| Research Abstract |
Screening of fungi having ability for degradation of dioxins from the nature was conducted in temperate and tropical zone, and selected several fungi. Degradation of dioxins in soils, incinerated ashes and water by bioremediation with the selected fungi was conducted. And, furthermore, formation of fusants having higher ability for degradation of dioxins was conducted by protoplast fusion between the two selected fungi.
1. Dioxins (2,7-DCDD, 2,8-DCDD, 2,4,8-TCDF, 2,3,7,8-TCDD, 2,3,4,7,8-PCDF and OCDD) were degraded by the selected fungi from the nature in a liquid medium. The degree of degradation of each dioxin was about 95%, 85%, 70%, 60%, 95% and 40%, respectively for 30 days incubation.
2. Biodegradation of dioxins (2,7-DCDD, 2,4,8-TCDF and 2,3,7,8-TCDD) in soils could be degraded by bioremediation with the selected fungi. Each dioxin was degraded about 70%, 60% and 50%, respectively for 30 days.
3. About 70% of dioxins in the soils (contamination level: about 1300pg-TEQ/g) was degraded by bioremediation with the selected fungi for 30 days. About 70% of the toxicity of dioxins in the soils was also removed by the bioremediation. And furthermore, the degree of degradation of the dioxins was increased about 10% by addition of a surfactant when the bioremediation was conducted.
4. About 65% of dioxins in incinerated ashes was degraded by bioremediation with the selected fungi for 60 days. It was found that the degree of degradation of dioxins in the ashes could be almost completely degraded by the repeated treatment of the bioremediation.
5. Dioxins in aqueous environment could be degraded considerably by bioremediation with the selected fungi after adsorption of dioxins by activated carbons and mixing of non-polluted soils with the adsorbed carbons. It was found that dioxins in water were almost completely adsorbed on to activated carbons.
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