Vegan spider silk: a new material for plastic replacement
From time immemorial, man has drawn inspiration from nature to innovate. By looking at the exceptional strength of spider webs and trying to replicate it with plant proteins, researchers at Cambridge University have developed a new, fully home-compostable plant-based polymer film that is as strong as fossil fuel-based plastics.
Bags, bottles, trays, tubes, cans, flasks, etc.; are all made of plastic. According to Elipso, in France, 2 million tons of plastic are used for packaging yearly, 68% of which for the food industry.
Evidently, plastic pollution has extremely harmful effects on our ecosystem. In the form of micro-plastics (size ~5 mm) from everyday consumer products or from the fragmentation of macro plastics. These dangerous materials are everywhere, and easily assimilated by living organisms, affecting plants (altered photosynthesis, inhibited root growth, reduced cell viability, etc) and animals (altered fertility, increased mortality, brain damage for instance).
Throughout 2016 in France, plastic production generated 2 billion tons of CO2, almost 6% of the total CO2 emissions[1]. Switching from plastic to other materials could significantly reduce greenhouse gas emissions, which is a current problem as 73% of consumers are concerned about carbon emissions[2]. While cardboard, glass and aluminum are already widely used to replace plastic, these materials do not possess the flexibility of plastic film.
Researchers from the University of Cambridge, became interested in why materials like spider silk are so strong despite having such weak molecular bonds. They found that one of the key features that gives spider silk its strength is the hydrogen bonds, arranged regularly in space and in very high density.
Spiders dissolve the silk protein in an aqueous solution, which then transforms it into an immensely strong fiber through a spinning process which requires very little energy. Researchers began looking at how to replicate this regular self-assembly in other proteins. They successfully replicated the structures found on spider silk by using soy protein isolate, a protein with a completely different composition.
The energy-efficient method, which uses sustainable ingredients, results in a plastic-like free-standing film, which can be made at industrial scale. Non-fading ‘structural’ color can be added to the polymer, and it can also be used to make water-resistant coating. This new material is as strong as many plastics in use today, fully home-compostable and could replace plastic in common household products. The future of plastics is about to change quite a lot thanks to all the research being made. Whether it is mycelium or spider silk, we are all learning from our environment to provide a solution to the fossil fuel plastics problem.
[1] Plastique(s), Club Science for Good, SoScience, july 2019
[2] Packaging intelligent, FMCG Gurus, 2020
Article by Sophie De Reynal, Marketing Director at Nutrimarketing