Synergistic Bioelectrodes and Dynamic Microbial Community Enable High-Efficiency Methanization of Corn Stalk in a Novel Hybrid Bioelectrochemical-Anaerobic Digestion System

Abstract

This study developed a hybrid bioelectrochemical-anaerobic digestion (BEAD) system integrating synergistic bioelectrodes and dynamic microbial communities. By systematically optimizing carbon-based electrode materials (AC@Ni/SSM, CB@Ni/SSM) and CS doses (1.0 – 8.0 g/L), the AC@Ni/SSM electrode demonstrated superior performance, achieving a cumulative methane production of 493.08 ± 1.0 mL/g VS, 2.8-fold higher than conventional AD (155.1 ± 1.2 mL/g VS). Electrochemical analyses revealed that the hierarchical structure of AC@Ni/SSM reduced charge transfer resistance by 42% and minimized ionic diffusion barriers, facilitating direct interspecies electron transfer (DIET) via conductive biofilms. Optimal CS dose (2.0 g/L) maximized substrate-microbe interaction, yielding 68.25% methane content and 90.23% COD removal. Microbial community dynamics highlighted the enrichment of Firmicutes (56%) and Bacteroidota (22%), key contributors to lignocellulose degradation and DIET-mediated methanogenesis. These findings underscore the BEAD system potential to overcome electron transfer bottlenecks, offering a sustainable pathway for high-efficiency valorization of lignocellulosic biomass.

Keywords: Methane production, Electrodes, Doses, microbial, Electron transfer pathway