Water Science & Technology Vol 52 No 8 pp 125–131 © IWA Publishing 2005
Cometabolic transformation of cis-1,2-dichloroethylene and cis-1,2-dichloroethylene epoxide by a butane-grown mixed culture
Y. Kim* and L. Semprini**
*Department of Environmental Engineering, Korea University, 208 Seochang-Dong, Jochiwon, Choong-Nam 339-800, Korea South Korea
**Department of Civil, Construction, Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
ABSTRACT
Aerobic cometabolism of cis-1,2-dichloroethylene (c-DCE) by a butane-grown mixed culture was evaluated in batch kinetic tests. The transformation of c-DCE resulted in the coincident generation of c-DCE epoxide. Chloride release studies showed ∼75% oxidative dechlorination of c-DCE. Mass spectrometry confirmed the presence of a compound with mass-to-charge-fragment ratios of 112, 83, 48, and 35. These values are in agreement with the spectra of chemically synthesized c-DCE epoxide. The transformation of c-DCE required O2, was inhibited by butane and was inactivated by acetylene (a known monooxygenase inactivator), indicating that a butane monooxygenase enzyme was likely involved in the transformation of c-DCE. This study showed c-DCE epoxide was biologically transformed, likely by a butane monooxygenase enzyme. c-DCE epoxide transformation was inhibited by both acetylene and c-DCE indicating a monooxygenase enzyme was involved. The epoxide transformation was also stopped when mercuric chloride (HgCl2) was added as a biological inhibitor, further support a biological transformation. To our knowledge this is the first report of the biological transform c-DCE epoxide by a butane-grown culture. Keywords Butane-grown mixed culture; aerobic cometabolism; cis-1, 2-dichloroethylene; cis-1, 2-dichloroethylene epoxide
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