Bio-based material developments — so good you could eat them (almost). Healthy, circular, plastic-free natural polymers for sustainable design.
The future of materials looks good when you zoom in on bio-based developments. These materials are wholly or partially derived from plants, trees or animals. There are three main groups, starting with the traditional biomaterials like plant fibres, wool, wood and so on. Made up of complex natural polymers, such as cellulose, proteins and lignin, the properties and qualities of these materials are determined by the environmental conditions that have shaped the plant or animal. So, while the boll fibres of the cotton plant are incredibly soft and light, designed to carry a seed on the wind; the bast fibres of hemp and flax are long, strong and tough enough to keep the plant upright against the wind; and wool, ranging from fine merino to heavy Cotswold, provides incredible insulation and protection.
These renewable materials are inherently circular, as long as the additives and processing do not undermine their toxicity or biodegradability. By mixing age-old crafts with modern manufacturing, companies are able to take advantage of their impressive properties, without undermining their sustainability. With a view to reducing their carbon footprint or removing plastics from their products, for example, companies are taking advantage of developments in bio-materials like hemp, banana (abaca), cotton, flax (linen), meadow grass, eel grass, coconut fibre (coir), pineapple and even bullrushes. Applications span fashion and textiles, composites, automotive, furniture, interiors and more.
Even these very familiar biomaterials are not exempt from innovation and transformation. With advances in technology their properties are enhanced while maintaining circularity. Mirum by Natural Fiber Welding (NFW) is a plastic-free plant-based leather made with natural rubber, plant-based oil, natural pigments, and minerals. Treekind from Biophilica is another plant-based leather, but this one is made with lignocellulosic waste ingredients, such as park leaves and forest offcuts. Bananatex fabric is crafted from 100% abaca banana fibre in its natural colour, with an optional wax-coating to enhance water resistance. Arboform injection moulded wood by Tecnaro is made with lignosulfonate (LS) leftover from the paper-making process. Wood and woody plants are converted into a wide range of engineered panels, which are available with plant-based adhesive binder or no added formaldehyde (NAF).
Natural polymers
Bio-based plastics and composites, also called bioplastics and biopolymers, are a group of biosynthesised materials that use biological ingredients instead of petrochemicals. They may be wholly or partially bio-based. There are several different types of natural polymer — the most commonly used in bioplastics are lignin, starch, cellulose, alginate and latex — each with their own characteristics and lots of opportunities for design, as explored in more detail here: Bioplastic — the good, the bad and the ugly. What is this group of materials and why are they so promising for sustainable design?. This article focuses more on the innovations and products that are born from these ingredients. So far only a handful of companies have mastered these materials on an industrial scale. After all, bioplastics account for only around 1% of total plastic production worldwide. But they have created impactful circular alternatives to polluting plastic products
Lignin bioplastic developments range from the familiar hardboard to mouldable and 3D printable liquid wood. This inexpensive natural polymer is typically seen as a waste product, and so can provide a very low-cost additive for bio-based plastics and composites.
Derived from sugary plants, starch bioplastic has been used in everything from PaperFoam packaging that provides a home compostable and recyclable alternative to expanded polystyrene (EPS) to BAUX acoustic pulp panels made with wood pulp, water, wheat (for colour), plant-based wax and acid from citrus fruit.
Cellulose appears in many formats including paper, chemically regenerated cellulose fibre and as semi-synthetic cellulose acetate (CA). Biosynthetic developments include lyocell fibre, which is manufactured in an almost closed loop processes, massively reducing the environmental impacts of fibre production; chemical recycling of cellulose fibres and cellulose rich textile waste, such as cotton and denim; lab-grown cotton which promises to be ten times more productive than conventional cotton agriculture in a process that uses 77% less water, 80% less land and emits 84% less CO2 than traditional cotton manufacturing; and home compostable transparent cellulose packaging films.
Seaweed-based biopolymers—alginate, agar and carrageenan—have emerged only recently as a potential source of industrial bioplastic, but innovation is already plentiful with Notpla compostable and non-toxic paper coatings for packaging, seaweed packaging films; Kelsun seaweed textile from Keel Labs; and Agoprene seaweed foam made from Norwegian kelp. See also What the kelp! Exploring this pioneering new breed of materials made from seaweed, including paper, packaging, foams and textiles..
