Biodegradation of pre-treated low-density polyethylene (LDPE)

Published in: Polymer Degradation and Stability 236 (2025) 111292
Authors: G. Buron-Moles (a,b,*) , V. Vandenbossche (c), N. Gorret (a), L. Santonja-Blasco (d), T. Gonzalez-Aranda (d), X. Cameleyre (a), S. Guillouet (a)

a) TBI, Universite de Toulouse, CNRS, INRAE, INSA, 135 Avenue de Rangueil, 35077 Toulouse, France
b) Present address: IRTA, Sustainability in Biosystems, Torre Marimon, 08140 Caldes de Montbui, Catalonia, Spain
c) Laboratoire de Chimie Agro-Industrielle (LCA), Universit´e de Toulouse, INRAe, 4 all´ee Emile Monso, 31030 Toulouse, France
d) Polymer Characterization, S.A. Valencia Technology Park. 8 Gustave Eiffel, 46980 Valencia, Spain

February 2025
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Abstract:

Millions of metric tonnes of plastic waste are generated every year, with a minimal portion being recycled. Therefore, there is an urgent need to find effective and sustainable methods for plastic degradation, especially polyethylene, the most manufactured polymer globally. Here, we emulate the strategies documented for beetles, characterized by a combination of physical, chemical, and microbiological treatments, to biodegrade low-density polyethylene (LDPE). Importantly, we characterize LDPE degradation through multiple techniques, including weight loss analysis, FTIR, GPC, GC–MS, and SEM, which allowed us to identify the optimal combination of treatments to enhance LDPE biodegradation. Contrary to some expectations, we find that ultrasonication does not contribute to LDPE degradation but may instead protect against its fragmentation. However, we successfully introduce carbonyl groups into the polymer backbone, by simply exposing LDPE to environmentally friendly anionic surfactant. This pretreatment effectively cleaves LDPE by approximately 9%, breaking it into shorter carbon chains that are more accessible to microbes for subsequent biodegradation. The yeast Yarrowia lipolytica, isolated from fuel tanks and able to grow in n-paraffines, not only outperforms other microbes in assays of short carbon chain degradation, but also attaches to the LDPE surface, where it survives and grows using LDPE as sole carbon source. Our findings, therefore, pave the way for further developing a potential solution to plastic waste, calling for interdisciplinary research and innovative solutions in tackling global environmental challenges.

Keywords: Physicochemical treatment, Ultrasonication, Microbial degradation, FTIR-ATR, GCMS, GPC-IR, SEM, Plastic pollution