Closed loop manufacture of bio-based polyester fibres for a circular bioeconomy
Lead Research Organisation:
University of Leeds
Department Name: Sch of Design
Abstract
Novel synthetic biology and engineering have an essential contribution to offer to the transition towards a circular bioeconomy for the textile industry, currently the fourth most polluting industry in the world (10% of carbon emissions), and this project intends to demonstrate this. Our vision is to disrupt the current textile recycling mindset of unaffordable downcycling attempts (e.g. turning used clothing into insulation materials) and enable revolutionary circular modalities that will transcend the use of fossil-derived raw materials and allow the creation of polyester textile fibres (the most dominant man-made fibre globally) from non-edible biomass, specifically, coffee waste in the form of used coffee grounds.
Coffee waste is a non-edible biomass of emerging importance due to its valuable organic composition, the lack of efficient recycling methods, and the coffee industry expansion, with the UK ranking among the largest coffee-consuming markets in Europe.
This research will exploit these appealing attributes of coffee waste to develop new bio-based polyester fibres that can be integrated, degraded and upcycled at the end of life into new forms of functional materials (e.g. environment-friendly face masks, antimicrobial coatings and controlled drug delivery devices) to enable future, circular textile manufacture. New synergistic research on microbial biorefineries, integrated fibre spinning, and molecular upcycling will enable breakthrough synthetic biology routes for the ethical transformation of non-edible biomass (coffee waste) into functional (dyed) polyester fibres. This will enable to meet the requirements of multiple industrial sectors and disrupt the textile industry overreliance on non-recyclable synthetic fibres, facilitating the creation of a truly circular and sustainable polyester economy.
Coffee waste is a non-edible biomass of emerging importance due to its valuable organic composition, the lack of efficient recycling methods, and the coffee industry expansion, with the UK ranking among the largest coffee-consuming markets in Europe.
This research will exploit these appealing attributes of coffee waste to develop new bio-based polyester fibres that can be integrated, degraded and upcycled at the end of life into new forms of functional materials (e.g. environment-friendly face masks, antimicrobial coatings and controlled drug delivery devices) to enable future, circular textile manufacture. New synergistic research on microbial biorefineries, integrated fibre spinning, and molecular upcycling will enable breakthrough synthetic biology routes for the ethical transformation of non-edible biomass (coffee waste) into functional (dyed) polyester fibres. This will enable to meet the requirements of multiple industrial sectors and disrupt the textile industry overreliance on non-recyclable synthetic fibres, facilitating the creation of a truly circular and sustainable polyester economy.
Technical Summary
The proposed textile biotechnology research will pursue environment-friendly microbial biorefineries, integrated fibre spinning and molecular upcycling to accomplish the ethical conversion of coffee waste (as non-edible biomass) into functional (dyed) bio-based polyester fibres that can be integrated, degraded and upcycled at the end of life for future textile manufacture.
The specific objectives of this project are:
- Environment-friendly bacterial transformation of coffee waste into bespoke, high yield polyhydroxyalkanoates (PHAs).
- Creation of bio-based functional fibres with controlled elasticity and textile functionality by exploiting novel spinning technologies and the nanoscale of fibre-forming PHA chains.
- Bacteria-directed depolymerisation of manufactured fibres for end-of-life upcycling into novel valuable materials.
- To demonstrate fibre recyclability and affordability of the proposed experimental platform for future textile manufacture and circularity
These will be realised via the following research strategies and methods:
- Green extraction of coffee oil (from coffee waste) as non-edible carbon source for bacterial transformation
- Use of bacterial halophiles as environment friendly biorefineries with high transforming ability
- Integrated, green wet spinning route enabling bespoke fibre formation and dyeing
- Enzymatic hydrolysis of manufactured fibres to raw materials (monomers and dyes)
- Molecular upcycling of collected raw materials via green re-polymerisation and spinning into functional fibres with no loss in fibre performance
The specific objectives of this project are:
- Environment-friendly bacterial transformation of coffee waste into bespoke, high yield polyhydroxyalkanoates (PHAs).
- Creation of bio-based functional fibres with controlled elasticity and textile functionality by exploiting novel spinning technologies and the nanoscale of fibre-forming PHA chains.
- Bacteria-directed depolymerisation of manufactured fibres for end-of-life upcycling into novel valuable materials.
