Unveiling potential of Gordonia species and their cutinases for polyester decomposition

The growing issue of petroleum-based polymer waste demands sustainable recycling strategies, with enzymatic processes offering a promising solution. This study investigates enzymatic decomposition of polyethylene terephthalate (PET) and polybutylene adipate terephthalate (PBAT) by Gordonia species, known for their pollutant-degrading capabilities. When cultivated with PET, G. phthalatica, G. paraffinivorans, and G. alkanivorans showed esterase activity on para-nitrophenyl butyrate (pNPB). G. phthalatica reached highest activity (485.0 ± 34.0 mU mL^-1) and released 9.2 ± 0.6 μM terephthalic acid (TPA) from PET. Sequence alignment revealed three cutinases for polyester hydrolysis (Gph_Cut1, Gpa_Cut1, Gpa_Cut2) which were expressed in E. coli. The enzymes were active at pH 6 and ≥ 45 °C and retained up to 70 % of their activity after 96 h at 30 °C. The cutinases hydrolyzed PBAT, releasing up to 47.0 ± 1.5 μM TPA. In contrast, PET hydrolysis yielded soluble oligomers hydrolyzable to 57.6 ± 0.1 μM TPA using a commercial cutinase. The data show that Gordonia species could contribute to the biodegradation of PBAT in nature.