Applied Microbiology and Biotechnology

, Volume 48, Issue 4, pp 553–562

Complete degradation of tetrachloroethene in coupled anoxic and oxic chemostats

  • J. Gerritse
  • G. Kloetstra
  • A. Borger
  • G. Dalstra
  • A. Alphenaar
  • J. C. Gottschal
ORIGINAL PAPER

DOI: 10.1007/s002530051096

Cite this article as:
Gerritse, J., Kloetstra, G., Borger, A. et al. Appl Microbiol Biotechnol (1997) 48: 553. doi:10.1007/s002530051096

Abstract

Anaerobic tetrachloroethene(C2Cl4)-dechlorinating bacteria were enriched in slurries from chloroethene-contaminated soil. With methanol as electron donor, C2Cl4 and trichloroethene (C2HCl3) were reductively dechlorinated to cis-1,2-dichloroethene (cis-C2H2Cl2), whereas, with l-lactate or formate, complete dechlorination of C2Cl4 via C2HCl3, cis-C2H2Cl2 and chloroethene (C2H3Cl) to ethene was obtained. In oxic soil slurries with methane as a substrate, complete co-metabolic degradation of cis-C2H2Cl2 was obtained, whereas C2HCl3 was partially degraded. With toluene or phenol both of the above were readily co-metabolized. Complete degradation of C2Cl4 was obtained in sequentially coupled anoxic and oxic chemostats, which were inoculated with the slurry enrichments. Apparent steady states were obtained at various dilution rates (0.02–0.4 h−1) and influent C2Cl4-concentrations (100–1000 μM). In anoxic chemostats with a mixture␣of␣formate and glucose as the carbon and electron source, C2Cl4 was transformed at high rates (above␣140 μmol l−1 h−1, corresponding to 145 nmol Cl min−1 mg protein−1) into cis-C2H2Cl2 and C2H3Cl. Reductive dechlorination was not affected by addition of 5 mM sulphate, but strongly inhibited after addition of 5 mM nitrate. Our results (high specific dechlorination rates and loss of dechlorination capacity in the absence of C2Cl4) suggest that C2Cl4-dechlorination in the anoxic chemostat was catalysed by specialized dechlorinating bacteria. The partially dechlorinated intermediates, cis-C2H2Cl2 and C2H3Cl, were further degraded by aerobic phenol-metabolizing bacteria. The maximum capacity for chloroethene (the sum of tri-, di- and monochloro derivatives removed) degradation in the oxic chemostat was 95 μmol l−1 h−1 (20 nmol min−1 mg protein−1), and that of the combined anoxic → oxic reactor system was 43.4 μmol l−1 h−1. This is significantly higher than reported thus far.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • J. Gerritse
    • 1
  • G. Kloetstra
    • 1
  • A. Borger
    • 1
  • G. Dalstra
    • 1
  • A. Alphenaar
    • 2
  • J. C. Gottschal
    • 1
  1. 1.Department of Microbiology, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands Tel.: +31 50 3632169 Fax: +31 50 3632154 e-mail: j.gerritse@biol.rug.nl.NL
  2. 2.TAUW milieu bv, P.O. Box 133, 7400 AC Deventer, The NetherlandsNL

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