Biochemical Characterization and Polyester-Binding/Degrading Capability of Two Cutinases from .

Two recombinant cutinases, CutA and CutB, derived from were heterologously expressed in and systematically characterized for their biochemical properties and polyester-degrading capabilities. CutA demonstrated superior catalytic performance compared with CutB, displaying higher optimal pH (8.0-9.0 vs. 7.0-8.0), higher optimal temperature (60 °C vs. 50 °C), and greater thermostability. CutA exhibited increased hydrolytic activity toward p-nitrophenyl esters (C4-C16) and synthetic polyesters. Additionally, CutA released approximately 3.2-fold more acetic acid from polyvinyl acetate (PVAc) hydrolysis than CutB. Quartz crystal microbalance with dissipation monitoring (QCM-D) revealed rapid adsorption of both enzymes onto polyester films. However, their adsorption capacity on poly (ε-caprolactone) (PCL) films was significantly higher than on polybutylene succinate (PBS) films, and was influenced by pH. Comparative modeling of catalytic domains identified distinct structural differences between the two cutinases. CutA possesses a shallower substrate-binding cleft, fewer acidic residues, and more extensive hydrophobic regions around the active site, potentially explaining its enhanced interfacial activation and catalytic efficiency toward synthetic polyester substrates. The notably superior performance of CutA suggests its potential as a biocatalyst in industrial applications, particularly in polyester waste bioremediation and sustainable polymer processing.