Carbon Dioxide Bio-Capture and Organic Carbon Production in Two Microalgae Strains Grown Under Different CO2 Conditions

The need to reduce anthropogenic greenhouse gas emissions drives the development of innovative carbon dioxide capture technologies. Microalgae-based biotechnologies represent a promising approach in this field. In this study, we evaluated the CO2 assimilation efficiency of two novel microalgae strains, Desmodesmus armatus ARC-06 and Tribonema minus ARC-10, under low (0.04%) and high (1.5%) CO2 conditions in a periodic cultivation system. The two strains exhibited distinct CO2 adaptation strategies. D. armatus demonstrated higher tolerance to low CO2 conditions, whereas T. minus showed superior performance under elevated CO2. Although elevated CO2 stimulated growth in both strains, their carbon dioxide sequestration efficiency (CDSE) differed markedly. The maximum CDSE was significantly higher in T. minus (30.0 ± 1.52%) compared to D. armatus (16.5 ± 1.12%). Similarly, the average CDSE over the cultivation period was greater in T. minus (19.1 ± 2.18%) than in D. armatus (11.8 ± 1.45%). These results underscore the importance of bioprospecting for novel microalgae strains, and the need for further research to develop efficient biological CO2 sequestration methods.