University of Brighton scientists have discovered a more environmentally-friendly way of preventing man-made toxins from leaching into the water system – using living organisms.
Polychlorinated biphenyls (PCBs), now banned by most countries including the UK (1981), are still posing serious health risks and are suspected of causing the death of a new-born orca which made headlines around the world earlier this year when its mother Tahlequah carried the dead calf for 17 days.
High levels of the toxins, found recently in the bodies of orcas, were once used widely in coolant fluids in electrical apparatus. They are now thought to cause cancer in humans, are long-lasting and have become a major contaminant in water supplies worldwide.
The most common way of destroying PCBs and other synthetic chemicals is to incinerate contaminated soils or to treat polluted water with other chemicals to degrade them, both difficult methods without the use of expensive industrial processes.
But the University of Brighton scientists are testing their ‘Cryobacteria-reactor’ which uses living organisms to tackle these pollutants: they have developed a method for immobilising bacteria into porous structures so that they can strip PCBs out of the water as they are filtered through the material.
Dr Irina Savina, Senior Lecturer in the University’s School of Pharmacy and Biomolecular Sciences (PABS) and who is leading the project, said: “There have been some attempts to use bacteria already but there are difficulties in keeping the bacterial biofilm stable and they can often be relatively inefficient.
“We have been able to produce a three-dimensional porous material directly from bacteria with a minimal amount of polymer.”
The Brighton researchers have been testing their technique using bacteria that degrades chemicals that they are using as models for PCBs. The living bacteria are fixed in place inside a sponge-like material that has pores 20-150 micrometres in size. They were able to biodegrade relatively high concentrations of the chemical contaminants over two-and-a-half to five days to leave just trace amounts behind.
These bacterial sponges can be reused at least 10 times, according to the project’s research, and they can also be frozen for storage, before being later re-activated.
Dr Savina said: “We can adapt the bioreactor to use local bacteria species that have the ability to tackle different chemicals. It gives us an environmentally-friendly way of removing pollutants from water.”
Dr Savina is working on the project with Dr Dmitryi Berillo, Marie Skłodowska-Curie Actions Individual Fellow in PABS; Ms A. Al-Jwaid, PhD student; Dr Jon Caplin, Principal Lecturer in Environmental Microbiology in the University’s School of Environment and Technology; and Professor Andy Cundy, formerly with the University and now with Southampton University.
For more information on the research, click here and in a Royal Society of Chemistry journal.