Enzymatic textile recycling

01Overview and value chain

Markers: [EC: EU Strategy for Sustainable and Circular Textiles (2030) + French IMPR Decree + EU REACH/ECHA | OECD: Circular bioeconomy | Regulator: EPA (USA), ECHA/REACH (EU), MARA (China)]

The textile industry produces more than 100 million tonnes of fibre a year, yet less than 1% of clothing is recycled back into new clothing. Mechanical recycling shortens fibres and degrades fabric quality, while thermochemical routes are energy-hungry, and both struggle with blended fabrics such as polycotton. Enzymatic textile recycling breaks this impasse with the absolute selectivity of biocatalysts operating at 50-70 C and neutral pH. Engineered cutinases and PETases hydrolyse the ester bonds of polyester (polyethylene terephthalate, PET) into its monomers, terephthalic acid (TPA) and ethylene glycol (EG), while cellulases convert the cotton fraction of blends into a glucose syrup for biochemical fermentation, leaving the polyester intact for recovery. The EU Strategy for Sustainable and Circular Textiles requires that, by 2030, all textiles sold in Europe be durable, recyclable and contain a high share of recycled fibre, and France’s IMPR decree grants a bonus of up to EUR 1,000 per tonne for recycled plastics from difficult streams, making enzymatic recycling a strategic pillar. The six organizations in this projection span enzymatic PET depolymerization (Carbios, Novonesis, Portsmouth CEI), molecular polyester regeneration (Ambercycle), AI-designed enzymes (Protein Evolution) and thermostable PETase research (TIB-CAS).

Key directions of enzymatic textile recycling:

1. Enzymatic PET depolymerization: engineered leaf-branch-compost (LCC) cutinases cleave crystalline PET into TPA and EG at more than 97% yield in under 14 hours.
2. Selective blend separation: cellulases hydrolyse the cotton fraction of polycotton to glucose while proteases and keratinases dissolve wool and silk, leaving clean polyester fibres for recovery.
3. Nylon and polyamide enzymatic recycling: nylonases and amidases cleave nylon-6 and nylon-6,6 into hexamethylenediamine and adipic acid under mild heat.
4. AI-directed enzyme evolution: generative protein-language models and directed evolution deliver thermostable enzymes active above the 70 C PET glass transition, sharply accelerating hydrolysis.

Sectoral value chain

[textile waste] ──> [sorting & amorphization] ──> [enzymatic hydrolysis]
                                                            │
                                                  (TPA + EG recovery)
                                                            │
                                                            ▼
[new rPET yarn] <─── [repolymerization] <─── [purification & crystallization]

Value chain levels

Cross-cutting technologies of the sector:

• pet-depolymerase: engineered LCC cutinases and PETases (e.g. LCCICCG, FastPETase) that cleave PET ester bonds at 60-70 C.
• cellulase-blend-separation: cellulase cocktails that dissolve the cotton fraction of polycotton into glucose, leaving polyester intact.
• ai-enzyme-design: protein-language-model and directed-evolution pipelines that deliver thermostable depolymerases for high-solids industrial hydrolysis.

02US

The United States leads molecular polyester regeneration and AI-designed enzymes, supported by DOE circularity grants and brand-driven demand.

Ambercycle cycora, Protein Evolution AI enzymes, DOE circularity grants

• Ambercycle (Los Angeles): its cycora regenerated polyester, made by molecular regeneration of end-of-life textiles, has been validated as virgin-grade by the European Center for Innovative Textiles (CETI); Ambercycle secured an USD 81 million, three-year contract with Inditex (Zara) in 2024, an Hyosung TNC partnership, and a BHF scale-up deal in early 2026, having raised more than USD 44 million and earned a Time Best Inventions 2024 listing.
• Protein Evolution (New Haven, CT): its Biopure platform uses AI-designed enzymes to depolymerize polyester waste, and an expanded collaboration with Basecamp Research targets polyurethane and nylon recycling, with partners including ESPCI Paris, JBEI and Fashion for Good.
• DOE circularity grants: the US Department of Energy funds enzyme and process optimization for plastic upcycling, including NREL and Harvard machine-learning enzyme programs in collaboration with the University of Portsmouth.

03CN

China, the world’s largest polyester and textile producer, treats scaled enzymatic recycling as a strategic priority to cut fossil feedstock use, with CAS institutes advancing thermostable PETase engineering under national circularity mandates.

CAS industrial biotech PETase R&D, national recycling mandates, Zhejiang scale-up

• Tianjin Institute of Industrial Biotechnology CAS (TIB-CAS): a leading Chinese centre for computer-designed, thermostable PETases active above 70 C, advancing directed-evolution and active-site engineering toward industrial PET hydrolysis.
• National textile recycling mandates: China’s five-year plans impose rising recycled-polyester quotas that push mills toward closed-loop bioreactors.
• Zhejiang industrial clusters: the country’s main textile region hosts experimental enzymatic hydrolysis lines for polycotton waste, scaling TPA recovery toward multi-thousand-tonne pilot capacity.

