Evaluation of Yarrowia lipolytica potential for the biodegradation of poly(ethylene terephthalate) (PET) from mooring lines of Oil & Gas offshore platforms

Abstract

Poly(ethylene terephthalate) (PET) is a widely used polyester with several applications, including offshore platforms and mooring lines of the Oil & Gas industry. Due to the widespread use of PET and the growing concern about its environmental impact, biotechnology emerges as a potential solution to mitigate this problem. This work aims to evaluate, for the first time, the potential of Y. lipolytica IMUFRJ 50682 in the biodegradation of PET from waste mooring lines of Oil & Gas offshore platforms. In this study, the biodegradation of PET from mooring lines by the yeast Yarrowia lipolytica was investigated through submerged cultivation or solid-state fermentation. After fermentation was complete, the biodegradation of PET sampled from the culture medium was evidenced by an increase in transmittance in areas related to the ester group detected through Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR) for both culture strategies and all media tested. Besides, the crystallinity of PET increased by 79% and 72% after submerged cultivation using CSL-G + DMSO medium (2% corn steep liquor, 2% glycerol, and 5% Dimethyl sulfoxide) and after solid-state fermentation, respectively. Scanning electron microscopy revealed the formation of scratches and erosions on the polymer's surface after the microbial cultivation. The presence of PET monomer, terephthalic acid (TPA) (up to 142 µmol L − 1), and some intermediates, such as bis(2-hydroxyethyl) terephthalate (BHET) and mono-(hydroxyethyl) terephthalate (MHET) in the medium after Y. lipolytica growth in the presence of PET proves that the polymer is being degraded. These results suggest a good biotechnological potential of Y. lipolytica for the depolymerization of PET from mooring lines.