Can worms eat away our plastics problem?

A consortium of European experts, led by the Spanish University of Almeria, is taking on agricultural plastic waste and food packaging by channelling the power of nature and using insects, worms and micro-organisms capable of degrading and synthesising plastic.

The worldwide production of plastics is about 350 million tonnes per year. The packaging sector swallows up an estimated 40% of which agricultural applications consume 3.5%. After it is used, plastic waste accumulates in the environment due to its limited recovery and resistance to degradation. Currently only the 31% of plastics entering waste management systems is recycled while the rest is incinerated or disposed of in landfills. Many tonnes more are not even collected.

Biotechnological tools

The overarching objective of the EU’s EUR 4.3 million ‘Recover’ R&D project is to demonstrate and upscale novel bio-based approaches to dealing with the problem of agri-food waste plastics. It is also looking to resolve the contamination of agricultural fields with non-biodegradable plastics by providing sustainable pathways for the non-recyclable packaging fraction of municipal waste management systems.

To achieve these objectives, it is looking at innovative biotechnological solutions by combining microorganisms, novel microbial enzymes, earthworms and insects to transform these non-recyclable plastic packaging waste streams and agricultural films. As a result, new raw materials for the primary sector bio-fertilisers and the bio-based industry (chitin and chitosan) would be produced.

The Recover project is based on the fresh concept that multiple species collaborate in an integrated and complementary way to either transform complex plastic mixtures or biodegrade and remove them.

The tools are:

• enzymes, developed using a synthetic biology approach
• microbial groups that attack mixed plastic waste under different environmental conditions
• insects and earthworms whose natural ability to ingest and digest plastics will be enhanced with probiotics

Treatment scenarios

The Recover project was launched in June 2020 and will last four years. It brings together 17 multidisciplinary partners to develop a set of biotechnology- based solutions to combat plastic waste. The innovative biotechnological processes currently in development are based on two scenarios: treating the waste in insect-rearing chambers or compost reactors and directly treating soils contaminated with plastics such as mulching films.

During the first 12 months of the venture, the most widespread plastic polymers in agri-food plastic waste were mapped and characterised. The logistics chain for their collection and current handling practices was also carefully analysed and reviewed. Insects, earthworms, microbial groups and families of target enzymes have also been selected and their ability to feed on or hydrolyse the target polymers is being tested.

In the coming months, the production of suitable biotechnological solutions will be scaled up and tested under full-scale conditions. An appropriate system of waste collection and delivery to the bio-recycling plant will be developed with the help of plastic monitoring tools, equipment and logistical studies. Simple conditions that can be replicated in farms or municipalities will also be established.

This topic was featured in the latest issue of Recycling Technology. Read the magazine here >>