Detoxification of polycyclic aromatic hydrocarbons by fungi

Abstract

The polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous environmental pollutants, many of which are acutely toxic, mutagenic, or carcinogenic. A diverse group of fungi, including Aspergillus ochraceus, Cunninghamella elegans, Phanerochaete chrysosporium, Saccharomyces cerevisiae, and Syncephalastrum racemosum, have the ability to oxidize PAHs. The PAHs anthracene, benz[a]anthracene, benzo[a]pyrene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene, as well as several methyl-, nitro-, and fluoro-substituted PAHs, are metabolized by one or more of these fungi. Unsubstituted PAHs are oxidized initially to arene oxides, trans-dihydrodiols, phenols, quinones, and tetralones. Phenols and trans-dihydrodiols may be further metabolized, and thus detoxified, by conjugation with sulfate, glucuronic acid, glucose, or xylose. Although dihydrodiol epoxides and other mutagenic and carcinogenic compounds have been detected as minor fungal metabolites of a few PAHs, most transformations performed by fungi reduce the mutagenicity and thus detoxify the PAHs.

Biological degradation of oil sludge: A review of the current state of development

“…According to report by Sutherland (1992), fungal decomposition of PAHs may produce mutagenic intermediates (Frick et al, 1999). In such instance, liming may be used to increase the pH from acidic to alkaline state so that bacterial growth may be favoured than fungal growth.…”

Aerobic Degradation of Anthracene, Benzo(a)Anthracene and Dibenzo(a,h) Anthracene by Indigenous Strains of Aerobic Heterotrophic Bacteria and Cyanobacteria Isolates From Crude Oil Contaminated Bodo Creek

“…They are highly toxic, mutagenic, carcinogenic and genotoxic and also exhibit toxicity to algae, fish and can bio accumulate along the food chain [2]. Anthracene is a tricyclic poly aromatic hydrocarbon which is characterized by a three fused benzene ring.…”

Phenanthrene Removal from Soil by a Strain of Aspergillus niger Producing Manganese Peroxidase of Phanerochaete chrysosporium

“…These microorganisms carry out a monooxygenation of the PAH molecules by the intracellular cytochrome P-450 dependent oxidase system [25]. These fungi do not produce extracellular peroxidases, however, they do produce cytochrome P450 monooxygenase which can oxidize PAHs to epoxides and dihydrodiols: highly potent carcinogens that accumulate in soil (figure 1) [26][27][28][29].…”