Reductive dechlorination catalyzed by bacterial transition-metal coenzymes
- Univ. of Minnesota, Navarre (United States)
The bacterial transition-metal coenzymes vitamin B{sub 12} (Co), coenzyme F{sub 430} (ni), and hematin (Fe) catalyzed the reductive dechlorination of polychlorinated ethylenes and benzenes, whereas the electron-transfer proteins four-iron ferredoxin, two-iron ferredoxin, and azurin (Cu) did not. For vitamin B{sub 12} and coenzyme F{sub 430}, reductive dechlorination rates for different classes of perchlorinated compounds had the following order: carbon tetrachloride > tetrachloroethylene > hexachlorobenzene. For hematin, the order of reductive dechlorination rates was carbon tetrachloride > hexachlorobenzene > tetrachloroethylene. Within each class of compounds, rates of dechlorination decreased with decreasing chlorine content. Regio- and stereospecificity were observed in these reactions. In the reductive dechlorination of trichloroethylene, cis-1,2-dichloroethylene was the predominant product formed with vitamin B{sub 12}, coenzyme F{sub 430}, and hematin. Pentachlorobenzene and pentachlorophenol were each dechlorinated by vitamin B{sub 12} to yield two out of three possible isomeric tetrachlorobenzenes. Similar relative kinetics and dechlorination products have been observed in anaerobic cultures, suggesting a possible role of transition-metal coenzymes in the reductive dechlorination of poly-chlorinated compounds in natural and engineered environments.
- OSTI ID:
- 5259999
- Journal Information:
- Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 25:4; ISSN ESTHA; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
AROMATICS
BACTERIA
CARBON TETRACHLORIDE
CATALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
CHLORINATED AROMATIC HYDROCARBONS
CHROMATOGRAPHY
COBALT COMPOUNDS
COENZYMES
COPPER COMPOUNDS
DECHLORINATION
DEHALOGENATION
ELECTRON TRANSFER
GAS CHROMATOGRAPHY
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
IN VITRO
IRON COMPOUNDS
KINETICS
LIQUID COLUMN CHROMATOGRAPHY
MASS SPECTROSCOPY
MICROORGANISMS
NICKEL COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
REACTION KINETICS
REDUCTION
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY
STEREOCHEMISTRY
TRANSITION ELEMENT COMPOUNDS
ULTRAVIOLET SPECTRA
VITAMIN B GROUP
VITAMINS