Olivier Hamelin

IRGA Funding

The chemical and biochemical upcycling of polyolefin plastics, such as polyethylene (PE) and polypropylene (PP), represents a significant step forward in the sustainable management of plastic waste. These materials, which are widely used (over 50% of world production) due to their mechanical properties and resistance to degradation, pose a major challenge in terms of recycling and disposal. The chemical route for recovering polyolefins involves particularly energy-demanding and/or dangerous processes such as pyrolysis, hydrocracking and catalytic depolymerisation. Pyrolysis, for example, breaks down polymers at high temperatures in the absence of oxygen, producing liquid and gaseous hydrocarbons that can be used as fuels or as raw materials for new chemical syntheses. Hydrocracking uses hydrogen under high pressure and in the presence of catalysts to produce lighter, higher added-value products. The biochemical route, still in the research and development phase, offers a complementary approach. It uses micro-organisms and specific enzymes capable of degrading polyolefins into simpler compounds of interest to the chemical industry.

In nature, two processes are involved in the degradation of this type of plastic. Firstly, an abiotic process leads to physical transformations (fragmentation of the material) and chemical ones (functionalisation of C-H bonds). This is followed by a biotic process involving extra- and intracellular enzymes (mainly oxidases and hydrolases) that cause oxidative fragmentation of the material.

In this project, inspired by Nature, we envisage to tackle this issue using two complementary approaches. In the chemical one, we plan to achieve oxidative cleavage of the C-C bonds once they have been activated by functionalization of the C-H bonds, using bioinspired catalysts already described in the literature. For the biochemical approach, the Versatile peroxidase from the fungus Pleurotus eyringii, involved in lignin degradation, was selected. Combining the two strategies for synergistic action is also envisaged.




The chemical and biochemical upcycling of polyolefin plastics represents an integrated, multidisciplinary strategy for meeting the environmental challenges posed by plastic waste, while creating opportunities for the sustainable production of new raw materials and energy. ​