Upcycling excess carbon dioxide with tiny microbes

The increasing concentration of greenhouse gases within the atmosphere has led to widespread global warming. To start to handle the issue, greenhouse gas emissions, including CO₂, should be significantly reduced. On top of that, the CO₂ already present might be removed. Methods to capture CO₂ are in development, and one promising option involves microbes. Genetic engineering can modify their natural biosynthetic pathways, turning the microbes into miniature living factories that may produce all forms of things — for instance, insulin.

One potential microbial factory is Cupriavidus necator H16, a bacterium favored due to its relatively unfussy nature about what it’s fed. Because it will probably survive on little greater than CO₂ and hydrogen gas, the bacterium is an amazing candidate for capturing and converting the gases into larger molecules. But regardless that the microbe’s DNA could be rewired to provide interesting products, it isn’t great at remembering those recent instructions over time. To place it scientifically, the plasmids (the genetic instructions) are relatively unstable. Katalin Kovacs and colleagues desired to see if they may improve C. necator’s ability to recollect its recent instructions and produce useful carbon-based constructing blocks out of CO₂ gas.

The team set to work hacking C. necator’s biochemical pathways answerable for converting CO₂ into larger six-carbon molecules. The important thing to improving the plasmid’s stability lies in an enzyme called RubisCo, which allows the bacterium to utilize CO₂. Essentially, the brand new plasmid was paired to the enzyme, so if a cell failed to recollect the brand new instructions, it could put out of your mind find out how to make RubisCo and die. Meanwhile, the remaining cells with higher memories would survive and replicate, passing along the plasmid.

In tests, the newly engineered microbes produced significantly more of the six-carbon molecule mevalonate compared with a control strain. Mevalonate is a molecular constructing block for all forms of substances in living and artificial systems alike, including cholesterol and other steroid molecules with pharmaceutical applications. In truth, this research produced the biggest amounts up to now of mevalonate from CO₂ or other single-carbon reactants using microbes. The researchers say this can be a more economically feasible carbon fixation system than previous systems involving C. necator, and it might be expanded to other microbial strains as well.

The authors acknowledge funding from the Biotechnology and Biological Sciences Research Council and the Engineering and Physical Sciences Research Council of the UK.