Multi-omics deciphers the enzymatic mechanisms of high-risk liquid crystal monomer biodegradation by Gordonia alkanivorans QZP3

Liquid crystal monomers (LCMs) are emerging contaminants of growing prevalence in aquatic environments, with cyano- and fluoro-substituted LCMs exhibiting particularly high biotoxicity. However, their biotransformation behavior remains poorly understood. Herein, we integrated a multi-omics approach to investigate the biodegradation mechanisms of two representative high-risk LCMs, namely 4-cyano-3-fluorophenyl 4-pentylbenzoate (CEB-F) and 4-cyano-3,5-difluorophenyl 4-pentylbenzoate (CEB-F2), by Gordonia alkanivorans QZP3. Whole-genome sequencing revealed that G. alkanivorans QZP3 encodes multiple enzymes involved in cyano group hydrolysis and dehalogenation, suggesting substantial metabolic potential toward cyano- and fluoro-substituted LCMs. Systematic biodegradation assays confirmed that this strain exhibits excellent ability to degrade and defluorinate both target LCMs. High-resolution mass spectrometry analysis revealed that CEB-F2 undergoes stepwise degradation via multiple pathways, including cyano group hydrolysis, defluorination, ester bond hydrolysis, demethylation, O-methylation, O-glycosylation, and malonylation, ultimately resulting in substantial detoxification. Combined transcriptomic and proteomic analyses further identified apolipoprotein N-acyltransferases, cyanate hydratases, haloacid dehalogenases, esterases, amidases, and amidohydrolases as the key functional enzymes mediating the multi-pathway biotransformation of CEB-F2. Molecular docking simulations verified the stable binding of these enzymes to CEB-F2 and its major intermediates within their active pockets, targeting distinct molecular sites. This study provides the first mechanistic evidence for the microbial degradation of cyano- and fluoro-substituted LCMs, offering new perspectives on the environmental fate and bioremediation potential of high-risk LCMs in aquatic ecosystems.