When the first full synthetic plastic was invented in 1906 – over 100 years ago – widespread use of the material for consumer products soon arose in the post-war period. Plastic was cheaper to produce than the more expensive paper, glass and metal materials used in throwaway items – such as consumer packaging – and was also stronger, lighter, safer and more durable, and it shifted the way that we use materials forever.
However, the properties of plastic that make it such an attractive material, such as durability and strength, also make it a lasting problem once it reaches the end of its useful life. Some types of plastic can take thousands of years to degrade, and it is estimated that a truckload of plastic enters the ocean every minute.
In response to such concerns, biodegradable plastics – that is, plastics that can break down or ‘biodegrade’ – have been in development since the end of the last century, to achieve similar usage and convenience of traditional plastics, but with the goal of breaking down quickly and harmlessly. But, as the global production of biodegradable plastics increases – from 1.5 million metric tons in 2023 to almost 5.3 million in 2028 – it is critical that we understand the impacts of these materials on the environment.
As such, a 12-week study has been underway in the laboratory in Mesocosm, a facility that enables scientists to conduct research in a controlled aquatic environment – which closely simulates natural conditions. The experiment aims to understand the impact of biodegradable plastic on marine coastal ecosystem processes, and to determine what exactly happens to the plastic once it enters the marine system. It is a collaboration between Plymouth Marine Laboratory, the University of Plymouth, and the University of Bath.
Dr Rachel Coppock, Marine Ecologist at PML and overseeing the experiment, said: “Our understanding about the impacts of biodegradable plastics is really in its infancy. Whilst biodegradable plastics pose the potential to reduce the longevity of plastic pollution in the environment, any additives in the plastic may leach out during degradation – and we don’t fully understand what impact that may have on fauna or ecosystems.” “Many biodegradable plastics are not designed to break down in the natural environment, but rather under specific conditions, like industrial composters. So, when these types of biodegradable plastics end up in the sea, they may take a long time to degrade. In fact, one study by colleagues at the University of Plymouth found that a biodegradable carrier bag could still hold a full bag of shopping after being submerged in the sea for 3 years.”
She went on to say: “The experiment concluded in December, and now we will be evaluating the findings. We hypothesise that both biodegradable and conventional plastic particles will be found in all compartments of the system, including buried in the sediment, within the animals, and in the water. We may see altered sinking rates of copepod faeces (biological carbon pump) and a shift in microbial community composition.”
Milk Byproducts
A US scientist from the Agricultural Research Service (ARS) is developing a new approach to combat it. Atanu Biswas, a research chemist at the ARS National Center for Agricultural Utilisation Research in Peoria, Illinois, has spent much of his career exploring ways to convert agricultural waste products into bioplastics. Biswas’ latest effort involves utilising dairy waste, specifically lactose, a type of sugar produced by the dairy industry as a byproduct.
While lactose-based bioplastics do not currently replicate the full range of characteristics that conventional plastics offer, they can be useful for certain niche applications like insulation, cushioning material for furniture, footwear, rubber flooring, or some medical equipment.
The novel bioplastics represent a “win-win-win situation” for industry, farmers, and consumers. For industry, they provide an opportunity to present a cleaner and greener image while taking advantage of a renewable feedstock that is readily available. Consumers who recognise the problem that plastics present will appreciate a less damaging option for the environment. For farmers, finding a use for what would otherwise be waste is also a win.
Dead Flies
Dead flies could be turned into biodegradable plastic, researchers have said. The finding, presented at the autumn meeting of the American Chemical Society (ACS), could be useful as it is difficult to find sources for biodegradable polymers that do not have other competing uses.
“For 20 years, my group has been developing methods to transform natural products – such as glucose obtained from sugar cane or trees – into degradable, digestible polymers that don’t persist in the environment,” said the principal investigator, Karen Wooley, from Texas A&M University. “But those natural products are harvested from resources that are also used for food, fuel, construction and transportation.”
A colleague suggested she could use waste products left over from farming black soldier flies. The larvae of the flies contain proteins and other nutritious compounds so are being raised for animal feed, and they break down waste so are being bred for that, too. However, adult flies are less useful and are discarded after their short life span. Wooley’s team has been trying to use these carcasses to make useful materials from a waste product.
The researchers found that chitin, a sugar-based polymer, is a major component of the flies and it strengthens the shell, or exoskeleton, of insects and crustaceans. Shrimp and crab shells are already used for chitin extraction. Researchers said the fly-sourced chitin powder seemed purer than that from crustaceans and obtaining chitin from flies could avoid concerns over some seafood allergies. From the fly products, the team created a hydrogel that can absorb 47 times its weight in water in just one minute. This product could be used in cropland soil to capture flood water and then slowly release moisture during droughts.
Wooley said: “Here in Texas, we’re constantly either in a flood or drought situation, so I’ve been trying to think of how we can make a superabsorbent hydrogel that could address this.” The scientists hope they will soon be able to create bioplastics such as polycarbonates or polyurethanes, which are traditionally made from petrochemicals, from the flies. These plastics will not contribute to the plastic pollution problem.
