Reduction of 2,4-dichlorophenol toxicity to Pseudomonas putida after oxidative incubation with humic substances and a biomimetic catalyst

Document Type

Article

Publication Date

3-1-2007

Abstract

The effect of a synthetic iron(III)-porphyrin meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate as a biomimetic catalyst in the oxidative treatment of 2,4-dichlorophenol (2,4-DCP) with humic substances and H2O2 was evaluated in factorial design experiments conducted at different concentrations of 2,4-DCP (0-25 ppm) and different incubation treatment times (0, 24, 96, or 120 h). In the absence of this treatment, bioassays with the bacterium Pseudomonas putida (ATCC11250) showed decreasing specific growth rates μ (used here to quantify 2,4-DCP toxicity) with increasing concentrations of 2,4-DCP. However, when 2,4-DCP was treated as mentioned above the toxicity of the resulting 2,4-DCP solution was reduced significantly. At low 2,4-DCP concentrations (up to 5 ppm) and long incubation periods (as long as 120 h), the specific growth rate μ was comparable to that of cultures grown in the absence of 2,4-DCP. The reduction in toxicity was directly correlated to a decrease in the concentration of 2,4-DCP in the treated solutions, as measured by high-performance liquid chromatography. The reduced concentrations of 2,4-DCP in the treated solutions could be correctly predicted based on the relationship between the specific growth rates and the 2,4-DCP concentrations in untreated solutions. These results indicate that the oxidative coupling of 2,4-DCP to humic substances catalyzed by the synthetic iron(III)-porphyrin catalyst in the presence of H2O2 is responsible for the removal of 2,4-DCP from solutions. This approach appears to be a promising alternative treatment to reduce 2,4-DCP bioavailability and thus toxicity in the environment. © 2006 Elsevier Inc. All rights reserved.

Identifier

33846849421 (Scopus)

Publication Title

Ecotoxicology and Environmental Safety

External Full Text Location

https://doi.org/10.1016/j.ecoenv.2006.02.004

e-ISSN

10902414

ISSN

01476513

PubMed ID

16616957

First Page

335

Last Page

342

Issue

3

Volume

66

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