Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338
May 12, 2003
Microbiologists put bacteria’s ‘taste for waste’ to work
Bacteria’s “taste for waste” is being used by a University of Guelph microbiologist to clean up environmental pollutants and chemicals.
Stephen Seah says bacteria’s drive to survive has made them remarkable evolutionary life forms. Many bacteria have evolved into efficient, adaptable and versatile consumption engines that can turn an array of carbon sources into a meal. To take advantage of these natural abilities, Seah and his research team are genetically modifying bacteria to “eat” some common chemical compounds — including harmful pollutants such as benzene and polychlorinated biphenyls (PCBs) — that are known to damage human health, wildlife and the environment.
It’s not as easy as it sounds, Seah said. Despite their longevity, bacteria remain picky eaters. Each strain can degrade only a narrow number of compounds, usually with similar chemical structures. Their digestion ability is determined by their enzymes — proteins inside the bacterial cell that catalyze chemical reactions and mediate the processes of life.
That’s where Seah’s work comes in. He and his research group are identifying the bacteria — and the enzymes they contain — that break down certain pollutants. Then, they’ll find and change the genes that code for these enzymes and “tell” them what to eat. For example, PCBs, once widely used as hydraulic fluids and electronic components, exist in more than 120 structural forms, many of which are carcinogenic or toxic. Although several PCB-degrading enzymes have been found in bacteria, they’re selective about the particular forms they can break down.
So by changing the enzymes that degrade certain PCB forms, Seah can also change the PCB forms that these new enzymes can break down — and broaden the dinner menu of pollutant-eating bacteria.
Seah’s research collaborators include graduate students Chris Vandenende and Pan Wang. The research is being supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council and the Ontario Innovation Trust.