Elsevier

Pedosphere

Volume 18, Issue 5, October 2008, Pages 554-563
Pedosphere

Characterization of a Strain Capable of Degrading a Herbicide Mixture of Quinclorac and Bensulfuronmethyl*1

https://doi.org/10.1016/S1002-0160(08)60049-1Get rights and content

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 °C. 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.

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  • Cited by (0)

    *1

    Project supported by the National Natural Science Foundation of China (Nos. 40501037 and 30570053) and the National Key Technologies Research and Development Program of China during the 11th Five-Year Plan Period (No. 2006BAJ08B01).

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