A team of researchers from the Rensselaer Polytechnic Institute (RPI) in the USA has made a revolutionary discovery: a process that not only addresses the problem of plastic waste but also paves the way for new, more sustainable materials. Using bacteria that can digest PET plastic, these scientists have found a way to quickly convert the waste into a biodegradable silk, inspired by the resilience and flexibility of spider silk.
The urgency of a solution
Hundreds of millions of tons of plastic are produced every year, most of which is not recycled. PET plastic, commonly found in single-use food containers, often ends up in landfill or the environment, where it can degrade into microplastic particles and end up in the most unexpected places, from vegetables to the placenta maternal, from the clouds al human heart.
The production of new plastic not only has a huge carbon footprint but also contributes to the accumulation of waste, and in many countries it shows no sign of diminishing.
The new RPI technology
RPI researchers turned their attention to bacteria pseudomonas aeruginosa. Bacteria naturally capable of consuming polyethylene. Through gene editing, these microorganisms were modified to produce a silk-like material by inserting a sequence of amino acids similar to a protein found in silk. You can find the complete study here.
The process used? It is comparable to the fermentation used in beer production. In this case, rather than feeding the microbes sugar, the researchers feed them a “predigested” form of plastic waste, transforming it into a new material.
Spider silk is nature's Kevlar. It can be almost as strong as steel under tension. However, it is six times less dense than steel, so it is very light. Being a bioplastic, it is elastic, resistant, non-toxic and biodegradable.
Helen Zha, Ph.D., assistant professor of chemical and biological engineering at Rensselaer Polytechnic Institute
The potential of biodegradable silk
The choice to start with silk was driven by its unique properties: it is strong, lightweight and naturally biodegradable. This material can function in many ways like the plastic we are used to, with the added benefit of degrading naturally without special treatment. Natural silk has already found applications in several fields, but the traditional production process is not sustainable.
The possibility of producing silk from plastic waste could allow a more extensive use of this material in applications where non-recyclable plastic is now used. Furthermore, the use of gene editing opens up the possibility of customizing the material, taking inspiration from the different types of silk produced by various types of spiders. This innovation demonstrates that it is possible to tackle the problem of plastic waste by producing useful materials that do not pollute the planet in the long term.
Silk from plastic: future prospects
Although the project is still in its early stages, the idea that bacteria can transform plastic waste into a valuable material is proven and successful. The RPI team is working to make the process more efficient. The target? Improve the yield of “bacterial silk” so that production can become commercially viable.
The grassroots approach could transform the way we think about materials production, replacing large chemical plants with more natural and sustainable processes. An important step towards a future where the materials necessary for our daily lives are produced sustainably, without compromising the health of our planet.
