Enhanced Anaerobic Digestion Performance Through Acyl Homoserine Lactone-Mediated Quorum Sensing and Supplemental Voltage Regulation

Traditional anaerobic digestion (AD) technology continues to have severe limitations in terms of complicated substrate degradation efficiency and methane production. This study optimizes the AD system using corn straw and cattle manure as substrates by introducing an exogenous N-Hexanoyl-L-Homoserine lactone (C6-HSL) signaling molecule in concert with an applied external voltage of 0.8 V, systematically investigating its impact on methanogenic performance and microbial community dynamics. The results show that the combined regulation significantly increased methane production (by 29.74%) and substrate utilization rate (by 74.73%) while preventing acid inhibition and ammonia nitrogen inhibition. Mechanistic analysis revealed that the external voltage enhanced the system’s electrocatalytic activity, while the C6-HSL signaling molecule further facilitated the electron transfer efficiency of the biofilm on the electrode. The combined regulation notably enriched hydrogenotrophic methanogens (with Methanobacterium predominating on the cathode and Methanobrevibacter in the digestate), establishing a stable metabolic cooperative network on both the electrode and in the digestate, optimizing the hydrogenotrophic methanogenesis pathway, and enhancing the synergistic effects among microbial communities and system robustness. This study uncovers the synergistic enhancement mechanism of C6-HSL and external voltage, providing new technological pathways and theoretical support for the efficient conversion of low-quality biomass resources and the production of clean energy.