Screening of human enteric microorganisms for potential biotransformation of polycyclic aromatic hydrocarbons.

This study examined the potential for metabolism of select polycyclic aromatic hydrocarbons (PAH) by human enteric microorganisms. Experiments were performed under anaerobic conditions with various combinations of enteric microbial suspensions, PAH concentrations, nutrient mixtures, and time courses. No PAH metabolites were detected upon GC-TOF-MS analysis of samples digested by tetramethylammonium hydroxide thermochemolysis. No mineralization of (14)C-labeled phenanthrene was observed. These results suggest the lack of partial or complete metabolism of PAHs by enteric microorganisms and therefore the absence of major bioactivation pathways that would expose intestinal lining to potentially carcinogenic PAH metabolites.