Tetrachloroethene metabolism of Dehalospirillum multivorans
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Dehalospirillum multivorans is a strictly anaerobic bacterium that is able to dechlorinate tetrachloroethene (perchloroethylene; PCE) via trichloroethene (TCE) to cis-1,2-dichloroethene (DCE) as part of its energy metabolism. The present communication describes some features of the dechlorination reaction in growing cultures, cell suspensions, and cell extracts of D. multivorans. Cell suspensions catalyzed the reductive dechlorination of PCE with pyruvate as electron donor at specific rates of up to 150 nmol (chloride released) min-1 (mg cell protein)-1 (300 μM PCE initially, pH 7.5, 25°C). The rate of dechlorination depended on the PCE concentration; concentrations higher than 300 μM inhibited dehalogenation. The temperature optimum was between 25 and 30°C; the pH optimum at about 7.5. Dehalogenation was sensitive to potential alternative electron acceptors such as fumarate or sulfur; nitrate or sulfate had no significant effect on PCE reduction. Propyl iodide (50 μM) almost completely inhibited the dehalogenation of PCE in cell suspensions. Cell extracts mediated the dehalogenation of PCE and of TCE with reduced methyl viologen as the electron donor at specific rates of up to 0.5 μmol (chloride released) min-1 (mg protein).-1 An abiotic reductive dehalogenation could be excluded since cell extracts heated for 10 min at 95°C were inactive. The PCE dehalogenase was recovered in the soluble cell fraction after ultracentrifugation. The enzyme was not inactivated by oxygen.
Key wordsDehalospirillum multivorans Perchloroethylene Tetrachloroethene Tetrachloroethene dehalogenase Trichloroethene Dichloroethene Reductive dechlorination
Perchloroethylene or tetrachloroethene
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- Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248–254Google Scholar
- DeBruin WP, Kottermann MJJ, Posthumus MA, Schraa G, Zehnder AJB (1992) Complete biological reductive transformation of tetrachloroethene to ethane. Appl Environ Microbiol 58: 1996–2000Google Scholar
- DiStefano TD, Gossett JM, Zinder SH (1992) Hydrogen as an electron donor for dechlorination of tetrachloroethene by an anaerobic mixed culture. Appl Environ Microbiol 58: 3622–3629Google Scholar
- Freedman DL, Gossett JM (1989) Biological reductive dechlorination of tetrachloroethylene and trichloroethylene to ethylene under methanogenic conditions. Appl Environ Microbiol 55: 2144–2151Google Scholar
- Gantzer CJ, Wackett LP (1991) Reductive dechlorination catalyzed by bacterial transition-metal coenzymes. Environ Sci Technol 25:715–722Google Scholar
- Holliger C, Schraa G, Stams AJM, Zehnder AJB (1993) A highly purified enrichment culture couples the reductive dechlorination of tetrachloroethene to growth. Appl Environ Microbiol 59:2991–2997Google Scholar
- Jablonski PE, Ferry JG (1992) Reductive dechlorination of trichloroethylene by the CO-reduced CO dehydrogenase enzyme complex from Methanosarcina thermophila. FEMS Microbiol Lett 96:55–60Google Scholar
- Kröger A, Geisler V, Lemma E, Theis F, Lenger R (1992) Bacterial fumarate respiration. Arch Microbiol 158:311–314Google Scholar
- Meßmer M, Wohlfarth G, Diekert G (1993) Methyl chloride metabolism of the strictly anaerobic, methyl chloride-utilizing homoacetogen strain MC. Arch Microbiol 160:383–387Google Scholar
- Vogel TM, Criddle CS, McCarty PL (1987) Transformation of halogenated aliphatic compounds. Environ Sci Technol 21: 722–736Google Scholar