Hence, the derivatives of DMAPA have previously been demonstrated to possess higher absorption capacities, faster kinetics and lower energy requirements than monoamines . C12-DMAPA, a derivative of DMAPA, was synthesized with a longer alkyl chain to balance the CO2 responsive system by increasing the hydrophobicity and increasing the CO2 emulsion . Testing C12-DMAPA with a mixed methanogenic culture as in the setup as MDEA showed full inhibition of the CO2 and H2 conversion into CH4 within a concentration range of 20 mM to 100 mM. Even when then concentration of microorganisms was increased to 4.3 wt%, 8.3 wt% and 20.3 wt% of the total liquid, no CH4 was produced. This lack of CO2 conversion could be attributable to either toxicity of the amine or inaccessibility to the absorbed CO2. The possibility of the CO2 being inaccessible was rejected because an average CO2 concentration of 3.9% ± 0.9% was measured in the reactor headspace, indicating that free bioavailable CO2 would also be present in the liquid. Supporting that the incompatibility was, in fact, due to the toxicity of C12-DMAPA is that long chain alkylamines like C12-DMAPA (Chain length of C12-C15) can be characterized as cationic surface-active agents, which often serve as antimicrobial agents or are used for disinfectants. Accordingly, these long-chain aliphatic diamines exhibits considerable antimicrobial activity if the alkyl chain consisted of 12 to 15 carbon atoms . The 12-carbon alkyl chain of C12-DMAPA is therefore potentially inhibitory to microbial activity. The experiments with C12-DMAPA underlines the necessity of testing biocompatibility and potential toxicity for any new capture agent used for the process of biomediated capture and utilization as demonstrated here. A high CO2 loading capacity with an associated high bioavailability of CO2 would increase growth conditions for the methanogenic microbes. The identification of a chemical agent, which is biocompatible even at higher concentrations is, therefore, an important part of further optimization. The chemical agent used for CO2 scrubbing does not have to rely on amines, as referred to in this study, and could include other chemical agents based on dissolving, adsorbing, or absorbing CO2. These could include i.e. amino acids , ionic liquids 33 , carbonates , ammonia , or simple base scrubbers which previously have been tested in regards to classical carbon capture by chemical scrubbing.