Author:
Puliga Federico,Zuffi Veronica,Baldo David,Cavatorta Daniel,Zambonelli Alessandra,Francioso Ornella,Sanchez-Cortes Santiago
Abstract
Abstract
Background
Plastic is one of the most widely used materials worldwide in various fields, including packaging and agriculture. Its large quantities require proper disposal and for this reason more and more attention is paid to the issue of degrading plastic. Thanks to the production of non-specific enzymes, fungi are able to attack complex and recalcitrant xenobiotics such as plastics. In recent years, several spectroscopic methods were used to study the plastic degradation ability of different fungal species. Among these, Fourier transform infrared (FT-IR) and FT-Raman spectroscopy techniques are the most used. Surface-enhanced Raman scattering (SERS) spectroscopy is a powerful technique which uses metal nanoparticles (NPs) to enhance the Raman signal of molecules adsorbed on the NPs surface. In this work, the isolation of different fungi from field-collected plastic debris and the ability of these isolates to growth and colonizing the low-density polyethylene (LDPE) were explored by using scanning electron microscope (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and SERS spectroscopies.
Results
Forty-seven fungal isolates belonging to 10 genera were obtained; among them only 11 were able to grow and colonize the LDPE film. However, after 90 days trial, only one isolate of Cladosporium cladosporioides (Clc/1) was able to carry out the initial degradation of the LDPE film. In particular, based on SEM observations, small cavities and depressed areas of circular shape were visible in the treated samples. Additionally, ATR-FTIR, normal Raman and SERS analyses supported the structural changes observed via SEM. Notably, ATR-FTIR and normal Raman spectra showed a significant decrease in the relative intensity of the methylene group bands. Similarly, the SERS spectra of LDPE after the fungal attack, confirmed the decrease of methylene groups bands and the appearance of other bands referring to LDPE polyphenolic admixtures.
Conclusions
These results suggest that Cladosporium cladosporioides Clc/1 is able to carry out an initial degradation of LDPE. Moreover, combining ATR-FTIR, Raman and SERS spectroscopies with SEM observations, the early stages of LDPE degradation can be explored without any sample pretreatment.
Graphical Abstract
Publisher
Springer Science and Business Media LLC
Subject
Agronomy and Crop Science,Biochemistry,Food Science,Biotechnology
Reference86 articles.
1. Gourmelon G. Global plastic production rises, recycling lags. Vital Signs. 2015;22:91.
2. Rhodes CJ. Plastic pollution and potential solutions. Sci Prog. 2018. https://doi.org/10.3184/003685018X15294876706211.
3. Carus M, Dammer L, Raschka A, Skoczinski P. Renewable carbon: key to a sustainable and future-oriented chemical and plastic industry: definition, strategy, measures and potential. Greenh Gases Sci Technol. 2020. https://doi.org/10.1002/ghg.1992.
4. Plastics Europe AISBL. Plastics—the facts 2022. Brussel: 2022.
5. Windsor FM, Durance I, Horton AA, Thompson RC, Tyler CR, Ormerod SJ. A catchment-scale perspective of plastic pollution. Glob Chang Biol. 2019. https://doi.org/10.1111/gcb.14572.