Wooley said: “Ultimately, we’d like the insects to eat the waste plastic as their food source, and then we would harvest them again and collect their components to make new plastics. So the insects would not only be the source, but they would also then consume the discarded plastics.”
Seaweed Solution?
The world is in dire need of a better bioplastic solution. FlexSea, a startup with its roots at Imperial, has announced the completion of a seed round worth £3 million in equity and grants. The investment will help the company commercialise a range of sustainable packaging solutions it has developed, based on plastics derived from seaweed.
The aim is to address the catastrophic impact of conventional plastics on the environment, in particular the single-use plastic products that persist in the ocean for many hundreds of years after they are discarded. In contrast, the biodegradable plastics devised by FlexSea will break down in the sea or the soil within a matter of weeks.
Carlo Fedeli, the co-founder and Chief Executive of FlexSea, first started to think about biodegradable plastics during the COVID pandemic, while he was at home finishing an MSc in Innovation, Entrepreneurship & Management at Imperial College Business School. “I noticed the amount of plastic packaging that was piling up at home, because of the online groceries and other deliveries we relied on at the time, and I just had enough,” he says.
He started looking into the biodegradable plastics that were already available, and found that they often had shortcomings. Some didn’t actually break down very rapidly under day-to-day environmental conditions, while others involved unsustainable production methods. For example, plastics derived from seaweed are often made from brown seaweed, which is usually harvested from nature, rather than the commonly cultivated red seaweed.
“If you want to make a sustainable material, why not use the most sustainable source for it, which is also the most abundant right now?” he asks. So he set out to develop a thin-film plastic from red seaweed. “By the end of lockdown I had the first prototype, a transparent flexi-film, and that is still the backbone technology of our solvent-cast thin films,” he says.
Along the way, the company has developed two lines of bioplastic: thin transparent films, for use in food and non-food packaging, and filaments and pellets for use in extruders, injection moulding devices and 3D printers to produce rigid and semi-rigid items. These materials are not only completely biodegradable in marine and soil environments, but also home-compostable within 8-12 weeks.
Meanwhile, the production process behind FlexSea’s biomaterials avoids the use of harsh chemicals and high temperatures, instead relying on renewable and natural ingredients. All production scraps and offcuts are recyclable, providing a closed-loop solution. The next steps for FlexSea are to complete R&D into the different products it might offer, and decide on the first to take to the market.
“This is a turning point for the company, and a great reward for the hard work and dedication of the whole team of 10 amazing people, who will benefit from this funding in their everyday research and development activities,” says Mr Monfort, FlexSea’s Chief Technology Officer. “We are heavily investing in equipment and machinery for in-house R&D, speeding up the process tremendously.”
San Diego-based Algenesis Corporation, the plant-based material science company behind the biodegradable shoe brand BLUEVIEW, announces it has raised $5 million in a seed funding round to expand production and commercialisation of Soleic PU, a plastic biomaterial made from plants and algae.
Algenesis, a leader in eco-innovation, has developed a technology that uses plants and algae to make biobased plastics. The company claims that Soleic is the world’s first renewable, high-performance, fully biodegradable, and backyard compostable bioPolyurethane. Soleic is free from plastic’s harmful PFAS chemical additives and is biodegradable even in compost. It is said to compete with petroleum-based plastic in functionality and cost. Regarding sustainability, its production process has 50% lower GHG emissions than petroleum PU3, Algenesis explains.
Twenty-five million tons of polyurethane (6% of total plastics) are used annually across footwear, medical, and textile industries. Due to its composition, PU is hard to recycle, ending up in landfills or as microplastics in the environment.
Polymateria
Polymateria, a scale-up based at Imperial’s White City Campus, has received £20m Series B funding to scale its tech for making plastics biodegradable. An estimated 32% of plastic ends up as leakage globally from the waste collection system, a problem Polymateria aims to address using a technology that attracts microbes to biotransform products such as plastic bags and packaging if they enter the natural environment, without leaving behind microplastics or harmful residues.
The technology allows manufacturers to control the lifespans of their plastic products, ensuring they remain functional long enough for their intended use, while importantly the plastics can still be recycled, an outcome that remains the intended method of disposal.
Polymateria’s CEO Niall Dunne said then: “Our mission to develop more credible and scalable scientific solutions to address the world’s plastic pollution pandemic has benefitted hugely from being part of Imperial’s ecosystem.”
Bioplastics make it possible to develop innovative, alternative solutions compared to conventional plastics. Even more, biobased plastics reduce dependence on fossil resources whilst improving a product’s carbon footprint. Biodegradable labels and plastics allow enhanced end-of-life scenarios for disposal and recycling. This may lessen the burden on our existing waste systems and also the environment. The packaging industry is currently the largest user of bioplastics, but there are many other suitable applications possible, and consumers are increasingly interested in alternative bio solutions.
