Tetrachloroethene metabolism of Dehalospirillum multivorans |
| |
Authors: | Anke Neumann Heidrun Scholz-Muramatsu Gabriele Diekert |
| |
Institution: | (1) Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany;(2) Institut für Siedlungswasserbau, Universität Stuttgart, Bandtäle 1, D-70569 Stuttgart, Germany |
| |
Abstract: | 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 M PCE initially, pH 7.5, 25°C). The rate of dechlorination depended on the PCE concentration; concentrations higher than 300 M 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 M) 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 mol (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.Abbreviations
PCE
Perchloroethylene or tetrachloroethene
-
TCE
Trichloroethene
-
DCE
cis-1,2-Dichloroethene
-
CHC
Chlorinated hydrocarbon
-
MV
Methyl viologen |
| |
Keywords: | Dehalospirillum multivorans Perchloroethylene Tetrachloroethene Tetrachloroethene dehalogenase Trichloroethene Dichloroethene Reductive dechlorination |
本文献已被 SpringerLink 等数据库收录! |
|