University of Toronto Magazine University of Toronto Magazine
Illustration of a metal can with a poison symbol sitting on its side on top of a field of flowers
Illustration: Brian Stauffer

Hungry for Hazardous Waste

How pollution-eating microbes could help clean up toxic sites

Professor Elizabeth Edwards of chemical engineering and her team have developed a secret weapon in the war against pollution: a mix of micro-organisms that eat toxic chemicals for breakfast. Now, funding from Genome Canada will help Edwards and her industrial partners bring the unique microbial culture to market.

Everywhere tanks of oil or gasoline are stored underground, hazardous chemicals leak into soil and groundwater. “The owner of every gasoline station on the planet probably has some contamination issues,” says Edwards, who holds the Canada Research Chair in Anaerobic Biotechnology.

To clean up the site, crews have to dig, wash or aerate the soil to encourage the growth of oxygen-loving micro-organisms that break down the pollutants – a labour-intensive, time-­consuming and expensive remediation process. Edwards and her team have discovered another set of organisms that live without oxygen and could do the job without having to churn up and process all the soil.

The microbial cultures Edwards works with now have evolved from soil samples taken at contaminated oil refinery and gas station sites more than 15 years ago. Since then, Edwards and her team have been enriching the cultures by feeding the organisms oil-derived chemicals that are difficult to degrade and selecting the samples that are most effective at breaking them down.

“What we have is a culture that can chow down on these chemicals when there’s no oxygen around,” says Edwards. Adding this culture to a contaminated site, a process known as bio-augmentation, may speed up the degradation of pollutants with minimal disruption to the environment.

In addition to demonstrating the effectiveness of the process in the lab, the team has done extensive genomic sequencing to understand which individual species in the culture are responsible for each step in the chemical breakdown. “We think it’s ready to be tested in the field, but to do that we have to scale it up,” says Edwards. Her team is partnering with SiREM, an environmental remediation laboratory in Guelph, Ontario, that specializes in bio-augmentation. The lab has already commercialized another one of Edwards’ microbial cultures, which is optimized to clean up chlorinated solvents such as those used in dry cleaning and other industrial applications. Adding more chemicals to the list of treatable ones could help increase SiREM’s share of the global market for bio-remediation, which is estimated in the billions of dollars.

“This project is a great example of the way our researchers work across disciplines to address challenges in sustainability,” says Prof. David Sinton, interim vice-dean, research, for the Faculty of Applied Science and Engineering. “Together with industrial partners, engineering researchers are bringing leading-edge solutions from the lab to the global marketplace.”

Other partners include Mitacs, a Canadian non-profit that’s funding a post-doctoral researcher on the project, and the Ontario Ministry of Research and Innovation, which will provide matching financial support.

If the pilot project is successful, the bio-augmentation culture could be used at contaminated sites around the world. “It’s a brand new tool to deal with difficult remediation,” says Edwards.

Recent Posts