Isolation and Characterization of Chlorothalonil-dissipating Bacteria from Soil

Chlorothalonil is a wide-spectrum fungicide that is widely used in the world. Chlorothalonil is known as a potential toxic pollutant due to its high application rate, persistence, and toxicity to humans and other species. With the increase of necessity of bioremediation, this study was conducted to isolate the chlorothalonil dissipation bacteria from soil. Soil samples were collected from 184 sites of farmland and wastewater disposal soil. 661 strains resistant to chlorothalonil were isolated by dilution method from chlorothalonil-containing enrichment culture. After incubating at 30°C in 1/10 LB media containing 10 ppm of chlorothalonil for a week, dissipation ability of chlorothalonil was investigated by HPLC. Finally, a strain SH35B, capable of dissipating chlorothalonil efficiently, was selected. The strain SH35B was identified as Ochrobactrum sp. Ten ppm of chlorothalonil in 1/10 LB media were completely dissipated by the growth of Ochrobactrum sp. SH35B for 30 h at 30°C. In the isolated strain, the content of glutathione and the activity of glutathione S-transferase were supposed to be ones of the important factors for chlorothalonil dissipation and were higher than those of control strains, Escherichia coli and Bacillus subtilis.