Meet the Solvent Breather, Dehalococcoides ethenogenes

Our final All-Star is a microbe that solved one of the most widespread and difficult groundwater pollution problems in the world. Meet Dehalococcoides ethenogenes, a tiny bacterium with a very big and very specific job: it is the only known organism that can fully detoxify industrial solvents like tetrachloroethylene (PCE) and trichloroethylene (TCE). (10/17/2025)

The Hero's Story

For decades, PCE and TCE—common chemicals used in dry cleaning and industrial degreasing—were a cleanup nightmare. Bacteria could break them down partially, but the process would stall, leaving behind an even more toxic byproduct called vinyl chloride. Then, in the 1990s, scientists discovered Dehalococcoides. This microbe is an anaerobe, meaning it lives in oxygen-free environments like deep groundwater. Its unique evolutionary trick is a process called dehalorespiration—it literally "breathes" chlorine atoms. 💨

Bioremediation Superpower: Completing the Chain Reaction

Dehalococcoides's superpower is its ability to finish the job. It methodically removes chlorine atoms from the solvent molecules, one by one, in a chain reaction. It takes the highly toxic PCE and TCE, breaks them down past the dangerous vinyl chloride stage, and turns them into harmless ethene, a simple, non-toxic gas.

This microbe was the missing link. Its discovery was a revolutionary breakthrough, making the complete bioremediation of solvent-contaminated sites possible for the first time. It is the specialist hero that environmental engineers call in (via bioaugmentation) for some of the toughest cleanup jobs, like the successful remediation of Dover Air Force Base we covered in a previous series.