Reductive transformation of dieldrin under anaerobic sediment culture

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• 作者：Tzu-Chuan Chiu ; Jui-Hung Yen ; Yar-Ning Hsieh and Yei-Shung Wang
• 关键词：Anaerobic transformation ; Biodegradation ; Denaturing gradient gel electrophoresis (DGGE) ; Dieldrin ; Epoxide reduction
• 刊名：Chemosphere
• 出版年：2005
• 期刊代码：15_00456535
• 类别：env
• 出版时间：2005
• 卷：60
• 期：9
• 页码：1182-1189
• 文件大小：200 K

摘要

A pathway of dieldrin transformation to aldrin by epoxide reduction was found in this study. Investigation of dieldrin degradation under anaerobic conditions was performed with a mixed culture containing indigenous microorganisms obtained from sediment of the Er-Jen River in Taiwan. During the incubation, the transformation of dieldrin to aldrin was analyzed by GC–ECD and GC–MS. Effects of incubation factors including dieldrin concentrations, incubation temperatures and kinds of carbon sources on the degradation of dieldrin were also studied. Original concentrations (from 0.5 to 10 μg ml⁻¹) of dieldrin affect the transformation rate of dieldrin, and lower concentrations indicated the higher degradation rates. But once the concentration higher than 100 μg ml⁻¹, almost no degradation occurred. The optimal temperature for degradation in mixed culture was found at 40 °C in this study. Dieldrin transformation rates varied with the type of major carbon sources in the mixed culture and were in order of yeast extract > sodium acetate > glucose. In addition, the denaturing gradient gel electrophoresis (DGGE) fingerprint revealed that four microbials evolved in dieldrin-amended cultures, but not in the dieldrin-free cultures. Partial sequence of 16S rDNA for these four organisms exhibited 94–99%similarity to those of genera Clostridium, Acidaminobacter and an uncultured bacterial group. These results suggest that the four microbials might promote the dieldrin transformation.