Biodegradation of oxidized low density polyethylene by Pelosinus fermentans lipase

• Published in: Bioresource technology 2024-07, Vol.403, p.130871, Article 130871
• Main Authors: Kim, Do-Wook, Lim, Eui Seok, Lee, Ga Hyun, Son, Hyeoncheol Francis, Sung, Changmin, Jung, Jong-Hyun, Park, Hyun June, Gong, Gyeongtaek, Ko, Ja Kyong, Um, Youngsoon, Han, Sung Ok, Ahn, Jung Ho
• Format: Article
• Language: English
• Subjects: Biodegradation, Environmental; Bioremediation; Hydrolysis; Hydrolytic enzyme; Lipase - chemistry; Lipase - metabolism; Molecular Docking Simulation; Oxidation-Reduction; Photo-oxidation; Plastic pollution; Plastic waste treatment; Polyethylene - chemistry
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.130871

[Display omitted] •Comprehensive analyses encompassing 20 distinct hydrolases were conducted.•The first enzyme capable of degrading oxidized polyethylene (PE) was reported.•Pelosinus fermentans lipase 1 (PFL1) hydrolyses ester bonds in oxidized PE.•Oxidized PE degradation was verified through FTIR, GPC, DSC, SEM, and WCA analyses.•Degradation mechanism of oxidized PE by PFL1 was elucidated by docking simulations. Polyethylene (PE) exhibits high resistance to degradation, contributing to plastic pollution. PE discarded into the environment is photo-oxidized by sunlight and oxygen. In this study, a key enzyme capable of degrading oxidized PE is reported for the first time. Twenty different enzymes from various lipase families were evaluated for hydrolytic activity using substrates mimicking oxidized PE. Among them, Pelosinus fermentans lipase 1 (PFL1) specifically cleaved the ester bonds within the oxidized carbon–carbon backbone. Moreover, PFL1 (6 μM) degraded oxidized PE film, reducing the weight average and number average molecular weights by 44.6 and 11.3 %, respectively, within five days. Finally, structural analysis and molecular docking simulations were performed to elucidate the degradation mechanism of PFL1. The oxidized PE-degrading enzyme reported here will provide the groundwork for advancing PE waste treatment technology and for engineering microbes to repurpose PE waste into valuable chemicals.