Jupyter notebooks

Microbial degradation provides an avenue for the remediation of select plastic polymers contributing to the urgent environmental problem of global plastic pollution. We demonstrate the degradation of polycaprolactone (PCL) and polyethylene terephthalate (PET) by Clonostachys rosea. We constructed the genome of this fungal strain and monitored changes in gene expression when exposed to PCL. Twelve genes linked to PCL degradation were found in the genome of C. rosea, and some of them were upregulated in the presence of the plastic, including genes coding for two cutinases. We heterologously expressed the enzymes coded by both genes and confirmed their activity against PCL polymers. We also demonstrate that one of the enzymes was active against PET polymers. Glucose inhibited the expression of both genes, completely halting the plastic biodegradation process, possibly serving as a preferred and readily metabolizable carbon source compared with PCL. In contrast to glucose, other carbon sources, such as potato starch, increased biodegradation rates compared with media without additional carbon sources. We confirm the presence of key metabolic pathways and processes linked to PCL degradation in C. rosea, such as those encoding for the degradation of related fatty acids and aromatic compounds, contributing additional evidence of the metabolic pathways and transcripts considered central to plastic degradation.