Simultaneous chromium(VI) reduction and phenol degradation in a fixed-film coculture bioreactor: Reactor performance

Evans M. Nkhalambayausi-Chirwa, Yi Tin Wang

Research output: Contribution to journalArticlepeer-review

79 Scopus citations


Simultaneous Cr(VI) reduction and phenol degradation was observed in a fixed-film bioreactor consisting of a coculture of phenol-degrading bacteria, Pseudomonas putida DMP-1, and Cr(VI)-reducing bacteria, Escherichia coli ATCC 33456. Near complete Cr(VI) reduction and phenol degradation was observed during steady-state operation of the reactor under loadings of 5-21mg Cr(VI) l-1d-1 and 840-3350mg phenol l-1d-1. 2-hydroxymuconic semialdehyde (2HMSA), succinate, and acetate were the detected steady-state organic acid metabolites which accounted for 13-23% of TOC in the effluent. Optimum Cr(VI) reduction rate was observed under a Cr(VI) loading of approximately 26.5mg Cr(VI) l-1d-1 just before system overload. System overload was characterized by the increase in effluent Cr(VI) and phenol concentrations. System resilience to Cr(VI) toxicity was demonstrated by rapid recovery of biological activity and reduced effluent Cr(VI) and phenol concentrations after off-loading the system from overloaded conditions.

Original languageEnglish
Pages (from-to)1921-1932
Number of pages12
JournalWater Research
Issue number8
StatePublished - 2001

Bibliographical note

Funding Information:
This work was supported by the United States Environmental Protection Agency through an exploratory research grant awarded to Yi-Tin Wang under the agreement R-822307-01-0 and partially by University of Kentucky Graduate School. We would also like to thank Jan Pyrek of University of Kentucky College of Pharmacy for the help with GC-MS.


  • Biofilm
  • Chromium
  • Diffusion-reaction
  • Escherichia coli ATCC 33456
  • Fixed-film coculture
  • Mass transport
  • Phenol
  • Pseudomonas putida DMP-1

ASJC Scopus subject areas

  • Water Science and Technology
  • Ecological Modeling
  • Pollution
  • Waste Management and Disposal
  • Environmental Engineering
  • Civil and Structural Engineering


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