04EU

The European Union is the world leader in enzymatic textile recycling, building the first industrial-scale plant and setting the regulatory frame.

Carbios Longlaville plant, Novonesis enzyme supply, EU circular textiles strategy

• Carbios (Clermont-Ferrand): pioneer of LCC-cutinase enzymatic PET recycling; its Longlaville plant (50,000 tonnes/yr input, next to an Indorama Ventures PET site, EUR 230 million capex with EUR 42.5 million public funding) targets a H1 2028 production start once project financing closes (Q3 2026 target), with pre-commercial contracts covering close to 50% of capacity and a 70% target, backed by L’Oreal, Nestle Waters, PepsiCo and Suntory.
• Novonesis (Denmark): the Novozymes-Chr. Hansen merged enzyme giant holds an exclusive agreement to manufacture and supply Carbios’s patented cutinases for the Longlaville plant.
• EU circular textiles strategy: by 2030 all textiles sold in the EU must be durable, recyclable and feature high recycled content, reinforced by France’s IMPR decree (up to EUR 1,000/t for recycled-from-difficult-streams plastic) and a likely inclusion of chemically recycled material under the Single-Use Plastics Directive.

05Leading companies and research institutes

06Tech stack and innovations

The stack couples polymer pretreatment, biocatalytic hydrolysis and monomer purification.

1. Hydrolysis reactors with alkali dosing:
   • 100-200 m3 stainless reactors with anchor agitation handle dense textile slurries; as ester bonds cleave and TPA is released, the pH falls, so NaOH or sodium carbonate is dosed continuously to hold pH at 7.5-8.0.
2. Twin-screw extruder amorphization:
   • shredded fibre is melted at about 260 C, vacuum-degassed at 5 mbar to strip volatiles, then quenched through fine dies into ice water, producing brittle amorphous granules whose ester bonds are exposed to the enzyme.
3. Isothermal TPA crystallization:
   • the purified disodium terephthalate solution is acidified with sulphuric acid to pH 2.0, instantly precipitating high-purity TPA as a white crystalline powder recovered on drum vacuum filters.

07Value chains and production pipelines

Industrial pipeline of enzymatic polycotton recycling (LCC-cutinase + cellulase, ISO 14044 / Oeko-Tex 100)

┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Sorting, shred &       │ ───> │ 2. Cellulase hydrolysis   │
│    amorphization          │      │    of cotton fraction     │
└───────────────────────────┘      └───────────────────────────┘
                                                  │
                                                  ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. PET depolymerization   │ <─── │ 3. Centrifugation & wash  │
│    by LCC-cutinase        │      │    of polyester cake      │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. TPA crystallization    │ ───> │ 6. QC, repolymerization   │
│    & EG recovery          │      │    & yarn spinning         │
└───────────────────────────┘      └───────────────────────────┘

Stage 1: Sorting, shredding and amorphization

Bales of polycotton waste (around 60% polyester, 40% cotton) are scanned by NIR, stripped of metal trim and zippers, and shredded to under 5 mm; the flake is melted at 260 C in a twin-screw extruder and quenched into ice water, yielding brittle amorphous PET granules around the cotton fibres.

Stage 2: Selective cellulase hydrolysis of cotton

The suspension is charged to a 100 m3 reactor with an industrial cellulase cocktail (about 5 kg per tonne of feed) at 50 C and pH 5.0 for 12 hours, fully saccharifying the cotton to soluble glucose while the amorphous polyester granules stay intact.

Stage 3: Centrifugation and polyester washing

A decanter centrifuge separates the glucose syrup (sent to fermentation) from the polyester cake, which is twice washed in 70 C deionized water to remove residual glucose, enzyme protein and cotton dyes.

Stage 4: PET depolymerization by LCC-cutinase

The washed polyester is charged to the main hydrolysis reactor with a thermostable LCC-cutinase (about 3 kg per tonne) at 62 C, with pH held at 8.0 by micro-dosing 30% sodium carbonate; over roughly 10 hours the polyester is depolymerized into soluble ethylene glycol and disodium terephthalate.

Stage 5: TPA crystallization and EG recovery

The solution is filtered, decolourized over activated carbon, then acidified with sulphuric acid to pH 2.0 to precipitate high-purity TPA, which is filtered and dried; the EG-bearing filtrate is neutralized and distilled to recover monoethylene glycol.

Stage 6: QC, repolymerization and spinning

Purified TPA (above 99.8%) and MEG (above 99.9%) are polycondensed at 280 C under deep vacuum into virgin-grade rPET pellets, QC-checked for melt viscosity, colour and heavy metals, then melt-spun into high-tenacity textile-to-textile polyester yarn.