Toxin munching microbes
by Geraldine Hinter
Cleaning
up highly contaminated sites such as the Port Stanvac oil refinery,
Mitsubishi Motors and the Adelaide railway yards could soon become
much easier using tiny microbes that destroy some of the worst
cancer-causing substances in contaminated soils.
Researchers from UniSA’s Centre for Environmental Risk Assessment and Remediation have identified microbes or bacteria found naturally in soil that destroy a group of toxic chemicals known as BTEX. Found in sites contaminated by petroleum and oil spills, hydrocarbons and explosives, BTEX has been linked to cancer, nerve damage and other diseases.
UniSA microbiologist and toxicologist, and member of CRC CARE, Professor Megh Mallavarapu has been able to isolate and characterise the genes in the microbes that break down BTEX.
"The microbes eat the carbon in the BTEX molecules, breaking down contaminants into harmless carbon dioxide and water," Prof Mallavarapu said.
"This discovery has enabled us to develop some new technologies based on these microbes – a world first – that we are looking at patenting," he said.
Prof Mallavarapu and his team of researchers have been working on highly contaminated Australian sites in areas ranging from Mediterranean to tropical climates, where the nature of the organic matter differs significantly.
"To develop microbes that eat toxins, we take thousands of microbes and when we spill chemicals in them, some of the sensitive microbes die but the stronger ones live. We provide the surviving microbes with the right food or nutrients and they start to grow. Slowly we withdraw the food and the hungry microbes begin to feed on the contaminants. We give them a little more food, then withdraw it and they eat their way through the contaminants. While this explanation is not quite as simple as it sounds, having the right conditions has enabled the team to develop highly tolerant microbes that can break down toxins," Prof Mallavarapu said.
Knowing what genes to look for has enabled Prof Mallavarapu to widen his search for other contaminants that can be destroyed by microbes.
Prof Mallavarapu has established a museum of different microbes that can detoxify contaminants in soils containing metals to highly toxic hydrocarbons – a first in Australia.
Now CERAR researchers are looking for pilot projects with industry to expand their research and see how the microbes perform on a wide range of contaminants.