Recent advances in fungal xenobiotic metabolism: enzymes and applications

Abstract

Fungi have been extensively studied for their capacity to biotransform a wide range of natural and xenobiotic compounds. This versatility is a reflection of the broad substrate specificity of fungal enzymes such as laccases, peroxidases and cytochromes P450, which are involved in these reactions. This review gives an account of recent advances in the understanding of fungal metabolism of drugs and pollutants such as dyes, agrochemicals and per- and poly-fluorinated alkyl substances (PFAS), and describes the key enzymes involved in xenobiotic biotransformation. The potential of fungi and their enzymes in the bioremediation of polluted environments and in the biocatalytic production of important compounds is also discussed.

Keywords: Biodegradation; Biotransformation; Lignin-degrading enzyme; Organic compounds; Pollutant.

Fig. 1

Structures of the synthetic cannabinoids EG-018 and EG-2201

Fig. 2

Biotransformation of drostanolone ethanate by F. lini and C. aphidicola generates nine metabolites: The compounds in blue were previously known and the remainder were newly discovered (Choudhary et al. 2017)

Fig. 3

Degradation of PBA-PU by Cladosporium sp. P7. The initial products of esterase and urethanase activity were further degraded by the fungus (Liu et al. 2023)

Fig. 4

Catalytic mechanism of CYP system involved interaction between CPR, Cyt b5 and CYP monooxygenase in the hydroxylation of substrate X-H

Fig. 5

General mechanism of peroxidases (LiP lignin peroxidase, MnP manganese peroxidase, VP versatile peroxidase, X-H substrate). The free radical product X^• non-specifically reacts with other phenolic compounds

Fig. 6

Mechanism of UPO

Fig. 7

Mechanism of laccase. For each O₂ molecule, four phenolic substrates are oxidised

Fig. 8

Catalytic mechanism of tyrosinase showing both cresolase and catecholase cycles. E_oxy/E_met/E_deoxy forms of oxidation state of tyrosinase. E_oxyM monophenolase E_oxy complex, E_oxyD diphenolase E_oxy complex, E_metM monophenolase E_met complex, and E_metD diphenolase E_met complex. A description of the mechanism is in the main text