- To demonstrate fibre recyclability and affordability of the proposed experimental platform for future textile manufacture and circularity
These will be realised via the following research strategies and methods:
- Green extraction of coffee oil (from coffee waste) as non-edible carbon source for bacterial transformation
- Use of bacterial halophiles as environment friendly biorefineries with high transforming ability
- Integrated, green wet spinning route enabling bespoke fibre formation and dyeing
- Enzymatic hydrolysis of manufactured fibres to raw materials (monomers and dyes)
- Molecular upcycling of collected raw materials via green re-polymerisation and spinning into functional fibres with no loss in fibre performance
Publications
Brooker C
(2023)
A collagen-based theranostic wound dressing with visual, long-lasting infection detection capability
in International Journal of Biological Macromolecules
Li M
(2025)
Photodynamic, UV-curable and fibre-forming polyvinyl alcohol derivative with broad processability and staining-free antibacterial capability
in European Polymer Journal
Phillips M
(2024)
Nonwoven Reinforced Photocurable Poly(glycerol seba-cate)-Based Hydrogels
in Polymers
Zhang R
(2024)
Mechanical and suture-holding properties of a UV-cured atelocollagen membrane with varied crosslinked architecture.
in Biomedical materials (Bristol, England)
| Description | The award has enable the development of a proof-of-concept technology through which coffee waste in the form of spent coffee grounds (SCGs) can be processed to generate new forms of biobased polyester fibres as the raw material for the textile manufacturing industry. Fossil-derived polyesters are the dominant fibres used by the textile industry, though its oil-derived composition and limited biodegradability generates significant environmental and socioeconomic risks. With this research, we have successfully demonstrated that SCGs can be used as an inedible biomass for the production of biobased, fossil-free microbial polyesters, and textile fibres thereof. This research has not only demonstrated an alternative route to the production of fossil-free polyester textile fibres, but has also laid down the doundations to a circular bioeconomy model for the coffee sector, at a time when the coffee market is expanding globally and the use of SCGs is limited to agriculture. |
| Exploitation Route | We are working to develop this proof-of-concept technology further, by engaging with the industry, aiming to further demonstrate how the development of a circular coffee bioeconomy can be key to the creation of next-generation biobased polyester fibres that are functional and use-inspired, in order to meet the demands of multiple manufacturing industries. |
| Sectors | Agriculture Food and Drink Chemicals Creative Economy Healthcare Manufacturing including Industrial Biotechology |
| Description | Polyester fibres are the market dominating raw material in the textile industry. As a fossil-derived raw material with very slow biodegradability, polyesters contribute significantly to global carbon emissions during both production and end of life. These sustainability challenges are further compounded by the fact that over 80% of global textile waste is currently disposed of through incineration or landfill. To address these challenges, our efforts have concentrated on the manufacture of bio-based polyester fibres from spent coffee grounds (SCGs), an inedible, underutilised organic waste with attactive chemical composition. By forging the textile /biotechnology interface, we have developed a proof of concept technology, whereby SCGs are converted (through bacterial fermentation) into fossil-free polyesters, i.e. polyhydroxyalkanoates (PHAs), with comparable chemical composition to the one of fossil-derived plastics. The resulting polymer product can then be converted into individual textile fibres as the raw material for further processing, e.g. into yarns and fabrics. This manufacturing route is industry-compliant, in that it can deliver fibres at meter scale; it avoids the use of fossil-derived organic solvents and can be tailored to equip resulting fibres with additional use-inspired functionalities, e.g. colour or antimicrobial activity. Our groundwork to develop biobased polyester fibres has initially focused on the green extraction of coffee oil (from SCGs) as the carbon source for the microbial synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). We have successfully demonstrated comparable yield and chemical composition of coffee oil extracted with green solvents with respect to coffee oil extracted with fossil-derived organic solvents. We have subsequently developed a microbial production line using salt-loving bacteria, in addition to the use of conventional PHBV producers, e.g. C. necator. These efforts contributed a streamlined production, separation and purification of the resulting PHBV, enabling the extraction of the polymer via incubation in non-salty water, rather than organic solvents. The research developed in this grant has enabled us to establish the foundations of a technology that directly responds to current industrial shifts towards the adoption of circular bioeconomy practices and fossil-free raw materials. To deliver on this vision, we are now expanding our industrial reach aiming to access a consistent supply chain of SCGs to enable manufacturing scale up and to pursue fibre processing into textile prototypes. Our ultimate vision is to integrate the aforementioned biobased polyester fibres into medical textiles, such as antimicrobial fabrics for infection control and Guided Bone Regeneration. To pursue this vision, we have leveraged the fibre manufacturing expertise developed in this grant to explore the modification of a biodegradable fibre-forming polymer with a photosensitiser dye, and successfully demonstrated the antibiotic-free antimicrobial effect via fibre exposure to localised visible light. Together with that, the resulting patent-pending prototype ensures suppressed dye-induced colouration (staining) following material contact with the biological environment, and is highly tolerated by mammalian cells, i.e. L929 mouse fibroblasts. These research expertise have contributed to the launch of HYFACOL Limited, a new University of Leeds spin out company that is developing a patented collagen manufacturing technology (originated from PI's research) for wound dressing and dentistry applications. |
