Recycled Plastic Material from Composting Process
In the ongoing battle against plastic pollution, scientists are making significant strides in developing biological recycling processes for one of the most common plastics – PET. Christian Sonnendecker from Leipzig University is at the forefront of this research, focusing on PET recycling.
However, another oil-based plastic, nylon, presents a more formidable challenge due to its chemical stability. A fishing net or a mobile phone case thrown into the sea could potentially still be found in a thousand years, while a PET bottle could potentially disappear from nature after a hundred to 400 years.
Researchers, including Wolfgang Streit and his team, are now turning their attention to nylon degradation. They have discovered enzymes in compost piles that break down PET exceptionally fast, and they are investigating if bacteria and fungi can decompose nylon, albeit slowly.
PET-degrading enzymes like PETase are well-characterized and increasingly engineered for plastic recycling. These enzymes hydrolyze the ester bonds in the polymer, breaking it down into its basic building blocks, from which high-quality new plastic can be made. Recent metagenomic studies have identified PET-degrading bacteria and enzymes distributed globally, expanding the known diversity and potential sources of these enzymes for improved plastic biodegradation.
Nylon, however, is a polyamide and structurally different from PET, making it more challenging to degrade. Enzymes known as nylonases have been identified that can break down certain nylon oligomers or byproducts, but complete biodegradation of nylon polymers is slower and less developed.
Streit and his team are examining plastic waste from Hamburg's waters to find nylon-degrading organisms and plan to discover enzymes that can break down nylon for potential use in future recycling processes. They are not optimistic about finding a "super-bug" for nylon degradation but remain hopeful about the potential of microorganisms.
Meanwhile, the French company Carbios has developed a technology for enzymatic recycling of PET and is building a commercial plant for it. Unfortunately, all other polymers, such as PE films, PVC, and polypropylene, cannot be degraded due to their high chemical stability.
Streit expresses excitement about the potential discovery of cool enzymes for nylon degradation and emphasizes the need for more research in the field of plastic degradation by microorganisms. As our world grapples with the mounting issue of plastic waste, these advancements in biological recycling offer a promising solution for a cleaner, greener future.
[1] Plastics, Microbes, and the Environment [2] Metagenomic discovery of a PET-degrading bacterium in the deep sea [3] Improving the enzymatic depolymerization of PET for recycling [4] Degradation of polyolefins by microorganisms
- As scientists continue to explore solutions for ocean plastic pollution, the focus has expanded to include the degradation of nylon, a challenging oil-based plastic.
- Research in the field of environmental science, specifically microbe-plastic interactions, is uncovering potential enzymes that could decompose nylon, paving the way for nylon recycling.
- Simultaneously, advancements in health-and-wellness research, such as metagenomic studies, are identifying PET-degrading bacteria and enzymes worldwide, offering promising solutions for a cleaner, greener planet.
