Fungal and enzymatic bio-depolymerization of waste post-consumer poly(ethylene terephthalate) (PET) bottles using species.

Poly(ethylene terephthalate) (PET) is a petroleum-based plastic that is massively produced and used worldwide. A promising PET recycling process to circumvent petroleum feedstock consumption and help to reduce environmental pollution is microbial or enzymatic biodegradation of post-consumer (PC) PET packages to its monomers-terephthalic acid (TPA) and ethylene glycol (EG)-or to key intermediates in PET synthesis-such as mono- and bis-(2-hydroxyethyl) terephthalate (MHET and BHET). Two species of filamentous fungi previously characterized as lipase producers ( and ) were evaluated in submerged fermentation for induction of lipase production by two inducers (BHET and amorphous PET), and for biodegradation of two substrates (BHET and PC-PET). BHET induced lipase production in , achieving a peak of 606.4 U/L at 49 h (12.38 U/L.h), representing an almost twofold increase in comparison to the highest peak in the control (without inducers). Microbial biodegradation by after 28 days led to a 3.09% mass loss on PC-PET fragments. In contrast, enzymatic PC-PET depolymerization by cell-free filtrates from a culture resulted in low concentrations of BHET, MHET and TPA (up to 9.51 µmol/L), suggesting that there are mechanisms at the organism level that enhance biodegradation. Enzymatic BHET hydrolysis revealed that extracellular enzymes catalyze the release of MHET as the predominant product. Our results show that is a promising biodegrader of PC-PET that can be further explored for monomer recovery in the context of feedstock recycling processes.