The researchers’ preliminary findings indicate that the nets could be used in polluted water, sticking the microplastics to them and gathering them into one recyclable mass.
Sylvia Lang Liu, microbiology researcher and study lead, said: “It is imperative to develop effective solutions that trap, collect, and even recycle these microplastics to stop the ‘plastification’ of our natural environments.”
The plastics, which are smaller than 5mm, are caused by the break-up of larger plastics, the breakdown of items such as plastic bags, or through washing nylons or using personal hygiene products containing microbeads. There can be up to 100,000 microbeads in some facial wash products.
Their knock-on effects are huge, despite their small size. Microplastics were found in more than 114 aquatic species in 2018, according to the International Maritime Organization, and have been discovered in salt, produce and in the placentas of unborn babies.
The study focused on engineering a biofilm from Pseudomonas aeruginosa bacteria, which could adhere to floating plastics in the water. The nets trap and group the microplastics, making them sink to the bottom of the water.
Then using a “capture-release mechanism”, from a biofilm-dispersal gene, the researchers could uncouple the microplastics and bacteria.
Dr Joanna Sadler, researcher at University of Edinburgh, told The Guardian: “This is a really innovative and exciting application of biofilm engineering to address the plastic pollution crisis. One of the biggest challenges in dealing with microplastics is capturing such small particles so they can be degraded and removed from the environment. Liu and co-workers have demonstrated an elegant solution to this problem, which holds great potential to be further developed into a real-world wastewater treatment technology.”
However, this is just a conceptual experiment, undertaken in a controlled environment using an aeruginosa bacteria strain, a disease-carrying bacteria for humans, so the exact result could not be used in large-scale projects and would need to be tested in ocean conditions.
Yet, the researchers believe the method can be replicated, finding natural bacteria already in sewage or waterways that will also be able to produce the sticky biofilm.