Closed loop manufacture of bio-based polyester fibres for a circular bioeconomy

Lead Research Organisation: University of Leeds
Department Name: Sch of Design


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.

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


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