Limitations in Mtbe Biodegradation

Fayolle, F.; François, Alan; Garnier, L.; Godefroy, D.; Mathis, Hugues; Piveteau, Pascal; Monot, Frédéric

doi:10.2516/ogst:2003033

Cited by 36 publications

(22 citation statements)

References 25 publications

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“…MTBE biodegradation has also been demonstrated in laboratory studies under a variety of redox conditions, where the highest MTBE degradation rates were observed under aerobic conditions (45). It has thus been suggested that biodegradation of MTBE in the field is often limited by the environmental conditions (12,37) and, in particular, by the limited concentrations of oxygen typically found in fuel-contaminated aquifers. As a consequence of these findings, in situ bioremediation of MTBE has been successfully enhanced by addition of air, pure oxygen (biostimulation), or previously enriched MTBE-degrading microorganisms (bioaugmentation) (49).…”

mentioning

confidence: 93%

Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert -Butyl Ether Biodegradation in Aerated Treatment Pond Systems

Jechalke

Rosell

Lavanchy

et al. 2011

Appl Environ Microbiol

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Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring in biofilms in an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway for MTBE oxidation was elucidated by linking the low-level stable isotope fractionation (mean carbon isotopic enrichment factor [ C ] of ؊0.37‰ ؎ 0.05‰ and no significant hydrogen isotopic enrichment factor [ H ]) observed in microcosm experiments to expression of the ethB gene encoding a cytochrome P450 monooxygenase able to catalyze the oxidation of MTBE in biofilm samples both from the microcosms and directly from the ponds. 16S rRNA-specific primers revealed the presence of a sequence 100% identical to that of Methylibium petroleiphilum PM1, a well-characterized MTBE degrader. However, neither expression of the mdpA genes encoding the alkane hydroxylase-like enzyme responsible for MTBE oxidation in this strain nor the related MTBE isotope fractionation pattern produced by PM1 could be detected, suggesting that this enzyme was not active in this system. Additionally, observed low inverse fractionation of carbon ( C of ؉0.11‰ ؎ 0.03‰) and low fractionation of hydrogen ( H of ؊5‰ ؎ 1‰) in laboratory experiments simulating MTBE stripping from an open surface water body suggest that the application of CSIA in field investigations to detect biodegradation may lead to false-negative results when volatilization effects coincide with the activity of low-fractionating enzymes. As shown in this study, complementary examination of expression of specific catabolic genes can be used as additional direct evidence for microbial degradation activity and may overcome this problem.

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mentioning

confidence: 93%

Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert -Butyl Ether Biodegradation in Aerated Treatment Pond Systems

Jechalke

Rosell

Lavanchy

et al. 2011

Appl Environ Microbiol

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“…Abiotic reactions or an esterase will then cleave TBF into TBA and formate (14). TBA is a key intermediate observed in various investigations (10,13,43,52 (17,52). Hydroxylation of a methyl group of TBA followed by two consecutive dehydrogenase steps yields 2-HIBA (Fig.…”

Section: Bacterialmentioning

confidence: 98%

“…1) (8,14,26,50,52). The reaction is believed to yield tert-butoxy methanol, an unstable and/or reactive intermediate (13,14,48,52) that may undergo dismutation to TBA and formaldehyde (19). Alternatively, a dehydrogenase reaction may form TBF (19,23,43).…”

Section: Bacterialmentioning

confidence: 99%

Carbon Conversion Efficiency and Limits of Productive Bacterial Degradation of Methyl tert -Butyl Ether and Related Compounds

Müller

Rohwerder

Harms

2007

Appl Environ Microbiol

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The utilization of the fuel oxygenate methyl tert-butyl ether (MTBE) and related compounds by microorganisms was investigated in a mainly theoretical study based on the Y ATP concept. Experiments were conducted to derive realistic maintenance coefficients and K s values needed to calculate substrate fluxes available for biomass production. Aerobic substrate conversion and biomass synthesis were calculated for different putative pathways. The results suggest that MTBE is an effective heterotrophic substrate that can sustain growth yields of up to 0.87 g g ؊1 , which contradicts previous calculation results (N. Fortin et al., Environ. Microbiol. 3:407-416, 2001). Sufficient energy equivalents were generated in several of the potential assimilatory routes to incorporate carbon into biomass without the necessity to dissimilate additional substrate, efficient energy transduction provided. However, when a growth-related kinetic model was included, the limits of productive degradation became obvious. Depending on the maintenance coefficient m s and its associated biomass decay term b, growth-associated carbon conversion became strongly dependent on substrate fluxes. Due to slow degradation kinetics, the calculations predicted relatively high threshold concentrations, S min , below which growth would not further be supported. S min strongly depended on the maximum growth rate max , and b and was directly correlated with the half maximum rate-associated substrate concentration K s , meaning that any effect impacting this parameter would also change S min . The primary metabolic step, catalyzing the cleavage of the ether bond in MTBE, is likely to control the substrate flux in various strains. In addition, deficits in oxygen as an external factor and in reduction equivalents as a cellular variable in this reaction should further increase K s and S min for MTBE.Methyl tert-butyl ether (MTBE) and the related compounds ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether, are widely used as oxygenating compounds in gasoline. Extensive use of these compounds for over 20 years has led to pollution mainly caused by unnoticed leakages and accidental spills. High water solubility facilitates the spread of these pollutants, which now severely threaten water resources (4,29,47,51) by their unpleasant odor and taste and suspected carcinogenicity. Consequently, a main concern is the environmental fate of the ether oxygenates and the development of measures against pollution. In this respect microbial degradation has been considered (11,14,48). However, MTBE and structurally related compounds prove recalcitrant to microbial attack. This is thought to be mainly caused by the ether bond in these compounds and the presence of a tertiary carbon atom. The search for degradative microorganisms was without success for a long time (25) or resulted at best in the enrichment of degrading consortia (6,15,28,44). However, provision of alkanes as a primary source of carbon and energy led to the enrichment of strains that are able to attack MTB...

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“…It is known that MTBE can be degraded by co-metabolism as was observed during growth of various microorganisms on different carbon substrates (Brusseau et al 1990;Bowman et al 1993;Fayolle et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Dual augmentation for aerobic bioremediation of MTBE and TCE pollution in heavy metal-contaminated soil

et al. 2008

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In this work we isolated from soil and characterized several bacterial strains capable of either resisting high concentrations of heavy metals (Cd 2? or Hg 2? or Pb 2? ) or degrading the common soil and groundwater pollutants MTBE (methyl-tertbutyl ether) or TCE (trichloroethylene). We then used soil microcosms exposed to MTBE (50 mg/l) or TCE (50 mg/l) in the presence of one heavy metal (Cd 10 ppm or Hg 5 ppm or Pb 50 or 100 ppm) and two bacterial isolates at a time, a degrader plus a metalresistant strain. Some of these two-membered consortia showed degradation efficiencies well higher (49-182% higher) than those expected under the conditions employed, demonstrating the occurrence of a synergetic relationship between the strains used. Our results show the efficacy of the dual augmentation strategy for MTBE and TCE bioremediation in the presence of heavy metals.

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Limitations in Mtbe Biodegradation

Cited by 36 publications

References 25 publications

Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert -Butyl Ether Biodegradation in Aerated Treatment Pond Systems

Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert -Butyl Ether Biodegradation in Aerated Treatment Pond Systems

Carbon Conversion Efficiency and Limits of Productive Bacterial Degradation of Methyl tert -Butyl Ether and Related Compounds

Dual augmentation for aerobic bioremediation of MTBE and TCE pollution in heavy metal-contaminated soil

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