Bioremediation of Complex Polycyclic Aromatic Hydrocarbons (PAHs)
by the Fungi Cunninghamella elegans
Matthew Tierney
Olatubi Sean
Dr. Robin Autenrieth
Dr. Thomas McDonald
Department of Civil Engineering
Texas A&M University
Polycyclic aromatic hydrocarbons (PAHs) has been of much interest recently due to their harmful effects on the environment and their potentially toxic and carcinogenic properties. Of particular interest is their microbial metabolism by the fungi Cunninghamella elegans, which utilizes the cytochrome P-450 enzyme system and is similar to the metabolism of xenobiotics in mammals. The toxicity thresholds of benzo[a]pyrene (BAP) and fluoranthene (FLA) for the fungi were determined to be 500 mg/L and 50 mg/L respectively. The metabolism of PAH mixtures of phenanthrene (PHE) and FLA at 1:1, 2:1, and 1:2 molar ratios were then quantitatively measured, dependent on time. The solubility of PHE and FLA were factored into the molar ratios. The metabolism of FLA was accurately quantified, yielding a first order rate equation. The rate constant for FLA was determined to be –0.1 hr-1. Trends involving molecular weight and the order of metabolism in complex mixtures of PAHs were observed.