Potential for cometabolic biodegradation of 1,4-dioxane in aquifers with methane or ethane as primary substrates

Paul B. Hatzinger, Rahul Banerjee, Rachael Rezes, Sheryl H. Streger, Kevin McClay, Charles E. Schaefer

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

The objective of this research was to evaluate the potential for two gases, methane and ethane, to stimulate the biological degradation of 1,4-dioxane (1,4-D) in groundwater aquifers via aerobic cometabolism. Experiments with aquifer microcosms, enrichment cultures from aquifers, mesophilic pure cultures, and purified enzyme (soluble methane monooxygenase; sMMO) were conducted. During an aquifer microcosm study, ethane was observed to stimulate the aerobic biodegradation of 1,4-D. An ethane-oxidizing enrichment culture from these samples, and a pure culture capable of growing on ethane (Mycobacterium sphagni ENV482) that was isolated from a different aquifer also biodegraded 1,4-D. Unlike ethane, methane was not observed to appreciably stimulate the biodegradation of 1,4-D in aquifer microcosms or in methane-oxidizing mixed cultures enriched from two different aquifers. Three different pure cultures of mesophilic methanotrophs also did not degrade 1,4-D, although each rapidly oxidized 1,1,2-trichloroethene (TCE). Subsequent studies showed that 1,4-D is not a substrate for purified sMMO enzyme from Methylosinus trichosporium OB3b, at least not at the concentrations evaluated, which significantly exceeded those typically observed at contaminated sites. Thus, our data indicate that ethane, which is a common daughter product of the biotic or abiotic reductive dechlorination of chlorinated ethanes and ethenes, may serve as a substrate to enhance 1,4-D degradation in aquifers, particularly in zones where these products mix with aerobic groundwater. It may also be possible to stimulate 1,4-D biodegradation in an aerobic aquifer through addition of ethane gas. Conversely, our results suggest that methane may have limited importance in natural attenuation or for enhancing biodegradation of 1,4-D in groundwater environments.

Original languageEnglish (US)
Pages (from-to)453-468
Number of pages16
JournalBiodegradation
Volume28
Issue number5-6
DOIs
StatePublished - Dec 1 2017

Bibliographical note

Funding Information:
Acknowledgements We wish to acknowledge the Strategic Environmental Research and Development Program (SERDP; Project ER-2306) and the Air Force Civil Engineer Center (AFCEC; BAA Project 769) for supporting some of the studies described herein. Dr Michael Hyman at North Carolina State University provided helpful comments and insights. We also wish to thank Dr. Randi Rothmel and Anthony Soto of CB&I for their analytical support. The results and interpretations presented herein are solely the opinion of the authors and not of SERDP or AFCEC unless otherwise stated in official documentation.

Publisher Copyright:
© 2017, Springer Science+Business Media B.V.

Keywords

  • 1,4-Dioxane
  • Biodegradation
  • Cometabolism
  • Ethane
  • Methane
  • Monooxygenase

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