Biodegradation of Chloroxylenol by <i>Cunninghamella elegans</i> IM 1785/21GP and <i>Trametes versicolor</i> IM 373: Insight into Ecotoxicity and Metabolic Pathways

• Main Authors: Marta Nowak, Katarzyna Zawadzka, Janusz Szemraj, Aleksandra Góralczyk-Bińkowska, Katarzyna Lisowska
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: International Journal of Molecular Sciences
• Subjects: biodegradation; chloroxylenol; cytochrome P450; detoxification; environmental xenobiotics; filamentous fungi
• Online Access: https://www.mdpi.com/1422-0067/22/9/4360

Chloroxylenol (PCMX) is applied as a preservative and disinfectant in personal care products, currently recommended for use to inactivate the SARS-CoV-2 virus. Its intensive application leads to the release of PCMX into the environment, which can have a harmful impact on aquatic and soil biotas. The aim of this study was to assess the mechanism of chloroxylenol biodegradation by the fungal strains <i>Cunninghamella elegans</i> IM 1785/21GP and <i>Trametes versicolor</i> IM 373, and investigate the ecotoxicity of emerging by-products. The residues of PCMX and formed metabolites were analysed using GC-MS. The elimination of PCMX in the cultures of tested microorganisms was above 70%. Five fungal by-products were detected for the first time. Identified intermediates were performed by dechlorination, hydroxylation, and oxidation reactions catalysed by cytochrome P450 enzymes and laccase. A real-time quantitative PCR analysis confirmed an increase in CYP450 genes expression in <i>C. elegans</i> cells. In the case of <i>T. versicolor</i>, spectrophotometric measurement of the oxidation of 2,20-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) showed a significant rise in laccase activity during PCMX elimination. Furthermore, with the use of bioindicators from different ecosystems (Daphtoxkit F and Phytotoxkit), it was revealed that the biodegradation process of PCMX had a detoxifying nature.