Anaerobic biodegradation of methyl tert-butyl ether (MTBE) and related fuel oxygenates

MTBE, used as an octane enhancer and fuel oxygenate in reformulated gasoline, has become a major contaminant of water resources. MTBE is resistant to common methods used for efficient removal of other fuel components from groundwater and is relatively resistant to biodegradation. There has been increasing interest in the development of effective technologies to remediate MTBE-contaminated sites, for instance pump-and-treat techniques, biostimulation, and bioaugmentation. The full-scale implementation of these techniques is, however, considerably costly and is currently economically applicable for a few sites with highly sensitive receptors. Therefore, the fate of MTBE in the environment is mainly dependent on natural remediation processes. Although anaerobic MTBE degradation has been demonstrated in the laboratory, it is not known how efficiently anaerobic degradation occurs in contaminated environments. Furthermore, no organisms have yet been identified from the anaerobic MTBE-degrading consortia, nor is the anaerobic biodegradation mechanism known. Our information about the role of anaerobic microbial communities involved in the biodegradation of MTBE is thus limited. Methods for in situ monitoring of natural attenuation are being developed through studies of the stable isotope fractionation values for anaerobic MTBE degradation. Compound-specific stable isotope analysis has emerged as a useful tool to demonstrate active in situ MTBE biodegradation and will contribute to the development of appropriate remediation measures. © 2007 Elsevier Inc. All rights reserved.