Plastic-munching enzymes could provide economic solution to pollution crisis, says Chalmers researcher

18 Jan 2022 --- Swedish researchers recently discovered that plastic-degrading enzymes are increasing in correlation with plastic pollution in the world’s natural environment. 

PackagingInsights sits down with Aleksej Zelezniak, associate professor at Chalmers University, Sweden, to discuss how these discoveries could be utilized by the packaging and waste management industries to tackle pollution. 

By analyzing DNA samples from across the globe, including soils, oceans and seas, the research group at Chalmers University identified 30,000 enzyme sequences with a potential to degrade plastic, including plastic bags. 

“What was especially interesting to see was the diversity of these plastic-invented enzymes positively correlated with the amounts of reported plastic pollution and non-recycled plastic waste,” explains Zelezniak.

The study focuses on all major pollutants, including polypropylene (PP), polyethylene (PE) and polyvinyl alcohol (PVA).

Harnessing enzymes 
Zelezniak says researchers still need to conduct many lab experiments to identify all the enzymes capable of plastic degradation. 

“This needs to be a global effort. If any of these enzymes could act on plastics with timeframes that would match the current plastics in mind, it actually could decrease the cause of this plastic accumulation of waste,” he says.

Plastic is degraded by microbes – very slowly and efficiently – and perhaps some enzymes are more active than others.Zelezniak’s study focuses on all major plastic pollutants that currently exist.

“If we found some ways that are quite active, we could further pursue them to develop an economically feasible process,” Zelezniak explains.

Economic opportunities 
Zelezniak stresses plastic waste is still poorly managed and is increasingly leaking into natural environments. 

“On the positive side, we found many enzyme candidates with the potential to degrade plastics and then one can find any economically feasible solution for plastic recycling.” 

In the future, this discovery could boost the plastics circular economy. However, its success largely depends on the processes in place and the policies determining plastic waste management, he says.

Key findings for industry 
It’s no secret the packaging industry wants to produce more materials that can serve increasing consumer demand, Zelezniak continues: “They care that their products are cheap and comply with current policies.”

Therefore, he suggests that policymakers should pay more attention to how plastic waste is recycled and support more environmentally sustainable alternatives to packaging materials, despite the higher costs. He also advocates for plastic-related taxes, similar to the incoming UK Plastic Packaging Tax.

Furthermore, Zelezniak highlights the necessity of supporting scientific research: “If such research would be more encouraged, eventually scientists and young enterprises could find an [environmentally] sustainable and economically feasible solution to fight the plastic waste problem.”A future step would be developing a process to recover plastic polymer precursors that can be repeatedly utilized in the plastic production, explains Zelezniak.

Circular ideas
A future step would be developing a process to recover plastic polymer precursors that can be repeatedly utilized in the plastic production, explains Zelezniak.

“This is a process which is still quite expensive. Thus, plastic producers prefer to use fresh raw materials, which results in this global plastic waste increase.”

Another scenario would be to circumvent the carbon from plastic waste to more economically viable products.

“Anything that is more economically viable than just waste, such as fuels or any other biomass-derived product, could be a potential future solution and could increase the plastic circular economy,” concludes Zelezniak.

By Natalie Schwertheim