Pyrene and benzo(a)pyrene metabolism by an Aspergillus terreus strain isolated from a polycylic aromatic hydrocarbons polluted soil

A strain of Aspergillus terreus was isolated from a polycyclic aromatic hydrocarbons (PAHs) polluted soil. The metabolism of pyrene and benzo( a) pyrene by this fungus was investigated in liquid submerged culture added of 50 and 25 ppm respectively of each compound. Depletion of pyrene and Bnzo( a) pyrene was evident during the first stages of growth and was 60% and 27.5% respectively of the added amount after nine days of culture. Solvent extracts of the fermentation broth and mycelium were analysed for presence of metabolites by HPLC-MS technique. Under the present cultural conditions pyrene was mainly metabolised to pyrenylsulfate similarly to benzo( a) pyrene that led to benzo( a) pyrenylsulfate. The structure of 1-pyrenilsulfate was determined after purification of extracts and H-NMR analysis. The result show that the isolated A. terreus strain metabolises PAHs by reaction similar to those previously reported for non lignolinolytic fungi with a mechanism that suggests the hydroxylation by a cytochrome P-450 monooxygenase followed by conjugation with sulfate ion.