Characterization of microbial communities associated with naphthalene mineralization under iron(III)-reducing conditions

Polycyclic aromatic hydrocarbons (PAHs) are persistent, carcinogenic pollutants in the environment. Upon contamination, sites rapidly become anaerobic. Without oxygen, microorganisms must rely on alternate terminal electron acceptors such as SO₄2+, NO₃−, and Fe(III) to degrade PAHs. Fe(III) is of particular interest because of its abundance relative to other terminal electron acceptors and its favorable thermodynamics in comparison with O₂. A study was conducted to characterize microbial communities associated with naphthalene (as a model PAH) degradation coupled to Fe(III)-reduction.; Using two different sources of PAH-contaminated lake sediment as inoculum, enrichments of naphthalene degraders and Fe(III)-reducers were obtained.; Microbial communities were characterized both by isolating cultures on solid media and by performing denaturing gradient gel electrophoresis on total community DNA. To obtain genomic DNA, an extraction protocol was devised. This protocol consisted of three basic steps: (1) cell lysis using freeze-thaw, (2) DNA recovery using glass milk, an aqueous suspension of silica particles, and (3) purification using polyvinylpolypyrrolidone (PVPP) columns. This protocol resulted in clean, amplifiable genomic DNA. (Abstract shortened by UMI.)...