Biodegradation of Polystyrene by Pseudomonas sp. Isolated from the Gut of Superworms (Larvae of Zophobas atratus)

Catégorie : Biodégradation des Débris Plastiques
Date :29 juin 2020
Avis TSC : Les auteurs de cette étude ont cherché à comprendre comment certains vers étaient capables de dégrader le polystyrène. Ils ont trouvé leur système digestif une nouvelle souche de bactérie de type Pseudomonas aeruginosa produisant une enzyme à l’origine de la biodégradation. Cette découverte ouvre la voie à un traitement des déchets de PS en bioréacteurs ou par catalyse enzymatique.
Kim, Hong Rae; Lee, Hyun Min; Yu, Hee Cheol; Jeon, Eunbeen; Lee, Sukkyoo; Li, Jiaojie; Kim, Dae-Hwan.
Environmental science & technology: 54 (DocId: 11) 6987–6996 (2020).
Recently, various attempts have been made to solve plastic waste problems, such as development of biodegradation without producing pollution. Polystyrene (PS) is the fifth most used plastic in many industries; therefore, degrading PS becomes a critical global issue. Here, we reported Pseudomonas aeruginosa strain DSM 50071, initially isolated from the gut of the superworms, Zophobas atratus, and the PS degradation by Pseudomonas sp. DSM 50071. We examined PS degradation using electronic microscopy and measured changes in atomic composition and contact angles with water droplets on the PS surface that represents a chemical change from hydrophobicity to hydrophilicity. We have further examined chemical structural changes using X-ray photoelectron spectroscopy, Fourier-transform-infrared spectroscopy, and nuclear magnetic resonance (NMR) to confirm the formation of carbonyl groups (C═O) in the oxidation pathway during PS biodegradation. In reverse transcription quantitative polymerase chain reaction analysis, the gene expression level of serine hydrolase (SH) in Pseudomonas sp. DSM 50071 was highly increased during PS degradation, and the enzyme-mediated biodegradation of PS was further confirmed by the SH inhibitor treatment test. Thus, the significance of these findings goes beyond the discovery of a novel function of Pseudomonas sp. DSM 50071 in the gut of superworms, highlighting a potential solution for PS biodegradation.