Synergistic action of different thermostable esterases in pet degradation: improvement of activity against intermediate degradation products by protein engineering

Polyethylene terephthalate (PET) is high molecular weight polymer of terephthalate (TPA) and ethylene glycol (EG) which constitutes a rapidly increasing environmental threat. It is broken down to bis- (BHET) and mono -(MHET) hydroxyethyl-terephthalate and ultimately to TPA. The bacterium, Ideonella sakaiensis 201-F6, uses PET as a primary carbon source, and contains a two-component PET-degrading system consisting of a PET/BHET-degrading esterase, which aggregate at temperatures above 30 °C, and a MHET-degrading esterase/lipase with optimal function at 30 °C.