Abstract
The potential capacity of a soil methyl parathion-degrading bacterium strain, Ochrobactrum sp. B2, for degrading various aromatic compounds were investigated. The results showed B2 was capable of degrading diverse aromatic compounds, but amino-substituted benzene compounds, at a concentration up to 100 mg L−1 in 4 days. B2 could use 4-nitrocatechol (4-NC) as a sole carbon and energy source with release of nitrite ion. The pathway for 4-NC degradation via 1,2,4-benzenetriol (BT) and hydroquinone (HQ) formation in B2 was proposed based on the identification and quantification of intermediates by gas chromatography-mass spectrometry (GC-MS), and high performance liquid chromatography (HPLC). Degradation studies carried out on a plasmid-cured derivative showed that the genes for 4-NC degradative pathway was plasmid-borne in B2, suggesting that B2 degrades both p-nitrophenol and 4-NC by enzymes encoded by genes on the same plasmid.
Acknowledgments
This research is financed by grants from the Innovation Program (No.KSCX2-SW-128) and the Presidential Fund of the Chinese Academy of Sciences. We would thank reviewers for valuable comments, and Ms. Xiaowei Qin for technical assistance in HPLC and GC-MS.
Current address for Qiuzan Zhong is Wenzhou Institute of Calibration and Testing for Quality and Technical Supervision. Received March 26, 2007.
Notes
aThe metabolites were identified after comparison with standard compounds.