Development of Photosynthetic Microorganisms Capable of Converting High-Concentration Carbon Dioxide

Modified microalgae have been introduced that are capable of rapidly performing the biosynthesis of high value-added materials directly from high-concentration dioxides obtained from industrial sites.


Professor Sim Sang-jun’s group from the Department of Chemical and Biological Engineering at the College of Engineering developed a biological carbon reduction technology based on microalgae that can rapidly convert carbon dioxide at a harshly high concentrations into high value-added materials, such as biofuels. In October the results of the study were published online in the prominent international journal Nature Communications.
 - Title of Paper : Augmented CO2 tolerance by expressing a single H+-pump enables microalgal valorization of industrial flue gas
 - Journal Title : Nature Communications
 - DOI : https://doi.org/10.1038/s41467-021-26325-5



Microalgae, which utilize carbon dioxide as a carbon source, are drawing attention, because they can be used to produce polymers such as biodegradable plastics, biofuels including bio-diesel, pharmaceuticals and other materials directly from carbon dioxide. However, their low tolerance to high carbon dioxide concentrations means that microalgae are unable to efficiently reduce and convert the high-concentrations of carbon dioxide generated by a wide range of industries in large quantities.

The research group found that the low carbon dioxide tolerance of microalgae is attributed to low plasma membrane H+-ATPase expression. An ATPase enzyme gene derived from a plant was introduced to the microalgae to modify them to continuously express the biological pump. The results showed that their carbon dioxide tolerance was increased to more than triple the tolerance of the wild type. The biological pump facilitated the extracellular discharge of the hydrogen ions that continuously accumulated in the microalgae as a result of carbon dioxide dissolution and the metabolism of the related materials, allowing the microalgae to remain active even under acidic conditions.

The research group verified the effect of increasing the carbon dioxide tolerance in a proof-of-concept outdoor cultivation of the algal cells. When directly exposed to coal combustion flue gas including high-concentration carbon dioxide, the modified algal cells converted carbon dioxide to biomass and biofuel twice as fast as the wild type microalgae.

Professor Sim expressed his expectation that “since the developed algal cell strain with augmented carbon dioxide tolerance has already been validated through a large-scale on-site cultivation test, it may be applied as a significant biological technology for rapidly reducing and converting carbon dioxide in the pursuit of realizing carbon neutrality by 2050.”

The present study, supported by the Korea Carbon to X R&D Center of the Ministry of Science and ICT and the National Research Foundation of Korea, was jointly conducted with Professor Choi In-geol from KU (Department of Biotechnology) and Professor Jin Eon-seon from Hanyang University (Department of Life Science).