Capture of Carbon Dioxide to Produce Ectoines : A Step Further Towards Circular Economy

This study demonstrates for the first time the feasibility of producing ectoine adding CO2 as the sole carbon source, and CO2 + glucose with Halomonas stevensii. Initially, CO2 alone was fed to continuous reactors, using thiosulphate as the electron donor. Maximum C 2 elimination capacities of 24.2 mg CO2 L-1 h-1 were obtained, and maximum ectoine yields of 7.3% (g ectoine g biomass-1 ). To enhance ectoine production, CO2 conversion coupled with discontinuous glucose addition was implemented. The amendment of 0.5 g L-1 of glucose at the beginning of reactor operation enhanced CO2 removal to 37.1 mg CO2 L-1 h-1 and increased ectoine yields up to 22%. Our results represent the proof of concept for a CO2 biotransformation platform to produce ectoines, so far unexplored. This can foster the development of more sustainable microbial processes for the production of ectoines helping in the abatement of CO2