Enzymatic degradation of trichloroethylene using enzyme extracts isolated from a bacterial consortium

Bilal El-Zahab, Liliana Meza, Teresa Cutright, Ping Wang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Degradation of trichloroethylene (TCE) using crude enzyme extracts from a bacterial consortium was examined for wastewater treatment. The effects of pH, chemical induction, and cof actor were investigated. Enzyme extracts showed an optimal activity (3.03 ± 0.03 mg of TCE/[mg of protein·d]) at neutral pH (6.5-7.5). In an attempt to increase the production of effective enzymes for TCE degradation, chemical induction using both toluene and TCE in the growth of the bacterium consortium was conducted. Although the induction increased the overall production of protein by about fourfold, the activity of the extracts was only slightly improved (up to 3.40 mg of TCE/ [mg of protein·d]), indicating that the induction did not specifically enhance the production of TCE-degrading enzymes. Interestingly, the addition of a cofactor (up to 0.02 mg/mL), NADH, led to an initial reaction rate of 5.30 ± 0.05 mg of TCE/ (mg of protein·d). This observation demonstrated that the availability of the cofactor played an important role in determining the over-all degradation reaction rates. The observations with NADH were in agreement with the assumption that toluene monooxygenases (which are NADH dependent) are the key enzymes for the degradation reactions.

Original languageEnglish (US)
Pages (from-to)165-174
Number of pages10
JournalApplied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology
Volume117
Issue number3
DOIs
StatePublished - Jun 2004

Bibliographical note

Funding Information:
We thank Ayman Ghazzaoui for assistance with the enzyme degradation experiments. This work was supported by the National Science Foundation under grant BES 0117042. Any opinions, findings, and conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Keywords

  • Bioremediation
  • Enzymatic degradation
  • NADH
  • Toluene monooxygenase
  • Trichloroethylene

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