(188u) Comparative Genomic Analysis for Two Methanothermobacter Species Isolated from the Reactor for Thermophilic and Hydrogenotrophic Bio-Methanation of CO2

Hydrogenotrophic methanogenesis (HM) has recently gained significant attention due to its potential as a CO₂ utilization process. The low temperature and pressure operating conditions required as well as the inexpensiveness of the microbial catalyst make the biological synthesis of CH₄ from CO₂ an attractive alternative to conventional biogas upgrading methods. Furthermore, the conversion of excess renewable electricity to methane (Power to Gas) has the potential to resolve many of the current inadequacies of existing power back up technologies, such as storage capacity, cost and geographical limitations and support renewable energy developments in terms of minimizing power curtailment and facilitating wider deployment of renewable energy generation in regions with limited electricity grid availability. To investigate the biomethanation of CO₂ sludge from wastewater treatment plant in Seoul, Korea was inoculated into the HM bioreactor and the reactor was operated at 60 ℃ with supply of CO₂ and H₂ (1:4) for 7 months. Conversion efficiency for CO₂ into CH₄ has increased to 60% and CH₄ production rate increased to 2.5 VVD. From the reactor, two Methanothermobater species were isolated and evaluated for methane production performance. Both strains were cultivated well into basic anaerobic medium containing CO₂/H₂ and produced methane gas using CO₂ as a sole carbon. Whole genomes of two strains analyzed by pyrosequencing method showed the obvious difference on genetic levels.