Degradation of 3-phenoxybenzoic acid by a Bacillus sp

PLoS One. 2012;7(11):e50456. doi: 10.1371/journal.pone.0050456. Epub 2012 Nov 30.

Abstract

3-Phenoxybenzoic acid (3-PBA) is of great environmental concern with regards to endocrine disrupting activity and widespread occurrence in water and soil, yet little is known about microbial degradation in contaminated regions. We report here that a new bacterial strain isolated from soil, designated DG-02, was shown to degrade 95.6% of 50 mg·L(-1) 3-PBA within 72 h in mineral salt medium (MSM). Strain DG-02 was identified as Bacillus sp. based on the morphology, physio-biochemical tests and 16S rRNA sequence. The optimum conditions for 3-PBA degradation were determined to be 30.9°C and pH 7.7 using response surface methodology (RSM). The isolate converted 3-PBA to produce 3-(2-methoxyphenoxy) benzoic acid, protocatechuate, phenol, and 3,4-dihydroxy phenol, and subsequently transformed these compounds with a q(max), K(s) and K(i) of 0.8615 h(-1), 626.7842 mg·L(-1) and 6.7586 mg·L(-1), respectively. A novel microbial metabolic pathway for 3-PBA was proposed on the basis of these metabolites. Inoculation of strain DG-02 resulted in a higher degradation rate on 3-PBA than that observed in the non-inoculated soil. Moreover, the degradation process followed the first-order kinetics, and the half-life (t(1/2)) for 3-PBA was greatly reduced as compared to the non-inoculated control. This study highlights an important potential application of strain DG-02 for the in situ bioremediation of 3-PBA contaminated environments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus / classification
  • Bacillus / genetics
  • Bacillus / metabolism*
  • Benzoates / metabolism*
  • Biodegradation, Environmental
  • Half-Life
  • Hydrogen-Ion Concentration
  • Hydroxybenzoates / metabolism
  • Kinetics
  • Phenols / metabolism
  • Phylogeny
  • Principal Component Analysis
  • RNA, Ribosomal, 16S / genetics*
  • Soil Microbiology*
  • Soil Pollutants / metabolism*
  • Temperature

Substances

  • Benzoates
  • Hydroxybenzoates
  • Phenols
  • RNA, Ribosomal, 16S
  • Soil Pollutants
  • protocatechuic acid
  • 3-phenoxybenzoic acid

Grants and funding

The authors would like to thank the financial support from the National Natural Science Foundation (No.30871660), P. R. China.