We have here demonstrated the use of MDEA as a capture agent, however, identifying new capture agents requires thorough screening to find other suitable candidates: (1) The absorbed CO2 should be available for utilization by the methanogenic microorganisms, which could rule out some capture agents where CO2 is bound by strong covalent bonds. ( ) The amine has to be biocompatible and not inhibit the methanogenic growth, which will increase the consumption rate of CO2 and thereby reduce the volumetric requirements for the biomethanation reactor. (3) Additionally, the amine has to possess a high CO2 absorption capacity so that CO2 concentrations high enough to support microbial growth.