Biochemical Characterization and Polyester-Binding/Degrading Capability of Two Cutinases from <i>Aspergillus fumigatus</i>

Two recombinant cutinases, <i>Af</i>CutA and <i>Af</i>CutB, derived from <i>Aspergillus fumigatus,</i> were heterologously expressed in <i>Pichia pastoris</i> and systematically characterized for their biochemical properties and polyester-degrading cap...

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Bibliographic Details
Main Authors: Haizhen Wang, Tianrui Zhang, Kaixiang Chen, Liangkun Long, Shaojun Ding
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/5/1121
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Summary:Two recombinant cutinases, <i>Af</i>CutA and <i>Af</i>CutB, derived from <i>Aspergillus fumigatus,</i> were heterologously expressed in <i>Pichia pastoris</i> and systematically characterized for their biochemical properties and polyester-degrading capabilities. <i>Af</i>CutA demonstrated superior catalytic performance compared with <i>Af</i>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. <i>Af</i>CutA exhibited increased hydrolytic activity toward p-nitrophenyl esters (C4–C16) and synthetic polyesters. Additionally, <i>Af</i>CutA released approximately 3.2-fold more acetic acid from polyvinyl acetate (PVAc) hydrolysis than <i>Af</i>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. <i>Af</i>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 <i>Af</i>CutA suggests its potential as a biocatalyst in industrial applications, particularly in polyester waste bioremediation and sustainable polymer processing.
ISSN:2076-2607