix. These findings indicate that coupling AHP with MnO2 is a promising approach to address the dual challenges of lignocellulosic recalcitrance and phenolic inhibition, providing a feasible pathway for agricultural waste valorization.