Highly Crystalline Post‐Consumer PET Waste Hydrolysis by Surface Displayed PETase Using a Bacterial Whole‐Cell Biocatalyst
David Gercke, Christoph Furtmann, Iasson E. P. Tozakidis, Joachim Jose
Abstract
Abstract The enzymatic degradation of polyethylene terephthalate (PET) is a promising new approach for the environmentally friendly recycling of PET waste, but so far, low degradation rates paired with releatively high costs have limited the economic feasibility of this method. Here we present the construction of a new bacterial whole‐cell biocatalyst utilizing a new inverse autotranspoter based surface display of PETase in E. coli . The resulting catalyst allows an extremely easy production of large amounts of enzyme and a five times more effective degradation of PET at a lower temperature of 25 °C compared to free PETase at 30 °C. Additionally, we demonstrate how rhamnolipids, which are environmentally benign and can be cost‐effectively produced using strains of E. coli , can be used to amplify the hydrolysis rates of PET even further, presumably by acting as mediators between PETase and PET. Cells displaying PETase in combination with externally supplied rhamnolipids outperformed free PETase by a factor of 16, allowing the degradation of highly crystalline post‐consumer PET waste to an extent of 8 % within 3 days at room temperature.