Mechanistic studies of a lipase unveil effect of pH on hydrolysis products of small PET modules

• Published in: Nature Communications
• Main Authors: Świderek, Katarzyna, Velasco Lozano, Susana, Galmés, Miquel À., Olazabal Lorea, Ion, Sardon Muguruza, Haritz, López Gallego, Fernando, Moliner, Vicent
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature 2023
• Subjects: Jaume; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10810/61926; https://doi.org/10.1038/s41467-023-39201-1

Biocatalysis is a key technology enabling plastic recycling. However, despite advances done in the development of plastic-degrading enzymes, the molecular mechanisms that govern their catalytic performance are poorly understood, hampering the engineering of more efficient enzyme-based technologies. In this work, we study the hydrolysis of PET-derived diesters and PET trimers catalyzed by the highly promiscuous lipase B from Candida antarctica (CALB) through QM/MM molecular dynamics simulations supported by experimental Michaelis–Menten kinetics. The computational studies reveal the role of the pH on the CALB regioselectivity toward the hydrolysis of bis-(hydroxyethyl) terephthalate (BHET). We exploit this insight to perform a pH-controlled biotransformation that selectively hydrolyzes BHET to either its corresponding diacid or monoesters using both soluble and immobilized CALB. The discoveries presented here can be exploited for the valorization of BHET resulting from the organocatalytic depolymerization of PET. This work was supported by the Spanish Agency of Research (AEI) (ref. PID2021–123332OB-C21, PID2021–124811OB-I00 and PID2019–107098RJ-I00), the Generalitat Valenciana (PROMETEO, with ref. CIPROM/2021/079, and SEJI/2020/007), Universitat Jaume I (UJI-A2019-04 and UJI-B2020-03). K.Ś. thanks Ministerio de Ciencia e Innovación and Fondo Social Europeo for a Ramon y Cajal contract (Ref. RYC2020-030596-I) and a European Cooperation in Science & Technology COST Action (ref. CA21101). This work was partially performed under the Maria de Maeztu Units of Excellence Program from the Spanish State Research Agency Grant MDM-2017-0720. The authors acknowledge the computational resources founded by the Spanish Ministry of Science–European Regional Development Fund (REF: EQC2019-006018-P) installed at Universitat Jaume I. We thank Dr. Grajales for his assistance in the analysis of UPLC-MS samples.