Microbiologists have come up with a sustainable way to use bacteria to remove microplastics from the environment.
Researcher Yang Liu and colleagues from the Hong Kong Polytechnic University (PolyU) have engineered a bacterial biofilm, a sticky substance created by microorganisms that can be used to form sticky microbe nets that, when placed in polluted water in a lab, trap the microplastics in the water and group them together, causing them to sink.
In the study, which was presented at the Microbiology Society Annual Conference 2021, the scientists showed how, once sunk, the microplastics could then be released from the biofilm matrix conveniently with the use of a “biofilm-dispersal gene”, so the microplastics could be recovered for recycling.
“It is imperative to develop effective solutions that trap, collect, and even recycle these microplastics to stop the ‘plastification’ of our natural environments,” said Sylvia Lang Liu, microbiology researcher at PolyU.
What are microplastics?
Microplastics are tiny fragments of plastic, usually smaller than 5mm, that can be divided into two categories:
- Primary microplastics: tiny particles designed for commercial use, such as the micro-beads you might find in cosmetics, as well as microfibres that shed from clothing when washed, or from fishing nets.
- Secondary microplastics: tiny plastic fragments which are released into the environment during the breakdown of bigger plastic items, such as water bottles, food packaging or plastic bags. This breakdown can be caused by exposure to environmental factors, such as the sun’s radiation or waves in the ocean and seas.
As the ocean is downhill from everything, microplastics end up in our waterways and while they decompose there, which can take hundreds or thousands of years, they are able to absorb toxic and harmful chemicals like pesticides, heavy metals and drug residues. Recent studies have shown that some of the toxic compounds microplastics accumulate can disrupt human as well as animal endocrine and immune systems. Because of their size and prevalence, microplastics are easily indigested by mammals, fish, plants and, via the food chain, humans. A 2019 study found that humans could be eating up to a credit card’s worth of plastic – and the toxins in the plastic – each week.
What can we do to prevent microplastic pollution?
While this study was carried out as a proof-of-concept test in a controlled environment, the researchers are confident that the method could be replicated to find natural biofilm-forming bacteria directly in sewage or other watery environments.
While they figure that out, here are three simple ways we can all help to prevent microplastic pollution:
1. Avoid products containing ‘microbeads’.
The sale of products containing microbeads has already been banned in some parts of the world, including the UK. Plastic microbeads can be found in products such as face scrubs, toothpastes, bodywashes and some cosmetics. Avoid these products by looking for “polythelene” and “polypropylene” on the ingredient labels (check out this list of products containing microbeads for more).
2. Avoid single-use plastic
Single-use plastic bans have recently come into force in South Australia, England and Canada, but no matter where you live, the simplest way to avoid contributing to the microplastic problem is by avoiding single-use plastics, like water bottles, straws, cutlery, take-out containers or plastic bags. These are the items that when discarded, will start to breakdown into secondary microplastics. Choose to reuse wherever you can and if you can’t reuse, make sure you recycle plastics properly. If you don’t have a kerb-side collection for everything, see if your local supermarket offers a solution – most UK supermarkets, for example, now collect plastic bags for recycling.
3. Organise or participate in a beach or river or street clean up
Organise a clean-up as a different and planet-loving activity for you and your family or friends, or join one of these:
- Planet Patrol combines activities, like paddle boarding, yoga, running, fitness, with litter picking and data collection. Its free app helps volunteers gather photographic evidence of brands, types and locations of litter polluting nature globally.
- Sea Shepherd’s Marine Debris Campaign Clean-Up Events are free to join, family-friendly and inclusive. Find an event local to you here.
- Get fit whilst cleaning up the planet by ‘plogging‘, combination of jogging and plocka upp, Swedish for “to pick up,” plogging involves jogging and quickly stopping to pick up trash while you go.