VATIS UPDATE Article

At the American Chemical Society national meeting, held on 13-17 March in San Diego, USA, researchers reported a way to protect bioremediation enzymes by packaging them in a protein cage. Shaily Mahendra, an environmental engineer at the University of California, Los Angeles, (UCLA), the United States, who led the team, pointed out that bioremediation isn’t a new process engineers invented. Nature has always been cleaning up messes in the environment with organisms that repurpose molecules excreted by others. “If it weren’t for bioremediation, we’d be sitting on mountains of dinosaur waste right now,” said Mahendra.

Engineers have exploited this natural process for various environmental clean-up jobs. For example, crews added fertilizers to Alaskan beaches to get soil bacteria to consume oil spilled by the Exxon Valdez. In the new work, the team put the enzyme manganese peroxidase inside vault particles. Peroxidases are known to oxidize and break down organic contaminants. The researchers modified the gene for the peroxidase so that when cells synthesized the enzyme it had an added domain that helped the enzyme bind to the inside of the vault particles. The team used insect cells to produce the vault components, as well as the modified enzyme.

The particles enhanced the peroxidase’s activity in lab tests involving contaminants in solution. After 24 hours, the vault-packaged peroxidase consumed >90% of bisphenol A, a contaminant from plastic production, while the free enzyme broke down just 40%. Also, compared with free enzyme, the packaged peroxidase was more stable between 20°C and 40°C. So far the UCLA team has tested the particles on just a handful of contaminants, but Mahendra would like to eventually work with other enzymes that can break down different classes of pollutants, as well as test the strategy under field-like conditions.