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.

Pathogenic variants of the mammalian optic atrophy 1 (OPA1) protein, a key regulator of mitochondrial fusion, may lead to severe mitochondrial dysfunction and morphological alterations, and have also been proposed to be involved in remodeling the mitochondrial membranes lipid profile. To address this last issue, a lipidomic workflow based on HILIC-ESI-HRMS was applied to profile major classes of mitochondrial membrane phospholipids (PL), namely phosphatidylcholines (PCs), -ethanolamines (PEs), and -inositols (PIs), along with cardiolipins (CLs), in mouse embryonic fibroblasts knocked out for Opa1 gene (Opa1^−/− MEFs) and expressing human OPA1 isoform 1 (ISO1) or one of four well-known pathogenic variants (I382M, D603H, G439V and R445H). A total of 122 common sum compositions were recognized for PLs in the four classes across the five sample types. Chemometrics on the respective quantitative data indicated a lower prevalence of alk(en)yl/acyl species (O-PCs and O-PEs) within the PC and PE classes, along with a higher relative contribution of highly unsaturated PI and CL species, when severely pathogenic R445H and G439V variants were expressed. In contrast, the I382M variant was associated with a greater relative contribution of less-unsaturated PI and CL species. These findings indicate that pathogenic OPA1 variants are associated with distinct mitochondrial phospholipid profiles, opening interesting perspectives for future direct experimental validation of an eventual relationship existing between OPA1 variants, inter-organelle phospholipid trafficking, and mitochondrial dysfunction.