ATR-FTIR characterisation of daily-use plastics mycodegradation

Abstract

Synthetic polymers, such as plastics, have permeated all aspects of modern life, and nowadays plastic pollution is a major environmental problem. Mycodegradation of these polymers could represent part of the solution to this problem since it calls on a broad toolbox of enzymes and applies non-enzymatic mechanisms to degrade and deteriorate recalcitrant materials. However, not enough is known about this ability for most of the representatives of the fungal kingdom. Another bottleneck is the harmonisation of technologies to analyse plastic degradation. This work involved the design of a biodegradation experiment, where the potential of four fungi representative of Dikarya and Penicillia (Funalia floccosa, Trametes versicolor, Pycnoporus cinnabarinus and Penicillium oxalicum) were tested on their ability to deteriorate the six most used plastics based on gravimetry and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The following correlation between changes in the band signals and the loss of mass after treatment was determined using polyethylene terephthalate, polypropylene, polyethylene, poly vinyl chloride, high density polyethylene, low density polyethylene and nylon. After treatment, the decrease in absorbance of the characteristic bands of the plastics was taken as an indication of the degradation of the corresponding bonds/functionalities. The four fungi used could transform CH, CH2, CH3, C–– O, C–O, C–N, N–H and C–Cl bonds. The best result was obtained using the fungus F. floccosa with 90-day treatments for high density polyethylene (~ 62.0 %), low density polyethylene (~ 23.6 %) and nylon (~ 35.6 %). Therefore, mycodegradation could open up new doors in the fight against plastic pollution.