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Patent applied for controlled-release fertilisers with Caleyda® – a truly biodegradable PHBV polymer

We are thrilled to bring you this exciting news!!

Delft Solids Solutions applied for a patent for controlled-release fertilisers using Caleyda®. For the last few months, Delft Solids Solutions, in close cooperation with the application team of Paques Biomaterials, has been developing a fertiliser coated with Caleyda®, a fully biodegradable coating that can still display a controlled release of nutrients. This makes the first application of Caleyda® a fact.

The current commercial fertiliser generation is made with a petroleum-based plastic coating that is not biodegradable! Accordingly, using these fertilisers poses a severe threat to microplastic pollution. The European Commission has also acknowledged this huge problem, and consequently, they have set up regulations that will finally prohibit the use of the current generation of controlled-release fertilisers.

The EU already set the rules for controlled-release fertilisers in 2021. A transition period of 5 years will apply, after which the microplastic regulation enters into force. Thus, from 2026 onwards, only polymers meeting the biodegradability requirements in the new regulation will be allowed on the market. Although these biodegradability criteria still need to be set in 2024, we are convinced that the biopolymer Caleyda® used in this research will meet these criteria!

Delft Solids Solutions has now successfully applied Caleyda® produced from second-generation feedstock as a fully biodegradable coating with controlled-release properties, facilitating the slow release of nutrients in a period from several days to weeks to months. This way, they can also fulfil the controlled release requirements described in the ISO 21263:2017 standard.

The research and the results described are laid down in a patent application, and in the meantime, Delft Solids Solutions is working on further optimisation of the Caleyda® coating and the associated release properties. This should avoid further (micro)plastic pollution of the soil using controlled-release fertilisers, entirely in accordance with the EC fertiliser regulations.

More information on the processes of granulation and particle coating is available on our website.