PolyU scientists find way to remove polluting microplastics with bacteria

Researchers from PolyU have found a way to use bacteria to trap microplastics, removing them from the environment and making them easier to recycle. The novel technique was discussed yesterday (28 April) at the Microbiology Society's Annual Conference. The paper was presented at the conference by researcher Yang Liu, a PhD student at the Department of Applied Biology and Chemical Technology.

The method uses bacterial biofilms – a sticky substance created by micro-organisms – to trap microplastic particles. Microplastics pose a major risk to the environment and human health, as they are not easily bio-degradable and retain in the ecosystems for prolonged durations. This results in the uptake of microplastics by organisms, leading to transfer and retention of microplastics down the food chain.

Liu and the team uses the bacterium Pseudomonas aeruginosa to capture microplastics in a bioreactor. This species of bacterium is found in all environments and has previously been shown to colonise microplastics in the environment. P. aeruginosa biofilms cause the microplastics to aggregate together and eventually sink, which makes the microplastics more convenient to collect. Once the microplastics are captured by the biofilms and sink to the bottom of the reactor, the researchers use a biofilm-dispersal gene to cause the biofilm to release the microplastics. The plastics could then be recovered for recycling.

Next, the researchers plan to move the proof-of-concept from the lab to an environmental setting. They hope the technique will eventually be used in wastewater treatment plants, stopping microplastics from escaping into the oceans.