Growth inhibition of sulfate-reducing bacteria for trichloroethylene dechlorination enhancement

Wei Han Lin, Chien Cheng Chen, Yih Terng Sheu, Daniel C.W. Tsang, Kai Hung Lo, Chih Ming Kao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

Trichloroethylene (TCE) is a frequently found organic contaminant in polluted-groundwater. In this microcosm study, effects of hydrogen-producing bacteria [Clostridium butyricum (Clostridium sp.)] and inhibitor of sulfate-reducing bacteria (SRB) addition on the enhancement of TCE dechlorination were evaluated. Results indicate that Clostridium sp. supplement could effectively enhance TCE reductive dechlorination (97.4% of TCE removal) due to increased hydrogen concentration and Dehalococcoides (DHC) populations (increased to 1 × 104 gene copies/L). However, addition of Clostridium sp. also caused the increase in dsrA (dissimilatory sulfide reductase subunit A) (increased to 2 × 108 gene copies/L), and thus, part of the hydrogen was consumed by SRB, which would limit the effective application of hydrogen by DHC. Control of Clostridium sp. addition is a necessity to minimize the adverse impact of Clostridium sp. on DHC growth. Ferric citrate caused the slight raise of the oxidation-reduction state, which resulted in growth inhibition of SRB. Molybdate addition inhibited the growth of SRB, and thus, the dsrA concentrations (dropped from 4 × 107 to 9 × 105 gene copies/L) and sulfate reduction efficiency were decreased. Increased DHC populations (increased from 8 × 103 to 1 × 105 gene copies/L) were due to increased available hydrogen (increased from 0 to 2 mg/L), which enhanced TCE dechlorination (99.3% TCE removal). Metagenomic analyses show that a significant microbial diversity was detected in microcosms with different treatments. Clostridium sp., ferric citrate, and molybdate addition caused a decreased SRB communities and increased fatty acid production microbial communities (increased from 4.9% to 20.2%), which would be beneficial to the hydrogen production and TCE dechlorination processes.

Original languageEnglish
Article number109629
JournalEnvironmental Research
Volume187
DOIs
Publication statusPublished - Aug 2020

Keywords

  • Clostridium sp.
  • Reductive dechlorination
  • SRB inhibitor
  • Sulfate-reducing bacteria (SRB)
  • Trichloroethylene (TCE)

ASJC Scopus subject areas

  • Biochemistry
  • Environmental Science(all)

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