Major consumer markets have imposed microbead bans in recent years to tackle marine pollution. For companies seeking biodegradable replacements, circular and plant-based options abound, waiting to be scaled.
The bead backlash
Plastic microbeads are among the most notorious pollutants from the cosmetics and personal care industries. These tiny grains of PE or PP plastics found inside face scrubs, body soaps, and toothpaste measure less than 5 mm in diameter but have had a huge impact on ocean environments.
According to the Plastic Soup Foundation in 2022, 87% of the products of the ten best-selling cosmetic brands in Europe contained microplastics. Small yet buoyant, they escape through most sewage treatment filters. Like other synthetic polymers, these beads are not built to biodegrade. Once eaten by fish in the open ocean, the plastics can find their way into the human food chain.
Awareness of their ecological impacts prompted a huge legal and consumer backlash around the mid-2010s. Microbeads concentrated a lot of consumer activism at the time and how companies dealt with the issue became seen as a barometer of their ethics among the buying public.
Many big brands withdrew plastic microbeads at the time: P&G and J&J announced they would remove plastic microbeads in face scrubs and in toothpaste in 2015 in order to pre-empt any legal bans. L’Oréal got rid of them from their exfoliant products in January 2017.
As well as reputational damage, a barrage of regulations in key markets over the last ten years mean that cosmetics companies will need to opt for biodegradable alternatives in future.
In 2015, the US prohibited the manufacturing, packaging and distribution of rinse-off cosmetics containing plastic microbeads. The UK implemented similar legislation in 2018 while in October of 2023, a much more comprehensive EU legislation banning microbeads and a whole host of other microplastics came into effect. China too has banned microplastics in rinse-off cosmetics.
In the coming years, it is likely that wider bans on microbeads beyond cosmetics will come into force around the world.
Perfectly plant-based spheres
Microplastics are popular because they enhance the cleaning properties and skin-feel of the liquid formula in which they were mixed. Luckily, alternative biobased materials are well up to the task of replacing them.
The UK’s Naturbeads is one of the best-known startups producing biobased alternatives to plastic microbeads. Naturbead’s spherical microbeads are biodegradable because they are derived from the plant material cellulose, which can be worked into a huge range of materials.
So far, its business model has focused on licensing, selling IP and a production process more than a particular product: its customers can take on and use Naturbeads’ patented equipment, software, and processes to create biodegradable microbeads in different colours and sizes.
Recently however the company began to construct its first full-scale production plant in Puglia, Italy after receiving its seventh funding round of £7.8 million in 2024. The company is now focused on scaleup and getting its plant-based material to price parity with oil-based versions – something that it says will be possible once it hits 500 tonnes per year of production.
Beyond beauty: microbeads in paint and biotech
For plant-based alternatives to become widely adopted, and to maximise revenue, biobased producers must understand the full range of microbead applications in industry today, creating a product that is just as versatile.
Naturbeads is keen to develop replacements for microbeads across the full spectrum of industries where plastic versions are used. Microbeads are best known as exfoliants in cosmetics and personal care. Yet they also have other somewhat surprising applications. As a cheap additive for certain paints and coatings, they can enhance pigment opacity, durability, and flow.
Paints and adhesives are in general a lower-value, higher-volume application for microplastics than personal care and cosmetics. However, removing oil-based microbeads from paint is just as important if we are to reduce the damaging impacts of plastic waste on wildlife and human health. Waste consultant Eunomia has estimated that far more plastic from building or road paint ends up in oceans than from cosmetics.
After reporting that it has successfully tested products for use in paints, and fillers in adhesives, Naturbeads now ambitions to produce microbeads for even more high-value uses: as carriers for enzymes in biocatalysis and cell scaffolding for laboratory meat. Since 2021 Natubeads has been working with Cellular Agriculture on developing new edible cellulose ‘microcarriers’ that can be used to make cultured meat.
Producing microbeads for the biotech industry presents its own set of R&D problems, as cultured meat scaffolds serve several functions at once. Three-dimensional scaffolds are anchoring structures for cells to attach, mature, and replicate. They give cultured meat density and texture. Given the right material and shape, scaffolds can make a huge difference in increasing cell growth rates, potentially contributing towards scaling cultured meat.
A sustainable plastic microbead?
Cellulose is not the only suitable replacement for plastic microbeads. Polymers made from plants rather than oil also have potential. Polyhydroxyalkanoate (PHA) is a natural polymer that can be produced by microbial biosynthesis from sugars and vegetable oils. It has excellent biodegradability, including in the deep ocean, with results comparable to that of plant cellulose materials.
Researchers at the University of Georgia New Materials Institute found microbeads made from the material degraded in 15 weeks in laboratory conditions, and 13 weeks in field conditions, resulting in no minute plastic particles.
Aside from biodegradability, the team investigated another crucial aspect of microbead sustainability: whether the compounds that PHA breaks down into are toxic to wildlife.
This was an important facet of the research since some biodegradable materials can still be toxic, turning into harmful compounds once environmental microbes consume and metabolise them. This can have impacts that ripple up the food chain. The researchers behind the study said that this was not the case with their PHA.
“Numerous and diverse types of invertebrates and microfauna were observed inhabiting the microbead environment, suggesting the PHA microbeads supported healthy microbial biomass production as organisms consumed the microbeads,” said Evan White, first author on the study and director of the New Materials Institute. “Most of the carbon from the microbead metabolized to CO2, and some was converted into the bodies of organisms in this vibrant ecosystem which can be seen in supporting microscopy videos.”
Research from elsewhere confirms the biodegradable properties of PHA. A recent paper in Nature by Japanese researchers confirmed the rapid biodegradability of PHA microbeads in natural habitats by leaving a sample on the seafloor of a Japanese port bay.
The team said that PHA microbeads are most likely to break down in products that end up in sewage wastewater since this is the environment that is richest in the microbes best capable of digesting the material.
PHA microbeads would need global PHA production to grow – currently production is no more than 40, 000 to 50, 000, according to a 2022 estimate, which amounts to less than 2% of the bioplastics market.
Despite this, one company that already offers PHA-based microbeads, known as Minerv PHA Bio Cosmetics, suitable for cosmetics use is Italy’s Bio-On.
Circular options for new biodegradable microbeads are also being explored. Last year, Canadian researchers showed that brewer’s spent grain, the main byproduct of brewing, can be used as a personal care exfoliant. The manufacturing process consisted of taking pulp from the grain, making it soluble, then dropping a solution of the grain into an acid bath to form solid beads.
Fortifying food without a trace
Beyond cosmetics, paints, adhesives, and cultured meat, biodegradable microbeads might have even more functions in the future, such as for storing and delivering drugs or nutritional compounds. Scientists have developed a new type of microbead material with special properties that make it useful for food fortification.
Food fortification, where common foods are loaded with beneficial nutrients and vitamins, play an essential role in public health, particularly in the developing world. Scientists found that biodegradable microbeads made from poly(beta amino esters) could be used to enclose and protect vitamins, allowing them to be safely placed inside food. The microbeads were found to be heat-resistant so they could be cooked without compromising their nutritional content.
With all their current and possible applications, microbeads show how even relatively simple biobased and circular materials can cut the ecological damage of various food and chemical industries. Innovation from startups like Naturbeads shows how biobased materials can often compete on performance with oil-based counterparts, including in high-precision applications like biotech and cultured meat.
