Using DNA-Stable Isotope Probing to Identify MTBE- and TBA-Degrading Microorganisms in Contaminated Groundwater

作者：Key Katherine C; Sublette Kerry L^*; Duncan Kathleen; Mackay Douglas M; Scow Kate M; Ogles Dora

来源：Ground Water Monitoring and Remediation, 2013, 33(4): 57-68.

DOI：10.1111/gwmr.12031

Although the anaerobic biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA-stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate-reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio-Sep (R) beads amended with C-13(5)-MTBE, C-13(1)-MTBE (only methoxy carbon labeled), or C-13(4)-TBA. C-13-DNA and C-12-DNA extracted from the Bio-Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the tert-butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading C-13-labeled MTBE and TBA in situ and the C-13 was incorporated into their DNA. Several sequences related to known MTBE- and TBA-degraders in the Burkholderiales and the Sphingomonadales orders were detected in all three C-13 clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate-reducing bacteria and iron-reducers, such as Geobacter and Geothrix, were only detected in the clone libraries where MTBE and TBA were fully labeled with C-13, suggesting that they were involved in processing carbon from the tert-butyl group. Sequences similar to the Pseudomonas genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with C-13. It is likely that members of this genus were secondary degraders cross-feeding on C-13-labeled metabolites such as acetate.

• 出版日期2013-11