When people think about plastic waste, they often think of the packaging that swaddles supermarket fruits and vegetables – shiny layers that are stripped away and thrown in the bin as soon as the produce is unloaded at home. It’s a wasteful cycle that California-based company Apeel says it can help end. The firm has developed an edible, tasteless and invisible plant-based spray for fruits and vegetables that works as a barrier to keep oxygen out and moisture in, increasing shelf life without the need for single-use plastic. It’s currently being sprayed on to cucumbers and avocados at retailers including Walmart. “We’re showing that you can actually reimagine a food system that’s not built on the foundation of single-use plastic”, said the CEO, James Rogers. Apeel, which is valued at $2bn, is part of a wave of startups and scientific projects racing to develop materials that could help replace traditional single-use plastics. Their production methods and applications vary widely, but their stated aim is the same: to end the scourge of plastic waste. Since the 1950s, the world has produced an estimated 8.3bn tonnes of plastic, nearly two-thirds of which has ended up in landfill or leaching into soil, rivers and oceans; choking wildlife. Plastics are a driver of the climate crisis – the vast majority are made from fossil fuels and if global production continues on current trends, plastics may account for about 20% of oil consumption by mid-century. The problem is that fossil-based plastics are not easy to replace. Plastic is a wonder material: cheap to produce, lightweight and incredibly durable. The latter is a great quality in use but not when it ends up in landfill or the environment – plastic can take centuries to degrade. Finding a material that is strong but can also essentially self-destruct when needed is incredibly tough. But plenty of scientists and companies are trying. Bioplastics have emerged as a popular alternative, even if they currently make up less than 1% of the market. Made from bio sources such as sugarcane, algae, even banana waste and shellfish, many pitch themselves as eliminating the need for fossil fuels and also breaking down easily after use. These green claims do not always stand up to scrutiny, said Sarah Kakadellis, a researcher in plastic pollution at Imperial College London. If the raw material is not sourced sustainably, bioplastics could end up increasing deforestation to clear land and competing with food production. They also do not always break down as easily as advertised – sometimes taking years – and others require industrial composting facilities, which can be scarce. Some companies say they have cracked these problems. The Dutch biochemicals company Avantium, which has partnered with brands such as Carlsberg, has developed a 100% plant-based plastic made from sugars that can be used for bottles and films. The company says its plastic is 100%-recyclable, has a significantly lower carbon footprint than fossil-based plastics and is sourced from sustainably grown plants. If this plastic falls out of the recycling stream, trials have shown that it takes about a year to decompose in an industrial composter. Left in the environment, the plastic starts to degrade after a year, according to initial results from a long-term study with the University of Amsterdam. Avantium plans to open its first plant in 2023 in the Netherlands and predicts its packaging will be in supermarkets in three years’ time. Other companies are developing plastics that avoid the need for crops altogether. In September, the UK-based biotech startup Shellworks launched a plastic made from microbes found in many marine and soil environments. These feed on carbon sources, building up a fat-like energy storage system. When this fat is extracted it behaves exactly like plastic, said Shellworks’ co-founder Amir Afshar; the difference is, when it returns to nature the same bacteria see it as food and start to eat it. “It comes from bacteria, and then goes back to bacteria,” Afshar said. The company has signed deals with beauty companies to work on products such as tubes, bottles and compacts, which often end up in landfill. When people have finished with Shellworks’ products, said co-founder Insiya Jafferjee, they can be treated like food waste and composted, with no special infrastructure needed. Other scientists are trying to turn plastic into a tool for tackling the climate crisis by making plastics from greenhouse gases. “One could see in the future capturing carbon dioxide from the air and then using that … to produce plastic,” Kakadellis said. Scientists at Rutgers University have developed technology that can turn water and CO2 into precursors for various plastics, which they say could replace PET and polyester fibre, ubiquitous in the fashion industry (about 60% of material made into clothing is plastic). The method is “essentially replicating nature’s process for making oil and gas over millions of years but doing so in a fraction of a second”, said Anders Laursen, the CEO of RenewCO₂, the startup spun out of Rutgers’ research. The company hopes to harness the CO2 emitted from plastics as they decompose or are incinerated and use it to create new products. RenewCO₂ is building a pilot plant and expects to reach commercialisation in 2025. Increasing consumer pushback on plastics has also led some companies to trial completely different materials. Mars and Unilever are experimenting with paper, which is widely recycled and less harmful than plastics if it ends up in the sea or landfill. This summer, Coca-Cola began testing a paper bottle in Hungary for its drink AdeZ, in partnership with Copenhagen-based startup Paboco, which makes bottles from moulded FSC-certified paper pulp. These bottles still have a plastic lid, however, and are lined with a recycled PET plastic film to keep the product from leaking or paper fibres from getting in. “Our ultimate vision,” said Paboco’s interim CEO, Gittan Schiöld, “is to develop a fully bio-based paper bottle that can also be recyclable in the paper stream”. The big questions for these innovations, said Sander Defruyt, who leads the new plastics economy initiative at the Ellen MacArthur Foundation, are: where is the material sourced from and where does it end up? Paper, for example, isn’t a sustainable packaging material if it contributes to deforestation or if the paper bottles and sweet wrappers don’t make it into recycling streams. It’s also likely to take many years before these materials can scale up enough to make a dent in the 300m tonnes of plastic produced every year. Mark Miodownik, professor of materials and society at University College London, worries about the proliferation of materials being developed without enough thought about how they fit into existing waste systems. “Mostly what we want to do is actually make plastics that are very durable and we want to keep them in the system – so we want to recycle,” he said. Where he thinks biodegradability and compostability make sense are products such as caddy liners for food waste bins, teabags (“why include the plastic that’s going to last you 100 years into a teabag? That’s crazy!”) and hygiene products such as nappies. Before they are potty-trained, a baby can use about 6,000 disposable nappies and these are nearly impossible to recycle. The Australian company gDiapers has created a plastic-free compostable nappy alongside a delivery and collection service. “We put this thing out into the world, we’re going to bring it back,” said Jason Graham-Nye, who co-founded gDiapers with his wife, Kim. The company is running a trial dropping off and collecting compostable nappies in West Papua, Indonesia, where nappies make up about 20% of the ocean waste – the resulting compost is used on the land. It is also working to launch its first UK trial in London. Products with very short shelf-lives could also suit compostable packaging. London-based Notpla makes plastic replacements from seaweed – a fast-growing, carbon sequestering plant – which break down anywhere within a few weeks. “It’s targeted at places where we pick something, we consume it, and it’s over within minutes,” said co-founder Pierre Paslier, “and that’s really where plastic is the worst material because it’s going to be around forever”. Notpla’s edible “Ooho” water bubbles were handed to runners at the 2019 London marathon. It has also partnered with the delivery service JustEat to provide compostable condiment sachets that can be put straight into the household food waste bins and has developed a seaweed coating to replace the plastic lining on cardboard takeaway boxes. Materials innovation is one part of the puzzle, said Defruyt, but truly dealing with plastic waste requires a hierarchy of action: eliminate as much plastic as possible; then use recycled plastic; finally, where virgin plastics are still required, use renewable feedstocks. “It really needs to be in that order”, he said. Scientists, engineers and companies may be tempted to look at plastic and say, “let’s swap it for another thing and that’s now solved”, Miodownik said, but “the truth is, you have to redesign the whole system if you’re going to solve the problem”.