Upcycling ethylene glycol (EG) and terephthalic acid (TPA), key monomers derived from the depolymerisation of polyethylene terephthalate (PET), is a promising strategy for advancing the circular economy of plastics. This study investigates the metabolic fate of EG and its conversion into glycolic acid (GA) by the non-conventional yeast Yarrowia lipolytica. While EG alone does not support growth in a minimal medium, the addition of acetate (Ac) significantly enhances EG assimilation and GA production. 13C labeling experiments and metabolic flux analysis revealed that a small but measurable fraction of EG-derived carbon is incorporated into biomass via glycine and serine biosynthesis and the glyoxylate cycle when acetate is supplied as a carbon source. Ac-EG co-feeding resulted in the production of 48.4 ± 1.4 g/L of GA after 66 h, corresponding to a molar yield of 73 % and a productivity of 0.73 g/(L·h). These results highlight the potential of Y. lipolytica as a microbial platform for EG valorisation and contribute to sustainable strategies for the bioconversion of plastic waste.
Acetate co-feeding increases ethylene glycol assimilation and glycolic acid production in Yarrowia lipolytica
Messina, Eugenia;Barile, Serena;Scarcia, Pasquale;Fosso, Bruno;Palmieri, Luigi;Pisano, Isabella;Agrimi, Gennaro
2025-01-01
Abstract
Upcycling ethylene glycol (EG) and terephthalic acid (TPA), key monomers derived from the depolymerisation of polyethylene terephthalate (PET), is a promising strategy for advancing the circular economy of plastics. This study investigates the metabolic fate of EG and its conversion into glycolic acid (GA) by the non-conventional yeast Yarrowia lipolytica. While EG alone does not support growth in a minimal medium, the addition of acetate (Ac) significantly enhances EG assimilation and GA production. 13C labeling experiments and metabolic flux analysis revealed that a small but measurable fraction of EG-derived carbon is incorporated into biomass via glycine and serine biosynthesis and the glyoxylate cycle when acetate is supplied as a carbon source. Ac-EG co-feeding resulted in the production of 48.4 ± 1.4 g/L of GA after 66 h, corresponding to a molar yield of 73 % and a productivity of 0.73 g/(L·h). These results highlight the potential of Y. lipolytica as a microbial platform for EG valorisation and contribute to sustainable strategies for the bioconversion of plastic waste.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
