Metals Are Key to Lessen CO2 Emission

The earth is heating up, a phenomenon called “greenhouse effect.” Through advancements in research, scientists found a way to lessen carbon dioxide emission through metal-catalyzed reactions, which include the carboxylation of pyruvate with CO2, addressing the greenhouse effect in the earth’s surface.

Metal ions, such as aluminum, promote the formation of carbon bonds, an important idea in the biosynthesis of complex molecules. Photo taken from https://www.osaka-cu.ac.jp/en/news/2020/200929

The greenhouse effect is an existing environmental issue, wherein heat is trapped inside the earth due to greenhouse gases (such as carbon dioxide, methane and nitrous oxides). Sources of carbon dioxide (CO2) emissions include the production of fossil fuels, deforestation, and vehicular & industrial smoke emissions.

According to Global Carbon Project, an international research consortium that tracks greenhouse gases, the total amount of CO2 emission in 2019 was 36.8 & 43.1 billion metric tons, both from fossil fuels and human-related emissions respectively. The data gathered, which was reported to be greater than the total 2018 CO2 emission, is an indication that there is a continuing rise of CO2 emission, contributing to global warming.

In addressing the greenhouse effect caused by CO2, current experimental conditions, such as artificial photosynthesis that produces molecules with 1 carbon atom, are insufficient in the production of more complex materials. Researchers in Osaka City University found a way to lessen these CO2 through chemistry. Metal ions, such as aluminum and iron, act as catalysts to allow carboxylation of pyruvate with CO2, producing malic acid, a molecule containing 4 carbons.

Osaka City University, from their research’s paper entitled "Trivalent metal ion promotes malic enzyme-catalyzed building carbon-carbon bonds from CO2 and pyruvate,” indicated that malic enzyme (ME), an enzyme responsible for the decarboxylation of malate into pyruvate and CO2, is bombarded with metal ions that would promote pyruvate carboxylation, such as aluminum and iron ions.

Surprisingly, lead author Takeyuki Katagiri said that he was astonished that the existing problem can be solved through the utilization of divalent and trivalent metals that are common in the surrounding. Supporting this claim, co-author Yutaka Amaeo cited that their goal in the advancement is “to create groups of molecules with as many as 100 carbon atoms,” thus exploring other possibilities of using CO2 as a raw material in biocatalytic CO2 utilization research.

Progression of this research would help reduce the effects of greenhouse gases, leading to a cooler earth.