Fungal PAH-metabolites resist mineralization by soil microorganisms

TY - JOUR

T1 - Fungal PAH-metabolites resist mineralization by soil microorganisms

AU - Schmidt, Stine Nørgaard

AU - Christensen, Jan H.

AU - Johnsen, Anders R.

PY - 2010/3/1

Y1 - 2010/3/1

N2 - This study investigated the mineralization of water-soluble polycyclic aromatic hydrocarbon (PAH) metabolites produced by the soil fungus Cunninghamella elegans. Eleven soil fungi were screened for their ability to metabolize 14Cphenanthrene, 14C-fluoranthene, and 14C-pyrene into watersoluble compounds. Eight fungi produced water-soluble metabolites from all or some of the PAHs. The composition of the water-soluble PAH-metabolites from the most effective solubilizer C. elegans was analyzed by an ultraperformance liquid Chromatograph interfaced to a quadrupole time-of-flight mass spectrometer. Thirty-eight metabolites were detected. All of 34 identified metabolites were sulfate-conjugated. The mineralization of 14C-metabolites, produced by C. elegans, was compared to mineralization of the parent 14C-PAHs in soil slurries. It was hypothesized that the increased bioavailability and metabolic activation of the metabolites would increase mineralization in soil slurries compared to mineralization of the parent PAHs. Unexpectedly, the mineralization of the 14Cmetabolites was in all cases extremely slow compared to the mineralization of the parent 14C-PAHs. Slow 14C-metabolite mineralization was not caused by metabolite toxicity, neither was cometabolic mineralization of 14C-metabolites stimulated by the presence of active PAH-degraders. High water solubility, low lipophilicity, and extremely slow mineralization of the metabolites indicate a potential problem of leaching of fungal PAHmetabolites to the groundwater.

AB - This study investigated the mineralization of water-soluble polycyclic aromatic hydrocarbon (PAH) metabolites produced by the soil fungus Cunninghamella elegans. Eleven soil fungi were screened for their ability to metabolize 14Cphenanthrene, 14C-fluoranthene, and 14C-pyrene into watersoluble compounds. Eight fungi produced water-soluble metabolites from all or some of the PAHs. The composition of the water-soluble PAH-metabolites from the most effective solubilizer C. elegans was analyzed by an ultraperformance liquid Chromatograph interfaced to a quadrupole time-of-flight mass spectrometer. Thirty-eight metabolites were detected. All of 34 identified metabolites were sulfate-conjugated. The mineralization of 14C-metabolites, produced by C. elegans, was compared to mineralization of the parent 14C-PAHs in soil slurries. It was hypothesized that the increased bioavailability and metabolic activation of the metabolites would increase mineralization in soil slurries compared to mineralization of the parent PAHs. Unexpectedly, the mineralization of the 14Cmetabolites was in all cases extremely slow compared to the mineralization of the parent 14C-PAHs. Slow 14C-metabolite mineralization was not caused by metabolite toxicity, neither was cometabolic mineralization of 14C-metabolites stimulated by the presence of active PAH-degraders. High water solubility, low lipophilicity, and extremely slow mineralization of the metabolites indicate a potential problem of leaching of fungal PAHmetabolites to the groundwater.

U2 - 10.1021/es903415t

DO - 10.1021/es903415t

M3 - Journal article

C2 - 20136075

SN - 0013-936X

VL - 44

SP - 1677

EP - 1682

JO - Environmental Science & Technology

JF - Environmental Science & Technology

IS - 5

ER -