Applied Microbiology and Biotechnology

, Volume 98, Issue 6, pp 2729–2737

Successful operation of continuous reactors at short retention times results in high-density, fast-rate Dehalococcoides dechlorinating cultures

  • Anca G. Delgado
  • Devyn Fajardo-Williams
  • Sudeep C. Popat
  • César I. Torres
  • Rosa Krajmalnik-Brown
Environmental biotechnology

DOI: 10.1007/s00253-013-5263-5

Cite this article as:
Delgado, A.G., Fajardo-Williams, D., Popat, S.C. et al. Appl Microbiol Biotechnol (2014) 98: 2729. doi:10.1007/s00253-013-5263-5

Abstract

The discovery of Dehalococcoides mccartyi reducing perchloroethene and trichloroethene (TCE) to ethene was a key landmark for bioremediation applications at contaminated sites. D. mccartyi-containing cultures are typically grown in batch-fed reactors. On the other hand, continuous cultivation of these microorganisms has been described only at long hydraulic retention times (HRTs). We report the cultivation of a representative D. mccartyi-containing culture in continuous stirred-tank reactors (CSTRs) at a short, 3-d HRT, using TCE as the electron acceptor. We successfully operated 3-d HRT CSTRs for up to 120 days and observed sustained dechlorination of TCE at influent concentrations of 1 and 2 mM TCE to ≥97 % ethene, coupled to the production of 1012D. mccartyi cells Lculture−1. These outcomes were possible in part by using a medium with low bicarbonate concentrations (5 mM) to minimize the excessive proliferation of microorganisms that use bicarbonate as an electron acceptor and compete with D. mccartyi for H2. The maximum conversion rates for the CSTR-produced culture were 0.13 ± 0.016, 0.06 ± 0.018, and 0.02 ± 0.007 mmol Cl Lculture−1 h−1, respectively, for TCE, cis-dichloroethene, and vinyl chloride. The CSTR operation described here provides the fastest laboratory cultivation rate of high-cell density Dehalococcoides cultures reported in the literature to date. This cultivation method provides a fundamental scientific platform for potential future operations of such a system at larger scales.

Keywords

Chemostat Dehalococcoides Geobacter Organohalide respiration Bioremediation Microbial community management 

Supplementary material

253_2013_5263_MOESM1_ESM.pdf (374 kb)
ESM 1(PDF 374 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Anca G. Delgado
    • 1
    • 2
  • Devyn Fajardo-Williams
    • 1
    • 3
  • Sudeep C. Popat
    • 1
  • César I. Torres
    • 1
    • 4
  • Rosa Krajmalnik-Brown
    • 1
    • 3
  1. 1.Swette Center for Environmental Biotechnology, Biodesign InstituteArizona State UniversityTempeUSA
  2. 2.School of Life SciencesArizona State UniversityTempeUSA
  3. 3.School of Sustainable Engineering and the Built EnvironmentArizona State UniversityTempeUSA
  4. 4.School for Engineering of Matter, Transport and EnergyArizona State UniversityTempeUSA