Enhanced biomethanation under hyperthermophilic conditions: Intake load effects on hydrogenotrophic methanogenesis

Abstract BACKGROUND As a sustainable energy carrier, biogas upgrading via biomethanation has emerged as a critical frontier in carbon mitigation. While ex‐situ microbiological methanogenesis offers distinct operational advantages, its industrial application is significantly hindered by gas–liquid mass transfer limitations. This study investigated a novel anaerobic horizontal rotating bioreactor (AHRB) designed to overcome these bottlenecks under hyperthermophilic conditions (70 °C). RESULTS An intake load optimization strategy was implemented to enhance hydrogenotrophic methanogenesis performance. The AHRB demonstrated exceptional efficiency, where increasing the intake load directly intensified the hydrogen mass transfer rate k L a and methane productivity. At an optimal intake load of 12 NL/(Lr·d), the system achieved a maximum methane yield of 7.20 ± 0.24 NL‐CH 4 /Lr·d with a remarkable hydrogen utilization rate of 96.8%. Microbial community analysis revealed a highly specialized consortium dominated by the hyperthermophilic methanogen Methanothermobacter thermautotrophicus . The bacterial population was characterized by Gelria , Coprothermobacter , and Tepidiphilus , forming a robust syntrophic network that sustained high‐flux methanogenic activity. CONCLUSION These findings demonstrate that the AHRB, coupled with hyperthermophilic operation, provides a high‐performance biocatalytic platform for ex‐situ biogas upgrading. This study offers a strategic roadmap for integrating biomethanation into Power‐to‐Gas (P2G) systems to achieve efficient renewable energy storage. © 2026 Society of Chemical Industry (SCI).