Biological Solution to Plastic Waste: Worm and Bacterial Enzymes Adapted for Recycling

While thousands of tons of plastic waste accumulating in a warehouse in Australia highlight the bottleneck in recycling infrastructure, the scientific world has launched new research on organisms capable of digesting plastic types.

The mountains of thousands of tons of plastic waste collected for recycling in warehouses in Australia have brought the global plastic pollution crisis back to the agenda. Environmental authorities inspecting a warehouse in Laverton near Melbourne in February 2023 encountered bales of bread bags, chip packaging, and stretch film reaching up to the ceiling. While this warehouse, flagged due to fire risk, revealed that the current recycling infrastructure is congested, it has driven the scientific world to seek radical and biological solutions.

Scientific research reveals that certain insect larvae and bacteria can digest specific types of plastic. Experts state that the solution is not to release millions of insects into nature, but rather to adapt the hidden biological mechanisms used by these creatures into industrial recycling technologies.

The defense mechanisms developed by nature against plastic waste have become clear through studies conducted on three different organisms. First, researchers at the University of Queensland discovered that Zophobas morio larvae, commonly known as superworms, can continue their development by eating polystyrene foam thanks to their gut microorganisms. In Spain, developmental biologist Federica Bertocchini identified two special enzymes in the saliva of wax moth larvae that break down polyethylene bags. Meanwhile, a bacterium called Ideonella sakaiensis, discovered in Japan, managed to break down thick PET plastics used in beverage bottles and textiles into their molecules in as short a time as six weeks through the components it secretes.

Laboratory experiments showed that the immune systems of larvae feeding solely on plastic eventually collapsed after a time. The fact that plastic alone is not a sustainable and healthy energy source ruled out the idea of releasing an army of insects into nature. The loss of microbial diversity as these organisms are overwhelmed by plastic waste caused researchers to shift their focus from the organisms themselves to the special enzymes they secrete.

The discovery of biological mechanisms has mobilized global recycling companies. The ability of enzymes to break large plastic molecules apart from their chemical bonds down to their root components has turned into commercial investments. French biotechnology company Carbios broke down PET waste within 10 hours in industrial environments thanks to a special enzyme formula it developed. Australia-based Samsara Eco is taking steps to establish facilities to convert polyester and nylon materials into reusable raw materials, while researchers in Singapore are working on artificial microbial bioreactors that mimic the gut flora of superworms.

Although biological recycling has created a revolution in the laboratory, cost remains the biggest obstacle on an industrial scale. Under current market conditions, producing virgin plastic from scratch still stands out as a cheaper method than collecting waste plastic and breaking it down into its molecules using enzymes. Furthermore, experts warn against the risk of plastics that cannot be fully degraded turning into microplastics and mixing into water sources and the food chain; they state that the ultimate solution lies in reducing plastic consumption and renewing waste management policies.