Building the Circular Bioeconomy: Scaling Sail Upcycling
Introduction
The global marine sector generates ~2000 tonnes of end-of-life sails each year (Haakman and Verkade 2022), and the market is anticipated to double by 2030 (Allwright 2018). 99% of this material currently ends up in landfill.
70-80% of sails on the market are composed of poly(ethylene terephthalate) (PET) and a further 10% are a composite of PET resins and carbon fibres. This mix of blended polymers makes them challenging to recycle using existing technologies.
Sustainable Extricko is developing a closed loop recycling process for petrochemical derived materials like sails, with the goal of integrating end-of-life (EoL) sails into the circular economy. The company has demonstrated that a novel “pressolysis” system, which uses steam, can degrade 100% of sail types into composite fibres and PET monomers including terephthalic acid and ethylene glycol and discontinuous carbon fibres. Some of the recyclates recovered are high value products such as recycled carbon fibre (£25 kg-1), while others are lower value, such as terephthalic acid (£0.5kg-1).
Challenge
The company has already collaborated with the University of Edinburgh to further demonstrate that the recovered recyclates can be used as a feedstock for the production of high value compounds using engineered microbes. In this project, they wanted to characterise microbial growth and tolerance to sail recyclates and optimise fermentation conditions to progress this technology towards scale-up and industrial application.
Solution
Sustainable Extricko supplied recyclate from three samples of end-of-life sails to the Sadler Lab at the University of Edinburgh. Joanna Sadler and her team undertook quantification of terephthalic acid (TPA) fraction of sail recyclate, analysis of the effect of sail recyclate on microbial cultivation, and demonstration of representative BioLector cultivation.
Through this characterisation and optimisation of key bioprocess parameters using the BioLector in a high throughput fashion, the pathway to larger scale cultivation was significantly accelerated.
Outcome
The project directly contributed to a successful Biomanufacturing Launchpad application, which was awarded by Innovate UK in May 2024.
The project also created significant additional expertise to the Sadler Lab through working with the Edinburgh Genome Foundry and their BioLector platform to rapidly progress waste textile upcycling technologies through miniaturised and parallel fermentation parameters screening. Particular expertise was gained in the optimisation of fermentation parameters to channel waste-derived C flux towards a high value chemical of interest.
