Global atmospheric carbon dioxide levels have increased over 20% in the past 45 years, and this recent increase makes up over 50% of the total increase in carbon dioxide since the beginning of the Industrial Revolution [1]. Natural carbon fixation systems, such as plant photosynthesis and oceanic absorption, are unable to keep up with this sharp rise in carbon emissions. The world is seeing heightened consequences of climate change as a result, including extreme weather phenomena, rising sea levels, and severe habitat loss [2].
Current atmospheric carbon levels are in excess of 424 parts per million (ppm), dangerously close to the brink point of 450 ppm after which climate change is effectively irreversable. Scientists project that if carbon emissions continue to increase unchecked, atmospheric levels could reach over 800 ppm by 2100, a concentration linked to historical mass extinction events [3]. Current mitigation technologies fall into one of two categories: carbon capture and storage (CCS), or carbon capture and utilization (CCU). CCS removes carbon dioxide from the atmosphere and stores it underground, while CCU uses carbon dioxide to create useful byproducts like cement, synthetic fuels, and more [4]. The overarching goal of this project is to essentially create a natural CCU system, where the byproduct helps the reactor's cells survive, thus creating a self-sustaining carbon sequestration machine.
This project aims to insert the simplest known synthetic carbon fixation pathway, the POAP cycle, into the simplest known synthetic organism, JCVI's Syn3.0b minimal cell. Ideally, the inserted pathway will allow the minimal cell to sequester carbon dioxide from the atmosphere and fix it into organic molecules that are useful for cell survival processes.
Successfully integrate all 4 genes required for the POAP pathway into the minimal cell's genome via the genome's only Cre-lox site.
Confirm all 4 enzymes are synthesized and functional within the minimal cell.
Quantify POAP-related metabolites (acetate, pyruvate, lactic acid) in transformed cells to confirm the cycle is functional.
Remove oxalate, a toxic byproduct created as a result of the pathway, from cells and media to increase system lifespan.
[1] www.globalchange.gov/indicators/atmospheric-carbon-dioxide#:~:text=Global%20monthly%20average%20concentrations%20of,than% 2020%25%20in%2045%20years.
[2] www.worldwildlife.org/threats/effects-of-climate-change
[3] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022EF003336
[4] Gayathri, R. et al. A review on Biological Carbon Sequestration: A sustainable solution for a cleaner air environment, less pollution and Lower Health Risks. Journal of King Saud University - Science 33, 101282 (2021).
[5] All MACS cell illustrations courtesy of the 2023-2024 MACS Senior Design team.
Made by Sachi Goel