FLUORESCENCE MONITORING OF POLYCYCLIC AROMATIC HYDROCARBON BIODEGRADATION AND EFFECT OF SURFACTANTS

Polycyclic Aromatic Hydrocarbons (PAH) are ubiquitous environmental pollutants that are suspected to be carcinogenic. Because some PAHs can undergo metabolic degradation, an interest has emerged in bioremediating contaminated sites and incorporating surfactants into treatment processes because the release of slowing desorbing, soil-bound PAH may be promoted. We employed fluorescence spectroscopy and quenching experiments to investigate micelle-naphthalene interaction and the dynamics of biodegradation in the presence and absence of micelles. These experiments were envisioned to provide some molecular-level insights as well as constitute the basis for subsequent work where realistic model systems will be investigated in a noninvasive manner. In the absence of micelles, naphthalene was observed to be degraded within three days and intermediates were detected. Micelles protected naphthalene against copper quenching and also suppressed biodegradation. Additionally, the emission spectrum of the naphthalene associated with the micelles changed over the course of days. Based on prior quenching and polarization studies, this finding suggests that micelle maturation may occur over the time scale of the days resulting in increased sequestering of naphthalene in the micellar phase.