| First Year Of Impact | 2023 |
| Sector | Healthcare,Manufacturing, including Industrial Biotechology |
| Impact Types | Cultural Societal Economic |
| Description | IEC\NSFC\223289 - International Exchanges 2022 Cost Share (NSFC) |
| Amount | £11,850 (GBP) |
| Funding ID | IEC\NSFC\223289 |
| Organisation | The Royal Society |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 03/2023 |
| End | 02/2025 |
| Description | Piezoelectric hydrogel for on-demand release of anticancer drugs for the treatment of bone cancer |
| Amount | £90,000 (GBP) |
| Organisation | Clothworkers Company |
| Sector | Private |
| Country | United Kingdom |
| Start | |
| Description | Piezoelectric materials |
| Organisation | Guangdong University of Technology |
| Country | China |
| Sector | Academic/University |
| PI Contribution | A Royal-funded collaboration with (GUOT /Professor Guoxin Tan) has been developed during this grant period, involving staff exchange in the UK and China and transfer of expertise with respect to the design of advanced piezoelectric materials. As contribution to this collaboration, we hosted a PhD student (Tianhua Xiao) from Prof. Tan's group for one month in our lab at Leeds and provided staff training on and demonstration of the fibre manufacturing process (wet spinning) under development during this BBSRC-funded research project. |
| Collaborator Contribution | Our partners in China hosted a PhD student from my group (Jon Gorman) for one month and provided research training on the characterisation of piezoelectric materials, with respect to the quantification of electric signal following mechanical stimulation. These investigations are relevant to the biobased polyester fibres we are developing in this award, aiming to expand their industrial applicability in healthcare, the textile industry and beyond. |
| Impact | - Participation at and Oral presentation by a PhD student in my group (Jon Gorman) at a research symposium at GDUT (November 2025) - Purchase and installation of a voltmeter for the quantification of the piezoelectric effect generated from biobased materials under mechanical stimulation, including polyesters. - Submission of a research manuscript to Nature Communication (currently under review) |
| Start Year | 2025 |
| Title | Polymeric materials |
| Description | The invention relates to the development of a photodynamic polymeric material that can be manufactured as a film, textile fibre or as a coating and that is able to generate antimicrobial effect following exposure to visible light. The material is designed such that it does not leach any chemical or photodynamic agent, so that it does not induce any colouration or staining following contact with the biological medium. While the material induces killing of both gram positive and gram negative bacteria, it is tolerated by mammalian cells, i.e. L929 murine fibroblasts. |
| IP Reference | |
| Protection | Patent / Patent application |
| Year Protection Granted | 2024 |
| Licensed | Yes |
| Title | Advanced collagen-based wound dressing prototype |
| Description | An advanced collagen-based wound dressing prototype has been realised through the research conducted by the PI at the University of Leeds. The underpinning technology generating this prototype has been patented by the University of Leeds (in the US and Europe). Following successful pre-clinical testing in vitro and in vivo, a new University of Leeds spin-out company has been formed in 2023 with a £0.5m first raise, aiming to progress the clinical development of this product, with the medium term aim (2 years) looking at securing regulatory compliance and human safety data. An exploratory clinical trial is due to start in March 2025 in order to assess (for the first time) the safety and efficacy of this medical device prototype in patients affected by non-self-healing wounds. |
| Type | Therapeutic Intervention - Medical Devices |
| Current Stage Of Development | Refinement. Non-clinical |
| Year Development Stage Completed | 2023 |
| Development Status | Under active development/distribution |
| Impact | a new University of Leeds spin-out company has been formed in 2023 with a £0.5m first raise, aiming to progress the clinical development of this product. |
| URL | https://hyfacol.co.uk/ |
| Company Name | Hyfacol |
| Description | Hyfacol develops a collagen manufacturing platform which produces collagen to be used for advanced wound care and guided bone regeneration. |
| Year Established | 2023 |
| Impact | HYFACOL's underpinning technology has been successfully patented in the US and Europe, with the latter covering highly profitable territories, such as France, Germany, Ireland, Italy, and the UK. |
| Website | https://hyfacol.co.uk/ |
| Description | 10th Anniversary of The Creative Dimension Trust Research Project |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | The Creative Dimension Trust (TCDT) aims to enable young people from underserved communities in London to work with world leading craft and industry specialists to develop fine hand skills and 3-D thinking for use in future careers. TCDT delivers on this mission through its workshops and extracurricular activities, which are designed to help young people better understand how current educational and training opportunities feed into employment opportunities. In preparation of its 10th Anniversary, TCDT surveyed seventy-six professionals from nineteen broad industry categories to assess how the effect of visual sensitivity and manual dexterity skills development is seen across industries. Given my research in textile fibres for healthcare and sustainability, I was approached by TCDT to share my views on how the above skills can affect employability and recruitment, technology development, and diversity in the workforce. This was obviously an enriching experience given the need to design textile materials that are better customised to the needs of patients and healthcare professionals, aiming to enhance usability, tolerability, and anatomic conformability. My survery contributed to the publication of the 10th Anniversary TCDT report (https://www.thecreativedimension.org/wp-content/uploads/2025/03/TCDT-Research-Paper-2025.pdf), which was presented at Buckingham Palace on the 4th of March 2025, an event to which I was invited and which I attended. |
| Year(s) Of Engagement Activity | 2025 |
| URL | https://www.thecreativedimension.org/wp-content/uploads/2025/03/TCDT-Research-Paper-2025.pdf |