Reductive dehalogenation of carbon tetrachloride by Escherichia coli K-12

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Applied and Environmental Microbiology; (USA)

OSTI ID:5961354

Criddle, C S; DeWitt, J T; McCarty, P L ^[1]

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1. Stanford Univ., CA (USA)

The formation of radicals from carbon tetrachloride (CT) is often invoked to explain the product distribution resulting from its transformation. Radicals formed by reduction of CT presumably react with constituents of the surrounding milieu to give the observed product distribution. The patterns of transformation observed in this work were consistent with such as hypothesis. In cultures of Escherichia coli K-12, the pathways and rates of CT transformation were dependent on the electron acceptor condition of the media. Use of oxygen and nitrate as electron acceptors generally prevented CT metabolism. At low oxygen levels ({approximately}1%), however, transformation of ({sup 14}C)CT to {sup 14}CO{sub 2} and attachment to cell material did occur, in accord with reports of CT fate in mammalian cell cultures. Under fumarate-respiring conditions, ({sup 14}C)CT was recovered as {sup 14}CO{sub 2}, chloroform, and a nonvolatile fraction. In contrast, fermenting conditions resulted in more chloroform, more cell-bound {sup 14}C, and almost no {sup 14}CO{sub 2}. Rates of transformation of CT were faster under fermenting conditions than under fumarate-respiring conditions. Transformation rates also decreased over time, suggesting the gradual exhaustion of transformation activity. This loss was modeled with a simple exponential decay term.

• OSTI ID: 5961354
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 56:11; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CARBON TETRACHLORIDE
DEHALOGENATION
ESCHERICHIA COLI
METABOLISM
CARBON 14 COMPOUNDS
CARBON DIOXIDE
FERMENTATION
RADICALS
TIME DEPENDENCE
TRACER TECHNIQUES
BACTERIA
BIOCONVERSION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
550501* - Metabolism- Tracer Techniques