Natural rubber and latex has been in use for sometime as industrial material for tyres, toys, footwear and garments. While it is an incredibly valuable material, its production creates vast monoculture plantations and uses a range of harmful chemistry. Choosing organic rubber and latex such as Theptex foam and certified products such as Yulex helps to minimise the negative environmental impacts. Meanwhile, alternatives have emerged that build on the legacy of natural rubber, but use alternative ingredients, such as Terraprene. This is a type of polychloroprene rubber (CR) synthetic rubber, but made from limestone instead of petrochemicals. It has a similar carbon footprint to petroleum-derived neoprene, such as used in wetsuits, but avoids the use of oil and associated negative impacts.
Soy contains protein which provides the foundation for a range of bio-adhesives. Typically supplied as a water-based formulation, the protein in soy flour is cross-linked with a resin to form a strong and water-resistant adhesive. The properties are similar to formaldehyde-based systems. They are formaldehyde-free and provide a renewable alternative to synthetic adhesives in engineered wood, such as plywood and glulam.
Chitosan natural polymer derived from chitin, which can be found in the shells of shrimp and other crustaceans, is being explored as another potential bioplastic ingredient. The biopolymer is extracted by the deacetylation of chitin, such as with sodium hydroxide. For example, TômTex have developed a bio-based leather-like material using this ingredient, which is still under development in the lab. Chitosan is non-toxic and biodegradable. It is being explored and testing in many different formats and applications, from 3D printing to disposable packaging.
Spider’s silk has long fascinated material scientists and products have emerged that are inspired by its simplicity, sustainable potential and incredible mechanical properties. Spiders produce silk from a protein gel, which it stores in its body, and solidifies into a filament in response to shear forces. As it is pulled through spinnerets, the proteins align and form into a solid with impressive strength-to-weight. Examples include MicroSilk by Bolt Threads, a regenerated protein-based fibre that mimics spider silk, and Spintex, a spin-off from Oxford University in the UK, who are developing a process that artificially spins protein fibre, through a spider inspired process.
Catalytic conversion
There is an alternative strategy, which can offer a drop-in replacement for some petrochemical products. Virent have developed the BioForming process to make hydrocarbons (the building blocks of polymers, fuels and other petroleum products) through the catalytic conversion of soluble carbohydrates. The Bioforming process can handle a wide variety of plant-based carbohydrate feedstocks, from sugar beet, sugar cane and corn starch to bagasse, grass, sorghum and wood. Unlike fermentation and other batch forming processes, catalytic conversion is continuous and so offers lots of opportunities for efficiency gains. The chemicals they produce provide the foundation for a range of conventional plastics like polyester (PET), polyurethane (PUR), polycarbonate (PC), synthetic rubbers, polystyrene (PS), nylon (PA) among others. In addition, these 100% bio-based chemicals have other wide-ranging non-polymer uses in solvents, dyes, food preservatives, detergents and pharmaceuticals.
Another example is AirCarbon polyhydroxybutyrate (PHB), biodegradable polyester, by Newlight Technologies. After a decade of research and development, they have a pilot plant producing PHB from captured methane and CO2. Their technology is inspired by natural processes that occur in the ocean, whereby microorganisms convert methane and CO2 into PHB. They reproduce these microorganisms, which function as biocatalysts, converting oxygen from the atmosphere and methane and CO2 into biopolymer. By capturing greenhouse gases and powered by renewable energy, AirCarbon has the potential to be carbon negative.
Crude tall oil, a byproduct of the kraft paper-making process, mainly contains fatty acids and resin acids. It is the third largest byproduct in the kraft paper mill after lignin and hemicellulose. With catalytic upgrading (hydrotreating) in a biorefinery, it is possible to convert tall oil into bio-based naphtha. This bio-naptha is already used to replace fossil raw materials in various products such as bio-based plastics, glues and films. UPM in Finland produce naptha that is used in a variety of products, helping to reduce their environmental footprint. For example, Sabic use UPM BioVerno naphtha in ethylene production as part of the Trucircle umbrella of solutions, which has allowed DSM Dyneema ultra high performance fibre to be produced with partially bio-based ingredients. UPM utilise bio-naptha in their own products, too, such as UPM Formi EcoAce, a bio-based polypropylene (bio-PP), and Forest Film packaging labels.
