UofI Urbana-Champaign researchers produce valueable chemicals with light-driven enzymatic reactions

In Illinois, a research lab at the University of Illinois Urbana-Champaign has achieved another milestone using light-driven enzymatic reactions to convert simple biological building blocks into valuable chemicals. The researchers, part of the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), developed a clean, efficient way to make complex chemicals called chiral ketones through photocatalysis — combining bioengineered enzymes with light to create novel reactions.

Many useful chemicals — especially in agrochemicals and medicines — exist in two mirror-image forms, like left and right hands. These are called chiral molecules, and often only one “hand” is effective or safe. While chemists can build chiral molecules from scratch using a strategy called asymmetric catalysis, this process can be complex and costly.

In contrast, making a racemic mixture — a 50:50 blend of both mirror-image forms — is often easier and cheaper. That’s why another approach, called enantioconvergent catalysis, is so valuable: It allows both versions in a racemic mixture to be converted into the product of one chirality. However, most current methods can only do this when the stereocenter is near the reactive site of the molecule. Reaching remote stereocenters — parts that are farther away and harder to access — is still a major challenge.

In this study, scientists solved the problem by using a photoenzymatic reaction. When exposed to light, the enzyme generates a nitrogen-centered radical — a very reactive intermediate that can break the remote chiral carbon-hydrogen bond through a process called 1,5-hydrogen atom transfer.