The Materials Landscape
Biodegradable materials fall into several broad families, each with different feedstocks, properties and end-of-life pathways.
Polylactic Acid (PLA)
Most widely used biodegradable polymerPLA is produced by fermenting plant sugars (typically from corn starch, sugarcane or cassava) to produce lactic acid, which is then polymerised. It is transparent, food-safe, and can mimic the properties of polyethylene or polypropylene.
Properties
- Tensile strength: 50–70 MPa
- Glass-transition temperature: ~60 °C
- Fully compostable under industrial conditions (EN 13432)
- Transparent; good gas-barrier properties at low humidity
Degradation
PLA undergoes hydrolysis at elevated temperatures and humidity. In industrial composters (58–60 °C) it degrades in 6–12 weeks. At ambient temperature it can persist for years, meaning landfill disposal offers little benefit.
Current uses
Food packaging, disposable cutlery, cups, agricultural films, 3D printing filament, medical sutures and tissue scaffolds.
Corn-derived PLA
1 kg of PLA requires approximately 1.6 kg of corn starch and emits 1.8 kg CO₂-eq (vs. 6 kg for conventional PET). However, land use and water consumption must be factored into full life-cycle analysis.
Polyhydroxyalkanoates (PHA)
Bacterial bioplasticsPHAs are a family of polyesters produced naturally by many bacteria as intracellular carbon and energy storage granules. They are synthesised when nutrients (nitrogen, phosphorus) are limited but carbon is in excess. The most commercially important members are PHB (polyhydroxybutyrate) and PHBV.
Why PHAs matter
- Marine-biodegradable: Degrade in seawater within months
- Home-compostable: Active at lower temperatures than PLA
- Diverse properties: Range from rigid to elastomeric depending on monomer composition
- Biobased: Produced from waste streams (wastewater, agricultural residues)
Production challenge
PHAs are currently 3–5× more expensive than PET. Scaling up fermentation using cheap feedstocks (methane, CO₂, food waste) is an active research priority.
Bacterial Factories
Certain bacteria accumulate PHA granules up to 80% of their dry cell weight — nature's own plastic production system.
Plant-Based Materials
A wealth of agricultural polymers form the basis of biodegradable films, fibres and coatings.
Starch
Extracted from corn, potato, wheat or cassava. Blended with plasticisers to make thermoplastic starch (TPS). Fully biodegradable in soil and water. Used in films, loose-fill packaging ("packing peanuts") and agricultural mulch films.
Degradation: Weeks–months in soil
Cellulose
Most abundant natural polymer on Earth. Paper and cardboard are obvious examples, but refined cellulose acetate, cellophane and nanocellulose composites push performance boundaries while remaining biodegradable.
Degradation: Weeks–months depending on crystallinity
Chitosan
Derived from chitin — the structural polymer in crustacean shells and insect exoskeletons. Antimicrobial, film-forming, and fully biodegradable. Used in food coatings, wound dressings and drug delivery.
Degradation: Weeks in soil and water
Proteins (Zein, Gluten, Soy)
Plant proteins form flexible, oxygen-barrier films. Corn zein creates glossy coatings used in confectionery and pharmaceuticals. Wheat gluten films compete with polyethylene for certain food-packaging applications.
Degradation: Days–weeks in compost
Alginate & Seaweed
Extracted from brown algae. High moisture content limits some applications, but dried alginate films, capsules and sachets biodegrade within days in the sea — ideal for single-use sachets to replace plastic sachets.
Degradation: Days in seawater
Lignin & Hemicellulose
Lignin — the "glue" of wood — is a massive by-product of paper-pulping. It is thermoplastic and biodegradable, with great potential as a black packaging material and carbon-fibre precursor.
Degradation: Months–years (dependent on form)
Novel & Emerging Materials
Mycelium Composites
Fungi mycelium (root networks) can be grown on agricultural waste to create lightweight, strong, fire-retardant foam-like materials — comparable in performance to expanded polystyrene (EPS) but fully home-compostable.
Ecovative Design pioneered this approach; their materials are now used by IKEA, Dell and other major brands for protective packaging. Mycelium "leather" is also emerging as a biodegradable alternative to animal hide.
Biodegradable Electronics Substrates
Cellulose nanopaper, silk and beeswax are being used as substrates for printed electronics and sensors that dissolve after use. This addresses the fast-growing global e-waste crisis. Nature has published multiple landmark papers on "transient electronics" — see the Research page.
Mycelium: Nature's Engineer
A single cubic metre of mycelium composite can be grown from agricultural waste in 7–10 days, using no fossil fuels, and requiring only water and air.
Material Comparison
Key properties at a glance — all data approximate; dependent on grade and processing.
| Material | Feedstock | Compostable? | Marine-degradable? | Typical Cost vs. PET | Key Limitation |
|---|---|---|---|---|---|
| PLA | Corn / sugarcane | Industrial only | No (very slow) | 1.5–2× | Low heat resistance; needs industrial composter |
| PHA | Microbial fermentation | Industrial & home | Yes | 3–5× | High cost; brittle grades |
| TPS (starch) | Corn, potato, cassava | Yes (home) | Yes | 1–1.5× | Moisture sensitive; poor barrier properties |
| Cellulose acetate | Wood pulp | Industrial | Slowly | 1–2× | Slow marine degradation; energy-intensive production |
| Mycelium | Agricultural waste | Yes (home) | Yes | 1–3× | Limited to non-structural, dry applications |
| Chitosan | Shellfish waste | Yes (home) | Yes | 2–4× | Feedstock supply constraints; allergen concerns |
See How These Materials Are Used
From farm to hospital to ocean — discover the real-world applications of biodegradable materials.
Explore Applications →