• Dolz, Mikel
• Mateljak, Ivan
• Alcalde, Miguel
• Viña-Gonzalez, Javier
• Santos, Patricia Gomez De
• Sánchez-Moreno, Israel
• Méndez-Sánchez, Daniel

Abstract

<jats:p>At present, the end-of-life management of thermoset composite epoxy resins is limited to incineration and landfill storage, highlighting the demand for the development of more sustainable measures. Due to their broad spectrum of C-H oxyfunctionalization reactions, fungal unspecific peroxygenases (UPOs) are becoming important biotechnological tools in organic synthesis while their potential use in biodegradation processes should not be underestimated. Here, we present a colorimetric screening assay aimed at engineering UPOs for the degradation of epoxy resins. We based our study on Hexflow<jats:sup>®</jats:sup> RTM-6, a commercial epoxy resin used extensively in the aeronautics sector. UPO mutants from the short and long families were initially benchmarked by GC/MS to determine their potential <jats:italic>N</jats:italic>-dealkylation activity on N,N-bis(2-hydroxypropyl)-<jats:italic>p</jats:italic>-toluidine (NNBT), the main structural scaffold of Hexflow<jats:sup>®</jats:sup> RTM-6. A reliable high-throughput colorimetric screening method was developed to quantify the lactaldehyde released by UPO attack on the tertiary amine of NNBT. Based on an evolved UPO from <jats:italic>Psathyrella aberdarensis</jats:italic> that was expressed by yeast, a small subset of mutant libraries with different mutational loadings was constructed and screened for NNBT <jats:italic>N</jats:italic>-dealkylation, thereby establishing a directed evolution platform as a vehicle to engineer UPO composite degrading variants.</jats:p>

Topics

• impedance spectroscopy
• composite
• mass spectrometry
• resin
• thermoset
• gas chromatography
• amine