유기염소계 농약 endosulfan의 생물학적 분해에 관한 연구

Abstract

Endosulfan, a organochlorine compound, is widely used as an insecticide all over the world. However, endosulfan is ubiquitous contamination in agricultural environments and considered potential pollutants due to its toxic and recalcitrant properties. To remove toxic organic compounds, both biological and chemical treatments have been suggested. Bioremediation of the toxic organic compounds, using microorganisms or enzymes produced from the microorganisms (bioaugmentation), is often considered as and environmentally favorable method. Therefore, many efforts have been made to isolate bacteria capable of degrading endosulfan. The objective of this study was to isolate a bacterium to degrade endosulfan and to evaluate the possibility of the bioremediation in soil environmental for the degradation of endosulfan. A endosulfan degrading bacterium, K-1321 strain, was isolated by endosulfan-containing enrichment culture from soil and seaside sediment samples. The strain was identified to by Serratia sp. based on the results of morphological, biochemical and 16S rDNA homology analysis. Serratia sp. K-1321 was able to degrade 100% on 10ppm endosulfan within 4 weeks and 100% on 50ppm endosulfan within 6 weeks in the culture media at 25℃. The pH value of the culture media was increased to pH 8.5 from pH 5.8 after 6 weeks of incubation. The experiment in soil, lab-scale model analysis, was performed to two group, sterile soil (Group A) and non-sterile soil (Group B). In soil, Serratia sp. K-1321 was able to degrade 99% of 50 ppm endosulfan within 6 weeks at 25℃ and the pH value of perform was increased to pH 8.2 from pH 5.5 after 6 weeks to began the observation in all group. GC/MS analysis revealed that endosulfan diol was an intermediate of the bacterial endosulfan degradation Considering above results, we concluded that Serratia sp. K-1321 utilized endosulfan as a carbon source and metabolized endosulfan via less toxic pathway such as the formation of endosulfan diol as and intermediate.