An oil-eating bacterium that can help clean up pollution and spills

In recent years, researchers have sequenced the genomes of thousands of bacteria from various sources. Research associate Dr.Tarek Rouissi poured over "technical data sheets" for many bacterial strains with the aim of finding the perfect candidate for a dirty job: cleaning up oil spills. He focused on the enzymes they produce and the conditions in which they evolve.

A. borkumensis, a non-pathogenic marine bacterium piqued his curiosity. The microorganism's genome contains the codes of a number of interesting enzymes and it is classified as "hydrocarbonoclastic" -- i.e., as a bacterium that uses hydrocarbons as a source of energy. A. borkumensis is present in all oceans and drifts with the current, multiplying rapidly in areas where the concentration of oil compounds is high, which partly explains the natural degradation observed after some spills. But its remedial potential had not been assessed.

"I had a hunch," Rouissi said, "and the characterization of the enzymes produced by the bacterium seems to have proven me right!" A. borkumensis boasts an impressive set of tools: during its evolution, it has accumulated a range of very specific enzymes that degrade almost everything found in oil. Among these enzymes, the bacteria'shydroxylases stand out from the ones found in other species: they are far more effective, in addition to being more versatile and resistant to chemical conditions, as tested in coordination by a Ph.D. student, Ms. Tayssir Kadri.

To test the microscopic cleaner, the research team purified a few of the enzymes and used them to treat samples of contaminated soil. "The degradation of hydrocarbons using the crude enzyme extract is really encouraging and reached over 80% for various compounds," said Brar. The process is effective in removing benzene, toluene, and xylene, and has been tested under a number of different conditions to show that it is a powerful way to clean up polluted land and marine environments."

The next steps for Brar's team are to find out more about how these bacteria metabolize hydrocarbons and explore their potential for decontaminating sites. One of the advantages of the approach developed at INRS is its application in difficult-to-access environments, which present a major challenge during oil spill cleanup efforts.