Plastic waste has become an escalating problem on our planet. The battle against non-biodegrable plastics feels like a battle that can't be won, but there in some hope in the unlikely form of fungi.While recycling plays a vital role, it has its limitations, primarily due to the availability of recycling technology and the condition of the plastic. However, there is a glimmer of hope on the horizon, as researchers at the University of Sydney made a remarkable discovery. In their recent study they found that two common forms of backyard fungi, Aspergillus terreus and Engyodontium album, can effectively break down polypropylene, a challenging-to-recycle plastic, in just 140 days.
Polypropylene, a plastic commonly used in everyday products such as food containers, coat hangers, and cling film, is notorious for its low recycling rate, which stands at a mere one percent. This plastic accounts for approximately 28 percent of the world's plastic waste, adding to the global plastic pollution crisis. The fungi in question, Aspergillus terreus and Engyodontium album, were introduced to pre-treated polypropylene that had undergone UV radiation and heat treatment. Over a period of 90 days, these fungi successfully degraded 27% of the plastic, and by the 140th day, they achieved complete degradation. Professor Ali Abbas, one of the researchers, described this as "the highest degradation rate reported in the literature." The team envisions scaling up this process, similar to fermentation, by drawing from existing knowledge in chemical process engineering.
This breakthrough offers a promising solution for areas with limited waste infrastructure, where plastic waste accumulates due to the lack of proper disposal methods. It adds to a growing list of innovations, including plastic-eating worms, aiming to address our plastic pollution crisis. However, it is essential to acknowledge that even with these breakthroughs, the ultimate goal should be to reduce plastic use. Both plastic production and recycling generate substantial carbon emissions. Degrading plastic through fungi also releases carbon. Therefore, while these solutions are valuable for existing waste, reducing plastic consumption remains the most effective approach.
Another study, led by researchers at the Royal Botanic Gardens, Kew, has identified a diverse microbiome of plastic-degrading fungi and bacteria in the coastal salt marshes of Jiangsu, China. This international team of scientists discovered 184 fungal and 55 bacterial strains capable of breaking down polycaprolactone (PCL), a biodegradable polyester widely used in the production of various polyurethanes. Some bacterial strains within the genera Jonesia and Streptomyces displayed potential for further degrading other petroleum-based polymers, whether natural or synthetic.
Plastics in aquatic ecosystems create a "microbial reef" for fungi and bacteria to thrive, making them an integral part of the ecosystem. Biodegradable plastics can provide a food source for these microbes. The researchers collected samples of plastic waste from different types of petroleum-based polymers, including polyethylene terephthalate (PET), expanded polystyrene (EPS), polyethylene (PE), polyurethane (PU), polyamide (PA), polypropylene (PP), and polyvinyl chloride (PVC). They identified various genera of fungi, including plant pathogens like Fusarium and Neocosmospora. These plant-pathogenic fungi, known for extracting nutrients from plants in ways that harm the host, might hold the potential for degrading synthetic polymers.
The discoveries made by researchers at the University of Sydney and the Royal Botanic Gardens, Kew, offer a glimmer of hope in our battle against plastic pollution. Fungi and bacteria, once considered mere microscopic entities, now stand as potential allies in the fight to reduce plastic waste and its harmful environmental impact. While we celebrate these breakthroughs, the urgency of reducing plastic consumption and increasing recycling efforts remains paramount in our quest to safeguard the planet's future.