Fungus, white rot

Trametes versicolor (L.) Lloyd

Turkey tail

A white-rot fungus widely studied as a laccase producer. It degrades chlorophenols in soil, with a field biopile trial lasting two and a half years, and in bioreactors removes pharmaceuticals from real, non-sterile urban wastewater. For several compounds the first attack is not extracellular but depends on cytochrome P450.

OhWeh, CC BY-SA 2.5

How it works

Mechanisms: mycodegradation
Enzymes: laccase, manganese peroxidase, cytochrome p450

Contaminants

Contaminant	Evidence	What was shown
Phenols and chlorophenols	field	New Zealand, aged soil from a former timber treatment site, in engineered soil cells (biopiles) set up in January 2000 and monitored for 2.5 years: pentachlorophenol fell from 800-1000 mg/kg to 4 mg/kg (range 0-9.4) following first-order kinetics; no effect of inoculum dose, reproducible results. In the laboratory, on field soil at 1043 mg/kg, maximum removal was 70% in 7 weeks, with minimal pentachloroanisole formation. Walter et al. (2005) Field-scale bioremediation of pentachlorophenol by Trametes versicolor. Int Biodeterior Biodegradation 56:51-57, 2005 Ford et al. (2007) Fungal inoculum properties: extracellular enzyme expression and pentachlorophenol removal in highly contaminated field soils. J Environ Qual, pubmed.ncbi.nlm.nih.gov, 2007
Pharmaceutical residues	laboratory	Liquid culture, 10 mg/L, 7 days: ibuprofen almost fully degraded, clofibric acid about 91%, carbamazepine about 58%; cytochrome P450 inhibitors block the first step for clofibric acid and carbamazepine. In a fluidised-bed bioreactor fed real non-sterile urban wastewater at its original concentrations (ng-µg/L): complete removal of 7 of the 10 pharmaceuticals detected, partial removal of 2, and lower Microtox toxicity. Marco-Urrea et al. (2009) Ability of white-rot fungi to remove selected pharmaceuticals and identification of degradation products of ibuprofen by Trametes versicolor. Chemosphere 74:765-772, 2009 Cruz-Morató et al. (2013) Degradation of pharmaceuticals in non-sterile urban wastewater by Trametes versicolor in a fluidized bed bioreactor. Water Res 47:5200-5210, 2013
Chlorinated solvents (TCE, PCE, chloroform)	laboratory	Trichloroethylene at 2-20 mg/L in culture: 53% of the chloride expected from complete degradation was released; main products 2,2,2-trichloroethanol and CO2 (traced with 13C-TCE), with chloral as intermediate. The pathway depends on cytochrome P450 and resembles the mammalian one, not the bacterial one. Marco-Urrea et al. (2008) Mechanistics of trichloroethylene mineralization by the white-rot fungus Trametes versicolor. Chemosphere 70:404-410, 2008
Polycyclic aromatic hydrocarbons	laboratory	In liquid culture (10 mg/L, 28 days) Trametes strains removed anthracene without accumulating anthraquinone, which is a dead-end product for Bjerkandera and Phanerochaete. Field et al. (1992) Biodegradation of polycyclic aromatic hydrocarbons by new isolates of white rot fungi. Appl Environ Microbiol 58:2219-2226, 1992

Limits

Wastewater treatment needed continuous glucose and ammonium tartrate feeding and pH held at 4.5; one pharmaceutical increased in concentration during treatment. In soil the outcome depends on inoculum age, growth substrate (poplar sawdust works better than pine or fir) and co-substrate, and PCP removal is not simply correlated with extracellular enzyme activity (Ford et al. 2007). The field biopile took years.