Pedosphere 18(5): 554--563, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Characterization of a strain capable of degrading a herbicide mixture of quinclorac and bensulfuronmethy |
LÜ Zhen-Mei , LI Zi-Mu, SANG Li-Ya and MIN Hang |
| College of Life Sciences, Zhejiang University, Hangzhou 310058 (China). E-mail: lzhenmei@zju.edu.cn |
| ABSTRACT |
| A bacterial strain, designated as LS, was isolated from a contaminated soil and was found to be capable of utilizing quinclorac, bensulfuronmethyl, and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties, 16S rDNA sequences, and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L-1 was 90% and 67%, respectively, as measured by high performance liquid chromatography (HPLC). When a herbicide mixture of 0.34 g L-1 quinclorac and 0.02 g L-1 bensulfuronmethyl was applied as carbon sources, quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%, respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8, respectively. Addition of 0.25 g L-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol, propisochlor, 4-chloro-2-methylphenoxyacetic acid sodium (MCPA-Na) and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues. |
| Key Words: bensulfuronmethyl, degradation, herbicide mixture, Ochrobactrum sp., quinclorac |
| Citation: LÜ Zhen-Mei, Li, Z. M., Sang, L. Y. and Min, H. 2008. Characterization of a strain capable of degrading a herbicide mixture of quinclorac and bensulfuronmethy. Pedosphere. 18(5): 554-563. |
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