Selective Hydrolysis by Engineered Cutinases: Characterization of aliphatic-aromatic polyester homo and co-polymers by LC and LC-MS methods

Polymers’ performance, biodegradability and recyclability can be tuned during synthesis by adopting monomers with differ-ent chemical characteristics. Recent research has shown the aptness of enzyme hydrolysis to depolymerize polyester under mild conditions with respect to chemical approaches. Herein, we engineered a cutinase from T. cellulosilytica (Tc_Cut2NVWCCG) for improved thermostability (up to 91°C) and performance, and compared it with previously reported leaf-branch compost cutinase (LCCWCCG) for the hydrolysis of oligomers, aliphatic and aromatic polyester homopolymers and co-polyester. Higher hydrolysis rates were observed towards aliphatic with respect to aromatic homopolyesters. SEC-MS revealed that the hydrolysis of aliphatic/aromatic co-polyesters preferentially occurred at the aliphatic monomers, significant-ly reducing the molecular weight and changing the end-group composition. These results underline the importance of co-polymer composition in the bio-degradation of co-polymer systems. Moreover, it underlines the potential to use enzymes to selectively reduce the molecular weight of synthetic polymers and characterize the distribution of polyester co-polymers.