Isolation and Characterization of Chlorothalonil-Degrading Bacterial Strain H4 and Its Potential for Remediation of Contaminated Soil

A chlorothalonil (CTN)-degrading bacterial strain H4 was isolated in this study from a contaminated soil by continuous enrichment culture to identify its characteristics and to investigate its potential for remediation of CTN in contaminated soil. Based on the morphological, physiological and biochemical tests and 16S rDNA sequence analysis, the strain was identified as Stenotrophomonas sp. After liquid culture for 7 d, 82.2% of CTN was removed by strain H4. The isolate could degrade CTN over a broad range of temperatures and pH values, and the optimum conditions for 114 degradation were pH 7.0 and 30 degrees C. Reintroduction of the bacteria into artificially contaminated soil resulted in substantial removal of CTN (> 50%) after incubation for 14 d. Soil samples treated by H4 showed significant increases (P < 0.05) in soil dehydrogenase activity, soil polyphenol oxidase activity, average well-color development obtained by the Biolog Eco plate (TM) assay and Shannon-Weaver index, compared with the control. Strain H4 might be a promising candidate for application in the bioremediation of CTN-contaminaied soils.