Comparative analysis of the effect of cell immobilization on the hydrogenothrophic biomethanation of CO2

Carbon capture and utilization (CCU) has been offered as a potential technological solution for mitigating the greenhouse gas emissions and climate change concern worldwide. Anaerobically carbon utilization has started to be in the agenda of researchers in recent years since this approach offers significant advantages such as use of catalysis reactions through environmentally friendly microorganisms under low temperature and pressure operational conditions. Moreover, a cleaner and more effective bioenergy production is realized in the form of biomethane. This study aimed to exploit the merits of cell immobilization in order to provide a stable hydrogenotrophic biomethanation process. For this purpose, two different immobilized bioreactors packed with plastic moving bed biofilm reactor (MBBR) and glass beads packing materials were comparatively investigated. To the best of our knowledge, these two immobilization materials were used for the first time for this purpose. Two different bioreactor configurations were compared for the performance parameters such as methane formation rate, H-2 consumption and methane contents in the headspace. Methane content in the headspace of these bioreactors were measured to be 80 and 75% for MBBR bioreactor and glass bead bioreactors, respectively. in addition, methane formation rates (MFR) of 5.14 and 4.8 m(3)/m(3)/day were achieved in MBBR and glass beads bioreactors, respectively. Even though both bioreactor configurations performed highly efficient biomethanation of CO2, the statistical evaluation of the results indicated that MBBR performance was more favourable for hydrogenotrophic biomethanation. (c) 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.Ege University Scientific Research Project FundEge University [17/CSUAM/002]The authors thank Ege University Scientific Research Project Fund for the financial support of this study under the Grant No 17/CSUAM/002 The authors also thank Aquaflex Company (Turkey) for the support of supplying bioaqua MBBR rings