Anaerobic Methyl tert-Butyl Ether-Degrading Microorganisms Identified in Wastewater Treatment Plant Samples by Stable Isotope Probing

Department of Civil and Environmental Engineering, Michigan State University, East Lansing, Michigan, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 02/2012; 78(8):2973-80. DOI: 10.1128/AEM.07253-11
Source: PubMed


Anaerobic methyl tert-butyl ether (MTBE) degradation potential was investigated in samples from a range of sources. From these 22 experimental
variations, only one source (from wastewater treatment plant samples) exhibited MTBE degradation. These microcosms were methanogenic
and were subjected to DNA-based stable isotope probing (SIP) targeted to both bacteria and archaea to identify the putative
MTBE degraders. For this purpose, DNA was extracted at two time points, subjected to ultracentrifugation, fractioning, and
terminal restriction fragment length polymorphism (TRFLP). In addition, bacterial and archaeal 16S rRNA gene clone libraries
were constructed. The SIP experiments indicated bacteria in the phyla Firmicutes (family Ruminococcaceae) and Alphaproteobacteria (genus Sphingopyxis) were the dominant MTBE degraders. Previous studies have suggested a role for Firmicutes in anaerobic MTBE degradation; however, the putative MTBE-degrading microorganism in the current study is a novel MTBE-degrading
phylotype within this phylum. Two archaeal phylotypes (genera Methanosarcina and Methanocorpusculum) were also enriched in the heavy fractions, and these organisms may be responsible for minor amounts of MTBE degradation
or for the uptake of metabolites released from the primary MTBE degraders. Currently, limited information exists on the microorganisms
able to degrade MTBE under anaerobic conditions. This work represents the first application of DNA-based SIP to identify anaerobic
MTBE-degrading microorganisms in laboratory microcosms and therefore provides a valuable set of data to definitively link
identity with anaerobic MTBE degradation.

Download full-text


Available from: Weimin Sun,
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ether oxygenates such as methyl tertiary butyl ether (MTBE) are added to gasoline to improve fuel combustion and decrease exhaust emissions. Ether oxygenates and their tertiary alcohol metabolites are now an important group of groundwater pollutants. This review highlights recent advances in our understanding of the microorganisms, enzymes and pathways involved in both the aerobic and anaerobic biodegradation of these compounds. This review also aims to illustrate how these microbiological and biochemical studies have guided, and have helped refine, molecular and stable isotope-based analytical approaches that are increasingly being used to detect and quantify biodegradation of these compounds in contaminated environments.
    Current Opinion in Biotechnology 10/2012; 24(3). DOI:10.1016/j.copbio.2012.10.005 · 7.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this work was to investigate the susceptibility of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to biodegradation in a range of soils and to identify RDX-degrading organisms using stable isotope probing (SIP). RDX degradation was examined in ten soils, primarily from agricultural areas. RDX biodegradation was observed in six samples and only when the microcosms were not aerated. For one soil, 15N- and 13C-based DNA SIP was used to identify the microorganisms responsible for RDX degradation. Two RDX concentrations were examined (10 and 20 mg/L), however, only the higher concentration resulted in a significant SIP signal. In these ultracentrifugation fractions, one terminal restriction fragment length polymorphism (TRFLP) fragment (260 bp) showed a reliable trend of label uptake. This fragment was of higher relative abundance in the heavier fractions from labeled samples compared with the heavier fractions from the unlabeled control samples, indicating that the organism producing this fragment was responsible for label uptake (hence RDX degradation). Partial 16S rRNA gene sequencing indicated the organisms represented by fragment 260 bp belonged to either Sphingobacteria (phylum Bacteroidetes) or the phylum Acidobacteria. To date, these organisms have not previously been directly linked to RDX degradation. The 16S rRNA sequences were compared with the NCBI database and, in all cases, were most similar to uncultured bacteria. The results suggest SIP is a viable method for discovering novel, previously uncultured, RDX degraders.
    Water Air and Soil Pollution 10/2013; 224(10). DOI:10.1007/s11270-013-1745-4 · 1.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This literature review provides a comprehensive overview of the research published in 2012 concerning anaerobic processes and their role in wastewater treatment technologies. Included in this review is a discussion on the characterization, development and optimization of novel approaches for waste treatment. The scope of this year's anaerobic processes literature review will include the following topics: process technology, integrated approaches, treatability studies, toxicity, modeling advances, microbiology, anammox, hydrogen production, and biogas treatment and use.
    Water Environment Research 10/2013; 85(10):1176-1231. DOI:10.2175/106143013X13698672321986 · 0.87 Impact Factor
Show more