Know more

Today, many alternative materials are biodegradable. Sorted at source, they can be treated with biowaste and degraded under industrial or domestic composting conditions. However, little is known about their behaviour in anaerobic digestion processes.

In this context, the IRMFood and Pandor teams are working together on a project funded by the French National Agency of Research (BioCyPlast ANR-21-CE43-0009). The project strategy is based on:

• the selection of commercial biodegradable materials and the construction of tailor-made materials (with different formulations, structures, sizes, crystallinity, etc.) dedicated to the study of their degradation
• experimental monitoring of their fate under controlled composting and anaerobic digestion conditions
• the development of tools to monitor the mechanisms of colonisation and degradation of plastics up to the generation of micro- and nanoplastics
• the integration of all these data into predictive modelling approaches to anticipate the ecological footprint of biodegradable plastics, from the design of materials to biowaste management systems.

The materials studied in this project are made from biosourced and biodegradable polymers. Most standardised methods for measuring biodegradability are based on mass measurements or biological tests, which do not allow on-line monitoring of the biodegradation progress. Monitoring by chemical or physico-chemical analysis is generally destructive.

The aim of the Plast-NMR project is to propose a new, non-destructive method that

1. enables quantitative measurement of the biodegradation process,
2. allows a better understanding of the biodegradation processes of biodegradable plastics under anaerobic digestion conditions.

The plastic degradation is conducted in pilot anaerobic digestion reactors, which need to be optimised to enable at-line analyses throughout the anaerobic degradation process. These analyses are focused on low-field NMR measurements (in time domain) due to their non-destructive and non-invasive nature. This method is validated using conventional techniques (in accordance with European standards) for measuring biodegradability, such as respirometric measurements (to measure biogas production) or other physico-chemical techniques such as thermogravimetric or FT-IR analyses.

In order to gain a better understanding of the biological mechanisms underlying this degradation, low-field NMR measurements are supplemented by characterization of the metabolites produced. Various spectrometric methods are used for this, including high-field NMR and mass spectrometry.

Contacts : Corinne Rondeau-Mouro & Patrick Dabert