Biofactories
Living cells like bacteria, enzymes and yeast have emerged as promising biofactories for creating the building blocks of a new class of bio-based materials. The natural polymers they create, like protein and cellulose, require some further processing and refinement to become useful industrial materials. Also referred to as biofabrication, the processing is engineered with a mix of biology and material science to create new materials with incredible sustainable and circular potential.
Using a fermentation process, like brewing beer, genetically engineered microorganisms are fed sugar crops and convert this into useful industrial chemistry. For example, yeast might produce collagen or protein, and bacteria may be used to produce cellulose or polyester (fatty acid). Alternatively, enzymes may be used to biologically break down plastic waste and convert it into reusable raw material as precursors for plastic production. The new material has properties indistinguishable from virgin petroleum-derived plastic. Protein Evolution developed the Biopure process, in which they have created enzymes using AI to optimise their ability to break down polyester, and they are developing similar solutions for other plastics like nylon (PA) and polyurethane (TPU). The company says that compared to virgin polyester, Biopure produces about 70% fewer CO2 emissions.
The process of developing these living bio-factories is complex and requires significant research and development. Once a promising strain of bacteria or yeast has been identified, or created, its fermentation conditions must be optimised. The material is not usually ready straight from the fermentation liquor, but requires extraction and conversion. For example, polyhydroxyalkanoates (PHA), a type of bio-based polyester, are stored as fatty acids in bacteria cells as an energy reserve. Once mature, the bacteria are treated with a mixture of enzymes or solvents that break down the cells walls and proteins surrounding the grain of PHA, and so allow it to be extracted. PHA is a family of biodegradable polyesters that exhibit thermoplastic properties when heated. It is not as cheap as fully synthetic materials and is not so widely available, but there are examples of PHA produced at scale already like Mirel by Telles and Phact by CJ Biomaterials.
Uluu in Australia have developed a novel type of PHA using seaweed as the feedstock. The seaweed is hydrolysed (cooked) with special enzymes, which break down the seaweed carbohydrates into fermentable sugars. These provide the food for PHA-producing microbes. The leftover seaweed has around 50% protein, which they further process into food products. The PHA microbes thrive in salt water, which helps the process and reduces the risk of contamination, because few other microbes like such salty conditions. Once mature, the PHA microbes are immersed in fresh water, which releases the plastic nurdles. These are collected and processed into bioplastic material, mixed with plant extracts to tweak the properties, suitable for injection moulding and fibre spinning.
Bioassembly
Bioassembly is another form of biofabrication, whereby the entire structure is grown directly by a living organism. The material may be wholly, or partially, made up of the living organism. Perhaps the best example is mycelium, the threadlike hyphae root structure of fungi. It is being developed and applied by several companies in a range of formats, including foam-like materials for packaging and acoustic insulation, flooring, and flexible textile that provides an animal-free alternative to leather. Also check out Magic mushrooms – exploring the huge potential of mycelium biofabrication for design and architecture, and the companies behind the development., which explores the development of this class of incredible new materials.
There are several manufactures exploring the potential of mycelium in new materials. Mogu in Italy make acoustic panels and floor tiles. Ecovative in the US make a range of mycelium based materials including the spawn for homegrown composites, packaging (Mycocomposite), foam (Airmycelium), vegan leather from compressed mycelium sheets (Forager), food and beauty products. MycoWorks in the US produce Reishi fabric using their Fine Mycelium process (hyphae develop in a bundled spiral arrangement resulting in highly organised structures to improve handle and allow properties to be tailored), which is marketed as a leather alternative. And Mycotech in Indonesia produce Mylea leather-like material (mycelium is grown on a fabric substrate) and Mycl composite (biodegradable solid composite).
Another material assembled by microorganisms is Celium by Polybion. Launched in 2022, Celium is a bacterial cellulose grown on agroindustrial fruit waste. In this way, the waste becomes nutrients that initiate growth. The cells create cellulose as a metabolic byproduct. Once the threadlike strands of cellulose have formed into a ‘skin’, the sheet is stabilised to ensure strength and resilience. There are no hazardous chemicals released as part of the process, and no significant biomass outputs between the growth cycles. Described by Polybion as a premium cultivated cellulose, Celium is produced as a leather-like material, providing a renewable and circular alternative to animal products and their synthetic equivalents. A versatile textile with endless design possibilities, it can be customised by colour, graining, embossing, and water resistance — all while preserving its mechanical properties.
@spot_material
hello@spotmaterial.com
