Microalgal-based carbon sequestration by converting LNG-fired waste CO₂ into red gold astaxanthin: The potential applicability

The combinatorial approach of anthropogenic activities and CO₂ sequestration is becoming a global research trend to alleviate the average global temperature. Although microalgae have been widely used to capture CO₂ from industrial flue gas, the application of bioproducts was limited to bioenergy due to the controversy over the quality and safety of the products in the food and feed industry. Herein, the waste CO₂ emitted from large point sources was directly captured using astaxanthin-hyperproducing microalgae Haematococcus pluvialis. Astaxanthin production was successfully carried out using the hypochlorous acid water-based axenic culture process under highly contamination-prone outdoor conditions. Consequently, after 36 days of autotrophic induction, the productivity of biomass and astaxanthin of H. pluvialis (the mutant) reached 0.127 g L⁻¹ day⁻¹ and 5.47 mg L⁻¹ day⁻¹ under high summer temperatures, respectively, which was 38% and 48% higher than that of wild type cell. After grinding the wet astaxanthin-enriched biomass, the extract was successfully approved by compliance validation testing from Korea Food and Drug Administration. The assorted feed improved an immune system of the poultry without causing any side effects. The flue gas-based bioproducts could certainly be used for health functional food for animals in the future.