Enhanced ectoines production by carbon dioxide capture: A step further towards circular economy

Recycling of greenhouse gases to produce industrially valuable products has become one of the big pillars to achieve circularity. This study demonstrates for the first time the feasibility of producing ectoine with Halomonas stevensii with CO2 as the added carbon source, and CO2 and glucose. Initially, CO2 alone was fed to continuous reactors, adding thiosulphate as the energy source. Maximum CO2 elimination capacities of 24.2 mg CO2 L-1 h-1 were obtained, and ectoine contents up to 7.3% (g ectoineg 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 contents 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.