Could ‘vegan spider silk’ be the answer to the plastic crisis?
Scientists have come up with a bioplastic that uses soy protein to mimic spider silk with all the tensile strength but none of the exploitation associated with other alternatives currently in development. But is it too good to be true?
The news that scientists from the University have created what they have dubbed a ‘vegan spider silk’ has caused quite the stir. Newspapers from the Independent to the Daily Telegraph, plus most of the plant-based press, have covered the story, eager to grab the attention of environmentalists and vegans alike.
It certainly is an incredible achievement to mimic one of the strongest substances produced by the natural world using soy proteins, broken down and then reconstituted in the same way as spiders’ silk. The process is energy efficient and results in a bioplastic film that can easily be composted at home, the researchers said.
“Because all proteins are made of polypeptide chains, under the right conditions we can cause plant proteins to self-assemble just like spider silk," said Professor Tuomas Knowles, an expert in protein folding from Cambridge’s Yusuf Hamied Department of Chemistry, further explaining that the spinning of silk proteins into fibres requires minimal energy.
“In a way we’ve come up with ‘vegan spider silk’ – we’ve created the same material without the spider,” said study co-author Dr Marc Rodriguez Garcia.
In creating a process that uses water and acetic acid to dissolve plant proteins prior to reassembling the isolate into a film, scientists may well have answered several challenges when it comes to bioplastics - cost efficiency, commercial viability, actual biodegradability, and all without having to rely on animal-derived ingredients.
The study published in the journal Nature Communications has found that the vegan silk film has a strength equivalent to plastics such as low-density polyethylene (LDPE), commonly used to make plastic bags but also a wide range of other applications such as computer parts, milk cartons and the much-vilified six-pack rings. Whether the silk can replace all of these remains to be seen, but a range of sachets and capsules are slated to be released by Xampla - a company with ties to the research team working to commercialise the silk - by the end of 2021, replacing products like dishwasher tablet wrappers and laundry capsules.
However, unlike LDPE, scientists say the new film can be thrown onto your compost heap at home, the same of which cannot be said of the world’s current leading bioplastic - polylactic acid (PLA), made from fermented corn starch and used for cups, straws and takeaway containers.
According to Wired in their 2019 article Why is it so damn hard to make a climate crisis-friendly plastic?, PLA takes 12 weeks to break down, which is great, but only in industrial composting conditions requiring oxygen and heat. If PLA is not thrown away correctly it can take just as long to degrade as normal plastic. A study by the University of Bayreuth found that PLA after a year in 25 centigrade seawater showed no signs of breaking down, making it virtually pointless in addressing the problem of plastic bags and packaging being thrown out with general waste and finding their way into our oceans. The issue with plastic isn’t just that it doesn’t biodegrade, but that people don’t care enough to recycle it properly in the first place.
What is clear is that the quest for the perfect bioplastic is still ongoing. There isn’t one type of plastic for all applications, so equally there cannot be one bioplastic to rule them all. Several other avenues are currently being explored, some utilising waste products of animal exploitation such as in the case of MarinaTex, a material made from fish scales and algae.
While using byproducts may seem a positive move in regards to sustainability, it is less than ideal when considering the rights of animals. As with leather, a so-called co-product of the animal agriculture industry, the last thing we want is a bioplastic that can potentially provide a new source of revenue to the fishing industry. However, we do not yet have the supply chain and refinement processes necessary to make fish plastic a commercial reality and are unlikely to until the big players invest in the technology.
Fortunately, fewer challenges face our vegan spider silk, which avoids having to work with animal proteins and the problem of where to source and how to refine them. By the sounds of it, making vegan spider silk is as simple as dissolving soy protein in water and acetic acid, the same acid found in vinegar, albeit with some sound waves and high temperatures - nothing that makes it more costly to produce than other alternative plastics.
With soy being one of the most widely farmed crops in the world, making its waste readily available, the future of vegan spider silk plastic is bright.
Andrew Gough is Media and Investigations Manager for Surge.
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