Matsumoto Emiko, Kawanaka Youhei, Yun Sun-Ja, Oyaizu Hiroshi
The Institute of Basic Environmental Research, Environmental Control Center Co., Ltd., Hachioji-shi, Tokyo, Japan.
Appl Microbiol Biotechnol. 2008 Oct;80(6):1095-103. doi: 10.1007/s00253-008-1670-4. Epub 2008 Sep 4.
This report describes the selective isolation of dieldrin- and endrin-degrading bacteria from soil with high degradation activity toward dieldrin and endrin. Several enrichment cultures from the soil were arranged with several structural analogs of dieldrin and endrin as a growth substrate and examined for their degradation activities toward dieldrin and endrin. An enrichment culture with 1,2-epoxycyclohexane (ECH) was found to aerobically degrade dieldrin and endrin. Denaturing gradient gel electrophoresis (DGGE) indicated that three types of bacteria were predominant in the ECH enrichment culture. Of the three major bacteria, two isolates, Burkholderia sp. strain MED-7 and Cupriavidus sp. strain MED-5, showed high degradation activity toward dieldrin and endrin. The degradation efficiencies of strain MED-7 and MED-5 were 49% and 38% toward dieldrin, respectively, and 51% and 40% toward endrin, respectively, in the presence of ECH for 14 days. These results indicated that ECH was a useful substrate for selective and efficient isolation of dieldrin- and endrin-degrading bacteria from soil containing numerous bacteria. Interestingly, the two isolates could also degrade dieldrin and endrin even in the absence of ECH. These are the first microorganisms demonstrated to grow on dieldrin and endrin as the sole carbon and energy source under aerobic conditions.
本报告描述了从土壤中选择性分离出对狄氏剂和异狄氏剂具有高降解活性的细菌。以狄氏剂和异狄氏剂的几种结构类似物作为生长底物，对土壤中的几种富集培养物进行了设置，并检测了它们对狄氏剂和异狄氏剂的降解活性。发现以1,2-环氧环己烷（ECH）为底物的富集培养物能够好氧降解狄氏剂和异狄氏剂。变性梯度凝胶电泳（DGGE）表明，在ECH富集培养物中三种类型的细菌占主导地位。在这三种主要细菌中，两株分离菌，伯克霍尔德氏菌属MED-7菌株和贪铜菌属MED-5菌株，对狄氏剂和异狄氏剂表现出高降解活性。在存在ECH的情况下培养14天，MED-7菌株和MED-5菌株对狄氏剂的降解效率分别为49%和38%，对异狄氏剂的降解效率分别为51%和40%。这些结果表明，ECH是从含有众多细菌的土壤中选择性高效分离狄氏剂和异狄氏剂降解细菌的有用底物。有趣的是，即使在没有ECH的情况下，这两株分离菌也能降解狄氏剂和异狄氏剂。它们是首次被证明在好氧条件下以狄氏剂和异狄氏剂作为唯一碳源和能源生长的微生物。
