Scientists from the California Institute of Technology were able to create a strain of bacteria capable of making small energy-packed carbon rings that can then be used to easily create other chemicals or materials.

Such rings, which have previously been cumbersome to create, can now be "brewed" in much of the same way as beer.

The team accomplished such a feat by engineering the enzymes of the bacteria in Frances Arnold's laboratory, employing previous techniques that have also been used in the lab, including something called directed evolution, which was developed in the '90s. In previous experiments, scientists were able to alter bacteria to produce carbon-silicon and carbon-boron bonds, which do not occur naturally.

Carbon Rings

Now, the team has managed to produce carbon rings, which similarly does not occur naturally. The bacteria responsible for this, according to Arnold, can now "churn" out the "versatile, energy-rich organic structures" which chemists and chemical engineers find difficult to create.

"With new lab-evolved enzymes, the microbes make precisely configured strained rings that chemists struggle to make."

Kai Chen, the paper's lead author, claims the enzymes could be engineered to make "crazy carbon rings under ambient conditions."

"This is the first time anyone has introduced a non-native pathway for bacteria to forge these high-energy structures," said Chen.

Making Bicyclobutanes

Bicyclobutanes are quite difficult to make simply for the fact that the bonds between carbon atoms are bent at certain angles which cause them incredible amounts of strain. They're not commonly occurring in nature because of their "inherent instability or the lack of suitable biological machineries for their assembly."

Disfiguring these bonds takes immense levels of energy and may result in unintended by-products if the conditions of the synthesis are incorrect. But the paper challenges that concept. To force bacteria in making high-energy structures, the team gave them a gene capable of encoding an enzyme called cytochrome P450. They previously had modified the enzyme via the aforementioned directed evolution method to produce molecules with small rings of three carbon atoms.

Ultimately, advances in this field will lead to chemistry being more green. In the future, according to Chen, humans might be able to program bacteria to let them make whatever we need instead of building chemical plants for making products. Imagine a world where bacteria can be engineered so as to help chemists and engineers produce materials that are typically very difficult to create.

More in-depth information about the chemical engineering process is available on Caltech's website.

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