Novel Biorecycling Method Transforms Nylon Waste into Bioplastics

A group of researchers from the Institute of Bio- and Geosciences – Biotechnology at Forschungszentrum Jülich, in collaboration with the company Novonesis, has successfully engineered a bacterium capable of “eating” individual building blocks of various types of nylon and converting them into value-added products.

This breakthrough has the potential to significantly enhance nylon recycling. The findings of this study have been published in the journal Nature Microbiology.

Nylon, a synthetic polyamide, is widely recognized for its durability and high tensile strength. It is used across numerous industries and in a variety of products, including tights, underwear, sportswear, parachutes, nets, fishing lines, and automotive components.

Despite its extensive applications, the recycling rate for nylon remains alarmingly low, at less than 5%. Most nylon waste ends up in landfills due to the absence of effective recycling methods, is discarded in the environment as fishing nets or ropes, or is incinerated, which can release harmful substances.

Traditional recycling methods for nylon are often insufficient. Mechanical recycling, which involves melting and reshaping nylon into fibers or plastic products, is only feasible on a small scale because it requires highly pure nylon waste.

Chemical recycling, on the other hand, breaks nylon down into its building blocks to create new plastic. However, this process often fails to fully decompose the material, leaving behind a mixture of individual molecules and short molecular chains, known as oligomers.

This mixture is more challenging to process compared to pure polymer building blocks. The innovation developed by the Jülich research team addresses this issue.

Novel Solution: Bacteria Use Nylon Waste as a Food Source

The research team, led by Professor Dr. Nick Wierckx from the Institute of Bio- and Geosciences – Biotechnology at Forschungszentrum Jülich, has genetically modified the harmless soil bacterium Pseudomonas putida. This modification enables the bacterium to metabolize the mixture of nylon building blocks and convert it into value-added products, such as biopolyesters.

The breakthrough was achieved through a combination of genetic engineering and laboratory evolution, which allows bacteria to acquire new capabilities efficiently.

Some bacteria develop the ability to recycle nylon building blocks more efficiently following random mutations in their genome. These cells have a growth advantage over others and can multiply faster. After a few generations in the laboratory, where nylon building blocks were the only source of nutrition, the bacterial culture eventually consists only of these specialized cells.”

Dr. Nick Wierckx, Professor, Institute of Bio and Geosciences-Biotechnology, Forschungszentrum Jülich

By conducting detailed genome analysis, the researchers identified the mutations responsible for this enhanced ability and introduced them into Pseudomonas putida cells.

Additionally, they incorporated genes for specific enzymes, known as nylonases, which enable the bacteria to utilize short nylon chains derived from chemically decomposed nylon as an additional food source. The potential of these enzymes had been previously explored in an earlier study conducted in collaboration with Novonesis.

The results of this research are part of the recently concluded European project Glaukos. The Glaukos project aimed to make the life cycle of clothing, fishing gear, and coatings more sustainable by developing innovative processes and bio-based textile fibers.

The project also sought to significantly reduce both the carbon footprint and plastic pollution associated with these materials.