Anaerobic Microbial Degradation of Recalcitrant Fuel Components by Estuarine Sediment Communities

摘要

To evaluate the restorative capacity of a contaminated estuarine ecosystem (NY/NJ Harbor Estuary) and to determine the contributions of anaerobic microorganisms in the degradation of refractory fuel components such as polyaromatic hydrocarbons (PAHs) and alkanes in the anoxic harbor sediment; Instrinsic biodegradation of a representative PAH, naphthalene occurs in anaerobic sediment microbial communities. This activity in-situ is complicated by other moderators which may be found in the harbor such as toxic heavy metals and/or other contaminants. In addition, the data clearly shows that hydrocarbons such as PAH and alkanes which have been considered to be resistant to biodegradation in the absence of oxygen can indeed be microbially metabolized and mineralized to carbon dioxide. Results indicate that the sulfate reducing anaerobic microorganisms appear to have novel mechanisms for PAH and alkane transformations. In the case of PAH, carboxylation occurs first, then ring reduction occurs prior to ring fission; while in the case of the alkanes, 2 different initial mechanisms of attack have been documented. Anaerobic sediment microbial communities from an impacted harbor estuary have an intrinsic restorative capacity with respect to PAH degradation. In addition, anaerobic microorganisms have novel mechanisms for PAH and alkane transformation. These microbial mechanisms, to our knowledge, have not been previously reported and have implications for biocatalysis as well as for biodegradation. This information potentially can lead to strategies for targeted in-situ remediation approaches and to alternatives for managing harbor sediments.