Biodegradation of phenanthrene by Phanerochaete chrysosporium: on the role of lignin peroxidase

Abstract

Lignin peroxidase H8 from the wood rotting basidiomycete Phanerochaete chrysosporium is able to catalyse oxidation of 9‐phenanthrol, forming phenanthrene‐9, 10‐quinone. This is of interest because 9‐phenanthrol is an intermediate in the major pathway for phenanthrene degradation that occurs in this fungus under non‐ligninolytic conditions whereas the product, phenanthrene‐9, 10‐quinone, is an intermediate in the pathway that occurs under ligninolytic conditions. It thus appears reasonable to suggest that, at the onset of idiophase (when cultures become ligninolytic), lignin peroxidases may function to link these two pathways.

Novel evidence of cytochrome P450-catalyzed oxidation of phenanthrene in Phanerochaete chrysosporium under ligninolytic conditions

“…5). Although LiPs can not oxidize phenanthrene (Hammel et al 1986), LiP H8 from P. chrysosporium was reported to be able to oxidize 9-phenanthrol to phenanthrene-9, 10-quinone which could be rapidly cleaved to DPA (Tatarko and Bumpus 1994). It was also reported that trace quantities of DPA could be detected after addition of phenanthrene trans-9,10-dihydrodiol to ligninolytic cultures (Hammel et al 1992).…”

“…In contrast, another ligninolytic enzyme, lignin peroxidase (LiP) can not oxidize phenanthrene, although it is able to oxidize many PAHs that have ionization potentials less than about 7.6 eV (Hammel et al 1986). However, LiP can catalyze oxidation of 9-phenanthrol to form 9,10-phenanthrenequinone (Tatarko and Bumpus 1994).…”

Genome-to-function characterization of novel fungal P450 monooxygenases oxidizing polycyclic aromatic hydrocarbons (PAHs)

“…Considering that the white rot fungi possess a comprehensive enzymatic machinery to completely degrade (to CO 2 ) PAHs, the P450 monooxygenases may link up with the PAH mineralization pathway components under appropriate conditions; such common pathway components (non-ligninolytic and ligninolytic) for cycling of PAH metabolites have been indicated in previous studies [18,32]. Hence, the presence of P450s in white rot fungi assumes greater significance than in other biological systems that have a standalone P450 enzyme system for PAH metabolism such as in non-basidiomycete fungi [4] and animals [19].…”

Bioremediation of PCDD/Fs-contaminated municipal solid waste incinerator fly ash by a potent microbial biocatalyst

“…These enzymes mediate dioxin degradation by a radical reaction which involves the cation-mediated cleavage of the C-O-C bond at the angular position adjacent to the ether bridge of molecules [15,33]. Many researchers have suggested that the peroxidases of these fungi are essential for the oxidative degradation of environmentally persistent compounds, such as polycyclic aromatic hydrocarbons [34,35].…”