In vitro treatment of dioxins by enzymes from white-rot fungus.

Research Project

Project/Area Number	10460076
Research Category	Grant-in-Aid for Scientific Research (B).
Allocation Type	Single-year Grants
Section	一般
Research Field	林産学
Research Institution	KYUSHU UNIVERSITY
Principal Investigator	KONDO Ryuichiro KYUSHU UNIVERSITY, Fac.Agriculture, Professor, 大学院・農学研究院, 教授 (80091370)
Co-Investigator(Kenkyū-buntansha)	TAKATA Satoshi Fukuoka Institute of Health and Environmental Science, Researcher, 専門研究員
Project Period (FY)	1998 – 2000
Project Status	Completed (Fiscal Year 2000)
Budget Amount *help	¥12,200,000 (Direct Cost: ¥12,200,000) Fiscal Year 2000: ¥2,500,000 (Direct Cost: ¥2,500,000) Fiscal Year 1999: ¥3,100,000 (Direct Cost: ¥3,100,000) Fiscal Year 1998: ¥6,600,000 (Direct Cost: ¥6,600,000)
Keywords	Dioxin / White rot fungi / Bioremediation / in vitro / lignin / Basidiomycetes / 環境汚染 / ダイオキシン類 / エーテル結合開裂 / ダイオキシン分解酵素 / エーテル結合 / 2,7-DCDD
Research Abstract	The decrease of 2,7-dichlorodibenzo-p-dioxin (diCDD)-recovery was observed by the incubation with the culture fluid from white-rot fungus Ceriporia sp.strain MZ-340. The decrease of recovery reached 40% of 50uM during 180min period. The recovery of diCDD in the boiled control was higher than 90%. Not recovered diCDD was remained in the water layer, and it was retrievable by treating reaction mixture by acid, alkali or surfactant. Such diCDD-trapping activity was lost by a protease treatment and heating. We characterized the diCDD-trapping activity of the extracellular protein solution (EPs) from the fungus. The pH optimum of the activity was obtained at pH 2.7. More than 80% of the maximal activity was observed within a range of 25-45℃. This activity decreased dramatically as the incubation temperature increased. In the effects of organic solvent concentrations, the activity was disappeared by the addition of 5.0% of acetone or 12.5% of N,N-dimethylformamide, respectively. The substrate specificity was examined on the trapping-activity. Less or no trapping activity was observed for dibenzofuran (DF), biphenyl (BP), dibenzothiophene, carbazole, fluorene, diphenyl ether and phenanthrene. The trapping-activity for triCDD, diCDF, diCBP and anthracene showed over 50%, and that for DD, monoCDD and tetraCDD were lower than 40%, when their rates were expressed as percentages of the activity for diCDD.These results showed that the specificity of the trapping activity depends on the hydrophobicity of the substrate. Furthermore, the concentrated EPs could trap even octaCDD.