title: Degradation of 3-phenoxybenzoic acid by a Bacillus sp.
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.
authors.affiliation: Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, P. R. China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
authors.forename: Yinyue
authors.initials: Y
authors.lastname: Deng
authors.forename: Jianwen
authors.initials: J
authors.lastname: Jia
authors.forename: Meiying
authors.initials: M
authors.lastname: Hu
mesh_terms: D001407:Bacillus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001565:Benzoates / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000378:metabolism; D007700:Kinetics; D010636:Phenols / Q000378:metabolism; D010802:Phylogeny; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
chemical_list: D001565:Benzoates; D062385:Hydroxybenzoates; D010636:Phenols; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; C009091:protocatechuic acid; C017618:3-phenoxybenzoic acid