Reducing Plastic Use by Transforming Crop Waste into Bio-Fillers with Tensei
- Growing Kent & Medway
- Jan 7
- 5 min read
Updated: 3 days ago
Tensei, supported by Growing Kent & Medway, led a project in Kent to turn Second Harvest farm waste into sustainable bio-fillers. This medium-sized R&D grant project proved that materials like hop bines can be compounded with plastic polymers, creating a new revenue stream for growers and reducing plastic use.
At A Glance: Project Quick Facts
Project Lead: Tensei (Annabelle Cox)
Collaborators: SACO, Plastek, A&R House, Canterbury Christ Church University
Total Funding: £113,183 (Grant Awarded: £63,183 / Co-investment: £50,000)
Key Findings: Developed three new pilot-scale bio-polymer formulations; one successfully injection moulded; proved agri-residue fillers integrate well into rigid/flexible polymers.
Food System Areas:
The Challenge: Plastic Pollution and Wasted Farm Residues
The UK faces immense pressure to reduce plastic pollution and lower carbon emissions across all industries. Meanwhile, Kent farmers generate vast quantities of agricultural waste, or Second Harvest – residues like straw, husks, and raspberry canes – that are often burned, mulched, or sold for low-value animal feed.
This represents a significant missed opportunity. Not only does disposing of this material release carbon back into the atmosphere, but it deprives growers of a potential revenue stream and forces manufacturers to rely on carbon-intensive virgin plastics. Tensei saw this dual problem as a chance to create a revolutionary solution rooted in Kent’s agricultural economy.
The Innovative Idea: A New Raw Material from Agri-Waste
Tensei recognised that successful development and commercialisation of a highly localised supply chain that used Kent's agri-residues to create sophisticated bio-fillers for plastic production could provide a true win-win for both growers and the environment.
By carefully compounding these materials with polymers – the building blocks of plastic – they could provide a new revenue stream for farmers and significantly reduce reliance on environmentally damaging virgin and recycled plastics. The team, led by CEO Annabelle Cox, aimed to prove that materials like hop bines and raspberry canes – which are currently discarded – could be processed consistently and perform reliably in complex manufacturing processes.
Annabelle explains the mission:
"The Second Harvest Principle is based on harvesting the value of the food grown twice. The regenerative rationality is for this to demonstrate that systemic change yields compounding positive returns – ecological and economic.
"The urgency for these solutions is not simply for farmers but in the demonstration that what we grow in the UK can support us if supply chains using current raw material are disrupted. The rational choice is no longer to preserve the status quo but to preserve the system by changing it."
The Approach: R&D Trials for Polymer Compounding
The R&D required to turn farm waste into a commercially viable industrial compound was complex, involving material science, supply chain logistics, and engineering. The project's methodology focused on formulating over thirty variations of the material and scaling up three pilot-scale blends that were then sent for injection moulding trials.
This proof-of-concept phase was essential, demonstrating that the materials could be manufactured efficiently with existing production equipment. Annabelle noted the project was a great opportunity, "sitting in the middle of Kent, working with nearby agricultural products from Kent."
Manufacturing partners even reported that the Tensei material ran faster than conventional talc-filled compounds.
The Results: A Proven Concept for Market Entry
The project successfully delivered a proof-of-concept for three new pilot formulations, one of which was successfully moulded into complex pallet spacers and small consumer items (scoops and spoons).
This work laid the foundation for achieving high economic and environmental impact. The potential economic impact is high: the new product creates an alternative revenue stream for farmers and a material option for manufacturers looking to reduce virgin plastic usage.
The environmental impact is also high, with preliminary modelling demonstrating a measurable reduction in CO₂ equivalent compared to conventional plastics.
See it Differently: Transforming Farm Waste into Sustainable Packaging Materials with Tensei
Looking Forward: Scaling Up Kent's Bio-Material Supply Chain
Tensei is now focused on securing further funding to refine the material’s processing, specifically developing specialised milling techniques to create the finer powder size needed for optimal dispersion. The business is also focused on creating a network of British farmers to secure a consistent supply of materials.
The project has already built valuable relationships, including a strong collaboration with Canterbury Christ Church University, which is using the compounds in student engineering projects.
Annabelle believes the material provides two key benefits for growers: "A revenue source, and a consistent revenue source," alongside the fact that "it will reduce their carbon footprint."
"It fundamentally ensures less plastic is used in the end products, and will also improve end of life impact in landfills – adding biogenic carbon whilst reducing fossil-based carbon will have a more positive effect on reducing greenhouse gas emissions."
Why This Project Worked: The Second Harvest Principle
 | The project demonstrated exceptional value for money, achieving a high leverage ratio with £63,183 of industry investment amplifying the £63,183 grant. This 1:1 match funding model successfully de-risked a complex R&D venture, accelerating the commercialisation of a technology that might otherwise have stalled due to technical and financial barriers. |
 | By successfully substituting a portion of virgin plastic with natural fibres, the project directly addressed the urgent need to reduce fossil-based materials. It validated the "Second Harvest" concept, proving that agricultural waste can be transformed from a disposal burden into a valuable resource, creating a circular materials stream that benefits both growers and manufacturers. |
 | The technical quality of the project was evidenced by the successful development of three pilot formulations that met rigorous industrial standards. The trials moved beyond theory to practical application, proving that renewable bio-fillers can meet the functional and mechanical requirements of commercial injection moulding, paving the way for scalable, low-carbon manufacturing. |
Our Support: Enabling the R&D Partnership
This R&D project was supported by one of our medium-sized grant programmes, which provided £63,183 in funding. This capital facilitated the comprehensive testing phase and the vital partnership between Tensei and their subcontractors.
Tensei stated: "Our Growing Kent & Medway project met all of the deliverables that we expected, and we are very happy with the results... The outcome of this project was a good understanding of how Kent based agri-materials interact in a polymer complex. Tensei would recommend others to apply for Growing Kent & Medway-funded opportunities."
